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Background. Currently, predictive models were not developed based on the signaling pathway signatures of immune-related lncRNAs in breast cancer (BRCA) patients. Methods. We selected unsupervised hierarchical clustering algorithm to classify patients with BRCA based on the significant immune-derived lncRNAs from the TCGA dataset. And different methods including ESTIMATE, ImmuneCellAI, and CIBERSORT were performed to evaluate the immune infiltration of tumor microenvironment. Using Lasso regression algorithm, we filtered the significant signaling pathways enriched by GSEA, GSVA, or PPI analysis to develop a prognostic model. And a nomogram integrated with clinical factors and significant pathways was constructed to predict the precise probability of overall survival (OS) of BRCA patients in the TCGA dataset (n = 1,098) and another two testing sets (n = 415). Results. BRCA patients were stratified into the PC (n = 571) and GC (n = 527) subgroup with significantly different prognosis with 550 immune-related lncRNAs in the TCGA dataset. Integrated analysis revealed different immune response, oncogenic signaling, and metabolic reprograming pathways between these two subgroups. And a 5-pathway signature could predict the prognosis of BRCA patients between these two subgroups independently in the TCGA dataset, which was confirmed in another two cohorts from the GEO dataset. In the TCGA dataset, 5-year OS rate was 78% (95% CI: 73–84) vs. 82% (95% CI: 77–87) for the PC and GC group (HR = 1.63 (95% CI: 1.17–2.28), p = 0.004 ). The predictive power was similar in another two testing sets (HR > 1.20, p < 0.01 ). Finally, a nomogram is developed for clinical application, which integrated this signature and age to accurately predict the survival probability in BRCA patients. Conclusion. This 5-pathway signature correlated with immune-derived lncRNAs was able to precisely predict the prognosis for patients with BRCA and provided a rich source characterizing immune-related lncRNAs and further informed strategies to target BRCA vulnerabilities.

TP53 mutations are frequent in non-small cell lung cancer (NSCLC). Different categories of TP53 mutations may be associated with survival in advanced NSCLC, but their effect on prognosis is diverse. To date, a comprehensive comparison of the relationship between different classes of TP53 alterations and survival in advanced NSCLC has rarely been performed. Moreover, the prognostic significance of a novel approach called the evolutionary action of TP53 (EAp53) in advanced NSCLC is unclear.A total of 210 patients with NSCLC harboring TP53 mutation data were enrolled. Genomic and clinical data for the Memorial Sloan Kettering Cancer Center (MSKCC) cohort with advanced NSCLC were obtained from cBioPortal. Relationship between clinical characteristics and TP53 mutations was performed by Fisher's exact test or χTP53 mutations were identified in 51.4% of NSCLC patients and were mainly located in exons 5, 7, and 8. The distribution patterns of missense and truncating mutations of TP53 were remarkably different. Among patients with advanced NSCLC who never received immune checkpoint inhibitor treatments, EAp53 high-risk mutations were significantly associated with poor OS in both our cohort and the MSKCC cohort. Moreover, marked differences were observed in the mutational landscape between patients with EAp53 high-risk mutations (HR group) and other patients (OT group). The HR group displayed higher mutation frequencies in the RTK, cell cycle, and DNA damage repair (DDR) pathways than the OT group. In addition, the tumor mutation burden in the HR group was significantly higher than that in the OT group.This study provided important insights into the molecular-clinical profile of TP53-mutated NSCLC patients. Moreover, the data revealed that EAp53 high-risk mutations were an independent prognostic factor for worse OS in advanced NSCLC.

Purpose: Acral melanoma is the major subtype of melanoma seen in Asian patients with melanoma and is featured by its insidious onset and poor prognosis. The genomic study that elucidates driving mutational events is fundamental to the development of gene-targeted therapy. However, research on genomic profiles of acral melanoma in Asian patients is still sparse. Experimental Design: We carried out whole-exome sequencing (WES) on 60 acral melanoma lesions (with 55 primary samples involved), targeted deep sequencing in a validation cohort of 48 cases, RNA sequencing in 37 acral melanoma samples (all from the 60 undergoing WES), and FISH in 233 acral melanoma specimens (54 of the 60 undergoing WES included). All the specimens were derived from Asian populations. Results: BRAF, NRAS, and KIT were discerned as significantly mutated genes (SMG) in acral melanoma. The detected COSMIC signature 3 related to DNA damage repair, along with the high genomic instability score, implied corresponding pathogenesis of acral melanoma. Moreover, the copy number gains of EP300 were associated with the response of acral melanoma to targeted therapy of A485 (a p300 inhibitor) and immune checkpoint blockade treatment. In addition, the temporal order in mutational processes of the samples was reconstructed, and copy-number alterations were identified as early mutational events. Conclusions: Our study provided a detailed view of genomic instability, potential therapeutic targets, and intratumoral heterogeneity of acral melanoma, which might fuel the development of personalized strategies for treating acral melanoma in Asian populations.

Current methods for the early detection and minimal residual disease (MRD) monitoring of urothelial carcinoma (UC) are invasive and/or possess suboptimal sensitivity. We developed an efficient workflow named urine tumor DNA multidimensional bioinformatic predictor (utLIFE). Using UC-specific mutations and large copy number variations, the utLIFE-UC model was developed on a bladder cancer cohort (n = 150) and validated in The Cancer Genome Atlas (TCGA) bladder cancer cohort (n = 674) and an upper tract urothelial carcinoma (UTUC) cohort (n = 22). The utLIFE-UC model could discriminate 92.8% of UCs with 96.0% specificity and was robustly validated in the BLCA_TCGA and UTUC cohorts. Furthermore, compared to cytology, utLIFE-UC improved the sensitivity of bladder cancer detection (p p p

Small bowel adenocarcinoma (SBA) is a rare malignancy with a poor prognosis and limited treatment options. Despite prior studies, molecular characterization of this disease is not well defined, and little is known regarding Chinese SBA patients. In this study, we conducted multigene next‐generation sequencing and 16S ribosomal RNA gene sequencing on samples from 76 Chinese patients with surgically resected primary SBA. Compared with colorectal cancer and Western SBA cohorts, a distinctive genomic profile was revealed in Chinese SBA cohorts. According to the levels of clinical actionability to targetable alterations stratified by OncoKB system, 75% of patients harbored targetable alterations, of which ERBB2, BRCA1/2, and C‐KIT mutations were the most common targets of highest‐level actionable alterations. In DNA mismatch repair–proficient (pMMR) patients, significant associations between high tumor mutational burden and specific genetic alterations were identified. Moreover, KRAS mutations/TP53 wild‐type/nondisruptive mutations (KRASmut/TP53wt/non‐dis ) were independently associated with an inferior recurrence‐free survival (hazard ratio [HR] = 4.21, 95% confidence interval [CI] = 1.94‐9.14, P, Molecular characterization of small bowel adenocarcinoma (SBA) is not well defined, and little is known regarding Chinese SBA patients. Compared with colorectal cancer and Western SBA cohorts, a distinctive genomic profile was revealed in Chinese SBA cohorts. A molecular subtype of KRAS mutations/TP53 wild‐type/nondisruptive mutations was found to be associated with an inferior recurrence‐free survival in SBA.

The genomic profiles of osteosarcoma (OS) patients have been extensively investigated; however, the genetic prognostic biomarkers still remain unclear. In the present study, we analyzed the mutational profiles of pre-treatment primary tumor samples from 33 OS patients using whole exome sequencing (WES). These 33 OS patients were divided into two groups according to clinical outcomes: a good prognosis group involving 21 patients with tumor free survival, and a poor prognosis group involving the remaining12 patients who had lung metastases at initial diagnosis. Overall we found that the MAPK signaling pathway may play an important role in determining a good prognosis, while the PI3K-Akt signaling pathway may be an important factor leading to a poor prognosis. Significant differences were observed in the number of somatic copy number alterations, including del (3p), amp (4q), del (7p) and amp (8q), between the two groups. Moreover, significant differences were observed in mutation sites and frequencies between these two groups. The good prognosis group exhibited a significantly higher mutation frequency in somatic JAK-STAT and germline base excision repair pathways than the poor prognosis group. Furthermore, significant difference was also observed in the frequency of potentially actionable alterations between the two groups, suggesting that patients with a poor prognosis potentially have access to a larger number of treatment options. These findings highlight the importance of evaluating genomic disparities in OS, and provide a novel insight into the potential prognostic biomarkers.

Background Occurrence at a young age is known to be associated with unique clinical features in colorectal cancer (CRC). However, the genomic differences between young and old patients with CRC are not well elucidated and, to the best of our knowledge, have never been investigated in a Chinese population. Methods Tumor tissue samples from 29 young (age ≤50 years) and 46 old (age >50 years) patients with CRC were collected. Targeted sequencing of 808 cancer‐related genes was conducted to characterize the genomic landscape for Chinese CRC. Results Overall, mutational profiles exhibited notable differences between the two groups. In particular, APC and PIK3CA mutations were more frequently observed in old patients (p = 0.009 and p = 0.012, respectively), while SMAD4 mutations tended to occur in young patients (p = 0.054). Mutation loci distributions of KRAS in the young cohort differed from those in the old cohort, and a higher frequency of KRAS codon 12 mutations was potentially associated with a young age (p = 0.076). The frequencies of clinically actionable alterations were analyzed by defined age categories, which unveiled a distinctive targeted genomic profile in the young group. Furthermore, among patients with mismatch repair‐proficient (pMMR) CRC, tumor mutation burden (TMB) was positively correlated with age (Pearson's r = 0.306, p = 0.011), and genomic alterations associated with high TMB in young patients differentiated from those in old patients. Conclusions These findings revealed different molecular characterization between young and old Chinese patients with CRC, which may provide novel insights for the personalized treatment of CRC., This is the first NGS study to compare genomic profiles between young and old Chinese cohorts with CRC. The results demonstrated that young patients with CRC presented with some unique molecular features. Moreover, the comprehensive investigation of clinically actionable mutations and TMB will contribute to the improvement of personalized therapy and clinical management in CRC.

Purpose: Because of their high tumor specificity and immunogenicity, neoantigens have been considered as ultimate targets for cancer immunotherapy. Neoantigen-based vaccines have demonstrated promising efficacy for several cancer types. To further investigate the antitumor potentials for other types of solid tumors, we designed a peptide-based neoantigen vaccine, iNeo-Vac-P01, and conducted a single-arm, open-labeled, investigator-initiated clinical trial (NCT03662815). Patients and Methods: Personalized neoantigen vaccines were designed and manufactured according to our bioinformatics analysis results from the whole-exome sequencing of tumor and peripheral blood cell DNAs. Patients were scheduled to be vaccinated subcutaneously with adjuvant on days 1, 4, 8, 15, and 22 (prime phase), and days 78 and 162 (boost phase). Additional immunizations were administrated every 2–3 months as per patient's potential benefit. The safety and efficacy were assessed through adverse events (AE), progression-free survival (PFS), overall survival (OS), and other parameters. Results: Of the 22 patients enrolled with advanced malignancies, 20 had no or mild AEs, while 2 had grade 3 or 4 acute allergic reactions only after their sixth boost vaccination. The disease control rate was 71.4%. The median PFS was 4.6 months, whereas the median OS was not reached (12-month OS = 55.1%). Around 80% of individual peptides or peptide pools elicited measurable specific immune response. In addition, our findings revealed several potential biomarkers for the prediction of better response. Conclusions: iNeo-Vac-P01 as monotherapy is feasible and safe for patients with advanced solid tumors. It could elicit T-cell–mediated immune response targeting tumor neoantigens, and might have promising antitumor efficacy. See related commentary by Filderman and Storkus, p. 4429

Purpose: Enhanced lipogenesis and mitochondrial function are two critical metabolic characteristics in melanoma, but their crosstalk involved in tumor biology and targeted therapy remains unknown. ATP-citrate lyase (ACLY) is a crucial lipogenic enzyme that is greatly implicated in tumor development, but its role in mitochondrial function and melanoma pathogenesis has not been elucidated. Experimental Design: In vitro and in vivo functional experiments were performed to determine the effect of ACLY on melanoma growth. mRNA expression profile analysis and a panel of biochemical assays were used to investigate the role of ACLY in mitochondrial oxidative phosphorylation and the underlying mechanism. The effect of combined ACLY inhibition on the efficacy of MAPK inhibition therapy was also examined. Results: We first found that ACLY expression was increased in melanoma and facilitated cell proliferation and tumor growth both in vitro and in vivo. Subsequent mRNA expression profile analysis and functional studies unveiled that ACLY specifically activated MITF–PGC1α axis to promote mitochondrial biogenesis and melanoma growth. Mechanistically, ACLY enhanced the activity of acetyltransferase P300, increasing the histone acetylation at MITF locus to promote MITF–PGC1α axis transcription. More importantly, the combined inhibition of ACLY sensitized BRAF-mutant melanoma to MAPK inhibition by suppressing MITF–PGC1α axis. Conclusions: We demonstrate that ACLY epigenetically potentiates oxidative phosphorylation to promote melanoma growth and MAPK inhibition adaptive resistance. Our study discovers the novel crosstalk between lipogenesis and mitochondrial function in tumor biology and highlights targeting ACLY as a potent therapeutic approach via simultaneously impairing tumor growth and MAPK inhibition resistance in melanoma.

BackgroundRenal cell carcinoma (RCC) is a disease of genomic alterations, of which the complete panorama helps in facilitating molecular-guided therapy. Germline mutation profiles and associated somatic and clinical characteristics remains unexplored in Chinese RCC patients.MethodsWe retrospectively profiled the germline and somatic mutations of 322 unselected RCC patients using a panel consisting of 808 cancer-related genes. We categorized patients into three groups based on germline mutation status and compared the somatic mutation spectrum among different groups.ResultsApproximately one out of ten (9.9%) RCC patients were identified to carry pathogenic/likely pathogenic (P/LP) germline variants (PGVs), of which 3.7% were variants in syndromic RCC-associated genes and 6.2% were other cancer-predisposition genes. The most common PGV was found in VHL (2.2%), followed by FH, TSC2, ATM, BRCA1, NBN, and BLM (0.6% each). Young patients (≤46 years) were more likely to harbor PGVs. Variants in syndromic RCC-associated genes were predominant identified in young patients, while variants in other cancer-predisposition genes were found in patients >46 years more frequently. Furthermore, 39.3% (11/28) of patients carrying PGVs were detected to have somatic “second hit” events. Germline and somatic sequencing, including microsatellite instability (MSI) status analysis, provided potentially actionable therapeutic targets in 17.1% of patients in the whole cohort.ConclusionsOur results revealed that approximately 10% of RCC patients carried clinically significant germline mutations. Current guidelines recommendation for genetic testing seemed not sensitive enough to identify patients with hereditary RCC susceptibility. It is rational to promote genetic testing in RCC population.

BackgroundColorectal cancer (CRC) is one of the most prevalent malignances worldwide. However, CRC with situs inversus totalis (SCRC) is extremely rare, and molecular characterization of this disease has never been investigated.MethodsTumor tissue samples from 8 patients with SCRC and 33 CRC patients without situs inversus totalis (NSCRC) were subjected to multigene next-generation sequencing.ResultsThe most frequently mutated genes in SCRC were APC, TP53, CHEK2, MDC1, GNAQ, KRAS, and SMAD4. A high frequency of SCRC tumors had mutations in DNA damage repair genes. Single amino acid substitutions in the DNA damage repair genes caused by continuous double base substitution was identified in the majority of this population. Furthermore, mutational profiles showed notable differences between the SCRC and NSCRC groups. In particular, CHEK2, MDC1, GNAQ, SMAD4, BRCA1, HLA-B, LATS2, and NLRC5 mutations were more frequently observed in SCRC patients. The mutation loci distributions of KRAS in the SCRC cohort differed from that of the NSCRC cohort. Additionally, differences in the targeted genomic profiles and base substitution patterns were observed between the two groups.ConclusionsThese findings comprehensively revealed a molecular characterization of SCRC, which will contribute to the development of personalized therapy and improved clinical management of SCRC patients.

The tumor mutational burden (TMB) calculated by whole-exome sequencing (WES) is a promising biomarker for the response to immune checkpoint inhibition (ICIs) in solid tumors. However, WES is not feasible in the routine clinical setting. In addition, the characteristics of the TMB in Chinese urothelial carcinoma (UC) are unclear. The aim of this study was to demonstrate the reliability of an Acornmed 808 panel and analyze the characteristics of the TMB in Chinese UC. An Acornmed 808 panel was designed and virtually validated using UC data from the cancer genome atlas (TCGA). Comprehensive analysis of sequencing and clinical data was performed to explore the characteristics of the TMB for 143 Chinese UC patients. Compared to the TMB calculated with random 808-, 500-, and 250-gene panels, the TMB calculated with the Acornmed 808 panel was closer to that calculated by WES. There were marked disparities in the mutational landscape and TMB between Chinese and TCGA UC data. The TMB was negatively associated with copy number variation (CNV). In contrast, the TMB was positive correlation with numbers of mutated DDR genes. Exposure to aristolochic acid signature was observed only in the TMB-high groups. The Acornmed 808 panel is a clinically practical method to assess the TMB. The TMB was associated with the DDR gene status and CNV counts and might be a biomarker for further stratification of UC patients. The study suggested that patients with high TMB may have a unique carcinogenic mechanism.

Anaplastic lymphoma kinase (ALK) fusions have been recognized as a therapeutic target in non‐small cell lung cancer (NSCLC). However, molecular signatures and clinical characteristics of the Chinese population with ALK‐rearranged NSCLC are not well elucidated. In the present study, we carried out targeted next‐generation sequencing on tissue and plasma ctDNA samples in 1688 patients with NSCLC. Overall, ALK fusions were detected in 70 patients (4.1%), and the frequencies of ALK fusions detected in tissue and plasma samples were 5.1% and 3.3%, respectively. Additionally, the prevalence of breakpoint locations for EML4‐ALK fusions in ctDNA was significantly correlated with that in tumor tissues (R 2 = .91, P = .045). According to age, the incidence rates of ALK fusions among young (age 70 years) patients were significantly different (P

e16560 Background: Concordance between tumor DNA (tDNA) and urine tumor DNA (utDNA) profiles using paired samples was analyzed. Genomic analysis of utDNA and tDNA showed a high consistency, indicating that urine is an optional sample for noninvasive detection and response evaluation of bladder cancer (BC). Methods: Methods and results data were analyzed from an ongoing study, collecting all cases from Second Hospital Affiliated to Tianjin Medical University. Cases with pathologically confirmed BC and matching tissue/urine/whole blood before treatments were recruited. In 85 patients, 48 with paired samples were enrolled in this analysis after excluding 37 paired samples failed in sample QC or sample collection. WES (Whole Exome Sequence) was applied to tDNA and paired white blood cell (WBC) DNA. An Acornmed 808-Gene panel was applied to utDNA and paired WBC DNA. Somatic events, including SNV (single nucleotide variant), InDel (insertion and deletion) of hot genes were analyzed. Consistency of tDNA and utDNA were identified and analyzed in the intersection set between the two chips, and tDNA profiling was used as the“golden standard”. Results: Among 48 patients, 24(50.0%) were MIBC, 21(43.8%) were NMIBC and 41 (81.5%) were male. With neoadjuvant therapy, 23(47.9%) are identified as responders (CR or PR), 7(14.6%) identified as non-responders (SD or PD), 18(37.5%) are still following up. Overall, 75.4% (214/284) tDNA mutations were found in utDNA, and 75.1% (214/285) utDNA mutations were found in tDNA. The top20 genes’ mutation landscape of utDNA highly resembled that of tDNA. The top20 genes could cover 97.9% (47/48) tissue samples and 89.6% (43/48) urine samples. Also, top20 mutated genes showed a strong correlation between tDNA and utDNA(r = 0.7371, p = 0.0002). TP53, KMT2D, ARIDA1A, CREBBP, ERBB2, ERCC2 and KDM6A are the most frequent abnormalities captured in tDNA and utDNA. Interestingly, we also found that the consistency of top20 genes in responders (n = 23, r = 0.7015, p = 0.0006) are higher than non-responders (n = 7, r = 0.4118, p = 0.1853). As a consequence, 70.1% (157/224), 61.8% (21/34) tDNA mutations were found in utDNA, and 72.0% (157/218), 25.0% (21/84) utDNA mutations were found in tDNA in responders and in non-responders, respectively. Conclusions: In brief, utDNA was robustly consistent and highly associated with tDNA, with 61.8%̃75.4% tDNA variations detected in utDNA target sequecing by acornmed 808 panel. The consistency would be higher if TERT promoter included in WES panel. While in non-responders, only 25.0% utDNA mutations were found in tDNA, indicating a spatial and temporal tumor heterogeneity. Our data provided initial prospective evidence on further developing urine as an optional sample for noninvasive detection and response evaluation of BC. The large prospective cohort study is still ongoing.

e15127 Background: Kirsten rat sarcoma viral oncogene homologue (KRAS) is the most frequently mutated oncogene in human cancers. Sotorasib (AMG 510) has shown promising anticancer activity in patients with heavily pre-treated KRAS p.G12C mutant solid tumors. Here, we provide an overview of genomic diversity of KRAS alterations in a large cohort of Chinese patients. Methods: Molecular profiles of 16,654 tumor specimens were obtained using gene-panel target-capture next-generation sequencing, and classified based on the presence and subtypes of KRAS mutation. Tumor mutation burdens (TMB) were calculated using an Acornmed panel with 808 cancer-related genes. Results: In total,15.04% (2505/16654) of pan-cancer patients harbored RAS mutations, and 13.58% (2262/16654) patients carried KRAS mutations in the current study. Five main subtypes of KRAS mutation were detected including G12D (642, 28.38%), G12V (392, 17.33%), G12C (354, 15.65%), G13 (220, 9.73%), G12A (101, 4.47%). In our cohort, the highest KRAS G12C mutation frequency tumor type was lung cancer (12.33%) followed by colorectal cancer (1.99%), which is comparable with the previously published data. Among all patients with KRAS G12C mutation, 77.40% (274/354) of the patients were male and 22.60% (80/354) were female. Tumor mutation burdens (TMB) were calculated for 151 samples of all the 352 KRAS G12C mutation samples. The median TMB was 10.15 mut/Mb with 50.99%≥10 mut/Mb and 14.57%≥20 mut/Mb. However, according to the results of CodeBreaK 100 exploratory analysis at the 2021 ASCO annual meeting, among all patients with KRAS G12C mutation, 17.86% of the patients had ≥ 10 mut /Mb, which was defined as TMB-high. Therefore, it can be found that the TMB of domestic and foreign patients is different. Conclusions: Genomic alterations in KRAS are widespread among Chinese pan-cancer patients. Results of CodeBreaK 100 exploratory analysis presented at the 2021 ASCO Annual Meeting showed no significant difference (40% vs 42%) in objective response rates between TMB high (≥ 10 mut/Mb) and TMB low (< 10 mut/Mb). Based on our data, the threshold of TMB high in the Chinese population should be higher. The molecular marker exploration of AMG 510 efficacy in the Chinese population needs to be further carried out and confirmed.

BackgroundAlthough anti-programmed cell death protein 1 (PD-1) immunotherapy is greatly effective in melanoma treatment, low response rate and treatment resistance significantly hinder its efficacy. Tumor cell ferroptosis triggered by interferon (IFN)-γ that is derived from tumor-infiltrating CD8+ T cells greatly contributes to the effect of immunotherapy. However, the molecular mechanism underlying IFN-γ-mediated ferroptosis and related potentially promising therapeutic strategy warrant further clarification. MicroRNAs (miRNAs) participate in ferroptosis execution and can be delivered systemically by multiple carriers, which have manifested obvious therapeutic effects on cancer.MethodsMiRNAs expression profile in IFN-γ-driven ferroptosis was obtained by RNA sequencing. Biochemical assays were used to clarify the role of miR-21-3p in IFN-γ-driven ferroptosis and the underlying mechanism. MiR-21-3p-loaded gold nanoparticles were constructed and systemically applied to analyze the role of miR-21-3p in anti-PD-1 immunotherapy in preclinical transplanted tumor model.ResultsMiRNAs expression profile of melanoma cells in IFN-γ-driven ferroptosis was first obtained. Then, upregulated miR-21-3p was proved to facilitate IFN-γ-mediated ferroptosis by potentiating lipid peroxidation. miR-21-3p increased the ferroptosis sensitivity by directly targeting thioredoxin reductase 1 (TXNRD1) to enhance lipid reactive oxygen species (ROS) generation. Furthermore, miR-21-3p overexpression in tumor synergized with anti-PD-1 antibody by promoting tumor cell ferroptosis. More importantly, miR-21-3p-loaded gold nanoparticles were constructed, and the systemic delivery of them increased the efficacy of anti-PD-1 antibody without prominent side effects in preclinical mice model. Ultimately, ATF3 was found to promote miR-21-3p transcription in IFN-γ-driven ferroptosis.ConclusionsMiR-21–3 p upregulation contributes to IFN-γ-driven ferroptosis and synergizes with anti-PD-1 antibody. Nanoparticle delivery of miR-21–3 p is a promising therapeutic approach to increase immunotherapy efficacy without obvious systemic side effects.

e16128 Background: Hepatocellular carcinoma (HCC) is a type of aggressive disease with poor prognosis. Although surgery is the most effective therapy for early liver cancer, recurrence rate is up to 50%. Therefore, it is crucial to predict the recurrence for improvement of prognosis of liver cancer. This study aim is to establish a prognostic model using for the prediction of recurrence in HCC. Methods: We collected the genomic and clinical data of 372 patients from the cancer genome atlas (TCGA) database. Mutational signature were established based on univariate Cox analysis and least absolute shrinkage and selection operation (LASSO) Cox regression analysis. A prognostic signature model were developed. Results: The patients with higher pathological T stage (p < 0.001) and old age (p = 0.05) were associated with a worse DFS. In addtion, patients with a HRD score over 24 had a worse DFS compared to those in patients with HRD score less than 24 (p < 0.001). Based on the 1 year DFS, 112 differential mutation gene (DMEs) and 326 differential expressed genes (DEGs) were identified. The univariate Cox and LASSO Cox regression models were employed to select 47 DMEs and 9 gene expression construct an prognosis model. The AUC is 0.612. A nomogram of DFS was established based on the prognosis model, HRD, and tumor stage. The AUC is 0.812 in training set and 0.842 in validation set. Conclusions: We established and validated a novel nomogram model based the genomic and clinical factors for predict DFS in Hepatocellular Carcinoma patients. This model has good predictive value for prognosis, which could improve the risk stratification and individual treatment of Hepatocellular Carcinoma patients.

e16293 Background: Besides BRCA1/2, there are various genes involved in DNA damage repair that could predict patients’ response to treatments such as platin-based therapy, PARP inhibitors, and immunotherapy. While the mutational pattern of DNA damage repair (DDR) gene alterations in pancreatic patients remains unknown. Methods: Tumors and blood samples from 490 pancreatic patients were analyzed with next-generation sequencing (NGS) that covered 808 genes. Patients were classified based on the presence or absence of deleterious mutations across a panel of 98 DDR genes. Results: 70.4% (345/490) pancreatic cancer patients harbored DDR gene pathogenic mutations (mut). Among DDR-mut patients, 84.6% (292/345) had only somatic DDR gene alterations, 6.4% (22/345) had only germline DDR gene alterations, and 9.0% (31/345) had both. The most frequently mutated somatic DDR genes were TP53 (73.9%), CDKN2A (17.1%), ARID1A (10.1%), ATM (4.1%), and BRCA2 (4.1%). The most commonly mutated germline DDR genes were BRCA2 (4.1%), RAD51B (2.0%), ATM (2.0%), FANCE (0.9%), PALB2 (0.9%). Among the functional pathways of DDR genes, the most commonly mutated pathways were others (77.2%), FA (10.1%), CCC (7.7%), HR (1.5%), NHEJ (1.4%), MMR (1.4%), and BER (0.8%). No patients were found to harbor mutations in NER, TLS, and DR pathways. In addition, the mean TMB was significantly higher in the DDR-mut group compared with the wild-type DDR (wt) group (6.2 vs. 5.0 muts/Mb; p < 0.05). No significant difference in microsatellite instability was observed between DDR-mut and DDR-wt patients (p = 0.67). In terms of HRD status, 87.5% (28/32) HRD-positive patients and 73.1% (19/26) HRD-negative patients had DDR gene mutations. No significant difference in DDR variants was found between HRD-positive and HRD-negative patients, suggesting that HRD detection is necessary for DDR-mut patients. Within individual DDR genes, CDKN2A mutation was significantly associated with HRD-positivity (p < 0.05) whereas BRCA1, BRCA2, ATM, and PALB2 were not. Conclusions: An expanding set of DDR genes profiling provides more therapeutic opportunities for pancreatic patients who might benefit from PARP inhibitor owing to pathogenic mutations in DDR genes. This retrospective study may serve as a benchmark for the future design of an expanded association study between DDR mutations and the therapeutic outcome of pancreatic cancer.

e14563 Background: Bladder cancer is a molecularly diverse disease with heterogeneous clinical outcomes. Transcriptome-based molecular subtypes of muscle invasive bladder cancer (MIBC) and non-muscle invasive bladder cancer (NMIBC) have been shown to be both prognostic and predictive. However, its predictive role in Chinese bladder cancer remains unclear. The aim of this study was to identify the predictive role of molecular subtypes in China bladder cancer with neoadjuvant therapy. Methods: The study was conducted from May 2020 to August 2021. Patients who were age 18 years or older, were diagnosed with NMIBC or MIBC, and neoadjuvant tislelizumab combining nab-paclitaxel followed by surgery were included. Multigenomic sequencing was performed. Molecular subtypes were identified by published consensus. Results: We prospectively recruited 30 patients for neoadjuvant tislelizumab combining nab-paclitaxel, including 14 patients with NMIBC and 16 patients with MIBC. For bladder cancer, 73.3% (22/33) patients responded to neoadjuvant tislelizumab combining nab-paclitaxel. In NMIBC groups, 64.3% (9/14) patients were pCR. The objective remission rate ( ORR) was 71.4%. 4 molecular classes were identified in Chinese NMIBC, including class 1 (7.1%), class 2a (35.7%), class 2b (50%), class 3 (7.1%). Interesting, ORR was significantly higher for patients with class 2b (5/7, 71.4%) as compared to class 2a (3/5,60%) before neoadjuvant. Molecular classes changed in 35.7% (5/14) of patients before and after neoadjuvant. After neoadjuvant, 80% of class 2b patients responded to neoadjuvant, and all class 2a patients did not respond to neoadjuvant. In MIBC groups, a pPR was achieved by 37.5% patients (6/16). The ORR was 75%. We found 4 molecular classes in Chinese MIBC: basal/squamous (43.8%), luminal unstable (25%), luminal papillary (25%), and stroma-rich (6.2%). Patients with basal/squamous (85.7%) and luminal unstable (75%) had significantly higher ORR than luminal papillary (50%) before neoadjuvant. Molecular classes changed in 44.4% (4/9) of patients before and after neoadjuvant. After neoadjuvant, all patients with stroma-rich responded to neoadjuvant. Conclusions: Molecular classification could predict the efficacy of neoadjuvant tislelizumab combining nab-paclitaxel in Chinese bladder cancer, which may be preferable when studying biomarkers of bladder cancer in the future.

e16126 Background: Hepatocellular carcinoma (HCC) is the most common liver malignancy associated with poor prognosis. With the rapid development of systematic therapy for liver cancer, immunotherapy has been widely used in therapy of liver cancer. Hyperprogression of tumor is a phenomenon of accelerated tumor growth, which occurs in patients with liver cancer and other solid tumors receiving systematic treatment, and is mainly related to immunotherapy hyperprogression genes. However, it is still unclear about the genes of immune hyperprogression in HCC patients. Therefore, we studied the molecular characteristics of HCC patients, including the genes related to immunotherapy hyperprogression. Methods: From June 2019 to August 2021, 102 patients with HCC were inculded in this study. Matched tumor/normal DNA from HCC patients (N = 102) were analyzed by whole exome sequencing (WES) or Acornmed panel with 808 cancer-related genes. Results: Overall, 86.3% (88/102) patients exhibited genetic alterations. TP53 (50%), TERT (23%), CTNNB1 (18%) and KMT2C (14%) were the most commonly mutated genes in HCC. In addition, 8.9% patinets harbored at least one immunotherapy hyperprogressive gene mutations, including CCND1 (7%), FGF19 (6%), FGF3 (5%), FGF4 (5%) and MDM4 (2%). In addition, CCND1 and FGF19 were frequently mutated genes in patients with liver cancer, ranking ninth and tenth, respectively. Compared with the TCGA data, there was no significant difference in immunotherapy hyperprogressive genes (25% vs 32.3%, p = 0.18). Interesting, CCND1, FGF19, FGF3 and FGF4 mutations occurred simultaneously in most patients and were mutually exclusive with MDM4 (p = 0.057). Conclusions: This study contributes to understand the molecular characteristics of patients with HCC, which will be useful to guide immunotherapy and promote the clinical management in this population. Furthermore, the study suggested that both Chinese and Western populations should pay attention to immunotherapy hyperprogression genes in immunotherapy selection.

e15068 Background: Cyclin-dependent kinases ( CDKs) are key regulators of both cell cycle progression and transcription. Analysis of mutation detection of CDK12 in pan-cancer could contribute to understand the complexity and diversity of genetic alterations present in CDK12 mutant cancers. Herein, we provide a pan-cancer analysis of CDK12 alterations in Chinese population. Methods: Using gene-panel target-capture next generation sequencing, we analyzed 17509 tumor tissue or plasma ctDNA samples from different patients. Testing included analysis of single nucleotide variants, insertions/deletions, fusions and amplifications. CDK12 variants of uncertain significance and synonymous variants excluded. Results: In total, 0.95% (167/17509) of pan-cancer patients harbored CDK12 mutation, and 32 patients carried at least two CDK12 mutations. The most common genetic alteration type was truncating mutations (128, 64%), followed by amplications (53, 26%), missense mutations (9, 5%) and splicing mutations (9, 5%). In our cohort, the highest CDK12 mutation frequency tumor type was prostate cancer(11.30%), followed by breast cancer (3.96%), bladder cacner (3.16%), stomach cancer (1.84%) and colorectal cacner (1.13%). The TCGA pan-cancer cohort confirmed that the CDK12-altered cancer was associated with shorter overall survival (81.11 vs 133.00 mos, p = 5.30×10−18) in prostate cancer. Tumor mutation burdens(TMB) were calculated for 137 samples of all the 167 samples. The median TMB was 7.66 mut/Mb with 38%≥10 mut/Mb and 17%≥20 mut/Mb. including a patient with hypermutated in colorectal cancer(TMB: 88.24 Mut/Mb), harboring three CDK12 mutations. Conclusions: Genomic alterations in CDK12 are widespread among Chinese patients, with alteration rates and alteration types varying by cancer type. We identified prostate cancer as the cancer type with the highest prevalence of CDK12 oncogenic alterations. Additional analyses are ongoing.

3115 Background: Somatic alterations of the MET oncogene are emerging as an attractive target in human cancers, thus, understanding the molecular epidemiology of MET alterations is essential. While the occurrence of MET exon 14 skipping mutations (MET ex14) in US lung cancer patients is well defined, it is not widely published for Chinese patients. In addition, reports on the occurrence of METex14 outside lung cancer and other clinically relevant MET alterations across all cancers are limited. Methods: The MET ex14 alterations and amplification data of 10475 Chinese cancer patients from 16 types of cancer were obtained in Acronmed database, including non-small cell lung cancer (NSCLC, n = 5719), Hepatocellular carcinoma (HCC, n = 511), colorectal cancer (CRC, n = 1779), renal cell carcinoma (RCC, n = 1169), Gastric carcinoma (GC, n = 679), etc. Genomic profiling of DNA was performed through a next-generation sequencing. Results: Of all pan-cancer patients, 141 cases (1.3%) with MET alterations were identified, including MET Amp (0.9%) and MET ex14 (0.7%). Compared to Western population (̃3%), the frequency of MET alterations is much lower in Chinese cancer patients (1.3%). MET Amp were most commonly found in HCC (1.7%), GC (1.3%), NSCLC (0.7%), RCC (0.7%), CRC (0.2%). MET ex14 occurred most in NSCLC (0.5%), HCC (0.3%), CRC (0.2%). HCC were significantly to have MET Amp than NSCLC (P = 0.01), while MET ex14 mutations were more likely to be observed in NSCLC (p = 0.02). We further analyzed the MET mutation characteristics of NSCLC. The most frequently co-mutated genes in MET ex14 cohort were TP53 (48%,15/31), KMT2B (23%,7/31) and EGFR (16%, 5/31). Except for TP53 (65%,22/34) and EGFR (56%,19/34) mutations. Interestingly,other gene mutations were rare in the patients with MET Amp. In addition, MET ex14 patients showed significant lower EGFR mutation comparing to the MET amp patients (P = 0.002). Conclusions: Our study demonstrated a landscape of MET alterations among the Chinese population. MET mutations occurs in a variety of solid tumors, indicating that these patients may benefit from MET inhibitors.

4583 Background: Current methods for the early detection and minimal residual disease (MRD) of urothelial carcinoma (UC) are often invasive and/or possess sub-optimal sensitivity, especially in upper tract urothelial carcinoma (UTUC). Methods: We developed an efficient workflow named the urine tumor DNA multidimensional bioinformatic predictor, utLIFE, by using low-coverage whole-genome sequencing and targeted deep sequencing. We identified the UC specific mutations and large CNV in the discovery cohort. The utLIFE-UC model was trained in a bladder cancer retrospective cohort (n = 150) and validated in an bladder cohort(n = 674) and UTUC cohort(n = 22). 31 patients established diagnosis of BC who are on neoadjuvant were also enrolled, including a MRD training cohort (n = 16) with serial urine samples at baseline, during treatment and before surgery; a independent MRD validation cohort (n = 15) with urine samples before surgery. Results: The utLIFE-UC model could discriminate UC with high accuracy (94.3%), sensitivity (92.8%), and specificity (96.0%). Furthermore, compared to cytology, the assay achieved a great improvement in sensitivity in the detection of non–muscle-invasive bladder cancer (NMIBC, 94.7% vs. 31.6%,p = 0.0002), and muscle-invasive bladder cancer(MIBC, 82.6% vs. 69.6%, p = 0.4894). The utLIFE-UC model was also validated in independent BC cohort (sensitivity 94.3%, specificity 92.6%) and UTUC cohort (sensitivity 90.9%, specificity 90.9%). utLIFE-UC score also showed outstanding potential on dynamic surveillance of residual disease in UC as the score showed dramatically decreased in pCR patients. As expected, utLIFE-UC score could classify pCR and non-pCR(PR, SD, PD) with NPV 100% in MRD training and validation cohorts, which showed superior sensitivity over that of urine cytology (100% vs.37.5%, p = 0.0070) and FISH (100 vs. 42.9%, p = 0.0125). Conclusions: utLIFE-UC diagnostic model for early diagnosis, residual disease detection in UC is a cost-effective, rapid, high-throughput, noninvasive, and promising approach, which may reduce the burden of cystoscopy and blind surgery.

e17575 Background: HRD score correlates with sensitivity to PARP inhibitors (PARPi). BRCA1/2 mutations are well-known causes of HRD, but other genetic abnormalities of the homologous recombination repair (HRR) pathway could also cause HRD, although no consensus has been reached. We aimed to analyze HRD score and its relationship with genetic characteristics in ovarian cancer, particularly the HRR-related genes mutations. Methods: Matched tumor/normal DNA from Chinese patients with ovarian cancer (N = 181) were analyzed by Acornmed panel with 98 cancer-related genes. The HRD score is the sum of these scar signature scores, namely, the loss of heterozygosity (LOH), telomeric allelic imbalance (TAI), and large-scale state transitions (LST). HRR genes mutations and clinical outcomes from the TCGA cohort were included. Results: In our cohort, 44.2% patients exhibited HRR genes mutations, yielded an increment of 12.2% than BRCA mutants. The most frequently mutated HRR genes were BRCA1 (25.0%), BRCA2 (8.0%), CDK12 (4.0%), and RAD51D (4.0%). Chinese cohort contained frequently somatic mutation of HRR genes compared with TCGA cohort (22.7% vs 13.6%, p < 0.010). Germline mutations of HRR genes and non-HRR genes occurred in 21.5% and 2.8% of cases detected, respectively. HRD score in HRR-related genes wildtype was lower than tumors with BRCA1/2 mutation and HRR genes mutation without BRCA1/2 carriers (median HRD score 33, 72 and 64; p < 0.001). Interestingly, no difference was observed in HRD scores between patients with somatic BRCA-mut and germline- BRCA mutants. The median HRD score in our cohort was 65 (range from 0 to 96), and 58.6% patients were HRD-high with the cutoff of HRD score ≥ 42. The HRD-high patients covered 89.7% of the BRCA-positive cases, besides, approximately 77.3% of the BRCA-wt/HRR-mut patients also harbored high HRD scores. Six mutated genes were significantly different between HRD-high and HRD-low group. ARID1A was frequently mutated in patients with HRD-low, while significantly more mutations in TP53 were identified among HRD-high patients. Interestingly, in the TCGA cohort, patients with TP53-mut (p = 0.024) and individuals without ARID1A mutation (p < 0.001) had remarkably high survival rates, as compared with the rest of these patients.Furthermore, tumors with HRD-high had a bit higher TMB (median TMB 4.56 vs 2.91, p = 0.018). Conclusions: Our data suggest that HRR genes mutations strongly affect HRD score, which may increase the number of patients who may benefit from PARPi treatment, and combining gene mutations and HRD score could optimize prognosis stratification in ovarian cancer. In addition, the molecular features of HRD provide new opportunities to predict the tumor response to multiple treatments.

ObjectiveThe incidence of early stage multiple primary lung cancer (MPLC) has been increasing in recent years, while the ideal strategy for its diagnosis and treatment remains controversial. The present study conducted genomic analysis to identify a new molecular classification method for accurately predicting the diagnosis and therapy for patients with early stage MPLC.MethodsA total of 240 tissue samples from 203 patients with multiple-non-small-cell lung cancers (NSCLCs) (n = 30), early stage single-NSCLC (Group A, n = 94), and advanced-stage NSCLC (Group B, n = 79) were subjected to targeted multigene panel sequencing.ResultsThirty patients for whom next-generation sequencing was performed on >1 tumor were identified, yielding 45 tumor pairs. The frequencies of EGFR, TP53, RBM10, ERBB2, and CDKN2A mutations exhibited significant differences between early and advanced-stage NSCLCs. The prevalence of the EGFR L858R mutation in early stage NSCLC was remarkably higher than that in advanced-stage NSCLC (P = 0.047). The molecular method classified tumor pairs into 26 definite MPLC tumors and four intrapulmonary metastasis (IM) tumors. A high rate of discordance in driver genetic alterations was found in the different tumor lesions of MPLC patients. The prospective Martini histologic prediction of MPLC was discordant with the molecular method for three patients (16.7%), particularly in the prediction of IM (91.7% discordant).ConclusionsComprehensive molecular evaluation allows the unambiguous delineation of clonal relationships among tumors. In comparison, the Martini and Melamed criteria have notable limitations in the recognition of IM. Our results support the adoption of a large panel to supplement histology for strongly discriminating NSCLC clonal relationships in clinical practice.

Chun Zeng,1,2 Jing Wang,3 Mingwei Li,4 Huina Wang,4 Feng Lou,4 Shanbo Cao,4 Changyu Lu3 1Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People’s Republic of China; 2China National Clinical Research Center for Neurological Diseases, Beijing, People’s Republic of China; 3Department of Neurosurgery, Peking University International Hospital, Beijing, People’s Republic of China; 4Acornmed Biotechnology Co., Ltd, Beijing, People’s Republic of ChinaCorrespondence: Changyu LuDepartment of Neurosurgery, Peking University International Hospital, Beijing, People’s Republic of ChinaTel +8669006144Email luchangyu2020@163.comShanbo CaoAcornmed Biotechnology Co., Ltd, Floor 18, Block 5, Yard 18, Kechuang 13 Road, Beijing, 100176, People’s Republic of ChinaTel +8653606156Email shanbocao@acornmed.comBackground: Tremendous efforts have been made to explore biomarkers for classifying and grading glioma. However, the majority of the current understanding is based on public databases that might not accurately reflect the Asian population. Here, we investigated the genetic landscape of Chinese glioma patients using a validated multigene next-generation sequencing (NGS) panel to provide a strong rationale for the future classification and prognosis of glioma in this population.Methods: We analyzed 83 samples, consisting of 71 initial treatments and 12 recurrent surgical tumors, from 81 Chinese patients with gliomas by performing multigene NGS with an Acornmed panel targeting 808 cancer-related hotspot genes, including genes related to glioma (hotspots, selected exons or complete coding sequences) and full-length SNPs located on chromosomes 1 and 19.Results: A total of 76 (91.57%) glioma samples had at least one somatic mutation. The most commonly mutated genes were TP53, TERT, IDH1, PTEN, ATRX, and EGFR. Approximately one-third of cases exhibited more than one copy number variation. Of note, this study identified the amplification of genes, such as EGFR and PDGFRA, which were significantly associated with glioblastoma but had not been previously used for clinical classification (P< 0.05). Significant differences in genomic profiles between different pathological subtypes and WHO grade were observed. Compared to the MSKCC database primarily comprised of Caucasians, H3F3A mutations and MET amplifications exhibited higher mutation rates, whereas TERT mutations and EGFR and CDKN2A/B copy number variations presented a lower mutation rate in Chinese patients with glioma (P< 0.05).Conclusion: Our multigene NGS in the simultaneous evaluation of multiple relevant markers revealed several novel genetic alterations in Chinese patients with glioma. NGS-based molecular analysis is a reliable and effective method for diagnosing brain tumors, assisting clinicians in evaluating additional potential therapeutic options, such as targeted therapy, for glioma patients in different racial/ethnic groups.Keywords: glioma, molecular pathology, molecular biomarker, copy number variations, multigene NGS panel

Background Different genomic characterization in urothelial carcinoma (UC) by site of origin may imply contrasting therapeutic opportunities and pathogenetic mechanisms. The aim of this study was to investigate whether differences between upper tract UC (UTUC) and UC of the bladder (UCB) result from intrinsic biological diversity. Materials and Methods We prospectively sequenced 118 tumors and matched blood DNA from Chinese patients with UC using next-generation sequencing techniques, including 45 UTUC and 73 UCB. Two hundred twenty-six patients with UTUC and 350 patients with UCB for The Cancer Genome Atlas were acquired from the cbioportal. Results There were marked disparities in the mutational landscape for UC according to race and site of origin. Signature 22 for exposure to aristolochic acid was only observed in the UTUC cohort. Conversely, signature 6 for defective DNA mismatch repair only existed in the UCB cohort. Compared with UCB, UTUC had higher clonal and subclonal mutation numbers. TP53, PIK3CA, and FGFR3 mutations may be the driver genes for UTUC, whereas for UCB, the driver gene may be BRCA1. Patients with UTUC had lower PD-L1 than those with UCB. There was no significant difference in the number of DDR mutations, copy number variation counts, and tumor mutational burden between UTUC and UCB. Conclusion UTUC and UCB exhibit significant differences in the prevalence of genomic landscape and carcinogenesis. Consequently, molecular subtypes differ according to location, and these results may imply the site-specific management of patients with urothelial carcinoma. Mutational signature may be used as a screening tool to assist clinical differential diagnosis between UTUC and UCB. Implications for Practice This study's findings lay the foundation for a deeper understanding of distinct molecular mechanisms and similar treatment opportunities between upper tract urothelial carcinoma (UTUC) and urothelial carcinoma of the bladder (UCB) and had important implications for the site-specific management of patients with urothelial carcinoma. A comprehensive understanding of the biology of UTUC and UCB is needed to identify new drug targets in order to improve clinical outcomes.

BackgroundThe therapeutic effect of immune checkpoint blockers, especially the neutralizing antibodies of programmed cell death (PD-1) and its ligand programmed death ligand 1 (PD-L1), has been well verified in melanoma. Nevertheless, the dissatisfactory response rate and the occurrence of resistance significantly hinder the treatment effect. Inflammation-related molecules like A20 are greatly implicated in cancer immune response, but the role of tumorous A20 in antitumor immunity and immunotherapy efficacy remains elusive.MethodsThe association between tumorous A20 expression and the effect of anti-PD-1 immunotherapy was determined by immunoblotting, immunofluorescence staining and flow cytometry analysis of primary tumor specimens from melanoma patients. Preclinical mouse model, in vitro coculture system, immunohistochemical staining and flow cytometry analysis were employed to investigate the role of A20 in regulating the effect of anti-PD-1 immunotherapy. Bioinformatics, mass spectrum analysis and a set of biochemical analyzes were used to figure out the underlying mechanism.ResultsWe first discovered that upregulated A20 was associated with impaired antitumor capacity of CD8+T cells and poor response to anti-PD-1 immunotherapy in melanoma patients. Subsequent functional studies in preclinical mouse model and in vitro coculture system proved that targeting tumorous A20 prominently improved the effect of immunotherapy through the invigoration of infiltrating CD8+T cells via the regulation of PD-L1. Mechanistically, A20 facilitated the ubiquitination and degradation of prohibitin to potentiate STAT3 activation and PD-L1 expression. Moreover, tumorous A20 expression was highly associated with the ratio of Ki-67 percentage in circulating PD-1+CD8+T cells to tumor burden.ConclusionsTogether, our findings uncover a novel crosstalk between inflammatory molecules and antitumor immunity in melanoma, and highlight that A20 can be exploited as a promising target to bring clinical benefit to melanomas refractory to immune checkpoint blockade.

2601 Background: Microsatellite instability (MSI) is a common genomic alteration in several tumors, such as colorectal cancer, endometrial carcinoma, and stomach, which is characterized as microsatellite instability-high (MSI-H) and microsatellite stable (MSS) based on a high degree of polymorphism in microsatellite lengths. MSI is a predictive biomarker for immunotherapy efficacy in advanced/metastatic solid tumors, especially in colorectal cancer (CRC) patients. Several computational approaches based on target panel sequencing data have been used to detect MSI; However, they are considerably affected by the sequencing depth and panel size. Methods: We developed MSIFinder, a python package for automatic MSI classification, using random forest classifier (RFC)-based genome sequencing, which is a machine learning technology. We included 19 MSI-H and 25 MSS samples as training sets. First, RFC model were built by 54 feature markers from the training sets. Second. The software was validated the classifier using a test set comprising 21 MSI-H and 379 MSS samples. Results: With this test set, MSIFinder achieved a sensitivity (recall) of 0.997, a specificity of 1, an accuracy of 0.998, a positive predictive value (PPV) of 0.954, an F1 score of 0.977, and an area under curve (AUC) of 0.999. We discovered that MSIFinder is less affected by low sequencing depth and can achieve a concordance of 0.993, while exhibiting a sequencing depth of 100×. Furthermore, we realized that MSIFinder is less affected by the panel size and can achieve a concordance of 0.99 when the panel size is 0.5 m (million base). Conclusions: These results indicated that MSIFinder is a robust MSI classification tool and not affected by the panel size and sequencing depth. Furthermore, MSIFinder can provide reliable MSI detection for scientific and clinical purposes.[Table: see text]

e17531 Background: Ovarian Cancer (OC) is the most lethal cancer of all gynecological malignancies.Circulating tumor DNA (ctDNA) has received substantial attention in recent years resulting from the non-invasive, safe and effective method with considerable potential for clinical diagnosis and treatment management in patients with OC. Here, we assessed the mutational feature in homologous recombination repair (HRR) using ctDNA in OC. Methods: Plasma ctDNA was isolated from blood of patients and then was analyzed by AcornMed Biotechnology NGS-based assay for 808 genes panel for genomic alterations. The somatic and germline pathogenic mutations were identified in 12 HRR genes (ATM, BRCA1, BRCA2, BRIP1, CHEK1, CHEK2, FANCA, PALB2, RAD51B, RAD51C, RAD51D, RAD54L). Results: At our institution, 85 patients underwent NGS analysis of ovarian cancer specimens. The median age was 57 (range from 26 to 83). Twenty-six patients(42.34%) harbored a mutation in at least 1 of the HRR genes in their tumor. The most commonly altered HRR gene was BRCA1 (18.25%), followed by BRCA2 (8.76%), ATM (5.84%), RAD51D(3.65%), CHEK2 (2.92%), FANCA(2.19%) and RAD51C (0.73%). To determine the difference of mutation landscape in HRR between Chinese and western populations, we compared prevalence and spectrum in cases between our cohort and the cohort of Heeke et al 1(Table). Prevalence of HRR were different from the Western cases(42.34% vs 20%, P＜0.05). Of note, BRCA1, BRCA2, ATM and CHEK2 alterations rate was higher in our cohort, and BRIP1 and PALB2 were only detected in the western cohort. Conclusions: CtDNA can characterize the mutational feature of HRR in OC. Around 42.3% of patients with OC harbour germline or somatic HRR mutations. The expanded use of PARP inhibitors in HRR deficient tumours using a signature of HRR by ctDNA in clinical practice requires validation.[Table: see text]

e15078 Background: Recently, homologous recombination deficiency (HRD) scores are associated with the efficacy of Poly‐(ADP‐Ribose)‐Polymerase (PARP) inhibition and platinum-based chemotherapy in a variety of cancers. Evaluating HRD level in patients with cancers is becoming far more important and influential, so far, there is no standard method to be used in clinical. In this study, we developed an algorithm to detect HRD from next-generation sequencing (NGS) for finding additional patients may potentially benefit from target therapy. Methods: Forty-eight patients were enrolled, including breast cancer, ovarian cancer, prostatic cancer. Fifteen cell lines with breast cancer and endometrial carcinoma were collected from Cobioer biosciences co., LTD. Forty-eight Formalin-fixed, paraffin embedded (FFPE) samples and 15 cell lines were performed by DNA extracting. We developed an HRD score algorithm, termed as AcornHRD algorithm. HRD score was analyzed by whole-genome sequencing, and GATK mutect2 software was used to detect BRCA1/2mutation by deep sequencing. Results: BRCA1/2 deleterious mutations were observed in 20 patients (41.7%). HRD was explained by deficiencies in 17 patients (85.0%) with BRCA mutation, whereas eight HRD-high tumors were non- BRCA related (28.6%). Among BRCA wild-type patients, the corresponding percentage of HRD positive patients in breast cancer, ovarian cancer and prostate cancer were 36.3%, 37.5% and 11.1%, respectively. Similar results were also verified in the cell line datasets. The findings showed that 100% (3/3) BRCA1/2 deficient cell lines are also HRD-high. Furthermore, HRD scores were highly correlated with standard results in the cell line datasets. Conclusions: We here report the NGS-based HRD scores to distinguish similarly well between BRCA mutant and BRCA wild-type cases in a cohort of Chinese population. AcornHRD scores were highly associated with BRCA1/2 deficiency. AcornHRD algorithm can be a useful tool to detect HRD events in clinical settings.

e16140 Background: Hepatocellular carcinoma (HCC) is one of the most common malignancies and leading cause of cancer deaths worldwide. Biomarkers contribute to predict the response of targeted treatments and immunotherapy. Therapy directed toward homologous recombination deficiency (HRD) is now approved in ovarian and breast cancer, but the pattern of HRD is not clear in HCC. The HRD phenotype has been defined as the presence of a non-silent somatic mutation in homologous recombination-related (HRR) genes. Thus, we aimed to analyze the molecular characteristics of resectable HCC, including HRR genes. Methods: Matched tumor/normal DNA from resectable HCC patients (N = 53) were analyzed by whole exome sequencing (WES) or Acornmed panel with 808 cancer-related genes. Results: Overall, 94.3% (50/53) patients exhibited genetic alterations. TP53, ARID1A, PTEN and NBPF1 were the most commonly mutated genes in resectable HCC. In addtion, 35.9% patinets harbored at least one HRR genes mutation. The frequently mutated genes were BRCA2 (4.4%), BRCA1(4.0%), ATM (3.9 %), and RAD50 (3.8%). Interesting, frequency of HRR genes mutation in the Chinese cohort was higher than that in TCGA (35.9 % vs 20.9%). Analysis of carcinogenic pathways shown that ERBB and PI3K-AKT signaling pathway were the common signaling pathway. In resectable HCC, 32.08% (17/53) patients disclosed high TMB (highest 25%). Further analysis found that PTEN mutations were remarkably associated with low TMB (p < 0.05). Conclusions: This study contributes to understand the molecular characteristics of patients with resectable HCC, which will be useful to guide personalized therapy and promote the clinical management in this population. Furthermore, the study suggested that it is feasibility for resectable HCC patients received PARP inhibitors, DNA-damaging chemotherapies, and immune checkpoint blockade therapy.

e20527 Background: Lung cancer is currently a leading cause of cancer-associated mortality worldwide. Germline mutations potentially predisposing patients to lung cancer have not been systematically defined. In this study, we sought to determine the prevalence of pathogenic/likely pathogenic (P/LP) germline mutations in patients with NSCLC. Methods: A total 1562 patients with NSCLC were included in this study. Leukocyte DNA was extracted and detected were using next generation sequencing technology. Allele frequencies were compared with publicly available database. Interpretation of sequence variations was classified according to the American College of Medical Genetics and Genomics guidelines. Results: Overall, median age at testing of individuals was 63 years (range 12 to 91). The majority of individuals tested were male (56.15%, 877/1562). of 1562 NSCLC, P/LP mutations were identified in 94 (6.02%) in 42 Cancer Susceptibility genes. No individuals carried more than 1 germline variant. The most common P/LP mutations in genes were MUTYH (n = 11, 0.70%), TP53 (n = 10, 0.64%), BRCA2 (n = 8, 0.51%), PALB2(n = 5, 0.32%), PTEN(n = 4, 0.26%), BLM(n = 3, 0.19%), WRN(n = 3, 0.19%), and ATR, BRCA1 and BRIP1 (n = 2, 0.13% each). Twenty eight patients were carried germline mutations in homologous recombination repair(HRR), including BRCA2 (8), PALB2 (5), PTEN (4), BRCA1 (2), BRIP1 (2), CHEK2 (2), FANCA (2), ATM (1), RAD51B (1), RAD54L(1). Of note, the clinical features of patients with HRR mutations were not young adult (median age [range], 57 [41-80] years). Conclusions: Of 1562 patients with NSCLC, 94 (6.02%) had germline mutations and 27 (1.73%) had mutations in HRR genes. The presence of HRR germline mutations could guide cancer screening for patients and their families and serve as predictive biomarkers of response to targeted or immunotherapies. More extensive germline testing in NSCLC should be considered.

e13006 Background: Breast cancer (BC) is the most common cancer in women world-wide. Assessments of genomic variants in circulating tumor DNA (ctDNA) have generated great enthusiasm for their potential application as clinically actionable biomarkers in the management of BC. Alterations in homologous recombination repair (HRR), are a determinant of sensitivity to platinum chemotherapy and poly (ADP-ribose) polymerase inhibitors (PARPi) in BC. However, as far as we known, most of HRR genes, except BRCA1/2, have not yet been fully understood to date. In this study, we aimed to elucidate the comprehensive HRR genetic alteration profile of breast tumors among Chinese patients by ctDNA analysis. Methods: Plasma ctDNA from 259 patients with BC were deeply sequenced via next-generation sequencing (NGS) techniques using AcornMed Biotechnology for 808 genes panel. Molecular profiles were reviewed to identify somatic and germline pathogenic mutations in the 14 HRR genes ( ATM, BRCA1, BRCA2, BRIP1, CHEK1, CHEK2, FANCA, PALB2, RAD51B, RAD51C, RAD51D, RAD54L, CDK12, and BARD1) . Results: At our institution, 259 patients underwent NGS analysis of BC specimens. The median age was 46 (range from 31 to 79). Based on the analysis of the genetic alteration profile from our cohort, at least one of the HRR genes was observed from 29.34% of the tumor samples, with BRCA1 (8.11%), BRCA2 (5.79%), RAD51C (5.02%), CDK12 (4.63%), CHEK2 (1.93%), ATM (1.16%), and BARD1 (1.16%) as the most commonly altered genes. As compared with MSKCC dataset (Table), genetic alterations detected from our cohort affected genes involved in HRR (29.34% vs. 14.03%, P＜0.0001) pathways, with statistically different genetic alteration rates. Moreover, BRCA1/2, RAD51C, CDK12 and CHEK2 mutations exhibited higher mutation rates, whereas ATM, BRIP1 and PALB2 mutations presented a lower mutation rate in Chinese patients with breast cancer (P＜0.05). Conclusions: CtDNA can characterize the mutational feature of HRR in BC. our study contributes to the understanding of the HRR pathways and specific genetic alterations harbored by Chinese patients with BC that could potentially be developed as markers of treatment response to targeted therapeutics. Ref: Razavi P, Chang MT, Xu GT, et al. The Genomic Landscape of Endocrine-Resistant Advanced Breast Cancers. Cancer Cell. 2018 Sep 10;34(3):427-438.e6. doi: 10.1016/j.ccell.2018.08.008.[Table: see text]

e15525 Background: Homologous recombination deficiency (HRD) might serve as a biomarker of immunotherapy and chemotherapy response. In addtion, HRD is associated with sensitivity to PARP inhibitor (PARPi) therapy. The HRD phenotype has been defined as the presence of a non-silent somatic mutation in homologous recombination-related (HRR) genes. Here, we focused on mutational landscape of HRR genes and the relationship between HRR-related genes and clinical outcomes in colon cancer. Methods: We prospectively sequenced 784 Chinese patients with colon cancer using next-generation sequencing techniques with 808 cancer-related genes. 290 patients with somatic mutation from the TCGA project were included. The 15 HRR genes were selected on clinical evidence of sensitivity to PARP inhibitors and immunotherapy. TCGA datasets were performed to identify the correlations between HRR gene mutations and clinical outcomes. Results: In the Chinese cohort, 11.5% (90/784) patients exhibited deleterious somatic mutation in HRR genes, including ATM (3.3%), BRCA2 (2.4%), CDK12 (2.4%), BRCA1 (1.0%), BRIP1 (1.0%), CHEK2 (0.5%), BARD1 (0.4%), RAD54L (0.4%), PALB2 (0.3%), and RAD51B (0.3%). In TCGA cohort, 28.6% (83/290) patients had at least one deleterious somatic mutation in HRR genes, including ATM (14.8%), BRCA2 (9.0%), CDK12 (7.9%), BRIP1 (3.8%), BRCA1 (3.4%), FANCL (3.1%), CHEK2 (2.4%), PALB2 (2.1%), PPP2R2A (2.1%), RAD54L (2.1%), CHEK1 (1.7%), BARD1 (1.4%), RAD51C (1.4%), RAD51B (1.0%), and RAD51D (0.3%). Overall, the mutational frequency of HRR genes in the Chinese cohort was lower than that in the TCGA cohort (p < 0.001). In the TCGA cohort, colon patients with HRR-mut had significantly higher tumor mutational burden and incidence of microsatellite instability high and enhanced immune activity than patients with HRR-wt. Furthermore, In the MSK-IMPACT cohort treated by immune checkpoint inhibitor, patients with HRR-mut had significantly better OS (p = 0.009) and increased immune activities, such as infiltration of cytotoxic cells (p < 0.05) and exhausted CD8+ T cells (p < 0.01), and increased the IFN-γ scores (p < 0.05) than patients with HRR-wt. Conclusions: Our data suggest that detection of somatic mutations in HRR genes might contribute to identify patients who might benefit from immune checkpoint blockade therapy and PARP inhibitors. In addition, the molecular features of HRR provide new opportunities to predict the tumor response to multiple treatments. Exploring other biomarkers of HRD to predict the response to PARPi and immunotherapeutic in colon cancer is necessary.

e15073 Background: Homologous recombination deficiency (HRD) can regulate the tumor immune microenvironment based on increasing tumor-infiltrating lymphocytes and therefore might serve as a biomarker of immunotherapeutic response. The HRD phenotype has been defined as the presence of a non-silent somatic mutation in homologous recombination-related (HRR) genes. Here, we focused on frequency of HRR genes mutation and the relationship between HRR genes mutation and clinical immunotherapy responses in melanoma. Methods: We prospectively sequenced 130 Chinese melanoma patients using next-generation sequencing techniques with Acornmed panel with 808 cancer-related genes. 208 patients with WES data from the TCGA project were included. Correlations between HRR gene mutations and clinical outcomes were identified via bioinformatic analysis using TCGA datasets. Results: In the Chinese cohort, 40% (52/130) patients exhibited genomic alterations in HRR genes. The frequently mutated genes were ATM (14%), BRCA2 (13%), CHEK2 (6%), PALB2 (6%), BRIP1 (4.6%), BARD1 (3%), BRCA1 (2%), CDK12 (2%), CHEK1 (1%), FANCL (1%), and RAD54L (1%). In TCGA cohort, 26% (53/208) patients had at least one somatic mutation in an HRR gene. The frequently mutated genes were BRCA2 (9%), BRCA1 (7%), ATM (6%), BRIP1 (4%), PALB2 (4%), BRAD1 (1%), CHEK2 (1%), PPP2R2A (1%), RAD51B (1%), RAD51C (1%), RAD54L (1%), CHEK1 (1%), and RAD51D. Chinese melanoma patients had higher frequently mutated HRR genes compared to that in TCGA patients (40% vs 26%, p=0.005). In addition, compared with TCGA cohort, the Chinese cohort had higher frequency for ATM (14% vs 6%, p=0.019) and CHEK2 (6% vs 2%, p=0.006). The TCGA cohort had a higher frequency of BRCA1 mutations than the Chinese cohort, although the difference was not statistically significant. Unfortunately, we did not find a significant correlation between HRR mutation and immune cells. Interestingly, in the TCGA cohort, patients with HRR-mut had significantly better OS than patients with HRR-wt (log-rank p=0.027). Conclusions: Our data suggest that detection of somatic mutations in HRR genes might contribute to identify patients who might benefit from immune checkpoint blockade therapy. In addition, the molecular features of HRD provide new opportunities to predict the tumor response to multiple treatments.[Table: see text]

Melanoma is among the most malignant cancers with notorious aggressiveness, and its prognosis is greatly influenced by progression status. Serum microRNAs are small noncoding RNAs with high stability and easy accessibility in human blood. Their expression profiles are frequently dysregulated in cancers; hence, levels of serum microRNAs may reflect progression status and thus predict melanoma prognosis. In a hospital based case-control study, we found a significant reduction of serum miR-16 level in melanoma patients compared with cancer-free controls (P0.001). In addition, serum miR-16 level markedly decreased in melanoma patients with increased tumor thickness, occurrence of ulceration, and advanced American Joint Committee on Cancer stages, and was highly correlated with tissue Ki-67 expression (r = -0.521, P0.0001). Kaplan-Meier analysis and Cox proportional hazards regression analysis revealed a prognostic role of serum miR-16 (hazard ratio 2.49, 95% confidence interval 1.10-5.63, P = 0.028), which independently evaluated patients' survival outcome. Finally, the suppressive role of miR-16 in melanoma growth was validated both in vitro and in vivo. In conclusion, we demonstrated that serum miR-16 is a potential biomarker for predicting melanoma prognosis.

e15586 Background: Next-generation sequencing (NGS) typically requires greater quantities of DNA than traditional molecular testing. Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) is a minimally invasive technique with high sensitivity in the mediastinal staging of lung cancer. This study aimed to evaluate the adequacy of EBUS-TBNA in providing adequate size specimens for genetic mutations and immunotherapy biomarkers analysis in patients with lung cancer. Methods: Tissue samples from patients with advanced lung cancer were collected by EBUS-TBNA and were formalin-fixed paraffin-embedded. NGS assay was carried on with acornmed panel including 808 genes. PD-L1 expression through immunohistochemistry was assessed. Results: A total of 98 patients was enrolled, of which 74 (76%) were adenocarcinoma and 20 (20%) were squamous cell carcinomas. Among the patients, 108 samples (including multipoint puncture of different location and retest of the same patient) were obtained. NGS assay was completed successfully on 106 of the 108 samples (98.14%), and 97.96% of patients had successful testing, identifying an average of 11.3 mutations. With a multi-gene panel comprising up to 808 tumor related genes, actionable variations were found in 93 (86%) samples. Of these, the positive rates of actionable alterations in lung adenocarcinoma samples and lung squamous cell carcinoma samples were 90% and 79%, respectively. The tumor mutation burden (TMB), Microsatellite instability (MSI) and PD-L1 expression were found High in 20 (41%), 1 (2%), and 37 (72%) patients respectively. Conclusions: NGS assay can be successfully conducted with tissue samples obtained from EBUS-TBNA. NGS assay provides more comprehensive information on genetic mutations in tumors, which greatly assists therapeutic decision making for advanced lung cancer.

e14650 Background: Gene fusions, resulting from chromosomal breakage and rearrangement, play a critical role during oncogenesis. Recently, a growing number of gene fusions are being considered as important therapeutic targets in oncology, for instance, Anaplastic lymphoma receptor tyrosine kinase (ALK) fusion, which confer exquisite sensitivity to ALK tyrosine kinase inhibitors (TKIs). However, available methods are inadequate for unbiased identification of potentially targetable fusions. Hence, we developed a novel fusion gene analyzing method named AcornFusion by DNA-seq data. Methods: The method is purely based on the mapping results of soft-clipped reads and the distribution of the positions where the candidate breakpoints locate, which is significantly different from the traditional methods with assembly of short reads and efficient way to do the detection. 309 patients with advanced non-small cell lung cancer (NSCLC) were enrolled. Formalin-fixed, paraffin embedded (FFPE) samples were used to DNA extracting and analyzed by AcornFusion method. Immunohistochemistry (IHC) and Reverse transcriptase polymerase chain reaction (RT-PCR) platform were also applied. Results: Of 309 pts, 17 patients were identified as fusion-positive cases by AcornFusion. 15 patients were EML4-ALK fusion positive and 1 patient was HIP-ALK fusion positive, which were all confirmed by IHC. 1 patient was ROS1 rearrangement positive, which was validated by Reverse transcriptase polymerase chain reaction (RT-PCR) method. Conclusions: With this advantage of high consistency with IHC and RT-PCR, AcornFusion can be a useful tool for investigating gene fusion events in clinical settings.

e20534 Background: While tumor genotyping is the standard treatment for patients with non-small cell lung cancer (NSCLC), spatial and temporal tumor heterogeneity and insufficient specimens can lead to limitations in the use of tissue-based sequencing. Circulating tumor DNA (ctDNA) fully encompasses tumor-specific sequence alterations and offers an alternative to tissue sample biopsies. The aim of the study was to evaluate whether the frequency of multiple genomic alterations observed following ctDNA sequencing was similar to that observed following tissue sequencing in NSCLC. Methods: A total of 99 NSCLC patients were enrolled in this study, including 40 tissue and 59 plasma samples. All kinds of variants of oncogenic drivers in NSCLC were identified by next-generation sequencing (NGS) with Acornmed panel. Results: The frequencies of genetic alterations detected in ctDNA were significantly correlated to those detected via tissue profiling (Spearman’s r = 0.812, P = 0.022). Genomic data revealed significant mutual exclusivity between alterations in epidermal growth factor receptor ( EGFR) and tumor protein 53 ( TP53; P = 0.020) and between those in EGFR and Kirsten rat sarcoma viral oncogene homolog ( KRAS; P = 0.008), as well as potential mutual exclusivity between alterations in EGFR and Erb-B2 receptor tyrosine kinase 2 ( ERBB2; P = 0.059). Furthermore, the EGFR mutant allele frequency (MAF) was strongly correlated with the TP53 MAF in individual tumors (Spearman’s r = 0.773, P = 0.005), and there was a marked difference in the EGFR MAF between patients with and without the TP53 mutation (P = 0.001). Levels of the tumor serum marker CA242 in patients with ctDNA-detectable mutations were higher than those in patients without ctDNA-detectable mutations. Conclusions: This study provides a better understanding of the spectra of genomic alterations detected by tissue and plasma ctDNA assays in Chinese patients with NSCLC. The present data also highlights the importance of tissue and plasma ctDNA screening by NGS to guide personalized therapy and promote the clinical management of NSCLC patients.

e22501 Background: Osteosarcoma (OS) is characterized by complex genetic features and mysterious biological behavior. Genomic technologies are starting to give more insights. However, recent investigations have focused on patients with the advanced or metastatic disease. This study intended to evaluate the genetic landscape and identify new prognostic biomarkers in OS pts with good prognosis. Methods: This study conducted in-depth genomic profiling in a cohort of 21 patients (MSTS stage II) with long-term follow-up. Whole exome sequencing of primary tumors with matched normal tissues were performed. Sequencing data were analyzed to call tumor specific single nucleotide variants (SNV), small insertions and deletions (Indels), copy number variations (CNV) and chromosomal rearrangements and their prevalence was compared to the pts with metastatic disease reported before (Wang et al, 2018). Tumor mutation burden (TMB) and microsatellite instability (MSI) was analyzed, with additional analysis for mutational signatures. The endpoint was disease free survival (DFS). Results: 21 participants were enrolled between July. 23th, 2008 and Aug. 19th, 2013. 21 pts (M/F 13/8), median age 17y (5-33). Median DFS was 88.4 (95% CI 61.27–111.77) months. The top ranked altered genes were MUC4 (67%), FRG1 (62%), TXNDC2 (62%), ZNF717 (62%), ANKRD20A4 (57%), IGSF3 (52%), MUC16 (52%), NBPF10 (52%), MUC12 (48%) and ARID1A (43%). TMB was evaluated as lower level with a median value of 1.11 muts/MB (range from 0.78 to 3.58), relative to the other solid tumors. None pathogenic and likely pathogenic germline mutations were detected. Mutation signature 5 and 6 were most prevalent. CNV were frequently happened in stage II OS with an incidence of 80.9% (17/21). Among these, The co-occurrence of copy number gain (CNG) and copy number loss (CNL) significantly correlated with DFS (p = 0.0164), comparing with pts of either CNG or CNL . While CNV of driver genes in stage II OS were different from those of stage III published before (Wang et al, 2018), TP53 (0% vs 30% ), RB1 (4.5% vs 60%), CDKN2A (0% vs 30% ), MYC (0% vs 60%) and MDM2 (0% vs 60%). Conclusions: Stage II OS with favorable prognosis has unique genetic characterizes relative to metastatic OS. This study indicates that MUC family could be one of prognostic indicators. Genes with CNV, and the state which CNV occurs could provide clinical significance for the discovery of prognostic markers, which need to be validated by prospective prognostic data.

e16071 Background: The mutation spectrum has been extensively studied in Renal Cell Cancer (RCC), a heterogeneous disease. While major investigations have focused on metastatic RCC (mRCC). This study intended to explore the molecular characteristics between early-stage (stage I/Ⅱ) and advanced-stage (Ⅲ/Ⅳ) of RCC patients (pts). Methods: 36 tumor specimens were obtained from individual pts diagnosed RCC, including 22 tissues paired with blood samples. Somatic mutations were identified via targeted next generation sequencing with Acornmed panel including 808 genes associated with tumor development. Sequencing data were analyzed to call tumor specific single nucleotide variants (SNV), small insertions and deletions (InDels), copy number alterations (CNA) and chromosomal rearrangements. Clinical data of a cohort from TCGA who had RCC was collected and analyzed. Results: Among the 36 pts enrolled, 61% were early-stage group and 39% were advanced-stage group. The most frequently mutated genes in RCC were VHL (50%), PBRM1 (14%), BAP1 (11%), TP53 (11%) and PIK3CA (6%). Truncating mutations were the most frequent alterations accounting for 66% (33/50) of genetic alterations. Mutations in VHL, BAP1, PBRM1 and TP53 were shared by both early and advanced RCC. While mutations in PIK3CA, CDKN2C, EGFR, FAMCA, GRIN2A, KDM6A, SOX17, TSC1 and APC were only detected in early stage group. KNSTRN, KRAS, MYD88, NF2, ATM, PTEN and STAT5B mutations were only detected in advanced group. Among 22 plasma samples, genomic alterations were detected in 40.9% (9/22) of pts postoperatively, such as TP53, PIK3CA, PTEN, and APC. Functional annotation clustering revealed that 4/9 in these genes were tumor suppressors, which negatively regulated apoptosis. Pts with genomic alterations in TP53 (p = 0.0034), PIK3CA (p = 0.0015) or PTEN (p = 0.00017) had worse OS significantly (TCGA). Conclusions: VHL, PBRM1, BAP1 were the most important driver genes mainly detected in all stages of RCC. The heterogeneity between early and advanced-stage may be related with clinical status. Gene alterations in plasma ctDNA postoperatively should have the potential to stratify patients with different prognostic outcome.

e14280 Background: Biomarkers would enrich patients(pts) with responsiveness to both targeted treatments and immunotherapy which have become a priority. However, molecular heterogeneous in actionable gene alterations and mutational loads need to be explored. In this study, based on a real world setting, Cancer Gene Panel (CGP） analysis was performed in a series samples of Chinese pts with advanced solid tumors, to delineate the landscape of actionable mutations and tumor mutational burden (TMB). Methods: 176 advanced pts were enrolled encompassing 19 common tumor types. All tissue samples were analyzed using next-generation sequencing with Acornmed panel including 808 genes. Results: The frequencies of genetic alterations among the most common driver genes were comparable to those reported by MSK-IMPACT (2018) ( TP53: 51.7% vs 44.8%; APC: 9.7% vs 9.8%; EGFR: 12.5% vs 7.7%; KRAS: 16.5% vs 13.6%; PIK3CA: 4.6% vs 12.0%; VHL: 4.0% vs 6.7%). 58.3% of pts with refractory solid tumors had at least one actionable mutation. Among those pts, 16.7% of them including CDK4, CDK6 or CDKN2A/B could benefit from palbociclib, and 32.1% of them including mTOR, PIK3CA, PTEN or STK11 could benefit from everolimus, and 61.9% of them including BRCA2, ARID1A, MSH1/2/6 or ATM could benefit from olaparib. Across all the specimens, the top 20% of TMB was 17.23 mutations/Mb, with a range of 0-48 mutations/Mb. The top 20% of TMB for each tumor type was 21.67(Bladder cancer), 17.23(Lung cancer), 16.45(Colorectal cancer), 11.04 (Renal cell cancer), 16.25 (Prostate cancer) , 19.70 (Hepatobiliary cancer), 14.78 (Esophagogastric cancer), 7.80 (Pancreatic cancer), 25.31 (undefined tumor) mutations/Mb respectively. Conclusions: This study indicates that most of pts with advanced refractory solid tumors have at least one actionable mutation, and matched therapies may confer clinical benefit. TMB fluctuated wildly across different cancer types, illustrating the unequal objective response rate of immunotherapy across various cancer type. Furthermore, CGP analysis in advanced pan-cancer pts can provide opportunities for targeted therapies and immunotherapy, especially in those with refractory cancer.

Background: The occurrence of invasion and metastasis is the major cause of mortality in melanoma. Recent studies suggest that dysregulated miRNAs play critical roles in this procedure, but the underlying mechanism remains elusive. Here, we show that down-regulated miR-23a can promote invasion-metastasis cascade through autophagy in melanoma.Methods: The role of miR-23a in prognosis was assessed in a cohort of melanoma patients (n = 192) with Kaplan-Meier analysis. The effects of miR-23a overexpression were investigated using assays of invasion, migration and in a xenograft model (n = 10 mice per group). Autophagy-related target of miR-23a was confirmed by bioinformatics analysis, luciferase assays and immunoblotting. Molecular studies were performed to determine the downstream cellular and molecular mechanisms. All statistical tests were two-sided.Results: Serum miR-23a level was significantly down-regulated in melanoma patients (P< .001) and was highly correlated with poor clinical outcomes (P = .027, log-rank test). In addition, miR-23a level was remarkably decreased in metastatic melanoma tissues and cell lines (P Note: This abstract was not presented at the meeting. Citation Format: Weinan Guo, Huina Wang, Yuqi Yang, Sen Guo, Weigang Zhang, Tao Zhao, Lin Liu, Zhe Jian, Ling Liu, Gang Wang, Tianwen Gao, Qiong Shi, Chunying Li. Down-regulated miR-23a contributes to invasion and metastasis of cutaneous melanoma by promoting autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 477. doi:10.1158/1538-7445.AM2017-477

834 Background: To compare the clinical outcomes of multiple and single cycle dose-intensive induction therapy with autologous stem cell rescue among 48 patients with recurrent or metastatic solid ...

9548 Background: E-cadherin is responsible for the cell-cell adhesion. Germline mutations in E-cadherin gene (CDH1) was firstly recognized in Maori kindred with hereditary gastric cancer(HGC) in Ne...