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Most cancers are caused by somatic mutations. Some common mutations in the same cancer type can form a "signature" to specifically predict the prognosis or to distinguish it from other cancers. In this study, 710 somatic cell mutations were identified in 142 cases, including digestive, lung and urogenital cancers, and the digestive cancers were further divided into liver, stomach, intestinal, esophageal and cardia cancer. The above mutations were located in 166 genes. In addition, a group of high-frequency mutation genes with specific characteristics were screened to form predictive signatures for each cancer. Verification using TCGA suggested that the signatures could predict the stages, progression-free survival, and overall survival of digestive, intestinal, and liver cancers (P 0.05). The validation cases further confirmed the predictive role of digestive and liver cancers signatures in diagnosis and prognosis. Overall, this study established predictive signatures for different cancer systems and their subtypes. These findings enable a better understanding in cancer genome, and contribute to the personalized diagnosis and treatment.

Liver cancer is a common malignant tumor worldwide, which is a serious threat to the health of people. We try to investigate some mutations and clinical indicators as candidate markers for the development of liver cancer through targeted region capture technology combined with next-generation sequencing. We collected peripheral blood and liver cancer tissue samples from 32 liver patients concurrently. The SeqCap EZ Prime Choice Probe was used to perform the targeted enrichment; this probe captures 1,000 known cancer-associated genes. We calculated the tumor mutation burden (TMB) for each patient. The high-frequency mutations and these relative genes were identified. Eventually, survival analysis was performed based on the mutations and clinical indicators. In 32 liver patients, a total of 29 high-frequency mutations were investigated. They were located in 25 genes, which were enriched in 9 cellular components (CCs), 6 molecular functions (MFs), and 21 biological processes (BPs). Among them, EZH2 c.1544A>G and CCND1 c.839A>T had the highest mutation frequency (5/32). In the protein–protein interaction (PPI) network, EZH2-DNMT3A, NOTCH1-CCND1, and ABL1-CCND1 were the top three pairs. The survival analysis showed that there were significant differences in progression-free survival (PFS) and overall survival (OS) between the Karnofsky performance score (KPS) groups. The PFS and OS in the TMB high group were higher than those in the TMB low group. OS and tumor stage had a remarkable relationship. In conclusion, EZH2 c.1544A>G and CCND1 c.839A>T might be potential biomarkers of liver cancer. TMB might be used as a prognosis and survival indicator of liver cancer.

Background Identifying gene mutation signatures will enable a better understanding for the occurrence and development of colorectal cancer (CRC), and provide some potential biomarkers for clinical practice. Currently, however, there is still few effective biomarkers for early diagnosis and prognostic judgment in CRC patients. The purpose was to identify novel mutation signatures for the diagnosis and prognosis of CRC. Methods Clinical information of 531 CRC patients and their sequencing data were downloaded from TCGA database (training group), and 53 clinical patients were collected and sequenced with targeted next generation sequencing (NGS) technology (validation group). The relationship between the mutation genes and the diagnosis, pathological type, stage and prognosis of CRC were compared to construct signatures for CRC, and then analyzed their relationship with RNA expression, immunocyte infiltration and tumor microenvironment (TME). Results Mutations of TP53, APC, KRAS, BRAF and ATM covered 97.55% of TCGA population and 83.02% validation patients. Moreover, 57.14% validation samples and 22.06% TCGA samples indicated that patients with mucinous adenocarcinoma tended to have BRAF mutation, but no TP53 mutation. Mutations of TP53, PIK3CA, FAT4, FMN2 and TRRAP had a remarkable difference between I-II and III-IV stage patients (P PIK3CA, LRP1B, FAT4 and ROS1 formed signatures for the prognosis and survival of CRC patients. The mutations of TP53, APC, KRAS, BRAF, ATM, PIK3CA, FAT4, FMN2, TRRAP, LRP1B, and ROS1 formed the signatures for predicting diagnosis and prognosis of CRC. Among them, mutation of TP53, APC, KRAS, BRAF, ATM, PIK3CA, FAT4 and TRRAP significantly reduced their RNA expression level. Stromal score, immune score and ESTIMATE score were lower in patients with TP53, APC, KRAS, PIK3CA mutation compared non-mutation patients. All the 11 gene mutations affected the distributions of immune cells. Conclusion This study constructed gene mutation signatures for the diagnosis, treatment and prognosis in CRC, and proved that their mutations affected RNA expression levels, TME and immunocyte infiltration. Our results put forward further insights into the genotype of CRC.

Background The purpose of this study was to construct a new typing model for diffuse large B-cell lymphoma (DLBCL) patients based on the B-cell receptor (BCR) and explore its potential molecular mechanism. Methods BCR repertoire sequencing and whole-exome sequencing were performed on formalin-fixed paraffin-embedded samples from 12 DLBCL patients. Subsequently, a typing model was built with cluster analysis, and prognostic indicators between the two groups were compared to verify the typing model. Then, mutation and bioinformatics analyses were conducted to investigate the potential biomarkers of prognostic differences between the two groups. Results Based on BCR sequencing data, we divided patients into two clusters (cluster 1 and cluster 2); this classification differed from the traditional typing method (GCB and non-GCB), in which cluster 1 included some non-GCB patients. The progression-free survival (PFS), overall survival (OS), metastasis and Shannon diversity index of IGH V-J and survival after chemotherapy were significantly different (P FTSJ3, MAGED2, and ODF3L2 were the specific mutated genes in all patients in cluster 2, and these genes could be considered critical to the different prognoses of the two clusters of DLBCL patients. Conclusion We constructed a new typing model of DLBCL based on BCR repertoire sequencing that can better predict the survival time after chemotherapy. FTSJ3, MAGED2, and ODF3L2 may represent key genes for the difference in prognosis between the two clusters.

High expression of PD-L1 marks the poor prognosis of pancreatic ductal adenocarcinomas (PDAC). However, the regulatory mechanism of PD-L1 remains elusive. We recently reported that cancer Forkhead box protein 3 (Cancer-FOXP3 or C-FOXP3) promoted immune evasion of PDAC by recruiting Treg cells into PDAC via upregulation of CCL5. In this study, we confirmed that PD-L1 was overexpressed in PDAC samples from two independent cohorts of patients with radical resection. Moreover, C-FOXP3 was colocalized and correlated with the expression of PD-L1 in tumor cells at the mRNA and protein levels, and this finding was confirmed by the The Cancer Genome Atlas (TCGA) database. Chromatin immunoprecipitation (ChIP) revealed that C-FOXP3 directly bound to the promoter region of PD-L1 in pancreatic cancer cells. Furthermore, overexpression of C-FOXP3 activated the luciferase reporter gene under the control of the PD-L1 promoter. However, mutation of the binding motif-a completely reversed the luciferase activity. In addition, C-FOXP3-induced upregulation of PD-L1 effectively inhibited the activity of CD8+ T cells. Based on our recent finding that the CCL-5 antibody achieved a better response to PDAC models with high C-FOXP3 levels, we further demonstrated that the PD-L1 antibody strengthened the antitumor effect of CCL-5 blockade in xenograft and orthotopic mouse models with high C-FOXP3 levels. In conclusion, C-FOXP3 directly activates PD-L1 and represents a core transcription factor that mediates the immune escape of PDAC. Combined blockade of PD-L1 and CCL-5 may provide an effective therapy for patients with PDAC that have high C-FOXP3 levels.

8059 Background: Lymphatic system cancer is characterized by high heterogeneity in histology and clinical manifestations, B-cell antigen receptor (BCR) plays a vital role in anti-tumor immune responses. This study aimed to compare the BCR repertoire and identify some specific immune markers for different pathological lymphomas. Methods: 5 pathological types of non-Hodgkin's lymphoma (T-LBL/ALL, PTCL-NOS, B-MCL, B-FL, DLBCL) were collected, with reactive lymph node (RLN) hyperplasia as control. All patients were tested by high-throughput immunohistochemical sequencing (HTS-IR) to analyze the correlation between B-cell immunohistochemistry and clinical indicators, and constructed new strategy typing and overall survival (OS) predicted models for lymphomas. Results: The BCR repertoire had the highest diversity in RLN, followed by T-LBL/ALL, PTCL-NOS, DLBCL, B-MCL and B-FL. The diversity of BCR repertoire and similarity of B cell antigens were higher in B-MCL and B-FL patients. Similar to RLN, T-LBL/ALL and PTCL-NOS had broad and diverse V-J pairs, and rare in B-MCL, B-FL and DLBCL. RLN patients were with the highest average number of amino acids, followed by T-LBL/ALL, DLBCL, PTCL-NOS, B-MCL and B-FL. The expressed amino acid sequencing of ARDLIALDY, ARRPGSFDY, ARDIAGWGAVAGLLGRAYYGMDV, and ARDGPYGGNSVEYFQH were markedly different among 5 groups. Patients tended to recurrence expressed ASLDSSPSGFC, ARGMTTVTTAPNY, ARVPLYDDQNINDV and AGGVGGYDWGSYYFDY (P = 0.01605, 0.02869, and 0.01569), and prone to metastasis with expressions of ARVKEFYGILTGYDY, AHSIIGSSWYNWFDP and VRDGGWQSNNWLGFDV (P = 0.04259, 0.0450 and 0.0481). For all patients, 18 (7 negative, 11 positive) and 12 (10 negative, 2 positive) IGH V-J pairs were respectively associated with lymphoma recurrence and metastasis. The top 3 most significant pairs were IGHV7-4-1_IGHJ4, IGHV3-53_IGHJ5 and IGHV3-7_IGHJ5 bound up with recurrence (P = 0.0019, 0.0020 and 0.0021), and IGHV3-74_IGHJ1, IGHV1-69_IGHJ3 and IGHV1-2_IGHJ1 related to metastasis (P = 0.0022, 0.010 and 0.019). The accuracy of typing model in training and test sets was 78.125% (25/32) and 60% (6/10), respectively. The OS model can predict long (≥ 24 months) or short ( < 24 months) OS. Conclusions: Our study identified new biomarkers, constructed novel lymphoma typing model and OS predicted model based on B cell repertoire. It provides a comprehensive understanding of immune response, and contributes to the diagnosis and prognosis of non-Hodgkin's lymphoma.

e16113 Background: Like most cancers, early diagnosis of colorectal cancer (CRC) contributes to a good prognosis. Recently, some studies indicated that mutation gene signatures have good performances in predicting the treatment and prognosis in CRC patients. However, incomplete understanding of the genotype is not conducive to proper treatment. The objective was to give further genetic insights into CRC and provide more comprehensive references for clinical practice. Methods: In the training group, the whole genome sequencing (WGS), clinical, and demographic data of 531 patients were downloaded from The Cancer Genome Atlas (TCGA). The validation group contained 53 patients, which were collected in Tianjin Medical University Cancer Institute and Hospital (Tianjin, China) from April 2014 to November 2018. The fresh tissues collected within 24 hours after operation were used to extract genomic DNA, and then sequenced with targeted next-generation sequencing (NGS) technology to examine somatic mutations and analyze relevant gene concerning clinical indicators. The correlation between gene variation distribution and various indexes such as cancer species, stage, total survival period, sex, age and race were evaluated. Results: A total of 44 mutant genes with mutation frequencies above 5% were found in both TCGA cases and validated cases. Mutations of TP53, APC, KRAS, BRAF and ATM covered 97.55% of TCGA population and 83.02% validation patients, which were proved to be associated with the development of CRC and could be used as a diagnostic signature. Importantly, mutations of TP53, PIK3CA, FAT4, FMN2 and TRRAP had a remarkable difference between early (I/II) and advanced (III/IV) stage patients (P < 0.0001). Besides, we also confirmed that PIK3CA, LRP1B, FAT4 and ROS1 were a mutated gene signature for the prognosis, LRP1B portended to a higher of recurrence and shorter progression-free survival (PFS); mutation of FAT4 portended to a lower of recurrence and longer PFS, which could predict the recurrence and survival of CRC patients. Conclusions: We have indicated gene mutation signatures related to the diagnosis, pathological classification, staging and prognosis in CRC, which provides further insights into the study of CRC genotype. It is helpful to further improve the personalized diagnosis and treatment.

e21652 Background: EGFR-TKI application is directed by the situation of mutations of epidermal growth factor receptor, in addition, the mutations of ALK, ROS-1,C-met, BRAF, Her-2, RET,NTRK1, PI3K, MEKI have potential effects on guiding treatment. This study aimed to investigate the uncommon and insensitive mutations and their effect on prognosis in non-small cell lung cancer (NSCLC) patients treated with EGFR-TKI. Methods: 21 NSCLC patients treated with EGFR-TKIs were enrolled, 9 with Gefitinib, 5 with Osimertinib and 7 with Icotinib. All patients were detected with targeted NGS 1000 gene panel. Afterwards, the EGFR sensitive mutation, uncommon mutation and mutations accompanied EGFR T790M were analyzed. Furthermore, the correlations of gene mutation with metastasis, OS and PFS were analyzed. SPSS 21.0 was used for statistical analysis, t test for continuous variables and χ2 test for classified variables. Results: In all the patients, EGFR p.[T790M] and p.[L858R] mutations were detected in 4.76% and 23.81% of the patients, respectively. In the 5 patients treated with Osimertinib, one had EGFR p.[T790M] mutation and curative effects was stable disease (SD). The mutations accompanied EGFR T790M included SMARCA4 p.[K1390Q] (2.23%), DNMT3A p.[F755S] (2.17%), MTOR p.[Y1450*] (2.15%), TPMT p.[L182R] (1.84%), etc. For the other four patients treated with Osimertinib, two of them were partial response (PR) and two were SD, accompanied with mutations such as EGFR p.[L858R] (55.00%), ARID1A p.[P16del] (2.83%), TP53 p.[R248W] (21.73%) and AR p.[Q60L] (4.24%). In addition, among all the mutations, 18 uncommon mutations were detected, in which ATM (23.26%), AR (23.26%) and MTOR (37.21%) were markedly associated with OS. Besides, the mutation frequency of 67 genes, such as ABCG2, AURKA, EPHA3 and ATR were correlated with OS. The mutation frequency of FGFR1 was significantly different between the patients with and without metastasis. The mutations of 22 genes, for instance ABCG2 p.[P21L], FAT1 p.[L398F], GNAS p.[F226V] and KMT2C p.[N2842Ilefs], were correlated with PFS during the treatment. Conclusions: EGFR-TKI has similar curative effects in EGFR p.[T790M] negative patients. Gene mutations, including uncommon mutations and EGFR insensitive mutations, can significantly affect the prognosis in NSCLC patients treated with EGFR-TKIs.