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Numerous studies in hepatocellular carcinoma (HCC) have proposed tissue-based gene signatures for individualized prognostic assessments. Here, we develop a novel circulating tumor cell (CTC)–based transcriptomic profiling assay to translate tissue-based messenger RNA (mRNA) signatures into a liquid biopsy setting for noninvasive HCC prognostication. The HCC-CTC mRNA scoring system combines the NanoVelcro CTC Assay for enriching HCC CTCs and the NanoString nCounter platform for quantifying the HCC-CTC Risk Score (RS) panel in enriched HCC CTCs. The prognostic role of the HCC-CTC RS was assessed in The Cancer Genome Atlas (TCGA) HCC cohort (n = 362) and validated in an independent clinical CTC cohort (n = 40). The HCC-CTC RS panel was developed through our integrated data analysis framework of 8 HCC tissue-based gene signatures and identified the top 10 prognostic genes (discoidin domain receptor tyrosine kinase 1 [DDR1], enoyl-CoA hydratase and 3-hydroxyacyl CoA dehydrogenase [EHHADH], androgen receptor [AR], lumican [LUM], hydroxysteroid 17-beta dehydrogenase 6[HSD17B6], prostate transmembrane protein, androgen induced 1 [PMEPA1], tsukushi, small leucine rich proteoglycan [TSKU], N-terminal EF-hand calcium binding protein 2 [NECAB2], ladinin 1 [LAD1], solute carrier family 27 member 5 [SLC27A5]) highly expressed in HCC with low expressions in white blood cells. The panel accurately discriminated overall survival in TCGA HCC cohort (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.4-2.9). The combined use of the scoring system and HCC-CTC RS panel successfully distinguished artificial blood samples spiked with an aggressive HCC cell type, SNU-387, from those spiked with PLC/PRF/5 cells (P = 0.02). In the CTC validation cohort (n = 40), HCC-CTC RS remained an independent predictor of survival (HR, 5.7; 95% CI, 1.5-21.3; P = 0.009) after controlling for Model for End-Stage Liver Disease score, Barcelona Clinic Liver Cancer stage, and CTC enumeration count. Our study demonstrates a novel interdisciplinary approach to translate tissue-based gene signatures into a liquid biopsy setting. This noninvasive approach will allow real-time disease profiling and dynamic prognostication of HCC.

Background Recent trends of hepatocellular carcinoma (HCC) mortality and outcome remain unknown in the United States. We investigated the recent trends of primary liver cancer (excluding intrahepatic cholangiocarcinoma) mortality and HCC stage, treatment, and overall survival (OS) in the United States. Methods The National Center for Health Statistics Database was analyzed to investigate the trend of primary liver cancer mortality. We analyzed the Surveillance, Epidemiology, and End Results 18 Database to assess the temporal trend of tumor size, stage, treatment, and OS of HCC. We investigated the association between HCC diagnosis year and OS using Cox regression analysis. All statistical tests were 2-sided. Results During 2000-2018, liver cancer mortality rates increased until 2013, plateaued during 2013-2016 (annual percent change = 0.1%/y, 95% confidence interval [CI] = −2.1%/y to 2.4%/y, P = .92), and started to decline during 2016-2018 (annual percent change = −1.5%/y, 95% CI = −3.2%/y to 0.2%/y, P = .08). However, mortality continues to increase in American Indian and Alaska Native, individuals aged 65 years or older, and in 33 states. There was a 0.61% (95% CI = 0.53% to 0.69%, P Conclusions Primary liver cancer mortality rates have started to decline in the United States with demographic and state-level variation. With an increasing detection of localized HCC, the OS of HCC has improved over the past decades.

Curative surgical treatments afford the best prognosis for patients with intrahepatic cholangiocarcinoma (iCCA); however, the comparative effectiveness of treatment options and factors associated with curative treatment receipt for early stage iCCA remain unknown.The authors identified patients who were diagnosed with early stage iCCA, defined as a unifocal tumor3 cm, during 2004-2018 from the National Cancer Database. Multivariable logistic and Cox regression analyses were used to identify the factors associated with curative treatment and overall survival (OS), respectively.The proportion of patients with early stage iCCA increased from 4.5% in 2004 to 7.3% in 2018, with the odds of early stage detection increasing by 3.1% per year (odds ratio [OR], 1.031; 95% CI, 1.015-1.049). Of 1093 patients who had early stage iCCA, 464 (42.5%) underwent resection, 113 (10.3%) underwent ablation, 62 (5.7%) underwent liver transplantation, and 454 (41.5%) received noncurative treatments. Hispanic patients (adjusted OR [aOR], 0.57; 95% CI, 0.33-0.97) and Black patients (aOR, 0.47; 95% CI, 0.28-0.77) were less likely to receive curative treatments than White patients. Compared with patients who underwent surgical resection, those who underwent liver transplantation had a trend toward improved OS (adjusted hazard ratio [aHR], 0.63; 95% CI, 0.37-1.08), whereas those who underwent local ablation (aHR, 1.39; 95% CI, 1.01-1.92) and noncurative treatments (aHR, 3.97; 95% CI, 3.24-4.88) experienced worse OS.More than one third of patients with early stage iCCA did not receive curative treatment, with Hispanic and Black patients being less likely to receive curative treatments than White patients. Surgical resection and liver transplantation were associated with improved survival compared with local ablation. Future studies should investigate disparities in curative treatment receipt and outcomes for early stage iCCA.

We report a covalent chemistry-based hepatocellular carcinoma (HCC)-specific extracellular vesicle (EV) purification system for early detection of HCC by performing digital scoring on the purified EVs. Earlier detection of HCC creates more opportunities for curative therapeutic interventions. EVs are present in circulation at relatively early stages of disease, providing potential opportunities for HCC early detection. We develop an HCC EV purification system (i.e., EV Click Chips) by synergistically integrating covalent chemistry-mediated EV capture/release, multimarker antibody cocktails, nanostructured substrates, and microfluidic chaotic mixers. We then explore the translational potential of EV Click Chips using 158 plasma samples of HCC patients and control cohorts. The purified HCC EVs are subjected to reverse-transcription droplet digital PCR for quantification of 10 HCC-specific mRNA markers and computation of digital scoring. The HCC EV-derived molecular signatures exhibit great potential for noninvasive early detection of HCC from at-risk cirrhotic patients with an area under receiver operator characteristic curve of 0.93 (95% CI, 0.86 to 1.00; sensitivity = 94.4%, specificity = 88.5%)., Extracellular vesicles (EVs) are present in circulation at relatively early stages of disease, providing potential opportunities for early cancer diagnosis. Here, the authors report a covalent chemistry-based hepatocellular carcinoma (HCC)-specific EV purification system for early detection of HCC by performing digital scoring on the purified EVs.

Rationale: Our objective was to develop a circulating tumor cell (CTC)-RNA assay for characterizing clinically relevant RNA signatures for the assessment of androgen receptor signaling inhibitor (ARSI) sensitivity in metastatic castration-resistant prostate cancer (mCRPC) patients. Methods: We developed the NanoVelcro CTC-RNA assay by combining the Thermoresponsive (TR)-NanoVelcro CTC purification system with the NanoString nCounter platform for cellular purification and RNA analysis. Based on the well-validated, tissue-based Prostate Cancer Classification System (PCS), we focus on the most aggressive and ARSI-resistant PCS subtype, i.e., PCS1, for CTC analysis. We applied a rigorous bioinformatic process to develop the CTC-PCS1 panel that consists of prostate cancer (PCa) CTC-specific RNA signature with minimal expression in background white blood cells (WBCs). We validated the NanoVelcro CTC-RNA assay and the CTC-PCS1 panel with well-characterized PCa cell lines to demonstrate the sensitivity and dynamic range of the assay, as well as the specificity of the PCS1 Z score (the likelihood estimate of the PCS1 subtype) for identifying PCS1 subtype and ARSI resistance. We then selected 31 blood samples from 23 PCa patients receiving ARSIs to test in our assay. The PCS1 Z scores of each sample were computed and compared with ARSI treatment sensitivity. Results: The validation studies using PCa cell line samples showed that the NanoVelcro CTC-RNA assay can detect the RNA transcripts in the CTC-PCS1 panel with high sensitivity and linearity in the dynamic range of 5-100 cells. We also showed that the genes in CTC-PCS1 panel are highly expressed in PCa cell lines and lowly expressed in background WBCs. Using the artificial CTC samples simulating the blood sample conditions, we further demonstrated that the CTC-PCS1 panel is highly specific in identifying PCS1-like samples, and the high PCS1 Z score is associated with ARSI resistance samples. In patient bloods, ARSI-resistant samples (ARSI-R, n=14) had significantly higher PCS1 Z scores as compared with ARSI-sensitive samples (ARSI-S, n=17) (Rank-sum test, P=0.003). In the analysis of 8 patients who were initially sensitive to ARSI (ARSI-S) and later developed resistance (ARSI-R), we found that the PCS1 Z score increased from the time of ARSI-S to the time of ARSI-R (Pairwise T-test, P=0.016). Conclusions: Using our new methodology, we developed a first-in-class CTC-RNA assay and demonstrated the feasibility of transforming clinically-relevant tissue-based RNA profiling such as PCS into CTC tests. This approach allows for detecting RNA expression relevant to clinical drug resistance in a non-invasive fashion, which can facilitate patient-specific treatment selection and early detection of drug resistance, a goal in precision oncology.

Simple Summary Extracellular vesicles (EVs) are particles naturally released from cells and mediate intercellular communication. Recently, emerging studies have shown that EVs play a crucial role in regulating progression of hepatocellular carcinoma (HCC), which is one of the leading causes of cancer-related death worldwide. With the advances of technologies in isolating EVs from patients’ blood, EVs are regarded as promising biomarkers for detecting HCC at an earlier stage. This review provides an overview of the current EVs isolation methods, the biological roles of EVs in mediating disease progression, and the feasibility of EVs’ use for detection of HCC. Abstract Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and one of the leading causes of cancer-related death worldwide. Despite the improvements in surveillance and treatment, the prognosis of HCC remains poor. Extracellular vesicles (EVs) are a heterogeneous group of phospholipid bilayer-enclosed particles circulating in the bloodstream and mediating intercellular communication. Emerging studies have shown that EVs play a crucial role in regulating the proliferation, immune escape, and metastasis of HCC. In addition, because EVs are present in the circulation at relatively early stages of disease, they are getting attention as an attractive biomarker for HCC detection. Over the past decade, dedicated efforts have been made to isolate EVs more efficiently and make them useful tools in different clinical settings. In this review article, we provide an overview of the EVs isolation methods and highlight the role of EVs as mediators in the pathogenesis and progression of HCC. Lastly, we summarize the potential applications of EVs in early-stage HCC detection.

e17004 Background: Optimizing outcomes in prostate cancer (PCa) requires timely detect of metastatic progression of prostate cancer patients. We aim to optimize an extracellular vesicle (EV)-based Digital Scoring Assay for detecting PCa metastasis and noninvasive monitoring disease progression. Methods: PCa EV Digital Scoring Assay was developed by combining EV Click Chip, a nanotechnology-enabled microfluidic device for purifying PCa-derived EV and reverse-transcription droplet digital PCR for profiling disease-relevant mRNAs. A panel of 11 PCa-relevant mRNA markers were selected from The Tissue Atlas and a blood-based biomarker study. Plasma samples from 20 localized, 20 metastatic PCa patients, and serial plasma from three PCa patients were used to assess the performance of PCa EV Digital Scoring Assay with the 11-gene panel. mRNA expression of the panel was computed using weighted Z score method. ROC analysis was applied to discriminate localized from metastatic PCa. Results: After optimization, the capability of EV Click Chips (92.5 ± 5.4%) for capturing PCa-derived EVs from artificial plasma samples spiked with EVs outperformed ultracentrifugation (41.0 ± 3.2%) or precipitation methods (34.9± 2.2%; P< 0.001). Strong signals of the 11-gene panel, i.e., ACP3, FOLH1, HOXB13, KLK2, KLK3, KLK4, MSMB, RLN1, SLC45A3, STEAP2, and TMPRSS2, were detected from three PCa cells (LNCaP, C4-2B, and 22Rv1) and their derived EVs, while rare signals were detected in either WBCs or EVs purified from male healthy donor. In the clinical study, the Z scores calculated from the 11-gene panel were significantly higher in metastatic than localized PCa with an area under the ROC curve of 0.88 (95% CI: 0.78-0.98). Finally, longitudinal analyses of three PCa patients with clinical progression, response, and stable diseases, respectively, showed the Z scores can precisely reflect the disease status even when it is undetectable by imaging. Conclusions: We demonstrate a sensitive PCa EV Digital Scoring Assay to identify metastatic PCa and dynamically monitor disease states in a noninvasive manner. This assay may augment current imaging tools for timely detection of PCa progression and provide a means to better personalized care.

Determining the status of epidermal growth factor receptor (EGFR) T790M mutation is crucial for guiding further treatment intervention in advanced non-small cell lung cancer (NSCLC) patients who develop acquired resistance to initial EGFR tyrosine kinase inhibitor (TKI) treatment. Circulating tumor cells (CTCs) which contain plentiful copies of well-preserved RNA offer an ideal source for noninvasive detection of T790M mutation in NSCLC. We developed a CTC-based digital assay which synergistically integrates NanoVelcro Chips for enriching NSCLC CTCs and reverse-transcription droplet digital PCR (RT-ddPCR) for quantifying T790M transcripts in the enriched CTCs. We collected 46 peripheral arterial and venous blood samples from 27 advanced NSCLC patients for testing this CTC-based digital assay. The results showed that the T790M mutational status observed by the CTC-based digital assay matched with those observed by tissue-based diagnostic methods. Furthermore, higher copy numbers of T790M transcripts were observed in peripheral arterial blood than those detected in the matched peripheral venous blood. In short, our results demonstrated the potential of the NanoVelcro CTC-digital assay for noninvasive detection of the T790M mutation in NSCLC, and suggested that peripheral arterial blood sampling may offer a more abundant CTC source than peripheral venous blood in advanced NSCLC patients.

182 Background: There is an unmet need to develop a noninvasive assay to detect the metastatic progression of prostate cancer (PCa) patients for timely treatment. We aim to optimize an extracellular vesicle (EV)-based Digital Scoring Assay to reflect the disease status of PCa. Methods: PCa EV Digital Scoring Assay integrated a PCa-derived EV purification device (i.e., EV Click Chip) and downstream reverse-transcription droplet digital PCR for transcriptomic profiling of PCa-derived EVs. The performance of the Assay for purifying PCa-derived EVs was assessed using artificial plasma samples with spiked EVs. In parallel, a panel of 11 PCa-relevant mRNA markers were selected and validated. PCa EV Digital Scoring Assay in conjugation with the 11-gene panel was tested using plasma from 20 localized, 20 metastatic PCa patients, and serial plasma from three PCa patients. mRNA expressions were computed using weighted Z score method. ROC analysis was utilized to distinguish localized from metastatic PCa. Results: After optimization, the capability of purifying PCa-derived EVs from artificial plasma samples by EV Click Chips (92.5 ± 5.4%) outperformed ultracentrifugation or precipitation methods (41.0 ± 3.2%; 34.9± 2.2%; P < 0.001). Eleven genes, i.e., ACP3, FOLH1, HOXB13, KLK2, KLK3, KLK4, MSMB, RLN1, SLC45A3, STEAP2, and TMPRSS, were selected using The Tissue Atlas and a gene set from a blood-based study as our panel. Strong signals of the panel were detected from three PCa cells (LNCaP, C4-2B, and 22Rv1) and their derived EVs, while rare signals were detected in either WBCs or EVs purified from male healthy donor. In the clinical study, the Z scores calculated from the selected 11-gene panel, were significantly higher in 20 metastatic PCa than 20 localized PCa with an area under the ROC curve of 0.88 (95% CI = 0.78-0.98). Lastly, longitudinal analyses of three PCa patients showed that the Z scores can reflect the clinical progression, response, and stable status, even when disease is undetectable by imaging. Conclusions: We develop a sensitive PCa EV Digital Scoring Assay to distinguish metastatic PCa and reveal the dynamic disease states in a noninvasive manner. This assay holds the potential to augment current imaging tools and tests for timely detection of PCa progression and improve care for patients.

e17008 Background: A morphological subset of prostate cancer (PCa) circulating tumor cells (CTCs) with particularly small nuclei (< 8.5 μm), named very-small-nuclear CTCs (vsnCTCs), were found to be correlated with the presence of visceral metastases. It is reported that the depletion of nuclear envelope protein emerin promotes PCa metastasis and is associated with nuclear shape instability. In this study, we hypothesize vsnCTCs as prognostic biomarkers in metastatic castration resistant PCa (mCRPC), and aim to investigate the correlation between emerin level and vsnCTCs. Methods: PCa CTCs were enriched using the NanoVelcro CTC Assay from 76 patients with mCRPC. The Kaplan-Meier analysis and log-rank test were used to estimate and compare the overall survival (OS) and progression free survival (PFS) of androgen receptor signaling inhibitor (ARSI), taxanes and other therapy in patients stratified by the presence of vsnCTCs. The correlation between the presence of vsnCTCs and OS and PFS were evaluated using the Cox proportional hazard regression. The expression level of emerin in patients with and without vsnCTC were compared using Mann-Whitney U test, and the correlation between emerin level and CTC nuclear size was tested by Pearson correlation coefficient. Results: Patients with vsnCTC (i.e, vsnCTC+) had significantly shortened OS and PFS compared with those without vsnCTC (i.e, vsnCTC-). The median OS was 34 (vsnCTC+, n= 49) vs. 149 (vsnCTC-, n= 27) weeks (hazard ratio [HR] = 2.6, 95% confidence interval [CI]: 1.5-4.5, P< 0.001). The median PFS was 12 (vsnCTC+, n= 32) vs. 26 (vsnCTC-, n= 18) weeks (HR = 2.2, 95% CI: 1.3 -4.0, P= 0.004). The emerin expression level was significantly higher in vsnCTC+ compared to vsnCTC- ( P= 0.009). In addition, we observed a significantly positive correlation between emerin expression and CTC nuclear size (r = 0.52, P< 0.001). Conclusions: This study casts light on the importance of the vsnCTCs in patients with mCRPC, as vsnCTC+ patients represented a group at risk for faster clinical progression who are at the highest risk for mortality. vsnCTC represents a new hallmark of an aggressive subtype of mCRPC and is related to emerin dysregulation, which promotes lethal progression and metastasis of PCa.

Transcriptomic profiling of tumor tissues introduces a large database, which has led to improvements in the ability of cancer diagnosis, treatment, and prevention. However, performing tumor transcriptomic profiling in the clinical setting is very challenging since the procurement of tumor tissues is inherently limited by invasive sampling procedures. Here, we demonstrated the feasibility of purifying hepatocellular carcinoma (HCC) circulating tumor cells (CTCs) from clinical patient samples with improved molecular integrity using Click Chips in conjunction with a multimarker antibody cocktail. The purified CTCs were then subjected to mRNA profiling by NanoString nCounter platform, targeting 64 HCC-specific genes, which were generated from an integrated data analysis framework with 8 tissue-based prognostic gene signatures from 7 publicly available HCC transcriptomic studies. After bioinformatics analysis and comparison, the HCC CTC-derived gene signatures showed high concordance with HCC tissue-derived gene signatures from TCGA database, suggesting that HCC CTCs purified by Click Chips could enable the translation of HCC tissue molecular profiling into a noninvasive setting.

167 Background: Circulating tumor cells (CTCs) have arisen as contemporary noninvasive prognostic biomarkers for prostate cancer (PCa). Previously, a subgroup of PCa CTCs, with particularly small nuclei ( < 8.5 μm), were found to be correlated with the presence of visceral metastases. This subgroup was named very-small-nuclear CTCs (vsnCTCs). We hypothesized vsnCTCs as a putative biomarker of a lethal subtype associated with androgen receptor (AR) indifference and nuclear shape instability in metastatic castration resistant PCa (mCRPC). Methods: CTCs in blood from 76 patients with mCRPC were analyzed using NanoVelcro CTC assay for CTC nuclear size measurement and CTC RNA profiling of AR-indifferent pathways. Overall survival (OS) and progression free survival (PFS) of androgen receptor signaling inhibitor (ARSI), taxanes and other therapy were correlated with CTC nuclear size using Kaplan-Meier analysis and Cox proportional hazards model. Emerin fluorescence intensity and localization from patients with and without vsnCTC were compared. RNA profiles of CTCs were scored using Prostate Cancer Subtype (PCS) classification system. The CTC-PCS scores from patients with and without vsnCTC were compared using Mann-Whitney test. To investigate the underlying biology of vsnCTC phenotype, the nuclear size, the nuclear sizes of ARSI-resistant and lineage plasticity PCa cell lines were measured and correlated with the expression levels of RNA related to ARSI-indifferent pathways and nuclear envelope protein Emerin. Results: Patients with vsnCTC (i.e., vsnCTC+) had significantly shortened OS and PFS compared with patients without vsnCTC (i.e., vsnCTC-). The median OS was 34 (vsnCTC+, n = 49) vs. 149 (vsnCTC-, n = 27) weeks (HR = 2.6 with 95% CI 1.5 to 4.5, p < 0.001). The median PFS was 12 (vsnCTC+, n = 32) vs. 26 (vsnCTC-, n = 18) weeks (HR = 2.2 with 95% CI 1.3 to 4.0, p = 0.004). CTC nuclear sizes were significantly smaller in patients with prior ARSI therapy. CTC-RNA analysis revealed that vsnCTC+ patients had a significant higher CTC-PCS1 Z score(n = 19) compared with vsnCTC- patients(n = 26)(p = 0.01). In the cell line models, nuclear sizes were significantly smaller in cell lines with ARSI-resistance(p = 0.002) and lineage plasticity (p = 0.006). Emerin expression is significantly lower in vsnCTC+ patients(p = 0.009) and ARSI-resistant cell lines(p = 0.03). Conclusions: This study casts light on the importance of the vsnCTC in patients with mCRPC, as vsnCTC+ patients represented a group at risk for faster clinical progression who are at the highest risk for mortality. This has potential importance in optimizing therapeutic choices. We posit that the vsnCTC represents a new hallmark of an aggressive subtype of mCRPC and is related to the cellular mechanism of AR-indifference and Emerin dysregulation, which promotes lethal progression of metastatic PCa.

Background: Genome and transcriptome-based analysis has begun to reshape the approach to prostate cancer (PC). Two different gene expression signatures have shown that PC can be divided into 3 subclasses reflecting luminal-basal biology. These subtypes point toward biological drivers that may strongly influence how care should be personalized including optimization of androgen receptor targeted therapy. The majority of work done in this area has been based on tissue-based gene expression. With the advent of newer nanotechnology platforms for isolation of circulating tumor cells (CTCs), profiling of PC gene expression from blood is now possible. Methods: We recruited 34 patients with metastatic castration resistant PC who had available blood specimens prior to initiation of androgen receptor signaling inhibitor (ARSI, e.g. abiraterone, enzalutamide and apalutamide) therapy. We combined variations of the NanoVelcro Assays (thermoresponsive, click-chemistry) allowing for capture and release of CTCs with intact mRNA. Gene sets from the PCS and PAM50 signatures were re-reviewed to optimize signal detection in the blood and enriched for genes upregulated in PC. The NanoString nCounter platform was applied to profile the resulting genes. A pilot study was conducted using banked samples available through the Urologic Oncology Program Blood and Biospecimen Bank at Cedars-Sinai Medical Center. Results: The final assay was tested in banked blood samples and provided classifications of patients that associated with clinical responsiveness to therapy. Validation was conducted to examine the performance of the CTC-specific PCS/PAM50 panel in public databases (including Prostate Cancer Transcriptome Atlas and GenomeDx). Our pilot study showed that the median overall survival was significantly worse in PCS1 patients. Conclusions: This study shows initial proof of principle that genomic classification in blood is possible using contemporary tool for blood component isolation and RNA profiling. Additional technical and clinical validations are needed prior to widespread implementation, but these methods may make it possible to increase the utilization of genomic classifiers in clinical studies and in practice. Citation Format: PAI-CHI TENG, Minhyung Kim, Yu Jen Jan, Jie-Fu Chen, Nu Yao, Gina C. Chu, Pin-Jung Chen, Jasmine J. Wang, Yi-Te Lee, Yazhen Zhu, Leland W. Chung, Felix Y. Feng, Michael R. Freeman, Sungyong You, Hsian-Rong Tseng, Edwin M. Posadas. Gene expression of circulating tumor cells is predictive of treatment response in patients with advanced prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5447.

Hepatocellular carcinoma (HCC) is the 4th most common cause of cancer-related deaths worldwide. The poor prognosis of HCC is due to the fact that diagnosis is often made at an advanced stage in disease development. It is crucial to develop a non-invasive liquid biopsy-based diagnostic solution for early detection of HCC. In this study, we developed a covalent chemistry-based nanostructured silicon substrate (“EV Click Chip”) for the isolation of HCC extracellular vesicles (EVs). The EV Click Chip leverages specific click chemistry reactions and sensitive multi-marker cocktail antibody identification of the HCC EVs. The EV Click Chip also allows for the subsequent release of the captured HCC EVs and is optimal for the downstream molecular analysis. A well-validated 10 liver-specific genes were quantified using reverse transcription droplet digital PCR (RT-ddPCR) in HCC EVs purified by the optimized EV Click Chips for the detection of HCC. Our EV Click Chip-based HCC-EV Assay is able to differentiate HCC from non-HCC controls (chronic liver diseases, healthy donors and other cancers) and outperformed clinical AFP test for distinguishing early-stage HCC from at-risk cirrhotic patients. Citation Format: Yi-Te Lee, Na Sun, Ryan Y. Zhang, Rueihung Kao, Pin-Jung Chen, Pai-Chi Teng, Jasmine J. Wang, Yingying Yang, Minhyung Kim, Edwin M. Posadas, Sungyong You, Ju Dong Yang, Vatche G. Agopian, Hsian-Rong Tseng, Yazhen Zhu. Purification and mRNA profiling of extracellular vesicles for early detection of hepatocellular carcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5436.

Background: Current risk stratification models in prostate cancer (PC) have been based on clinical and pathological variables. Beyond serum prostate-specific antigen (PSA) concentration measurements, there remain few new biomarkers to help identify patients at risk for poor clinical outcomes. Morphological analyses using Gleason scoring along with cell nuclear size and shape remains to be a fundamental pathological practice of PC that have been utilized to identify aggressive diseases and to associate with aggressive metastasis. In particular, changes in nuclear shape and composition have been associated with outcome in early stage disease. Circulating tumor cells (CTCs) have arisen as contemporary noninvasive prognostic biomarkers for PC. Previously, a subgroup of PC CTCs, with prominently small nuclei (< 8.5 μm), were found to be correlated with the presence of visceral metastases. This subgroup was named very-small-nuclear CTCs (vsnCTCs). We proposed vsnCTCs as a putative biomarker of a lethal subtype in metastatic castration resistant PC (mCRPC). Methods: In this study, 76 patients with mCRPC were recruited for overall survival (OS) analysis. Of the 76 patients, 50 had available pre-treatment blood specimens prior to the initiation of androgen receptor signaling inhibitor (ARSI, e.g. abiraterone and enzalutamide) or taxane or tyrosine kinase inhibitor therapy. Using the NanoVelcro CTC Enumeration Assay, CTCs were captured and subjected to immunofluorescence staining. CTCs were identified as DAPI+/CK+/CD45- with a round or oval nucleus. Additionally, CTC nuclear size was measured and defined as the square root of the product of the long axis and the short axis. Kaplan-Meier analysis and Cox proportional hazards model were conducted. Results: Patients with vsnCTC (i.e., vsnCTC+) had a significantly shortened OS compared with patients without vsnCTC (i.e., vsnCTC-). The median OS was 34 (vsnCTC+, n=49) vs. 149 (vsnCTC-, n=27) weeks (log-rank HR=2.6 with 95% CI 1.5 to 4.5, p=0.0006). Progression free survival (PFS) analysis was performed for the 50 patients with pre-treatment blood samples. The median PFS was 12 (vsnCTC+, n=32) vs. 26 (vsnCTC-, n=18) weeks (log-rank HR=2.2 with 95% CI 1.3 to 4.0, p=0.0038). We also found that the hazard ratio of overall survival increased significantly as the CTC nuclear size decreased using the p-spline plot. Conclusions: Our study showed that nuclear size reduction has importance in CTCs in a fashion similar to its utility in tissue. This study points toward the importance of the vsnCTC in patients with mCRPC, as vsnCTC+ patients represented a group at risk for faster clinical progression who are at the highest risk for morality. We posit that the vsnCTC represents a new hallmark of an aggressive subtype of mCRPC. This has potential importance in optimizing therapeutic choices. Citation Format: JASMINE J. WANG, Pai-Chi Teng, Yu Jen Jan, Jie-Fu Chen, Galen Cook-Wiens, Nu Yao, Gina C. Chu, Pin-Jung Chen, Yingying Yang, Yee Hui Yeo, Yi-Te Lee, Leland W. Chung, Sungyong You, Yazhen Zhu, Michael R. Freeman, Andre Rogatko, Ju Dong Yang, Hsian-Rong Tseng, Edwin M. Posadas. Nuclear size of circulating tumor cells is associated with prognosis in metastatic, castration-resistant prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4331.

e17509 Background: Genomic profiling has strongly impacted the contemporary understanding of prostate cancer (PCa). Clinical trials are now testing the utility of genomic classifiers such as the PCS (You, Ca Res 2016) and PAM50 (Zhao, JAMA Onc 2017) systems to optimize therapy selection. As contemporary tissue is not always readily available, especially in metastatic, castration-resistant PCa (mCRPC), a blood-based test would be better suited for assessing patients and predicting treatment response. Methods: The CTC-RNA assay combines the Thermoresponsive (TR)-NanoVelcro system with the NanoString nCounter platform. This allows for CTC purification and RNA analysis. Using a novel bioinformatics approach that accounts for differences in background signals between tissue and blood, we reconstructed the PCS and PAM50 panels to recapitulate both classifiers in this blood-based assay. A weighted Z-score and nearest centroid classifier were used to calculate gene expression and to assign PCS and PAM50 subtypes. Performance of the revised signatures and CTC-RNA assay was benchmarked on simulated spiked-blood specimens. An initial clinical test was performed using clinically annotated, banked blood specimens within the Translational Oncology Program Blood and Biospecimen Bank. Results: CTC-RNA profiles of C4-2B AR signaling inhibitor (ARSI)-resistant sublines were compared to parental C4-2B. C4-2B ARSI-resistant cells had significantly higher PCS1 Z scores, PCS1 probability, and basal probability compared to the parental C4-2B cells. Blood samples from 34 mCRPC patients prior to initiation of therapy with ARSIs (abiraterone, enzalutamide, or apalutamide) were then analyzed. Samples were classified as PCS1 (n = 3), PCS2 (n = 20), and PCS3 (n = 11); luminal A (n = 12), luminal B (n = 11), and basal (n = 11). The biochemical progression-free survival (bPFS) on ARSI and overall survival (OS) for PCS1/Basal vs. other are shown in the table. Conclusions: The CTC-RNA assay is capable of generating luminal-basal classifications such as those in the PCS and PAM50 systems. Given early data of these classifiers and their potential to guide therapeutic decisions, this approach may be useful as an alternative to biopsy to facilitate such decisions. Larger prospective studies will be needed to confirm and validate its clinical utility. [Table: see text]

e17512 Background: Very-small-nuclear circulating tumor cells (vsnCTCs) as a subset of CTCs with nuclear size < 8.5 μm associated with visceral metastases (VM) in advanced metastatic, castration-resistant prostate cancer (mCRPC). As VM predicts foreshortened survival, we hypothesized that vsnCTCs would be directly associated with poor overall survival (OS). Methods: Clinically annotated, blood samples from patients with mCRPC with survival follow-up within the Translational Oncology Program Blood & Biospecimen Bank were selected for analysis. CTCs were isolated and analyzed using the NanoVelcro assay. The nuclear size from all CTCs from each patient sample was compared to OS and progression-free survival (PFS) from the time of the blood draw. Results: A total of 76 patients had samples suitable for analysis. Sixty-six (87%) had CTCs; 49 (64%) were vsnCTC+ (≥1 vsnCTC). vsnCTCs were more common in mCRPC patients with previous androgen receptor signaling inhibitor (ARSI) therapy and/or 2 or more lines of treatment. OS was significantly shorter for vsnCTC+ than vsnCTC- patients (median 34 vs. 149 weeks; log-rank HR = 2.6; 95% CI = 1.5 to 4.5; P = 0.0006). Fifty patient samples were available for PFS analysis (i.e. drawn within 4 weeks of starting therapy). vsnCTC+ patients experienced more rapid progression than vsnCTC- patients (median 12 vs. 26 weeks, log-rank HR = 2.2, 95% CI = 1.3 to 4.0; P = 0.004). Multivariable Cox regression revealed that vsnCTC status was independently associated with OS and PFS. P-spline plot analysis showed that the HR of OS increased as the minimum CTC nuclear size decreased. The minimum CTC nuclear size was also independently associated with OS and PFS in a multivariable Cox regression analysis. Patients with prior use of androgen receptor signaling inhibitor (ARSI) therapy had significantly smaller minimum CTC nuclear size compared to those without prior use of ARSI. Average and median nuclear size did not strongly associate with OS or PFS. Conclusions: vsnCTC+ patients are at risk for more rapid clinical progression and have greater risk of death than vsnCTC-. We posit that the vsnCTC may be a biomarker of aggressive mCRPC with foreshortened survival. Interestingly, the CTCs with the smallest nuclei appear to best reflect the observed clinical behavior. This has potential importance in optimizing therapeutic choices and may point toward a unique biology relating nuclear size to aggressive molecular features. Our group continues to explore the biology underlying the vsnCTC.

168 Background: Circulating tumor cells (CTCs) have arisen as contemporary noninvasive prognostic biomarkers for prostate cancer (PC). Previously, a subgroup of PC CTCs, with particularly small nuclei (

170 Background: Transcriptome-based analysis has begun to reshape the approach to prostate cancer (PC). Two different gene expression signatures have shown that PC can be divided into 3 subclasses reflecting luminal-basal biology. These subtypes point toward biological drivers that may strongly influence how care should be personalized including optimization of androgen receptor targeted therapy. The majority of work done in this area has been based on tissue-based gene expression. With the advent of newer nanotechnology platforms for isolation of circulating tumor cells (CTCs), profiling of PC gene expression from blood is now possible. Methods: We recruited 34 patients with metastatic castration resistant PC at Cedars-Sinai Medical Center who had available blood specimens prior to initiation of androgen receptor signaling inhibitor (ARSI, e.g. abiraterone, enzalutamide and apalutamide) therapy.We utilized the NanoVelcro Assays which allow for capture and release of CTCs with intact mRNA. Gene sets from the PCS and PAM50 signatures were re-reviewed to optimize signal detection in the blood and enriched for genes upregulated in PC. The NanoString nCounter platform was used for RNA profiling. Results: The final assay was tested in banked blood samples and provided classifications of patients that associated with clinical responsiveness to therapy. Validation was conducted to examine the performance of the CTC-specific PCS/PAM50 panel in public databases (including Prostate Cancer Transcriptome Atlas and GenomeDx). Our pilot study showed that the median overall survival was significantly worse in PCS1 patients. Conclusions: This study shows initial proof of principle that genomic classification in blood is possible using contemporary tool for blood component isolation and RNA profiling. Additional technical and clinical validations are needed prior to widespread implementation, but these methods may make it possible to increase the utilization of genomic classifiers in clinical studies and in practice.