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Summary Background Therapeutic synergism between radiotherapy and immune checkpoint blockade has been observed in preclinical models of hepatocellular carcinoma. We aimed to study the safety and efficacy of sequential radioembolisation with yttrium-90-resin microspheres (Y90-radioembolisation) followed by nivolumab in patients with advanced hepatocellular carcinoma. Methods Patients with Child-Pugh A cirrhosis and advanced hepatocellular carcinoma not suitable for curative surgery were treated with Y90-radioembolisation followed by intravenous nivolumab 240 mg 21 days after Y90-radioembolisation and every 2 weeks thereafter. The primary endpoint, assessed in the per-protocol population, was the objective response rate, determined by RECIST version 1.1, defined as the proportion of patients with a confirmed complete or partial response observed for lesions both within and outside the Y90-radioembolisation field. This study is registered with ClinicalTrials.gov , NCT03033446 and has been completed. Findings 40 patients were enrolled, of whom 36 received Y90-radioembolisation followed by nivolumab. One (3%) patient had a complete response and ten (28%) had a partial response; the objective response rate was 30·6% (95% CI 16·4–48·1). The most common treatment-related adverse events of any grade were pruritus (18 [50%] of 36 patients) and maculopapular rash (13 [36%]). Two (6%) patients experienced grade 3–4 treatment-related adverse events: one patient had a grade 3 increase in alanine aminotransferase levels, grade 3 bilirubin increase, and grade 4 increase in aspartate aminotransferase levels, while the other had a grade 3 maculopapular rash. Five (14%) patients had a treatment-related serious adverse event (Steven-Johnson syndrome, hepatitis E infection, fever, liver abscesses, and ascites). Interpretation Y90-radioembolisation followed by nivolumab resulted in an encouraging objective response rate in patients with advanced hepatocellular carcinoma, although the activity observed was not as high as the study was powered for. This strategy should be further evaluated in patients with Barcelona Clinic Liver Clinic (BCLC) stage B hepatocellular carcinoma that is ineligible or refractory to transarterial chemoembolisation and patients with BCLC C disease without extrahepatic spread. Funding National Medical Research Council Singapore, Bristol-Myers Squibb, Sirtex.

Tumor-specific T cells likely underpin effective immune checkpoint-blockade therapies. Yet, most studies focus on Treg cells and CD8

Regulatory T cells (Tregs) are often enriched in tumors, where their immunosuppressive function has a key role in tumor persistence and progression. In colorectal cancer (CRC), however, Tregs are frequently associated with an improved clinical outcome. Tumor-infiltrating Tregs have been shown to exhibit a distinct signature comprising the co-stimulatory molecules (OX40, 4-1BB), cytokine receptors (IL1R2, IL21R, CCR8, CD30), and co-inhibitory molecules (PD-L1, TIGIT). Here, we showed by flow cytometry that circulating CD45RO+ Tregs from patients with CRC (n = 25) have elevated CD30 and OX40 expression compared to healthy subjects (n = 14). We identified co-expression of CD30 and OX40 on circulating CD45RO+ Tregs using single-cell images captured by the DEPArray™ system. The frequency of CD30+OX40+CD45RO+ Tregs was significantly higher in CRC patients than in healthy subjects (P +OX40+ Treg subset could strongly discriminate between CRC patients and healthy subjects with the highest accuracy of 92.3%, an AUC of 0.92, a sensitivity of 88%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 82.35%, and a trade-off value of 3.44%, compared to other Treg subsets. Consistently, multiplex-IHC/IF of tumor-infiltrating Tregs revealed a significant association between high densities of CD30+OX40+ Tregs and improved overall survival; no such association was found for other subsets. These data suggest a potential role for CD30+OX40+ Tregs as a diagnostic or prognostic biomarker in CRC.

The consensus molecular subtype (CMS) classification of colorectal cancer is based on bulk transcriptomics. The underlying epithelial cell diversity remains unclear. We analyzed 373,058 single-cell transcriptomes from 63 patients, focusing on 49,155 epithelial cells. We identified a pervasive genetic and transcriptomic dichotomy of malignant cells, based on distinct gene expression, DNA copy number and gene regulatory network. We recapitulated these subtypes in bulk transcriptomes from 3,614 patients. The two intrinsic subtypes, iCMS2 and iCMS3, refine CMS. iCMS3 comprises microsatellite unstable (MSI-H) cancers and one-third of microsatellite-stable (MSS) tumors. iCMS3 MSS cancers are transcriptomically more similar to MSI-H cancers than to other MSS cancers. CMS4 cancers had either iCMS2 or iCMS3 epithelium; the latter had the worst prognosis. We defined the intrinsic epithelial axis of colorectal cancer and propose a refined 'IMF' classification with five subtypes, combining intrinsic epithelial subtype (I), microsatellite instability status (M) and fibrosis (F). ispartof: NATURE GENETICS vol:54 issue:7 pages:963-+ ispartof: location:United States status: published

Background: The over-expression of CD73 has been linked to many cancers. NZV930, an investigational, CD73-targeting monoclonal antibody (mAb), forms bidentate structures with the CD73 dimer, shutting down the catalytic activity of cell surface and soluble CD73. Taminadenant is an investigational A2AR antagonist and spartalizumab is an anti-PD-1 mAb. Preclinical studies provide compelling antitumor activity when combining CD73, A2AR, and PD-1 blockade. Methods: This first-in-human study (NCT03549000) comprised dose-escalation and dose-expansion parts. Here, we present the dose-escalation results of the four treatment (tx) arms: NZV930 single agent (SA; 60-1000 mg Q2W), NZV930 (200-600 mg Q2W) + spartalizumab (400 mg Q4W) or taminadenant (80-240 mg Q2W), or in combination with spartalizumab (400 mg Q4W) + taminadenant (80-240 mg BID). Eligible pts had selected malignancies, and disease progression following standard therapy. Primary objectives included assessing safety and tolerability and determining the recommended dose for expansion (RDE) of NZV930 SA and its combinations. Secondary objectives were to determine efficacy, characterize the pharmacokinetics (PKs) of NZV930 SA and its combinations, and assess the immunogenicity of spartalizumab and NZV930. Biomarker tumor samples were obtained at screening, C2D1, and C4D1. Results: As of June 10, 2021, 105 pts were enrolled for dose escalation, including pts with CRC (n=63), ovarian cancer (n=15), pancreatic cancer (n=11), NSCLC (n=8), TNBC (n=5), RCC (n=2), and prostate cancer (n=1). Most pts (81%) had been treated with ≥3 lines of prior therapy. In total, 98 pts discontinued, mainly due to disease progression (72%); six were ongoing. At least one tx-related adverse event (TRAE) was reported by 89 pts (85%); these were mostly grade 1-2. A triad of headache, fever, and nausea/emesis was observed after the first infusion of NZV930. Most common TRAEs (≥30%) were headache (67%), nausea and vomiting (32% each), and pyrexia (30%). At least one grade ≥3 TRAE was reported in 15 pts (14%); headache (4%) was most common, accounting for 4/7 DLTs (all grade ≥3). There were no tx-related deaths. Overall, no responses were reported; 12 pts (11%) had stable disease and 69 pts (66%) had progressive disease. NZV930 has good PK properties, with target-mediated drug disposition at lower doses, which normalize to typical IgG-like PKs at higher doses. Biomarker data confirm CD73 target engagement in plasma. Adenosine pathway modulation in tumors and plasma was seen post-NZV930 tx. Conclusions: NZV930 reduced adenosine levels in plasma and tumors. The RDE of NZV930 SA or in combination with spartalizumab and/or taminadenant is 600 mg Q2W with a step-up dosing regimen. NZV930 SA and its combinations exhibited a tolerable safety profile in multiple advanced solid tumors and showed good PK properties. Citation Format: Siqing Fu, Udai Banerji, Philippe L. Bedard, Aitana Calvo Ferrándiz, Alberto Chiappori, Jayesh Desai, Rahima Jamal, Desamparados Roda Perez, Noboru Yamamoto, Erica Vieira, Gabrielle Wong, Kulandayan K. Subramanian, Shunguang Wang, Britta Mueller, Javier A. Otero, Si-Lin Koo. A phase I/Ib study of the safety and preliminary efficacy of NZV930 alone and in combination with spartalizumab and/or taminadenant in patients (pts) with advanced malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT503.

Proposed short titleY90-Resin Microspheres Radioembolization Followed by Nivolumab in Advanced Hepatocellular CarcinomaBackground : Nivolumab (N) and Y90-resin microspheres radioembolization (Y90-RE) aretherapeutic options in advanced hepatocellular carcinoma (aHCC). Emerging evidence suggests synergy between radiotherapy and immune checkpoint inhibitors. Methods : Eligible Child-Pugh A aHCC patients were treated with Y90-RE followed by N 240mg, 21 days after Y90-RE and every 2 weeks thereafter. Pre- and on-treatment tumor biopsies were obtained. Primary end-point was overall response rate (ORR) (RECIST v1·1), defined as the composite overall response observed for lesions both within and outside Y90-RE field. Secondary end points included progression free survival (PFS), overall survival (OS), and safety. This study is registered with ClinicalTrials.gov, NCT03033446 .Findings : Forty patients were enrolled, 36 received Y90-RE followed by N. At baseline: 61·1% had hepatitis B; 66·7% BCLC stage C; 50·0% had AFP > 400ng/mL; median number of liver lesions was 5 (range 1- >20); median size of largest liver lesion was 78·5 mm (range 14-177mm); 38·9% had prior TACE/RFA/MWA; and 12·5% had prior systemic therapy. ORR was 30·6% (16·4% to 48·1%). ORR was 43·5% in patients with no extra-hepatic spread (EHS) (n=23). 81% of target lesions within Y90-RE field regressed. Median PFS and OS were 5·6 months (95% CI 2·1 to 8·8 months) and 16.9 months (95% CI 8·1 to 27·6 months). Treatment was well tolerated with only 13·8% experiencing grade (G) 3/4 treatment related adverse events (TRAEs). Immune activation predicted response to Y90-RE followed by N. Interpretation : Y90-RE followed by N resulted in an encouraging ORR of 30·6% in aHCC and of 43·5% in subjects with no EHS. 81% of target lesions within Y90-RE field regressed suggesting synergy. Importantly, this combination is safe and tolerable with low G 3/4 TRAEs of 13·8%. Trial Registration: NCT number: NCT03033446 Funding: Funding for this study was acquired from National Medical Research Council Singapore (NMRC/CIRG/1454/2016), Bristol-Myers Squibb (BMS), and SIRTEX Declaration of Interest: David Tai All support for the present manuscript (e.g., funding, provision of study materials, medical writing, article processing charges, etc.): BMS, SIRTEX, NMRC Singapore (CIRG/1470/2017) Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: IPSEN, Eisai, BMS Consulting fees: Novartis, BMS, MSD Choo Su Pin Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Roche, BMS, Ipsen, Lilly, AZ, Roche. Consulting fees: BMS, Roche, Ipsen, Servier, Eisai, AstraZeneca. Leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid: MOH Medishield Life Cancer Drug committee Stock or stock options: BMS David Ng All support for the present manuscript (e.g., funding, provision of study materials, medical writing, article processing charges, etc.): SIRTEX Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: SIRTEX Joycelyn Lee Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: BMS, IPSEN, Bayer Research Funding: Bayer Pierce K.H. Chow Grants or contracts from any entity: Sirtex Medical, Ipsen, IQVIA, New B Innovation, Perspectum, AMiLi, MiRXES, Genentech, Engine Biosciences. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Sirtex Medical, Ipsen, Oncosil, Bayer, Roche, New B Innovation, MSD, BTG PLC, Eisai, Abbott, AZ, IQVIA, Genentech, Worrell Guerbet, LEK Consulting, COR2ED. Leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid: AVATAMED Stock or stock options: AVATAMED Too Chow Wei Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: SIRTEX Consulting fees: SIRTEX Ethical Approval: All patients provided written informed consent and the institutional review board committee approved the protocol (Singhealth IRB Ref No. 2016/2613). The study was done in accordance with the Declaration of Helsinki and Good Clinical Practice.

Tumor-specific T cells likely underpin effective immune checkpoint-blockade therapies. Yet, most studies focus on Treg cells and CD8+tumor-infiltrating lymphocytes (TILs). Here we study CD4+TILs in human lung and colorectal cancers and observe that non-Treg CD4+TILs average more than 70% of total CD4+TILs in both cancer types. Leveraging high dimensional analyses including mass cytometry and single-cell sequencing, we reveal that CD4+TILs are heterogeneous at both gene and protein levels, within each tumor and across patients. Consistently, we find different subsets of CD4+TILs showing characteristics of effectors, tissue resident memory (Trm) or exhausted cells (expressing PD-1, CTLA-4 and CD39). In both cancer types, the frequencies of CD39−non-Treg CD4+TILs strongly correlate with frequencies of CD39−CD8+TILs, which we and others have previously shown to be enriched for cells specific for cancer-unrelated antigens (bystanders).Ex-vivo, we demonstrate that CD39−CD4+TILs can be specific for cancer unrelated antigens, such as HCMV epitopes. Overall, our findings highlight that CD4+TILs cells are not necessarily tumor-specific and suggest measuring CD39 expression as a straightforward way to quantify or isolate bystander CD4+T cells.Graphical abstract

Summary Growing evidence indicates a role for the gut microbiota in modulating anti-tumor treatment efficacy in human cancer. Here we study mucosa-associated invariant T (MAIT) cells to look for evidence of bacterial antigen recognition in human colon, lung, and kidney carcinomas. Using mass cytometry and single-cell mRNA sequencing, we identify a tumor-infiltrating MAIT cell subset expressing CD4 and Foxp3 and observe high expression of CD39 on MAIT cells from colorectal cancer (CRC) only, which we show in vitro to be expressed specifically after TCR stimulation. We further reveal that these cells are phenotypically and functionally exhausted. Sequencing data show high bacterial infiltration in CRC tumors and highlight an enriched species, Fusobacteria nucleatum, with capability to activate MAIT cells in a TCR-dependent way. Our results provide evidence of a MAIT cell response to microbial antigens in CRC and could pave the way for manipulating MAIT cells or the microbiome for cancer therapy., Graphical Abstract, Highlights Comprehensive profiling of tumor-infiltrating MAIT cells in colorectal cancer (CRC) Identification of a tumor-infiltrating MAIT cell subset expressing CD4 and Foxp3 TCR-driven CD39 expression is enriched in tumor-infiltrating MAIT cells CRC-related Fusobacterium nucleatum can activate MAIT cells in a TCR-dependent way, By investigating human colon, lung, and kidney carcinomas, Li et al. propose MAIT cells as part of the missing link between the gut microbiota and tumor biology. This work will open new avenues in cancer therapy by manipulating MAIT cells or MAIT-related bacterial ligands in the context of microbiota-influenced cancers.

In recent years, the impressive number of cancer immunotherapy drugs approved has been unprecedented—building on over a century of understanding on how the immune system combats cancer, and how cancer evades it. Leading the charge are the immune checkpoint inhibitor monoclonal antibodies, and adoptive cell therapy with chimeric-antigen-receptor (CAR)-T cell therapy. These breakthrough therapies have led to improved survival in patients with many advanced cancers. Some of the clinical outcomes have been striking, and may even be potentially curative in some terminal cancer patients. While immune checkpoint inhibitors work by blocking regulatory immune checkpoint signals between cancer and the immune cells to awaken an effective anticancer immunity, CAR-T cell therapy targets specific molecules on cancer cells. Tumour antigens as cancer targets take many forms and may not necessarily be proteins related to known functional cellular mechanisms. The convergence of cutting edge omics, bioinformatics, protein synthesis, immunobiology and immunotherapy have led to novel, potentially highly effective cancer targeting against neoantigens, hence reviving the quest for anticancer vaccines. Early clinical trials of neoantigen vaccines have provided proof-of-principle efficacy, especially in melanoma patients. Combinations of immunotherapies through rational design are underway aiming to further improve clinical outcomes. Moving forward, cancer immunotherapy will gain even more momentum from the discovery of more cancer targets—both on the cancer itself and in the tumour microenvironment as well as the identification of biomarkers of treatment resistance and efficacy. Key words: Checkpoint inhibitor, Microenvironment, Neoantigens, Vaccine

Various forms of immunotherapy, such as checkpoint blockade immunotherapy, are proving to be effective at restoring T cell-mediated immune responses that can lead to marked and sustained clinical responses, but only in some patients and cancer types1–4. Patients and tumours may respond unpredictably to immunotherapy partly owing to heterogeneity of the immune composition and phenotypic profiles of tumour-infiltrating lymphocytes (TILs) within individual tumours and between patients5,6. Although there is evidence that tumour-mutation-derived neoantigen-specific T cells play a role in tumour control2,4,7–10, in most cases the antigen specificities of phenotypically diverse tumour-infiltrating T cells are largely unknown. Here we show that human lung and colorectal cancer CD8+ TILs can not only be specific for tumour antigens (for example, neoantigens), but also recognize a wide range of epitopes unrelated to cancer (such as those from Epstein–Barr virus, human cytomegalovirus or influenza virus). We found that these bystander CD8+ TILs have diverse phenotypes that overlap with tumour-specific cells, but lack CD39 expression. In colorectal and lung tumours, the absence of CD39 in CD8+ TILs defines populations that lack hallmarks of chronic antigen stimulation at the tumour site, supporting their classification as bystanders. Expression of CD39 varied markedly between patients, with some patients having predominantly CD39− CD8+ TILs. Furthermore, frequencies of CD39 expression among CD8+ TILs correlated with several important clinical parameters, such as the mutation status of lung tumour epidermal growth factor receptors. Our results demonstrate that not all tumour-infiltrating T cells are specific for tumour antigens, and suggest that measuring CD39 expression could be a straightforward way to quantify or isolate bystander T cells. Human lung and colorectal tumours contain a population of tumour-infiltrating lymphocytes that are specific for tumour-unrelated antigens and, unlike tumour-antigen-specific tumour-infiltrating lymphocytes, do not express CD39.

OBJECTIVES Currently, there are no studies that have established the self-perceived cognitive trajectories experienced by breast cancer patients (BCPs) post-chemotherapy. Therefore, we characterized the long-term trajectory of self-perceived cognitive function among Asian early-stage BCPs using the minimal clinically important difference of a subjective measure of cognitive function. METHODS Early-stage BCPs who received chemotherapy were recruited and assessed at 4 time points: Before chemotherapy initiation (T1), 6 weeks post-chemotherapy initiation (T2), 12 weeks post-chemotherapy initiation (T3), and 15-months post-chemotherapy initiation (T4). All assessments were performed approximately within 2 weeks post-chemotherapy. Subjective and objective cognitive function were assessed using Functional Assessment of Cancer Therapy-Cognitive (version 3) and Headminder™. RESULTS A total of 166 BCPs were recruited, of whom 131 completed assessment at all time points. Using the minimal clinically important difference of Functional Assessment of Cancer Therapy-Cognitive, 5 distinct cognitive trajectories were established. Of the 131 patients, 70 (53.4%) did not report any clinically significant cognitive impairment. Twenty-one (16.0%) patients reported acute cognitive changes during chemotherapy (T2 and/or T3) but not at T4. Forty patients (30.5%) reported clinically significant cognitive impairment at T4, of whom 18 did not report any cognitive impairment at earlier time points. Fifteen (11.5%) patients reported persistent cognitive impairment throughout all time points, while 7 (5.3%) patients reported intermittent cognitive impairment at T2 and T4 but not at T3. CONCLUSION This is the first study to establish the existence of heterogeneous cognitive trajectories based on clinically significant thresholds of self-perceived cognitive impairment. The findings have important implications on the window for screening and management of post-chemotherapy cognitive impairment.

Cancer-related cognitive impairment (CRCI) adversely affects cancer patients. We had previously demonstrated that the BDNF Val66Met genetic polymorphism is associated with lower odds of subjective CRCI in the multitasking and verbal ability domains among breast cancer patients receiving chemotherapy. To further assess our previous findings, we evaluated the association of BDNF Val66Met polymorphism with subjective and objective CRCI in a temporally separate cohort of patients and pooled findings from both the original (n = 145) and current (n = 193) cohorts in a meta-analysis. Subjective CRCI was assessed using FACT-Cog. Objective CRCI was evaluated using computerized neuropsychological tests. Genotyping was carried out using Sanger sequencing. The association of BDNF Val66Met genotypes and CRCI was examined with logistic regression. A fixed-effect meta-analysis was conducted using the inverse variance method. In the meta-analysis (n = 338), significantly lower odds of CRCI were associated with Met allele carriers based on the global FACT-Cog score (OR = 0.52, 95% CI 0.29–0.94). Furthermore, Met allele carriers were at lower odds of developing impairment in the domains of memory (OR = 0.34, 95% CI: 0.17–0.70), multitasking (OR = 0.33, 95% CI: 0.18–0.59), and verbal ability (OR = 0.46, 95% CI: 0.24–0.88). Consistent with the previous study, lower odds of subjective CRCI among patients with the BDNF Met allele was observed after adjusting for potential confounders in the multitasking (OR = 0.30, 95% CI: 0.14–0.67) domain. In conclusion, carriers of the BDNF Met allele were protected against global subjective CRCI, particularly in the domains of memory, multitasking, and verbal ability. Our findings further contribute to the understanding of CRCI pathophysiology. Electronic supplementary material The online version of this article (10.1007/s12035-018-1410-4) contains supplementary material, which is available to authorized users.

Tumour-infiltrating lymphocytes (TILs) signify immune response to tumour in a variety of cancers including breast cancer. However, earlier studies examining the clinical significance of TILs in breast cancers have generated mixed results. There are only a few that address the relationship between TILs and clinical outcomes in triple-negative breast cancers (TNBC). The aim of this study is to evaluate the clinical significance of TILs that express CD4 + and CD8 + , in TNBC. Immunohistochemical staining of CD4 and CD8 was performed on tissue microarrays of 164 cases of TNBC. TILs were counted separately as intratumoral when within the cancer cell nests (iTILs) and as stromal when within cancer stroma (sTILs). High CD8 + iTILs and sTILs, and CD4 + iTILs correlated with histologic grade. On Kaplan-Meier analysis, a significantly better survival rate was observed in high CD8 + iTIL (disease-free survival, DFS: P = 0.004, overall survival, OS: P = 0.02) and both high CD4 + iTILs (DFS: P = 0.025, OS: P = 0.023) and sTILs (DFS: P = 0.01, OS: P = 0.002). In multivariate analysis, CD8 + iTILs (DFS: P = 0.0095), CD4 + sTILs (DFS: P = 0.0084; OS: P = 0.0118), and CD4 (high) CD8 (high) CD8 iTILs (DFS: P = 0.0121; OS: P = 0.0329) and sTILs (DFS: P = 0.0295) showed significantly better survival outcomes. These results suggest that high levels of both CD8 + iTILs and CD4 + sTILs as well as CD4 (high) CD8 (high) iTILs and sTILs are independent prognostic factors in TNBC.

Background: Colorectal cancer is a heterogeneous disease, harboring tremendous differences in genetic mutations, gene expression pathways, and the tumor microenvironment. While there has been recent progress in understanding immune infiltration patterns in colorectal cancer, the majority of patients are thus far largely refractory to immunotherapy, and the underlying mechanism remains poorly understood. Here, we present a large-scale multi-omics analyses on 161 colorectal cancer tumors. More specifically, we aim to characterize the spatial and phenotypic profiles as well as the relationships between the different cell populations in the tumor microenvironment using multiplex immunohistochemistry. Methods: Tissue microarrays were constructed, comprising the tumor core, close-to-edge, tumor edge, and adjacent normal tissues for each tumor. H&E and multiplex immunohistochemistry were performed by staining 7 markers (cytokeratin [CK], CD3, CD8, FOXP3, CD68, PD-L1 and DAPI). This allows for simultaneous detection of different cell populations, including CK+ epithelial cells, CD68+ macrophages, CD3+ T cells, CD8+ T cells, and FOXP3 regulatory T cells. Further complementing the study were whole genome sequencing to describe genetic mutations and tumor mutation burden, along with whole transcriptome sequencing to investigate differential gene expression and pathway enrichment. MSI status was determined from whole genome sequencing data, and molecular subtypes were called from RNA-sequencing data. Results: Based upon spatial patterns of immune cell infiltration, we qualitatively and quantitatively describe several immune infiltration subtypes which were further correlated with tumor mutation burden and neoantigen burden, activation of major oncogenic pathways and inflammatory signatures. The density of immune cells varies across the different tumor sites, from the adjacent normal tissue into the tumor core. We have also uncovered interactions between the different cell populations within the tumor microenvironment. Overall, the integration of data from multiple platforms represents a comprehensive interrogation into the complex tumor microenvironment in colorectal cancer. Conclusion: There exists a substantial variability in the transcriptomic landscape and the immune infiltration patterns across different patients. This demonstrates the complex interplay between the different cell populations in the tumor microenvironment, representing the fine balance between immune activation and suppression. Citation Format: Christine L. Eng, Joe P. Yeong, Andy Nguyen, Amanda Y. Guo, Brenda Tay, Mei Mei Chang, Sherlly Lim, Clarinda W. Chua, Harini Srinivasan, Lindsay H. Kua, Fiona Y. Lee, Dominique C. Macalinao, ThinZar Aung, Anders J. Skanderup, Tony K. Lim, Iain B. Tan, Si-Lin Koo. Spatial and multi-omics characterization of the tumor microenvironment in colorectal 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 3872.

4590 Background: Nivolumab (N) and Y90-radioembolization (RE) are both therapeutic options in advanced hepatocellular carcinoma (aHCC). Increasing evidence suggests that radiotherapy synergizes with immune checkpoint inhibitors to augment anti-tumour effects. Methods: Eligible Child-Pugh A aHCC patients (pts) were treated with Y90-RE followed by N 240mg, 21 days after Y90-RE and every 2 weeks thereafter. Pre- and on-treatment tumor biopsies together with circulating biomarkers were obtained. Primary end-point was overall response rate (ORR) (per RECIST v 1.1). Overall response was defined as the composite overall response observed for the lesions within Y90-RE field and outside Y90-RE field. Key secondary end points included disease control rate (DCR), progression free survival (PFS), overall survival (OS), and safety. 36 evaluable pts were needed to assess whether the addition of N improved the ORR of Y90-RE from 21% to 41% as determined by Simon two-stage optimal design with 80% power and one sided significance level of 0.05. Results: Forty pts were enrolled of which 36 were evaluable. At baseline: 63.9% were HepB in aetiology; 63.9% BCLC stage C; 47.2% had AFP > 400ng/mL; number of liver lesions – median 5 (range 1- 20); size of largest liver lesion – median 80mm (range 14-177mm); 27.8% had prior TACE; and 13.9% had prior systemic therapy. ORR was 31% (95% CI 16.4 - 48.1%). Eight out of 11 responders had not progressed at study cut-off. DCR was 58.3%. 81% of target lesions within Y90-RE field regressed. With a median follow up of 16.4 months, median PFS and OS were 4.6 months (95% CI 2.3m - 8.4m) and 15.1 months (95% CI 7.8m - NE) respectively. Six- and 12-month PFS rates were 44.2% (95% CI 27.3% - 59.9%) and 26.1% (95% CI 11.2% - 43.8%) respectively. Overall, N+ Y90-RE was well tolerated and safe; only 11% had grade 3/4 treatment related adverse events (AEs). Responders demonstrated significant alterations of LIF, MIG and Eotaxin3 levels in the pre-treatment cytokine analyses. Conclusions: Combination N+Y90-RE resulted in an encouraging ORR of 31% (95% CI 16.4 - 48.1%) in aHCC. 81% of target lesions within Y90-RE field regressed suggesting synergy in combining Y90-RE with nivolumab. This combination is safe and tolerable with low G3/4 treatment related AEs of 11%. Further biomarker analyses will be presented at the meeting. Clinical trial information: NCT03033446 .

Triple negative breast cancer (TNBC) is a heterogenous disease often characterised by aggressive biology and poor prognosis. Efforts to precisely treat TNBC have been compounded by the lack of specific therapeutic molecular targets. Recent transcriptomic studies have revealed, among others, an immunomodulatory subtype of TNBC, whereby activated immune response genes are associated with good prognosis. Since then, a great deal of effort has been made to understand the immune microenvironment of some TNBC subtype, which comprises several immune cell populations including lymphocytes and macrophages. There is increasing evidence that the basal subtype may be significantly regulated by tumour-infiltrating T-cells and that high levels of tumour-infiltrating CD8+ T-cells may be a reflection of improved prognosis with chemotherapy sensitivity in TNBC. On the other hand, tumour-associated macrophages have been associated with a relatively poor outcome in TNBC. Comparison of the immune signatures in TNBC with non-TNBC may furthermore help us to understand these immune mechanisms potentially leading to new therapeutic approaches. Within this short review, we discuss the current scientific evidence regarding (a) the role of tumour-infiltrating lymphocytes in the clinical outcome in TNBC and (b) the newly discovered immunomodulatory genotype that may provide for a therapeutic target in TNBC.

Cancer-related fatigue (CRF) and chemotherapy-related cognitive impairment (CRCI) are reported to be associated with mitochondrial dysfunction. Hence, mitochondrial DNA (mtDNA) content, a biomarker of mitochondrial dysfunction, is hypothesized to correlate with the onset of CRF and CRCI. This study aims to evaluate the association between peripheral blood mtDNA content reduction and severity of CRF and CRCI in patients receiving chemotherapy. This was a prospective cohort study. Early-stage breast cancer patients receiving anthracycline- or taxane-based chemotherapy were recruited. CRF was assessed using MFSI-SF, and CRCI was assessed using FACT-Cog and CANTAB at two timepoints: baseline (T1; prior to treatment) and 6 weeks after initiation of treatment (T2). mtDNA content was measured at both timepoints using real-time quantitative polymerase chain reaction. Multiple logistic regression was utilized to evaluate the association between mtDNA reduction and worsening of CRF and CRCI, adjusting for age, anxiety, insomnia, plasma cytokines concentrations, and other clinically important covariates. A total of 108 patients (age 52.0 ± 9.2 years; 82.4% Chinese; 64.8% receiving anthracycline-based chemotherapy) were recruited. Proportions of patients with worsening of CRF increased from the lower to the upper quartiles of mtDNA reduction (22.2, 33.3, 55.6, and 63.0% in quartiles 1, 2, 3, and 4, respectively, p = 0.001 for trend). Reduction of mtDNA content was significantly greater among those with worsening of CRF and CRCI compared to those without CRF [mean reduction (± SD): 36.5 (46.1) vs. 9.4 (34.5), p

Various forms of immunotherapy, such as checkpoint blockade immunotherapy, are proving to be effective at restoring T cell-mediated immune responses that can lead to marked and sustained clinical responses, but only in some patients and cancer types

e14178 Background: Colorectal Cancer (CRC) is the third most commonly diagnosed cancer in the world. Yet, CRC has been difficult to treat with immunotherapy, as majority (85%) of CRC are Microsatellite stable (MSS), lowly immunogenic and do not respond well. To investigate immuno-cytotoxicity in MSS cancers, we set up an ex vivo co-culture model using patient-derived tumor epithelial cells and autologous tumor-infiltrating lymphocytes (TILs). Aims: To perform phenotypic and functional characterisation of the model, and show we are able to modulate immuno-cytotoxicity. Methods: Fresh tumor, adjacent normal and/or liver metastasis samples were collected and freshly dissociated from 29 colorectal cancer patients undergoing surgery. TILs and tumor epithelial cells were grown in culture. Weekly immunophenotyping of TILs was performed via flow cytometry and data was analysed to identify temporal changes in proportions of cell types. To modulate cytotoxicity, epithelial cell lines were co-cultured with autologous and allogeneic TILs at various effector:target ratios with and without anti-PD1 (Pembrolizumab). Caspase dye was used to detect apoptosis and measure cell death. Results: TILs from most patients were successfully expanded, with a theoretical potential of up to 10,000 times. CD4+ T cells were selectively expanded, while CD8+ T cells decreased in proportion over time. A select group of patients showed an opposite trend. Cell type proportions in metastases mirrored those of the primary tumour while NK cells expanded more in tumour samples than normal samples. Selection proceeded up to 3 weeks then decreased. In the cytotoxicity experiment, we show that cell death is increased at higher effector:target ratios in the presence of autologous TILs. Addition of Pembrolizumab further modulates cytotoxicity in vitro. Conclusions: We have developed and characterised an autologous T cell and epithelial cell co-culture system to evaluate immuno-cytotoxicity in colorectal cancer. This will allow screening of perturbations for improved immuno-cytotoxicity in colorectal cancer.

528 Background: Dysregulation of DNA mismatch repair pathway can lead to microsatellite instability in many GI tumors, and microsatellite instability is an important diagnostic and prognostic marker. Microsatellite instable (MSI) tumors comprise about 15% of colorectal malignancies and can be found in other gastrointestinal (GI) tumor types. We present results of analysis of genomic and immune infiltration differences between MSI and microsatellite stable (MSS) GI tumors spanning multiple cancer types. Methods: A total of 521 GI patients with deep whole exome sequencing (WES) of tumor and blood samples, and whole transcriptomic sequencing (RNA-Seq) (∼200M reads per tumor) were available for this analysis from a commercial database. Variant calling was performed through joint probabilistic analysis of tumor and normal DNA reads, with germline status of variants being determined by heterozygous or homozygous alternate allele fraction in the germline sample. Results: Gene expression and pathway analysis found significantly higher immune signaling in MSI cohort and higher metabolic signaling in MSS cohort. We also found upregulation of structural cellular integrity pathways in MSI tumors. Per-sample deconvolution of immune infiltration using cell type gene markers shows some MSI samples with high CD8 T-cells. Co-expression analysis of checkpoint and TME genes shows higher correlation of FOXP3 and CTLA4 in the MSS cohort compared to the MSI samples, whereas correlation between FOXP3 and PDL1 is decreased. TIM3, LAG3, and OX40 are significantly more expressed in MSI samples than MSS samples. Within the subset of colorectal tumors, additional checkpoints are significantly differentially overexpressed in MSI malignancies. 50 somatic variants are significantly differential in MSI tumors. Conclusions: MSI tumors demonstrably exhibit higher immune signaling, with many immune and checkpoint markers expressed at higher levels in MSI tumors. Some cellular integrity pathways also appear to be up in MSI cohort. A number of potentially important somatic variants are associated with MSI samples.

Circulating tumour DNA (ctDNA) has the potential to be a specific biomarker for the monitoring of tumours in patients with colorectal cancer (CRC). Here, our aim was to develop a personalised surveillance strategy to monitor the clinical course of CRC after surgery. We developed patient-specific ctDNA assays based on multiplexed detection of somatic mutations identified from patient primary tumours, and applied them to detect ctDNA in 44 CRC patients, analysing a total of 260 plasma samples. We found that ctDNA detection correlated with clinical events – it is detectable in pre-operative but not post-operative plasma, and also in patients with recurrent CRC. We also detected ctDNA in 11 out of 15 cases at or before clinical or radiological recurrence of CRC, indicating the potential of our assay for early detection of metastasis. We further present data from a patient with multiple primary cancers to demonstrate the specificity of our assays to distinguish between CRC recurrence and a second primary cancer. Our approach can complement current methods for surveillance of CRC by adding an individualised biological component, allowing us not only to point to the presence of residual or recurrent disease, but also attribute it to the original cancer.

Background: Somatic mutations are attractive therapeutic targets for “individualized neoantigen vaccines” because of lack of host central tolerance and reduced risk of autoimmunity. Here, we perform large-scale-omic analyses to assess the neoantigen landscape of colorectal cancer (CRC), a cancer largely refractory to immune-checkpoint inhibition. Methods: We performed whole genome sequencing (WGS) (60x tumor, 30x normal) and deep whole transcriptomic sequencing (RNA-Seq) (∼200x106 reads per tumor) on 158 colorectal cancers of which 32 are microsatellite instability high (MSI-H) tumours and 126 are microsatellite stable (MSS). Whole exome sequencing (200x tumor, 100x normal) was also performed on 120 tumours. HLA typing, somatic mutations, gene expression and neoepitope predictions were computationally evaluated. Inferred HLA-A alleles were orthogonally validated with Pacbio long-read sequencing. Tissue microarrays (TMAs) with tumour core, tumour edge and normal adjacent tissue of these 158 CRCs were constructed. Histopathological analyses using multiplex immunohistochemistry (mIHC) to simultaneously evaluate 7 markers, i.e. cytokeratin (CK), CD3, CD8, FOXP3, CD68, PD-L1, DAPI, have been performed. Results: The most common HLAs were, by allele count: A*11:01: 56; A*33:03: 38; B*58:01: 33; B*46:01: 29; B*40:01: 26; C*01:02: 41; C*07:02: 33. Inferred HLA-A alleles from WGS data was largely concordant (>90%) with Pacbio long-read sequencing. There were a median of 2,850 (1229-6909) [MSI] & 213 (27-13,835) [MSS] coding variants, from which 10,487 (4,307-27,365) [MSI] & 726.5 (50-59,096) [MSS] possible neoepitopes were derived, after accounting for epitope processing, the normal proteome and general population variome based on dbSNP, Of these, 5,707 (2,608-15,218) [MSI] & 320 (14-25,243) [MSS] neoepitopes are expressed (based on RNA-Seq). Epitope prediction algorithms revealed a median of 423 (17-1,056) [MSI] & 26 (0-1,102) [MSS] bound & expressed neoepitopes. 5 MSS tumors did not have any predicted bound nor expressed neoepitopes, 112 of 126 (89%) of MSS tumors had at least 5 predicted bound, expressed neoepitopes. Histopathological correlations between extent of immune infiltrates in fixed tissues, tumour PD-L1 expression and neoantigen burden is ongoing. Conclusions: There is substantial variability in the neoantigen landscape amongst MSI & MSS CRCs. MSI contains multiple-fold higher neo-antigens. Amongst MSS tumours, 89% of patients have at least 5 predicted bound and expressed neo-epitopes that could be targeted in neoantigen-based vaccines for personalized immunotherapy. Citation Format: Si-Lin Koo, Joe Poh Sheng Yeong, Andy Nguyen, Clarinda Wei Ling Chua, J Zachary Sanborn, Steve Benz, Wah Siew Tan, Choong Leong Tang, Su Yan, Min Hoe Chew, Brian Goh, Chung Yip Chan, Xiao Qing Koh, Alexander Lezhava, Tony Kiat Hon Lim, Shahrooz Rabizadeh, Anders Skanderup, Iain Beehuat Tan. Systematic identification of tumour-specific neoantigens(by whole-genome sequencing) and correlation between tumour neoantigen burden, PD-L1 expression and immune infiltrates in 158Asian colorectal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5725.

Background: Colorectal cancer (CRC) is a cancer largely refractory to immune checkpoint inhibition. There is substantial interpatient molecular heterogeneity in colorectal cancer reported from studies on tumor RNA and studies on immunohistochemical analyses of fixed tumor tissue. Several major transcriptomic analyses from microarrays and RNA-seq data have identified major transcriptomic subtypes and major activated pathways and deconvoluted cell-type enrichments. Immunohistochemical (IHC) analyses of formalin-fixed, paraffin-embedded (FFPE) tissue microarrays have identified several different histomorphologic/spatial patterns of immune infiltrates in the tumor microenvironment. Here, we perform large-scale -omic analyses on tumor RNA and multiplex IHC simultaneously on 158 Asian colorectal cancers. Methods: We performed whole-genome sequencing (WGS) (60x tumor, 30x normal) and deep whole-transcriptomic sequencing (RNA-seq) (∼200x106 reads per tumor) on 158 colorectal cancers. To evaluate the spatial patterns of the tumor microenvironment, we constructed a tissue microarray comprising the tumor core, tumor edge and normal adjacent tissue of these 158 CRCs. We performed H&E analyses of the TMA and multiplex immunohistochemistry to simultaneously evaluate 7 markers, i.e., cytokeratin (CK), CD3, CD8, FOXP3, CD68, PD-L1, DAPI, using the an Opal Multiplex fIHC kit. Images were acquired using a Vectra 3 pathology imaging system microscope (PerkinElmer, Waltham, MA, USA). Results: 32 are microsatellite instability high (MSI-H) tumors and 126 are microsatellite stable. (MSS). The major transcriptomic subtypes (Consensus molecular subtypes (CMS 1-4) and CRC assigner (Goblet-like, Enterocyte, Stem-like, Inflammatory, Transit-amplifying subtypes) were identified with good concordance between both classification systems. CMS1 and Inflammatory subtypes were enriched amongst MSI-H tumors. Major oncogenic pathway activations (RAS, Wnt), cell-cycle and inflammatory signatures (interferon-rich) were also identified across the populations. We deconvoluted cell-type enrichment scores from the transcriptomic data to identify different cell-type enrichment patterns across the cohort. On the TMAs, we identified cell type populations and immune infiltrate patterns in the tumor core and invasive edge across the cohort. Correlations across these analyses will be presented at the meeting. Conclusions: There is substantial interindividual variability in the transcriptomic landscape and spatial patterns of immune cell infiltrates in CRCs. Citation Format: Clarinda Wei Chua, Engin Cukuroglu, Elisa Fontana, Si Lin Koo, Joe Poh Yeong, Andy Nguyen, J. Zachary Sanborn, Steve Benz, Emile John Tan, Ronnie Mathew, Ee-Lin Toh, Sarah Boon Ng, Tony Kiat Lim, Anders Jacobsen Skanderup, Shahrooz Rabizadeh, Anguraj Sadanandam, Jonathan Göke, Iain Bee Tan. Tumor whole-transcriptome sequencing and multiplex immunohistochemistry of immune cell populations in 158 Asian colorectal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5693.

e15597Background: Responses to anti-PD1 is ~35% in microsatellite unstable (MSI-h) and near 0% in microsatellite stable (MSS) Colorectal cancer (CRC). Understanding the composition of immune cell p...

3612Background: Brain metastases (BM) from colorectal cancer (CRC) are a rare but increasing event as patients survive longer. While human epidermal growth factor receptor 2 (HER2) gene amplificati...

e15531Background: Response to immune checkpoint inhibition is dismal in colorectal cancer (CRC). There are limited experimental models to evaluate immunotherapy in human CRC. We developed an ex viv...

TPS542 Background: In recent years, Yttrium-90 (Y90) trans-arterial radioembolization (TARE) has emerged as a therapeutic option for intermediate stage hepatocellular carcinoma (HCC). Cancer immunotherapy targeting tumour immune evasion has shown remarkable successes in various cancers. Nivolumab, an immune checkpoint inhibitor of programmed death 1 (PD1), has demonstrated encouraging activity in advanced stage HCC. Similarly, chronic hepatitis B virus (HBV) infection, a strong risk factor for HCC, is characterized by immune escape mechanisms. We hypothesize that TARE will stimulate tumor and/or HBV specific T cell responses that can be boosted using nivolumab. We thus propose an open label phase 2 trial investigating the combination of TARE with nivolumab in BCLC intermediate stage HCC. Methods: Eligible patients (pts) have ECOG performance status ≤ 2, Child-Pugh A score, intermediate stage HCC planned for TARE according to institutional practice with adequate organ function. Pts will be treated with TARE followed by nivolumab 240mg, 21 days after TARE and every 2 weeks thereafter. Pre- and on-treatment tumor biopsies will be taken. Primary end-point is response rate (RR) of combinational TARE and nivolumab. Key secondary end points are: progression free survival, overall survival, safety and quality of life using FACT-HEP score and EORTC QLQ-C30. Exploratory objectives are to evaluate how tumor PD L-1 expression, HCC mutational burden and blood lymphocyte activation/phenotypic profiles correlate with tumor response. Where possible, serial changes in antigen-specific T cell responses to HBV and/or tumour antigens will also be assessed. This study aims to enroll 40 pts as calculated using the Simon two-stage optimal design with 80% power and one sided significance level of 0.05. This will assess whether the addition of nivolumab improves the RR of TARE at 8 weeks from 21% to 41%. Patient accrual was initiated in December 2016 and as of September 2017, 9 pts have been treated. Clinical trial information: 03033446.

572 Background: Comprehensive molecular profiling of CRC can inform treatment decisions by identifying patient subgroups at varying risks of death. Microsatellite instability (MSI) is prognostic in CRC and is used to select patients for immunotherapy. High tumor mutational burden (TMB) is associated with genomic instability and is prognostic in melanoma. Expression of p16 protein is prognostic in many tumor types. We used proteomic and genomic profiling to measure MSI, TMB and p16 in CRC tumors and to assess associations with patient survival. Methods: In archived clinical samples of CRC, 76 proteins were quantitated with mass spectrometry-based proteomics. MSI was measured by WGS and RNA-seq; unstable loci were quantified in tumor and normal samples. Cutoffs were derived via ROC analysis: high TMB was defined as > 4.5 somatic mutations per megabase; p16 as > 108 amol/ug. Patients were grouped by microsatellite status (MSI vs. microsatellite stable [MSS]), TMB (high vs. low), and p16 protein expression level. Survival curves were compared with the Mantel-Cox log-rank test. Results: Of 145 samples, 39 (27%) had high TMB and 29 (20%) had MSI. Patients with MSI tumors had longer OS than patients with MSS tumors (HR: 0.096; p = 0.003). Similarly, patients with high TMB had longer OS than those with low TMB (HR: 0.076; p < 0.001). High p16 expression was prognostic of poor survival (HR: 2.874; p = 0.019). Among patients with MSS tumors or low TMB, those with low p16 levels had longer OS than patients with high p16 (HR: 0.257; p = 0.002 and HR: 0.249; p = 0.002, for MSS and low TMB, respectively). A combination of MSS, low TMB, and low p16 also differentiated between long and short survivors (HR: 0.249; p = 0.002). These associations remained after adjustment for tumor sidedness. Further analyses of clinical correlates will be presented. Conclusions: A combination of MSS, low TMB and low p16 expression characterized a subset of patients with longer survival. This is important because patients with MSS tumors have limited treatment options but may respond to CDK4/6 inhibitors due to low p16 expression. Molecular profiling of CRC may identify patient subgroups with a relatively poor prognosis who could benefit from personalized therapy.

Animal models have highlighted the importance of innate lymphoid cells (ILCs) in multiple immune responses. However, technical limitations have hampered adequate characterization of ILCs in humans. Here, we used mass cytometry including a broad range of surface markers and transcription factors to accurately identify and profile ILCs across healthy and inflamed tissue types. High dimensional analysis allowed for clear phenotypic delineation of ILC2 and ILC3 subsets. We were not able to detect ILC1 cells in any of the tissues assessed, however, we identified intra-epithelial (ie)ILC1-like cells that represent a broader category of NK cells in mucosal and non-mucosal pathological tissues. In addition, we have revealed the expression of phenotypic molecules that have not been previously described for ILCs. Our analysis shows that human ILCs are highly heterogeneous cell types between individuals and tissues. It also provides a global, comprehensive, and detailed description of ILC heterogeneity in humans across patients and tissues.

Background: Some health websites provide a public forum for consumers to post ratings and reviews on drugs. Drug reviews are easily accessible and comprehensible, unlike clinical trials and published literature. Because the public increasingly uses the Internet as a source of medical information, it is important to know whether such information is reliable. Objective: We aim to examine whether Web-based consumer drug ratings and reviews can be used as a resource to compare drug performance. Methods: We analyzed 103,411 consumer-generated reviews on 615 drugs used to treat 249 disease conditions from the health website WebMD. Statistical analysis identified 427 drug pairs from 24 conditions for which two drugs treating the same condition had significantly and substantially different satisfaction ratings (with at least a half-point difference between Web-based ratings and P

Background Brain-derived neurotrophic factor (BDNF), a neurotrophin that regulates neuronal function and development, is implicated in several neurodegenerative conditions. Preliminary data suggest that a reduction of BDNF concentrations may lead to postchemotherapy cognitive impairment. We hypothesized that a single nucleotide polymorphism (rs6265) of the BDNF gene may predispose patients to cognitive impairment. This study aimed to evaluate the effect of BDNF gene polymorphism on chemotherapy-associated cognitive impairment. Methods Overall, 145 patients receiving chemotherapy for early-stage breast cancer (mean age: 50.8 ± 8.8 y; 82.1% Chinese) were recruited. Patients' cognitive functions were assessed longitudinally using the validated Functional Assessment of Cancer Therapy–Cognitive Function (v.3) and an objective computerized tool, Headminder. Genotyping was performed using Sanger sequencing. Logistic regression was used to evaluate the association between BDNF Val66Met polymorphism and cognition after adjusting for ethnicity and clinically important covariates. Results Of the 145 patients, 54 (37%) reported cognitive impairment postchemotherapy. The Met/Met genotype was associated with statistically significant lower odds of developing cognitive impairment (odds ratio [OR] = 0.26; 95% CI: 0.08–0.92; P = .036). The Met carriers were less likely to experience impairment in the domains of verbal fluency (OR = 0.34; 95% CI: 0.12–0.90; P = .031) and multitasking ability (OR = 0.37; 95% CI: 0.15–0.91; P = .030) compared with the Val/Val homozygote. No associations were observed between Headminder and the BDNF Val66Met polymorphism. Conclusions This is the first study to provide evidence that carriers of the BDNF Met allele are protected against chemotherapy-associated cognitive impairment. Further studies are required to validate the findings.

10018 Background: Cancer-related fatigue (CRF) is reported to be associated with mitochondrial dysfunction. Hence, mitochondrial DNA (mtDNA) content, a biomarker of mitochondrial dysfunction, is hypothesized to correlate with the onset of CRF. This study aimed to evaluate the association between peripheral blood mtDNA content and CRF in patients receiving chemotherapy. Methods: This was a prospective cohort study. Early-stage breast cancer patients (Stages I to III) receiving anthracycline or taxane-based chemotherapy were recruited. CRF was assessed using the validated Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF) at two time points: baseline (T1; prior to treatment) and 6 weeks after initiation of treatment (T2). Worsening of CRF was defined as ≥10% increase in the overall MFSI-SF score at T2. Peripheral blood mtDNA content was measured at both time points using real-time quantitative polymerase chain reaction. Multiple logistic regression was utilized to evaluate the association between mtDNA reduction and worsening of CRF, adjusting for age, anxiety, insomnia and other clinically important covariates. Results: A total of 91 patients [mean age (±SD): 51.3 (9.2) years; 81.3% Chinese; 63.3% receiving anthracycline-based chemotherapy] were recruited. Proportions of patients with worsening of CRF increased from the lower to the upper quartiles of mtDNA reduction (26.1%, 30.4%, 52.2%, and 59.1% in quartiles 1, 2, 3, and 4, respectively, P = 0.010 for trend). Reduction of mtDNA content was significantly greater among those with worsening of CRF compared to those without CRF [mean reduction (±SD): 16.3 (23.5) vs 6.0 (17.3), P = 0.018]. After adjusting for covariates, every 1-unit reduction of the mtDNA content was associated with a 4% increase risk for worsening of CRF (95% CI, 1%-8%; P = 0.016). Conclusions: This is the first study to show that reduction of mtDNA content in peripheral blood is associated with onset of CRF in patients receiving chemotherapy. Further validation studies are required to confirm the findings.

e21609 Background: Chemotherapy-associated cognitive impairment (CACI) experienced during survivorship can dramatically impair quality of life, particularly among patients receiving treatment with curative intent. We construct a web-based tool to predict the risk of self-perceived CACI at 15 months post-chemotherapy initiation among early stage breast cancer patients, to facilitate screening and early intervention. Methods: We recruited patients receiving chemotherapy for early-stage breast cancer between 2011 and 2014. Subjective cognitive function was assessed using FACT-Cog before, during and at 15 months after initiating chemotherapy. Based on a previously established minimal clinically important difference, an 11-point reduction in FACT-Cog score relative to that at baseline was considered as clinically significant CACI. Factors evaluated as potential predictors of CACI included clinical, laboratory and demographic factors, behavioural symptom and quality of life assessments (EORTC-QLQ-C30). Logistic regression was used to construct a model predicting CACI. Validation was performed on an external cohort recruited between 2015 and 2016. Model discrimination and calibration were evaluated using the receiver operating curve (ROC) and Hosmer-Lemeshow goodness-of-fit, respectively. The model was implemented as a web-based tool. Results: A total of 131 patients were recruited for model development. The model consisted of baseline EORTC-QLQ-C30 fatigue subscale percentage [effect size (95% confidence interval), 5.0% (2.0% to 7.0%), p < 0.001] and the change in FACT-Cog score after 2 cycles of chemotherapy, relative to baseline [-4.0% (-7.0% to -1.0%), p = 0.007]. The model was validated on an external cohort of 33 patients, with an ROC of 0.60, Hosmer-Lemeshow goodness-of-fit statistic of 5.86 (p = 0.44), sensitivity of 57.1% and specificity of 76.9%. The web application is accessible at http://bit.ly/CognitiveRisk Conclusions: A web application to predict CACI risk has been developed and externally validated. The tool facilitates early screening for patients at high risk for CACI and allows timely interventions to prevent or minimize the impact of CACI during survivorship.

10096 Background: Genetic variations among genes regulating neuronal function, neurotransmission and plasticity may contribute to varying risk of CACI. In order to fully elucidate the complex genetic structure underlying CACI, a GWAS meta-analysis was performed to identify genetic variants associated with CACI among ESBC patients. Methods: A GWAS meta-analysis of two independent cohorts totaling 266 chemotherapy-receiving ESBC patients (mean age: 51.0 ± 9.2 years; 80.8% Chinese) was performed. Patients’ self-perceived cognitive function was assessed using the validated FACT-Cog (v.3). Genome-wide genotyping was performed using the Illumina HumanOmniExpress-24 version 1.1 BeadChips kits. Each beadchip contains over 700,000 genetic markers. Covariates included in the meta-analysis were the first two dimensions of the multi-dimensional scaling. Results: After applying stringent quality control measures and removing four population outliers, data from 546,399 SNPs were available for 84 cases and 170 controls. In the meta-analysis, two SNPs (rs6443264 and rs4686371) exceeded the suggestive threshold of P < 1×10-5 (Table). Following adjustment for the first two MDS dimensions in the meta-analysis, both SNPs remained as top two SNPs with P < 1×10-4. Both rs6443264 and rs4686371 are located in chromosome 3p25 and lie in the intronic regions encoding OGG1 and ARPC4 genes, respectively. Alteration of the OGG1 gene could compromise the functions of downstream neuronal genes, and modification of the ARPC4 gene could affect the formation of the actin-related protein 2/3 complex and impair memory formation. Conclusions: To the best of our knowledge, this is the first GWAS meta-analysis to identify two loci, namely rs6443264 and rs4686371 that are suggestive of genome-wide association with CACI among Asian ESBC patients. [Table: see text]

10014Background: Epigenetic regulation via methylation plays a crucial role for the functioning and survival of neuronal cells. DNA methyltransferase 1 (DNMT1) is an enzyme to maintain methylation ...

9616 Background: BDNF is a neurotrophin that regulates neuronal function and development, which is implicated in several neurodegenerative conditions. There is preliminary data to suggest that the ...

Introduction: The immunophenotype and density of immune cell infiltrates in colorectal cancer (CRC) has consistently been shown to correlate with patient prognosis suggesting that the immune microenvironment plays an important role in regulating tumor progression. However, the immune repertoire of these tumor infiltrating lymphocytes has not been well characterized. Methods: In this pilot study, we characterized the immue repertoire through TCR sequencing of T lymphocytes in the CRC tumor microenvironment and normal adjacent colonic mucosa. We collected fresh tumor and adjacent normal colonic mucosal tissue specimens from 2 patients who underwent surgery for CRC. A part of the tumor specimen was dissociated and sorted for collection of CD4+ and CD8+ T lymphocytes using FACSAria III cell sorter. 4 samples consisting of fresh frozen tumor, sorted CD4+ and CD8+ TILs and fresh frozen adjacent normal colonic mucosal tissue of each of the 2 patients were then sent for T-cell receptor β (TCRβ) complementarity-determining region 3 (CDR3) amplification and high-throughput next generation sequencing using the ImmunoSEQ platform at Adaptive Biotechnologies. The TCRβ CDR3 regions were then determined based on the definitions established by the ImMunoGeneTics Collaboration. Results: The median total number of unique TCRβ CDR3 sequences identified in each of the 8 specimens evaluated was 5726 (range 475 to 54699), with an average of 78.3% of each specimen being productive sequences (range 75.1% to 81.9%). We next evaluated the diversity of T cell repertoire in terms of abundance and distribution of the T cell populations. There were more unique T cell clones present in the adjacent normal colonic mucosa (54699 and 24255) than in the tumor (7026 and 20887). Amongst the sorted TILs, there were less unique CD8+ T cell clones (561 and 475) compared to unique CD4+ T cell clones (2913 and 4426). There were fewer numbers of dominant clones making up 50% of total CDR3 reads in the CD8+ sorted TILs (15 and 29) compared to sorted CD4+ TILs (150 and 179), tumor tissue (390 and 668) and adjacent normal mucosa (1125 and 185). Conclusion: Preliminary data from this pilot study suggests an oligoclonal population of cytotoxic T cells within the tumor microenvironment. We hypothesize that clonal expansion of these cytotoxic T cells were in response to specific tumor antigen stimulation. We have expanded the T cells and generated patient derived CRC cell lines. Further analysis of this population of expanded tumor infiltrating lymphocytes against their specific tumor cell lines are ongoing to evaluate T cell recognition and cytotoxic activity. Citation Format: Si Lin Koo, Rachel Rui Xian Ten, Thin Zar Aung, Dennis Koh, Who Whong Wang, Wei Qiang Leow, Kiat Hon Lim, Suk Peng Chew, Ju Yuan, Bing Lim, Salvatore Albani, Iain Beehuat Tan. Immune repertoire amongst subpopulations of tumor infiltrating lymphocytes (TILs) in colorectal cancer: Oligoclonality is predominantly observed in cytotoxic CD8+ TILs. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1654. doi:10.1158/1538-7445.AM2014-1654