Molecular landscape of colorectal cancers harboring R-spondin fusions

3588

Background: Gene fusions involving R-spondin ( RSPO) family members have been shown to drive Wnt-dependent tumor initiation in colorectal cancer (CRC). Therapies targeting Wnt pathway are being actively investigated for tumors harboring RSPO2/3 fusions. Here we set out to characterize the molecular features of CRC with and without RSPO fusions to gain insight into potential rationale combination therapy strategies. Methods: Tumor DNA sequencing of 592 genes (NextSeq, Illumina), RNA sequencing of 53 gene fusions (ArcherDx FusionPlex) and immunohistochemistry for PD-L1 on tumor cells (SP142) were tested on CRC tumors at Caris Life Sciences, Phoenix, AZ. Molecular profiles of RSPO2/3 positive (pos) were compared with negative (neg) tumors, Fisher-Exact was used for comparative analysis. Results: A total of 1356 CRC samples were analyzed. RSPO3 and RSPO2 fusions were detected in 42 (3.1%) and 4 (0.3%) samples, respectively, including 5 fusion events not previously reported (e.g., IFNGR1-RSPO3). A female predominance was seen in RSPO fusion pos vs. neg tumors (71.7% vs 45.0%, p < 0.001); no association with age or tumor sidedness was seen. RSPO2/3 fusions were mutually exclusive of MSI-high (0 vs. 5%), ERBB2 alterations (0 vs. 1% mutation, 4% amplification) and other Wnt pathway activation drivers including APC (2 vs. 75%), CTNNB1 (0 vs. 1.4%) and RNF43 (0 vs. 5.3%) mutations. Significantly higher BRAF (26 vs. 7%), RAF1 (4.5 vs. 0.4%) and SMAD4 (30 vs. 11%) mutation rates were seen in RSPO pos vs. neg tumors (p < 0.05). A universal co-activation of MAPK pathway ( KRAS, NRAS or BRAF) was seen with RSPO fusions. There was a significantly elevated PD-L1 expression in RSPO3 pos tumors (14%) compared to RSPO neg (6%, p = 0.04) and APC-mutated (5%, p = 0.02) tumors that are MSS. Conclusions: This is the largest series of CRC cases harboring an RSPO rearrangement reported to date. Comprehensive molecular analyses asserted the unique molecular landscape associated with RSPO fusions in CRC and suggested potential combinatorial approach to target Wnt/MAPK pathway. The immune modulatory effects specific to RSPO2/3 fusion revealed by PD-L1 expression suggest co-targeting Wnt pathway with PD1/PDL1 inhibitors in RSPO pos tumors.

Genetic variants in RNA binding protein (RBP) to predict outcome in metastatic colorectal cancer (mCRC): Data from FIRE-3, TRIBE, and MAVERICC trials

3545

Background: RNA binding proteins (RBPs) post-transcriptionally regulate gene expression by stabilizing or destabilizing target messenger RNA. Although alteration of RBPs affects many steps of cancer development, its clinical implication in mCRC remains unclear. Methods: We analyzed data from mCRC patients (pts) enrolled in three first-line randomized trials (FIRE-3, TRIBE, and MAVERICC). Genomic DNA from blood samples of pts was genotyped through the OncoArray, a custom array manufactured by Illumina. Candidate 30 SNPs in 10 RBP genes (MSI1, MSI2, ELAVL1, RBM3, LIN28A, LIN28B, IGF2BP1, IGF2BP2, IGF2BP3, ZFP36) were tested on association with progression-free survival (PFS) and overall survival (OS). To evaluate prognostic effects and heterogeneities across treatment arms, meta-analysis approach using the METASOFT software was conducted. We also tested interaction between each SNP and treatment within each trial, i.e. FIRE-3 cohort (FOLFIRI+cetuximab (Cet) vs FOLFIRI+bevacizumab (Bev)) and MAVERICC cohort (FOLFIRI+Bev vs FOLFOX6+Bev). For multiple testing, p values were adjusted by the false discovery rate (FDR) method. Results: A total of 884 pts’ SNPs data were available (FIRE-3: n = 236, TRIBE: n = 324, and MAVERICC: n = 324). Meta-analysis combining three trials showed RBM3 rs926152 (adjusted p = 0.045) and RBM3 rs2249585 (adjusted p = 0.016) were significantly prognostic for PFS. Whereas, in terms of OS, only LIN28B rs314277 (adjusted p = 0.045) was significant, and RBM3 rs926152 (adjusted p = 0.057) and RBM3 rs2249585 (adjusted p = 0.059) had a trend. Interaction test showed several SNPs were potentially predictive (raw p < 0.05), although without any significance after FDR adjustment: in FIRE-3 cohort, MSI2 rs1822381, RBM3 rs926152, LIN28B rs221635, IGF2BP1 rs2969 for OS; in MAVERICC cohort, MSI1 rs1179442 and MSI2 rs3826301 for OS, ELAVL1 rs4804244 for PFS. Conclusions: Our results indicate prognostic potential of SNPs in RBP genes, such as RBM3 and LIN28B, in mCRC. However, we find no distinct evidence that these SNPs can predict differential effect between Cet and Bev, or between oxaliplatin- and irinotecan-based chemotherapy.

Gene expression and genetic variants in Parkinson's disease (PD) genes to predict outcome in metastatic colorectal cancer (mCRC): Data from FIRE-3 phase III trial

3595

Background: PD is one of the most common age-related neurodegenerative disorders. Large epidemiological studies have consistently reported a reduced risk of CRC in PD patients (pts), but the biology behind this evidence is unclear. The methylation status of SNCA, one of the causal PD genes, has been identified as a tool for CRC screening and early diagnosis when detected in stool samples, and alterations in core PD genes are prevalent across human malignancies including CRC. Methods: The impact on outcome of 13 SNPs within 6 core PD genes ( SNCA, PRKN, UCHL1, PINK1, DJ-1, LRRK2) was analyzed in pts enrolled in the randomized FIRE-3 trial. Genomic DNA from blood samples of pts treated with first-line FOLFIRI-cetuximab (cet, n = 129) and FOLFIRI-bevacizumab (bev, n = 107) was genotyped through the OncoArray, a custom array manufactured by Illumina. Gene expression levels were measured from 102 tumor samples of pts in the cet arm by HTG EdgeSeq Oncology Biomarker Panel. Results: In the cet cohort, pts carrying the G/G variants of SNCA rs356165 and rs2736990 had significantly shorter mOS (30 vs 41.1 mo) compared to any A genotype in both uni- and multivariable analysis (adjusted P[ Padj] = .047 and .042, respectively). LRKK2 rs3761863 T/T allele carriers showed shorter mPFS (9.5 vs 13.3 mo, Padj = .01), while rs11564148 any A carriers had longer mPFS (14.2 vs 10.2 mo, Padj = .01) compared to reference genotypes. LRKK2 rs11564148 any A carriers also showed longer mOS in multivariable analysis (43.7 vs 33.2 mo, Padj = .044). Any C allele carriers of PINK1 rs1043424 showed longer mPFS in uni- and multivariable analysis ( Padj < .001). No significant interaction was found with gender, tumor location and RAS status. These associations were not observed in bev arm. High SNCA expression was associated with worse mPFS (log2 > 7.89, 5.9 vs 11.2 mo) and mOS (log2 > 7.68, 17.9 vs 31.1 mo) in FIRE-3 cet arm ( P < .05). Conclusions: We provide the first evidence that gene expression and genetic variants in PD genes may have a predictive value in mCRC pts receiving first-line cetuximab-based treatment. Our findings open new perspectives on the role of PD genes in CRC biology warranting further investigation.

Molecular Profiling of Appendiceal Adenocarcinoma and Comparison with Right-sided and Left-sided Colorectal Cancer

PURPOSE

The natural history and prognosis of appendiceal adenocarcinomas differ from those of adenocarcinomas arising in other large bowel sites. We aimed to compare the molecular profiles exhibited by appendiceal adenocarcinomas and colorectal cancers, or between the histopathologic subtypes of appendiceal adenocarcinoma.

EXPERIMENTAL DESIGN

A total of 183 samples from appendiceal adenocarcinoma [46 adenocarcinoma, not otherwise specified (NOS), 66 pseudomyxoma peritonei (PMP), 44 mucinous adenocarcinoma (MU), and 27 signet ring cell carcinoma (SR)], 994 from right-sided colorectal cancer (R-CRC), and 1,080 from left-sided CRC (L-CRC) were analyzed by next-generation sequencing (NGS) and IHC markers. Microsatellite instability (MSI) and tumor mutational burden (TMB) were tested by NGS, and programmed death ligand 1 (PD-L1) by IHC.

RESULTS

We observed high mutation rates in appendiceal adenocarcinoma samples for KRAS (55%), TP53 (40%), GNAS (31%), SMAD4 (16%), and APC (10%). Appendiceal adenocarcinoma exhibited higher mutation rates in KRAS and GNAS, and lower mutation rates in TP53, APC, and PIK3CA (6%) than colorectal cancers. PMP exhibited much higher mutation rates in KRAS (74%) and GNAS (63%), and much lower mutation rates in TP53 (23%), APC (2%), and PIK3CA (2%) than NOS. Alterations associated with immune checkpoint inhibitor response (MSI-high, TMB-high, PD-L1 expression) showed similar frequency in appendiceal adenocarcinoma compared with L-CRC, but not R-CRC, and those of NOS were higher than other subtypes of appendiceal adenocarcinoma and L-CRC.

CONCLUSIONS

Molecular profiling of appendiceal adenocarcinoma revealed different molecular characteristics than noted in R-CRC and L-CRC, and molecular heterogeneity among the histopathologic subtypes of appendiceal adenocarcinoma. Our findings may be critical to developing an individualized approach to appendiceal adenocarcinoma treatment.

Genetic variants in the lipopolysaccharide (LPS) receptor complex and TLR4 expression levels to predict efficacy of cetuximab (cet) in patients (pts) with metastatic colorectal cancer (mCRC): Data from the FIRE-3 phase III trial

564

Background: Large metagenomic studies associate disrupted gut microbiome signatures, comprising more prevalently gram-negative bacteria, with CRC carcinogenesis. TLR4, the LPS receptor, has been involved in microbiota-mediated tumorigenesis. High TLR4 expression is associated with poor prognosis in CRC and TLR4 can activate EGFR through ligands epiregulin and amphiregulin. Hence, we hypothesized that genetic variants in the LPS receptor complex and TLR4 expression levels may predict cetuximab efficacy in mCRC pts. Methods: Genomic DNA from blood samples of pts enrolled in the randomized FIRE-3 trial was genotyped through the OncoArray, a custom array manufactured by Illumina. The impact on outcome of 5 functional SNPs within TLR4, MD2 and CD14 was analyzed in 129 pts treated with first-line FOLFIRI/cet (discovery, mPFS/OS: 12.8/49.8 mo) and 107 pts treated with FOLFIRI/bevacizumab (bev) (mPFS/OS: 11.5/31.4 mo). Gene expression levels were measured from 102 tumor samples of pts in the cet arm by HTG EdgeSeq Oncology Biomarker Panel. Results: In the discovery cohort, pts carrying the C/T variant of TLR4 rs4986791 had significantly shorter mPFS and OS compared to the C/C genotype in both uni- and multivariable analysis (PFS: 5.4 vs 13.3 mo, adjusted P[ Padj] = .01; OS: 21.7 vs 40.7 mo, Padj= .03). Conversely, C/C carriers of rs12377632 had a longer mPFS compared to any T in uni- and multivariable analysis (15.8 vs 12.2 mo, Padj< .001). Any A allele carriers of MD2 rs12546552 and any G allele carriers of CD14 rs2569190 showed shorter mPFS in multivariable analyses. These associations were not observed in bev arm. Significant interaction was found between TLR4 rs12377632 and RAS status ( P= .015). High TLR4 expression (log2 > 10.93) was associated with worse mPFS (7.2 vs 11 mo, P= .003) and OS (19.1 vs 29.8 mo, P< .001) in FIRE-3 cet arm. Conclusions: Our results provide the first evidence that polymorphisms in the LPS receptor complex and TLR4 expression levels may have a predictive value in mCRC pts receiving first-line cetuximab-based treatment and, overall, contribute to resistance to anti-EGFRs.

Characteristics of colorectal cancer (CRC) patients with BRCA1 and BRCA2 mutations

606

Background: Between 3-5% of CRC patients have BRCA1/2 pathogenic mutations. This study aims to identify associations between BRCA1 and BRCA2 mutations and clinical characteristics in CRC. Methods: A total of 6396 CRC tumor samples were tested with Next-Generation Sequencing (NGS) on a 592-gene panel, pathogenic or presumed pathogenic variants were counted as mutations (mt). Microsatellite instability (MSI) and tumor mutational burden (TMB) were tested by NGS. Statistical correlations were investigated using ANOVA, Chi-square and t-test. Results: Among tumors sampled, 53% derived from male patients and median age was 60 years. BRCA1 mt were detected in 1.1% (n = 72) of tumors, while BRCA2 in 2.8% (n = 179). BRCA1 mt were more frequent in women (W;65%) than men (M;35%) (p = 0.0019) while no relationship with sex was seen for BRCA2 mt (42% F vs. 58% M). No significant associations with age were noticed. Majority of pathogenic mt in BRCA1 (52%; n = 34) and BRCA2 (62%; n = 103) occurred in MSI-High (MSI-H) cases. MSI-H pts had more frameshift mt in both BRCA1/2 than MSS pts. MSS cases had lower rates of BRCA1 and 2 pathogenic mt (44% and 37%, respectively). Right-sided tumors were significantly associated with BRCA1 (p = 0.0056) and BRCA2 (p < 0.0001) mt in MSI-H cases only. BRCA1/2 mt were associated with higher TMB in all CRCs, including MSI-H and MSS cases (p < 0.001). POLE mt (n = 31) were associated with higher BRCA1/2 mt rates (9.6%, 55% respectively). Among MSS cases with POLE wild-type status, BRCA1 (p = 0.0269) and BRCA2 (p = 0.0151) mt were associated with high TMB and combining both BRCA1/2 mutations led to an even higher TMB (3.6%; p = 0.001). Conclusions: This is the first study to show that BRCA1/2 mutations are more frequent in MSI-H, and independently associated with higher TMB, pathogenic POLE mutations, and right-sided tumors in MSI-H CRCs. Given their relationship with TMB, the presence of BRCA1/2 mutations may be potential predictive biomarkers for checkpoint or PARP inhibitors in CRC, a finding that should be prospectively evaluated.

Polymorphisms in the telomerase complex to predict outcome in patients (pts) with metastatic colorectal cancer (mCRC): Data from TRIBE and FIRE-3 phase III trials

566

Background: Telomere/telomerase interplay is involved in the regulation of genomic stability and cellular replicative potential. In CRC, shortening of telomeres promotes early steps of carcinogenesis but the prognostic role of telomere length is debated. High circulating levels of telomerase reverse transcriptase (TERT) appear to be a negative prognostic biomarker and polymorphisms in the telomerase RNA component (TERC) are associated with increased cancer risk. We hypothesized that genetic variants in the telomerase/telomere capping complex may predict first-line treatment outcome in mCRC pts. Methods: The impact on outcome of 21 selected SNPs within 13 genes ( TERT, TERC, CLPTM1L, TERF1/2, POT1, ACD, NOP10, NHP2, GAR1, STN1, CTC1) was analyzed through the OncoArray, a custom array manufactured by Illumina, on genomic DNA from blood samples of 451 pts enrolled in two independent randomized trials. TRIBE FOLFIRI/bevacizumab (bev) arm (n=215, mPFS/OS: 9.7/26.2 mo) served as discovery cohort, FIRE-3 FOLFIRI/bev arm (n=107, mPFS/OS: 11.5/31.4 mo) as validation and FOLFIRI/cetuximab (cet) arm (n=129, mPFS/OS: 12.8/49.8 mo) as control. Results: In the discovery cohort, pts carrying any A allele of TERT rs2075786 showed longer mPFS (11.1 vs 9.3 mo, P= .021) and OS (33.5 vs 25 mo, P= .005) compared to the G/G genotype in multivariable analysis. Same results were observed for pts carrying any T allele of CLPTM1L rs401681 compared to the C/C genotype ( P= .022). Any C allele carriers of TERC rs2293607 also showed longer mOS in multivariable analysis ( P= .041) and the A/A genotype of ACD rs6979 was associated with longer mPFS in both uni- and multivariable analysis. Interestingly, the T/T genotype of CLPTM1L rs401681 was associated with shorter mPFS (7.8 vs 13.5 mo) in the cet cohort in uni- ( P= .003) and multivariable analysis ( P= .041). In subgroup analyses based on RAS mutational status several SNPs in additional genes were associated with PFS and/or OS in different cohorts. Conclusions: Our results suggest that SNPs in core telomerase/telomere capping complex genes may have a predictive and prognostic value in mCRC pts receiving targeted first-line treatments.

Genetic variations within the CD40L immune stimulating gene predict outcome for mCRC patients treated with first-line FOLFIRI/bevacizumab: Data from FIRE-3 and TRIBE

558

Background: The introduction of immunotherapy has significantly improved outcome in various tumors. Immune stimulating proteins exert an anti-tumor effect mainly through enhancing T-cell mediated immune response. Additionally, preliminary data suggest a major role of immune stimulating proteins in modulating angiogenesis. We therefore hypothesize that variations in genes involved in the immune activation pathway may predict outcome in pts with mCRC treated with first-line FOLFIRI/ bevacizumab (bev). Methods: The impact of 4 functional SNPs within the CD40L, Light, OX40L and ICOS genes on outcome was evaluated in 322 pts with mCRC treated with first-line FOLFIRI/bev in two randomized phase III trials. We used TRIBE as a discovery (n = 215) and FIRE-3 as a validation set (n = 107). One hundred twenty-nine pts treated with FOLFIRI/cetuximab (cet) served as a control cohort (FIRE-3). OncoArray, a custom array manufactured by Illumina was used for data extraction. Genomic DNA was extracted from blood. Results: Baseline characteristics: FOLFIRI/bev, discovery set (TRIBE), median PFS/OS/FU 9.7/26.2/48.9 mo; FOLFIRI/bev, validation set (FIRE-3), PFS/OS/FU 11.5/32.4/71.1 mo; FOLFIRI/cet, control set (FIRE-3) PFS/OS/FU 12.8//23.9/70.7 mo. The CD40L rs1126535 SNP showed significant association with OS. Pts in the discovery cohort harboring any T allele and treated with FOLFIRI/bev had a longer median OS compared to C/C carriers (27.9 vs. 20.0 mo) in both univariate (HR 1.83, 95% CI 1.19-2.81, p = 0.005) and multivariate analyses (HR 1.62, 95% CI 1.03-2.56, p = 0.038). Similarly, any T allele carriers in the validation cohort had a significantly longer median OS than those harboring a C/C genotype (40 vs. 19.0 mo) in the multivariate analysis (HR 2.80, 95% CI 1.05-7.50, p = 0.040). However, this association could not be shown in pts receiving FOLFIRI/cet (HR 0.60, 95% CI, 0.18-1.94, p = 0.38). Conclusions: We show for the first time that the CD40L polymorphism rs1126535 might serve as a predictive marker in pts with mCRC treated with FOLFIRI/bev. Targeting CD40L might be promising to further improve treatment against mCRC and to overcome resistance to anti-angiogenic therapy.

Th17 cell pathway-related genetic variants in metastatic colorectal cancer: A meta-analysis using TRIBE, MAVERICC, and FIRE-3

594

Background: Th17 cells constitute a subset of T-helper cells, and play a role in immune response to extracellular pathogens in the human intestinal tract. Further, Th17 cells are associated with tumor angiogenesis and enhanced efficacy of 5-FU treatment. We thus investigated associations between the Th17 cell pathway-related SNPs and clinical outcomes in patients with metastatic colorectal cancer (mCRC) treated with conventional chemotherapy. Methods: We analyzed a total of 884 patients with mCRC enrolled in three randomized clinical trials (TRIBE, MAVERICC, and FIRE-3: where patients were treated with FOLFIRI, mFOLFOX6, or FOLFOXIRI combined with bevacizumab or cetuximab as the first-line chemotherapy). Multivariable logistic regression and Cox regression were performed to evaluate the association between candidate SNPs in the Th17 cell pathway and clinical outcomes [tumor response (TR), progression-free survival (PFS), and overall survival (OS)] in each treatment cohort. The meta-analysis approach using the METASOFT software were implemented to quantify the prognostic effect of each SNP using the inverse-variance-weighted effect size, and also to evaluate the heterogeneity across cohorts using the Q statistic. SNPs were coded as additive, dominant, or recessive in the analysis. The Pegasus analysis was also used to identify effects across multiple SNPs and treatment arms. Results: Pathway analysis showed that the Th17 cell pathway was significantly associated with TR ( P = 0.011). There were suggestive associations of IL17F rs763780 with TR (log OR = 0.64, SE = 0.31; P = 0.038), of IL23R rs10889677 with TR (log OR = 0.37, SE = 0.18; P = 0.039), of IRF4 rs872071 with TR (log OR = -0.26, SE = 0.13; P = 0.037), and of IL21 rs2221903 with PFS (log HR = 0.33, SE = 0.15; P = 0.026), although these results were not significant after FDR adjustment. In addition, IL23R rs10889677 had suggestive heterogeneity of effects for PFS across the six cohorts after Cochran’s Q statistic ( P = 0.013). Conclusions: Th17 cell pathway-related SNPs may be predictors for the first-line chemotherapy in mCRC. Upon validation, our findings would provide novel insight for selecting treatment strategies for mCRC.

Comprehensive molecular profiling of signet-ring-cell carcinoma (SRCC) from the stomach and colon

63

Background: Signet ring cell carcinoma (SRCC) is a rare variant of adenocarcinoma, accounting for about 10% of gastric cancer (GC) and 1% of colorectal cancer (CRC). SRCC is associated with poor prognosis, however little is known about the underlying molecular characteristics. Herein, we aimed to characterize the molecular features of SRCCs, and to compare the molecular profile of SRCC to adenocarcinoma; further, we assessed the impact of tumor location on the molecular profile of SRCC. Methods: SRCCs were analyzed using NGS (MiSeq on 47 genes, NextSeq on 592 genes), immunohistochemistry, and in-situ hybridization. Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci. Chi-square and t-tests were used for comparative analyses. Results: A total of 8,500 CRC and 1,100 GC were screened for SRCC histology. Seventy-six SRCC were identified from the CRC cohort (<1%) and 98 from the GC cohort (9%). The most frequently mutated genes in CRC-SRCC were TP53 (47%), ARID1A (26%), APC (25%), KRAS (22%), RFN43 (16%), KMT2D (12%), KMT2C (11%), SMAD4 (10%) and BRAF (10%), while in GC-SRCC were TP53 (42%), ARID1A (27%), CDH1 (11%), BAP1 (7%), PIK3CA (7%), ERBB2 (5%). When compared to non-SRCC histology (N=3522), CRC-SRCC (N=37) showed more frequently mutation in BRCA1 (11% vs 1%, P < .001) and less mutation in APC (19% vs 78%, P < .001), KRAS (22% vs 51%, P = .001) and TP53 (47% vs 73%, P = .001). Among GC cohort, SRCC (N=54) had a higher frequency of mutations in CDH1, BAP1, and ERBB2, and higher rate of amplification MYB compared to non-SRCC (N=540), although none of these differences were statistically significance. When we compared GC-SRCC vs. CRC-SRCC, only the mutation rate in APC (0% vs 25%) and KRAS (2% vs 22%) genes were significantly different (P < .001). Conclusions: Our research is the first to comprehensively characterize the molecular features of SRCC. Our data suggest that SRCCs harbor similar molecular profile, regardless the tumor location. On the other hand, significant differences were observed between SRCCs and non-SRCC tumors, therefore tailored therapy should be provided to these patients.

The impact of preoperative anaemia and anaemic subtype on patient outcome in colorectal cancer

AIM

Preoperative anaemia is associated with adverse outcomes in colorectal cancer (CRC). To clarify the reason for this we aimed to comprehensively assess the association of preoperative anaemia with tumour characteristics, host systemic inflammation and nutrition status, and perioperative blood transfusion.

METHOD

We used an integrated database of 592 CRC patients. The association of preoperative anaemic subtype, calculated from haemoglobin and erythrocyte mean corpuscular volume levels, with patient outcome, preoperative serum data relating to systemic inflammation and nutrition and perioperative blood transfusion was analysed.

RESULTS

Preoperative anaemia was significantly associated with poorer overall survival and relapse-free survival (RFS); in particular microcytic anaemia had a trend to poorer RFS than other forms of anaemia (P = 0.0648). In addition, preoperative anaemia was significantly correlated with right-sided tumours, greater depth of tumour invasion, use of neoadjuvant chemotherapy, poorer prognostic nutritional index and higher modified Glasgow Prognostic Score (mGPS). Microcytic anaemia in particular had a strong association with a greater depth of tumour invasion (P = 0.0072) and higher mGPS (P = 0.0058) than other causes of anaemia. Perioperative blood transfusion for CRC patients with anaemia was associated with adverse outcomes.

CONCLUSIONS

Preoperative anaemia, especially microcytic anaemia, was associated with poor patient outcomes, possibly due to poor systemic inflammatory and nutritional status, and it was not improved by perioperative blood transfusion. Our data suggest that preoperative anaemia and the anaemic subtype may serve as an easily available predictor of outcome in CRC.

B cell and B cell-related pathways for novel cancer treatments

B cells are recognized as the main effector cells of humoral immunity which suppress tumor progression by secreting immunoglobulins, promoting T cell response, and killing cancer cells directly. Given these properties, their anti-tumor immune response in the tumor micro-environment (TME) is of great interest. Although T cell-related immune responses have become a therapeutic target with the introduction of immune checkpoint inhibitors, not all patients benefit from these treatments. B cell and B cell-related pathways (CCL19, -21/CCR7 axis and CXCL13/CXCR5 axis) play key roles in activating immune response through humoral immunity and local immune activation via tertiary lymphoid structure (TLS) formation. However they have some protumorigenic works in the TME. Thus, a better understanding of B cell and B cell-related pathways is necessary to develop effective cancer control. In this review, we summarize recent evidences regarding the roles of B cell and B cell-related pathways in the TME and immune response and discuss their potential roles for novel cancer treatment strategies.

Enhancer of zeste homolog 2 (EZH2) regulates tumor angiogenesis and predicts recurrence and prognosis of intrahepatic cholangiocarcinoma

BACKGROUND

Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of the polycomb repressive complex 2 (PRC2) and regulates tumor malignancy by gene silencing via histone methylation. In this study we investigate the role of EZH2 in angiogenesis of intrahepatic cholangiocarcinoma (ICC).

METHODS

The influence of EZH2 on tumor angiogenesis was examined by bioinformatics analysis of a public database. We also assessed the correlation between EZH2 and vasohibin 1 (VASH1) expression in 47 patients with ICC by immunohistochemical (IHC) staining and in vitro gene silencing assays. The prognostic significance of EZH2 and VASH1 expression by IHC was also examined in the ICC cohort.

RESULTS

Bioinformatics analysis showed that EZH2 was associated with several angiogenesis gene sets in the public database. EZH2 suppressed VASH1 expression in in vitro assays and IHC studies. EZH2-high/VASH1-low status was independently associated with poor disease-free survival (P = 0.019) and poor overall survival (P = 0.0055).

CONCLUSION

The current study demonstrated that high EZH2 expression was associated with activation of tumor angiogenesis, and activation of the EZH2-mediated angiogenesis pathway predicted the prognosis of patients with ICC.

Percutaneous transluminal plasty: a novel approach for refractory anastomotic stricture after esophagectomy

Anastomotic stricture is often observed after esophagectomy. Surgical treatment is considered for refractory stricture to conservative treatments. However, it is not established what type of surgery is safe and effective. In this report, we present a novel approach, percutaneous transluminal plasty, for refractory anastomotic stricture reconstructed via the subcutaneous route in esophagectomy. We believe that the effectiveness and safety of this technique is considerably good and can become a good alternative for refractory stricture after esophagectomy.

Prognostic Effect of Adenosine-related Genetic Variants in Metastatic Colorectal Cancer Treated With Bevacizumab-based Chemotherapy

BACKGROUND

Adenosine has an immunosuppressive and angiogenic modulation of the tumor microenvironment. The present study explored the efficacy of single nucleotide polymorphisms (SNPs) in adenosine-related molecules for patients with metastatic colorectal cancer treated with bevacizumab-based chemotherapy.

PATIENTS AND METHODS

We analyzed genomic DNA extracted from 451 samples from 3 independent cohorts: a discovery cohort of 107 patients treated with FOLFIRI (5-fluorouracil, leucovorin, oxaliplatin, irinotecan) plus bevacizumab in FIRE-3 (ClinicalTrials.gov identifier, NCT00433927); a validation cohort of 215 patients with FOLFIRI plus bevacizumab in TRIBE (ClinicalTrials.gov identifier, NCT00719797); and a control cohort of 129 patients treated with FOLFIRI plus cetuximab in FIRE-3. The relationship between the selected SNPs and clinical outcomes was analyzed.

RESULTS

In the discovery cohort, patients with any C allele in CD39 rs11188513 had significantly shorter median progression-free survival compared with those with the T/T variant (11.3 vs. 13.1 months; hazard ratio [HR], 1.70; 95% confidence interval [CI], 1.04-2.77; P = .022) on univariate analysis. Also, their overall survival (OS) was shorter (27.4 vs. 49.9 months; HR, 2.10; 95% CI, 1.07-4.10; P = .031) on univariate and multivariable analyses. The significant association between CD39 rs11188513 and OS was confirmed in the validation cohort (25.8 vs. 31.6 months; HR, 1.53; 95% CI, 1.09-2.15; P = .013). CD73 rs2229523 and A2BR rs2015353 in the discovery cohort and CD39 rs2226163 in the validation cohort showed significant correlations with OS on univariate and multivariable analyses. None of SNPs were significant in the cetuximab control cohort.

CONCLUSION

Selected SNPs in the adenosine pathway could affect the clinical outcomes of patients with metastatic colorectal cancer treated with FOLFIRI plus bevacizumab.

Controlling Nutritional Status (CONUT) Score Is a Prognostic Marker in Metastatic Colorectal Cancer Patients Receiving First-line Chemotherapy

BACKGROUND/AIM

The Controlling Nutritional Status (CONUT) score is a useful nutritional evaluation, that is calculated from serum albumin, total cholesterol concentrations, and total lymphocyte count. This study aimed to investigate the association between the CONUT score and prognosis in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

The CONUT score was retrospectively calculated in 211 patients with mCRC receiving first-line chemotherapy. The patients were divided into three groups: the CONUT low-group (0-1), intermediate-group (2-4), and high-group (5-). The associations of the CONUT score with clinicopathological factors and survival outcomes were evaluated.

RESULTS

The higher CONUT score was significantly associated with synchronous metastases, and no primary tumor resection. The higher CONUT score group showed a significant shorter progression-free survival (log-rank p<0.05) and overall survival (log-rank p<0.001).

CONCLUSION

The CONUT score is a useful prognostic marker for predicting survival outcomes of patients with mCRC.

Increased EZH2 expression during the adenoma-carcinoma sequence in colorectal cancer

The adenoma-carcinoma sequence, the sequential mutation and deletion of various genes by which colorectal cancer progresses, is a well-established and accepted concept of colorectal cancer carcinogenesis. Proteins of the polycomb repressive complex 2 (PRC2) function as transcriptional repressors by trimethylating histone H3 at lysine 27; the activity of this complex is essential for cell proliferation and differentiation. The histone methyltransferase enhancer of zeste homolog 2 (EZH2), an essential component of PRC2, is associated with the transcriptional repression of tumor suppressor genes. EZH2 expression has previously been reported to increase with the progression of pancreatic intraductal papillary mucinous neoplasm. Thus, we hypothesized that EZH2 expression also increases during the adenoma-carcinoma sequence of colorectal cancer. The present study investigated changes in EZH2 expression during the colorectal adenoma-carcinoma sequence. A total of 47 patients with colorectal adenoma, 20 patients with carcinoma in adenoma and 43 patients with colorectal carcinoma who underwent surgical or endoscopic resection were enrolled in this study. Non-cancerous tissue from the clinical specimens was also examined. The association between EZH2 expression, pathology and expression of tumor suppressor genes during colorectal carcinogenesis were analyzed. Each specimen was immunohistochemically stained for EZH2, proliferation marker protein Ki-67 (Ki-67), cyclin-dependent kinase inhibitor (CDKN) 1A (p21), CDKN1B (p27) and CDKN2A (p16). Total RNA was extracted from formalin-fixed paraffin-embedded blocks and reverse transcription-quantitative polymerase chain reaction analysis of these genes was performed. Ki-67 and EZH2 expression scores increased significantly during the progression of normal mucosa to adenoma and carcinoma (P=0.009), and EZH2 expression score was positively associated with Ki-67 expression score (P=0.02). Conversely, p21 mRNA and protein expression decreased significantly, whereas expression of p27 and p16 did not change significantly. During the carcinogenesis sequence from normal mucosa to adenoma and carcinoma, EZH2 expression increased and p21 expression decreased significantly. EZH2 may therefore contribute to the development of colorectal cancer from adenoma via suppression of p21.

Abstract 2614: Macrophage erythroblast attacher (MAEA) polymorphisms are associated with clinical outcome in TRIBE study mCRC patients treated with 5-fluorouracil/bevacizumab-based therapy

Background: Macrophage erythroblast attacher (MAEA) also known as Emp (Erythroblast macrophage protein) plays indispensable role in erythroblast and macrophage development and targeted disruption of Emp is embryonically lethal (Soni et al., JBC 2006). Recently, down-regulation of Emp was implicated in abnormal cell motility and higher expression of mitogen-activated protein kinase 1 (MAPK 1) and thymoma viral proto-oncogene 1 (Akt 1) (Gulnaz et. al., BCMD 2016). Our preliminary studies, shows that higher expression of MAEA is associated with longer colorectal cancer (CRC) patient survival. We tested two MAEA polymorphisms (rs13149952 and rs1128427), whether these are correlated with clinical outcome in mCRC treated with 5-Fluorouracil / Bevacizumab based therapy. Methods: Genomic DNA was isolated from blood samples of two cohorts of mCRC patients. Cohort 1 included 227 patients treated with FOLFIRI/BEV (TRIBE trial Arm A, RAS wildtype/mutant=55/116, median age=60 years old, median follow-up period=49.3 months). Cohort 2 had 229 patients treated with FOLFOXIRI/BEV (TRIBE trial Arm B, RAS wildtype/mutant=60/115, median age=60 years old, median follow-up period=46.6 months). PCR-based direct Sanger sequencing was used to determine polymorphism. Results: Our results showed that MAEA rs1128427 in TRIBE arm A patients with RAS mutant tumors having any C genotype was significantly associated with longer overall survival as compared to TT genotype in univariate analysis {25.9 vs 18.8 months, HR(95% CI)=0.61(0.38,0.98), p=0.036}. In TRIBE arm B cohort, MAEA rs1128427 in patients with RAS mutant tumors carrying CC genotype showed significantly longer overall survival than patients with any T allele in both univariate and multivariable analyses {33.4 vs 25 months, uni: HR(95% CI)=0.57(0.34,0.95), p=0.028; multi: HR(95% CI)=0.56(0.32,0.96), p=0.034}. Conclusion: Our findings suggest for the first time, that polymorphisms in MAEA may predict the clinical outcome in Bevacizumab based therapies. Further prospective studies are warranted.

Citation Format: Shivani Soni, Yuji Miyamoto, Wu Zhang, Martin D. Berger, Shu Cao, Elizabeth Melendez, Alberto Puccini, Madiha Naseem, Ryuma Tokunaga, Francesca Battaglin, Michelle Mcskane, Chiara Cremolini, Alfredo Falcone, Fotios Loupakis, Heinz-Josef Lenz. Macrophage erythroblast attacher (MAEA) polymorphisms are associated with clinical outcome in TRIBE study mCRC patients treated with 5-fluorouracil/bevacizumab-based therapy [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 2614.

Minimally invasive esophagectomy may contribute to long-term respiratory function after esophagectomy for esophageal cancer

Evidence suggests that minimally invasive esophagectomy has several advantages with regard to short-term outcomes, compared to open esophagectomy in esophageal cancer patients. However, the impact of minimally invasive esophagectomy on long-term respiratory function remains unknown. The objective of this study is to assess the association between use of the minimally invasive esophagectomy and long-term respiratory dysfunction in esophageal cancer patients after esophagectomy. This retrospective single institution study using prospectively collected data included 87 consecutive esophageal cancer patients who had undergone esophagectomy. All patients underwent a respiratory function test before, and one year after esophagectomy. Logistic regression analysis was used to compute the hazard ratio for long-term respiratory dysfunction. Minimally invasive esophagectomies were performed in 53 patients, and open esophagectomies in 34 patients. The two groups showed no significant differences in terms of postoperative complications and postoperative course. Nor were any differences observed between the two groups in terms of volume capacity (L) and forced expiratory volume 1.0 (L) before esophagectomy (P > 0.34). However, one year after esophagectomy, the decreases in volume capacity and forced expiratory volume 1.0 were significantly less in the minimally invasive esophagectomy group than in the open esophagectomy group (P = 0.04 and P = 0.007, respectively). Multivariate analyses revealed that minimally invasive esophagectomy was an independent favorable factor for maintenance of forced expiratory volume 1.0 (hazard ratio = 0.17, 95% confidence interval 0.04-0.71; P = 0.01). Minimally invasive esophagectomy may be an independent favorable factor for maintenance of long-term respiratory function in esophageal cancer patients after esophagectomy.

Outlooks on Epstein-Barr virus associated gastric cancer

Epstein-Barr virus associated gastric cancer (EBVaGC) comprises approximately 10% of gastric carcinomas. Multiple factors contribute to tumorigenesis, including EBV driven hypermethylation of tumor suppressor genes, inflammatory changes in gastric mucosa, host immune evasion by EBV and changes in cell cycle pathways. The unique molecular characteristics of EBVaGC, such as programmed death ligand 1 (PD-L1) overexpression, highlight the potential for using EBV as a biomarker for response to immunotherapy. Few studies have reported benefit from immunotherapy in EBV positive cancers, and clinical trials investigating the impact of checkpoint inhibitors in EBVaGC are currently underway. This review provides the most recent updates on molecular pathophysiology, epidemiology, clinical features and treatment advances pertaining to EBVaGC.

Pharmacogenomics in colorectal cancer: current role in clinical practice and future perspectives

The treatment scenario of colorectal cancer (CRC) has been evolving in recent years with the introduction of novel targeted agents and new therapeutic strategies for the metastatic disease. An extensive effort has been directed to the identification of predictive biomarkers to aid patients selection and guide therapeutic choices. Pharmacogenomics represents an irreplaceable tool to individualize patients treatment based on germline and tumor acquired somatic genetic variations able to predict drugs response and risk of toxicities. The growing knowledge of CRC molecular characteristics and complex genomic makeup has played a crucial role in identifying predictive pharmacogenomic biomarkers, while supporting the rationale for the development of new drugs and treatment combinations. Clinical validation of promising biomarkers, however, is often an issue. More recently, a deeper understanding of resistance mechanisms and tumor escape dynamics under treatment pressure and the availability of novel technologies are opening new perspectives in this field. This review aims to present an overview of current pharmacogenomic biomarkers and future perspectives of pharmacogenomics in CRC, in an evolving scenario moving from a single drug-gene interactions approach to a more comprehensive genome-wide approach, comprising genomics and epigenetics.

Controlling Nutritional Status (CONUT) score is a prognostic marker for gastric cancer patients after curative resection

BACKGROUND

Controlling Nutritional Status (CONUT), as calculated from serum albumin, total cholesterol concentration, and total lymphocyte count, was previously shown to be useful for nutritional assessment. The current study investigated the potential use of CONUT as a prognostic marker in gastric cancer patients after curative resection.

METHODS

Preoperative CONUT was retrospectively calculated in 416 gastric cancer patients who underwent curative resection at Kumamoto University Hospital from 2005 to 2014. The patients were divided into two groups: CONUT-high (≥4) and CONUT-low (≤3), according to time-dependent receiver operating characteristic (ROC) analysis. The associations of CONUT with clinicopathological factors and survival were evaluated.

RESULTS

CONUT-high patients were significantly older (p < 0.001) and had a lower body mass index (p = 0.019), deeper invasion (p < 0.001), higher serum carcinoembryonic antigen (p = 0.037), and higher serum carbohydrate antigen 19-9 (p = 0.007) compared with CONUT-low patients. CONUT-high patients had significantly poorer overall survival (OS) compared with CONUT-low patients according to univariate and multivariate analyses (hazard ratio: 5.09, 95% confidence interval 3.12-8.30, p < 0.001). In time-dependent ROC analysis, CONUT had a higher area under the ROC curve (AUC) for the prediction of 5-year OS than the neutrophil lymphocyte ratio, the Modified Glasgow Prognostic Score, or pStage. When the time-dependent AUC curve was used to predict OS, CONUT tended to maintain its predictive accuracy for long-term survival at a significantly higher level for an extended period after surgery when compared with the other markers tested.

CONCLUSIONS

CONUT is useful for not only estimating nutritional status but also for predicting long-term OS in gastric cancer patients after curative resection.

Additional lymph node dissection for primary colorectal cancer invading another colon region

PURPOSE

Surgery remains the curative treatment of choice for colorectal cancer (CRC). However, to our knowledge, no report has addressed the usefulness of additional regional lymph node dissection for primary CRC that has invaded another colon region.

METHODS

We reviewed the clinicopathological characteristics and outcomes of eight patients who underwent surgery between March, 2005 and August, 2014, for CRC that invaded another region of the colon.

RESULTS

Five patients underwent additional regional lymph node dissection in the area of the invaded colon and one patient had lymph node metastasis in the region. Two of three patients who did not undergo additional regional lymph node dissection were found to have regional lymph node recurrences in the area during the follow-up period. Although there was no statistical correlation between extra-regional lymph node metastasis and clinicopathological or operative factors, the patients with extra-regional lymph node metastasis or recurrence had primary regional lymph node metastasis.

CONCLUSION

For curative intent, surgeons may need to perform additional regional lymph node dissection for primary CRC invading another colon region.

Polymorphisms in beta-defensin pathways and clinical outcomes in metastatic colorectal cancer patients treated with FOLFIRI-bevacizumab in two randomized phase III trials

662

Background: Beta defensin 1 (DEFB1) and 2 (DEFB4A) are antimicrobial peptides secreted from colonic epithelial cells in response to inflammation. DEFB1 has been shown to serve as a tumor suppressor, whereas high concentrations of DEFB4A are linked with angiogenesis. This study examines the impact of single nucleotide polymorphisms (SNPs) in beta-defensin pathways in two independent phase III trials: FIRE-3 and TRIBE. Methods: The OncoArray database containing 530K SNP markers provided by Illumina was used to find associations between clinical outcomes and 10 functional SNPs from DEFB1, DEFB4A, PPARG, NFKB1, MUC2, and TLR4 genes. Patients treated with first-line FOLFIRI/bevacizumab (bev) in the randomized phase III FIRE-3 trial (n = 107) and TRIBE trial (n = 215) served as discovery and validation cohorts respectively. The FIRE-3 FOLFIRI and cetuximab (cet) arm served as a negative control (n = 129). Results: A total of 451 patients were included. The NFKB1 rs3821958 SNP showed significant association with OS and PFS in overall pts and those with left-sided CRC. Compared to pts carrying the mutant A allele, those with the wild-type G/G genotype had a shorter median OS (19 vs 40 mts) and PFS (9.2 vs 11.7 mts) in both univariate ((OS: HR = 2.32, 95%CI 1.21-4.42, p = 0.006) (PFS: HR = 1.93, 95%CI: 1.11-3.37, p = 0.014)) and multivariable analysis ((OS: HR = 2.90, 95%CI 1.47-5.70, p = 0.002) (PFS: HR = 2.08, 95%CI:1.18-3.67, p = 0.012)). This finding was validated in TRIBE, where carriers of G allele had shorter PFS in univariate analysis (HR = 1.44, p = 0.019). Opposite results were observed in pts receiving cet, where G/G carriers had improved OS in univariate analysis (HR = 0.46, p = 0.048). Pts with left-sided CRC who carried the wild-type allele had poorer OS and PFS in both trials. Conclusions: NFKB1 rs3821958 SNP is known to activate DEFB1 and is downstream of EGFR. Harboring a mutant allele in this SNP confers a mortality benefit in left-sided and overall pts treated with bev, and worsens OS in pts receiving cet. Hence, NFKB1 could serve as an important predictive biomarker. Future studies are warranted to further elucidate its role in colorectal cancer.

The impact of Tfh cell/ B cell pathway-related genetic variants in metastatic colorectal cancer patients with bevacizumab-based chemotherapy

651

Background: B cells are recognized for their immune activation and lymph-angiogenesis, which attract us to clarify the correlation between B cells and the effect of bevacizumab in cancer patients. We thus investigated whether genetic polymorphisms in Tfh cell/ B cell pathway could predict clinical outcomes in metastatic colorectal cancer (mCRC) patients with bevacizumab-based chemotherapy in first-line treatment. Methods: Genomic DNA was extracted from 451 samples of three independent cohorts: a discovery cohort of 215 patients with bevacizumab plus FOLFIRI in TRIBE (NCT00719797); a validation cohort of 107 patients with bevacizumab plus FOLFIRI in FIRE-3 (NCT00433927); a control cohort of 129 patients with cetuximab plus FOLFIRI in FIRE-3. The OncoArray including 530K single nucleotide polymorphisms (SNPs) from Illumina was used in this study. The correlation between selected SNPs in Tfh cell/ B cell pathway ( CCL19, CCL21, CCR7, CXCL13, CXCR5, and S1PR2) and clinical outcomes were analyzed. Results: In the discovery cohort, patients with any CXCL13 rs355687 C allele had shorter OS than those with T/T variant (22.9 vs. 30.8 months, HR 1.36, 95%CI: 1.00–2.86, P = 0.050), which remained significant in multivariable analysis (HR 1.51, P = 0.013); they also showed a trend of lower response rate (51 vs. 63%, P = 0.093); patients with any CCL21 rs11574915 C allele had shorter OS than those with A/A variant (25.6 vs. 27.9 months) in both univariate (HR 1.43, 95%CI: 1.01–2.02, P = 0.043) and multivariable analyses (HR 1.50, P = 0.030). In the validation cohort, patients with any CXCL13 rs355687 C allele had a trend which showed lower response rate than those with T/T variant (56 vs. 71%, P = 0.099). The findings were not detected in the control cohort. Conclusions: Genetic polymorphisms of CXCL13 and CCL21 may impact the angiogenic environment and patients survivals. They are impacting efficacy of bevacizumab-based chemotherapy in first-line treatment.

Association of genetic variations within the PD-L2 immune checkpoint gene with outcome in stage II and III colon cancer

626

Background: Immune checkpoints can either inhibit or stimulate T-cell responses and therefore play a key role in maintaining an equilibrium between self tolerance and autoimmunity. Targeting immune checkpoint molecules can result in increased antitumor immunity by stimulation of the immune system. We hypothesize, that variations in genes encoding for both inhibitory or stimulatory immune checkpoint proteins may predict outcome in stage II and III colon cancer patients. Methods: The impact of 6 functional single nucleotide polymorphisms (SNPs) within the PD1, PD-L1, PD-L2, TIM3, OX40 and CD27 genes on time to recurrence was evaluated in 201 patients with stage II and III colon cancer. Genomic DNA was extracted from formalin-fixed paraffin embedded tissue and the SNPs were analyzed by PCR-based direct sequencing. Results: Baseline characteristics were as follows: female/male ratio = 42.8% / 57.2%; median age = 70y (19-91); median follow-up = 43months. The PD-L2 rs16923189 SNP showed significant association with recurrence rate. Patients with a G/G genotype had a higher 3-years recurrence rate compared to those harboring any A allele (41% vs 19%) in both univariate (HR 2.68, 95% Confidence interval (CI) 1.28-5.61, p = 0.006) and multivariate analyses (HR 3.13, 95% CI 1.42-6.28, p = 0.003). The high recurrence rate was most evident among patients with stage III and left-sided tumors carrying the G/G genotype (53% vs 24% and 65% vs 18%) in both univariate (HR 2.87, 95% CI 1.24-6.66, p = 0.009 and HR 5.28, 95% CI 2.24-12.44, p < 0.0001) and multivariate analyses (HR 4.32, 95% CI 1.76-9.91, p = 0.001 and HR 5.20, 95% CI 2.02-12.75, p = 0.001). Conclusions: Our results provide the first evidence, that polymorphisms within the PD-L2 gene might serve as prognostic markers in patients with stage II and III colon cancer. Interestingly, the prognostic effect is most significant among patients with stage III and left-sided colon cancers. Targeting PD-L2 might be a promising approach to further optimize treatment options and to improve outcome of colon cancer patients in the adjuvant setting.

Genetic variants in methylation and demethylation pathways to predict clinical outcome in metastatic colorectal cancer (mCRC) patients (pts) treated with first-line FOLFIRI/Bev: Data from TRIBE and FIRE-3 trials

646

Background: DNA hypermethylation in CpG islands (CIMP) has been shown to promote CRC by silencing the expression of tumor suppressor genes. However, global DNA hypomethylation is now considered a common characteristic of CRC. A new family of genes (TET) has been shown to play a crucial role in actively demethylating the DNA. We explored whether genetic polymorphisms in the genes which promote DNA methylation and demethylation are associated with outcome in pts enrolled in TRIBE and FIRE-3 trials. Methods: Genomic DNA from blood samples was genotyped through the OncoArray, a custom array by Illumina including 530K SNP markers. 17 functional SNPs within 11 genes related to methylation (DNMT1/3A/3B, MDM2) and demethylation pathways (TET1/2/3, IDH1/2, MBD4, TDG) were analyzed. Results: A total of 451 pts were included. FOLFIRI/bevacizumab (bev) arms from TRIBE (N = 215, median PFS/OS: 9.7/26.3 months (mts)) and FIRE3 (N = 107, median PFS/OS: 11.6/31.5 mts) served as discovery and validation cohorts respectively. FIRE-3 FOLFIRI/cetuximab arm (N = 129, median OFS/OS: 12.8/49.8 mts) served as control. In the discovery cohort, overall pts carrying TET1 rs3814177 C/C variant showed lower response rate (RR) (42.1% vs 61.8%, p = 0.026) and shorter median PFS (9.5 vs 10.3 mts; HR = 1.54, 95%CI = 1.04-2.27; p = 0.024, univariate analysis) compare to those with any T allele. The effect was more significant among KRAS mutant pts in RR (21.4% vs 60.8%, p = 0.007) and median PFS (8.6 vs 9.5 mts) both in univariate (HR = 2.00, 95%CI = 1.07-3.73; p = 0.020) and multivariable analysis (HR = 2.01, 95%CI = 1.03-3.92 p = 0.041). These findings were validated in overall pts in FIRE-3 cohort in median OS both in univariate (23.7 vs 41.9 mts; HR = 2.08, 95%CI = 1.07-4.05; p = 0.023), and multivariable analysis (HR = 2.36, 95%CI = 1.15-4.81; p = 0.019). No significant association was observed in the control arm. Conclusions: Our results provide the first evidence that TET1 polymorphism may be used as a predictive biomarker in mCRC pts treated with FOLFIRI/bev. Therefore, TET enzymes could serve as promising new treatment targets for mCRC pts.

Polymorphism in cancer-associated fibroblasts (CAFs) related genes and clinical outcome in metastatic colorectal cancer (mCRC) patients (pts) enrolled in two independent randomized phase III trials: TRIBE and FIRE-3

645

Background: Tumor microenvironment plays a critical role for CRC development and progression. CAFs are the most dominant cellular components which orchestrate tumor cell proliferation, survival and invasion and have been shown to be associated with prognosis in pts with CRC. We aimed to evaluate whether single-nucleotide polymorphisms (SNPs) in CAFs related genes predict outcome in mCRC pts treated with first-line FOLFIRI/bevacizumab (bev) in TRIBE and FIRE-3 trials. Methods: The OncoArray, a custom array by Illumina including 530K SNP markers, was used to genotype genomic DNA from blood samples and served as our database, from which 15 functional SNPs within 9 genes (OPN, CD44, TCN, CD63, TIMP1, SLIT2, ROBO1, LOXL2, INHBA) related to CAF pathway were analyzed. Results: A total of 451 pts were included. Those treated with FOLFIRI/bev in TRIBE (N = 215, median PFS/OS: 9.7/26.3 months (mts)) and FIRE-3 (N = 107, median PFS/OS: 11.6/31.5 mts) served as discovery and validation cohorts respectively, while FIRE-3 FOLFIRI/cetuximab arm (N = 129, median PFS/OS: 12.8/49.8 mts) was used as the control. In overall pts in discovery set, OPN (osteopontin) rs11728697 any C variants showed longer PFS (median 10.8 vs 9.0 mts; HR = 0.68, 95%CI = 0.49-0.95; p = 0.025) and OS (median 30.6 vs 23.8 mts; HR = 0.69, 95%CI = 0.50-0.95; p = 0.025) than the homozygous wild type genotype (T/T) in multivariable analysis. These data were validated in the FIRE-3 cohort in OS both in univariate (median 49.3 vs 23.7 mts; HR = 0.40, 95%CI = 0.21-0.77; p < 0.001) and in multivariable analyses (HR = 0.31, 95%CI = 0.16-0.60; p < 0.001). However, the favorable impact on outcome was not shown among C allele carriers treated with FOLFIRI/cetuximab in the control arm. Conclusions: Our findings confirm that CAFs play a crucial role in mCRC and suggest that OPN polymorphisms could serve as predictive biomarkers for mCRC pts treated with first-line FOLFIRI/bev.

Para-sacral approach for large gastrointestinal stromal tumor of the lower rectum

Rectal gastrointestinal stromal tumor (GIST) is comparatively rare and usually already large when detected. As resection is the main therapy for patients with primary resectable GIST, the surgical procedure must be tailored to the tumor status. For GISTs of the lower rectum, laparoscopic low anterior resection or abdominoperineal resection is one of the procedures of choice. However, rectal tumor, including rectal GIST, can also be surgically treated using a variety of posterior approaches. Of these, para-sacral approach is both simple and less invasive, even for large rectal GISTs, and provides a good view of the operative field. Here, we describe our procedure for the surgical treatment of large GISTs of the lower rectum.

Monitoring sputum culture in resected esophageal cancer patients with preoperative treatment

Pneumonia is a major cause of postesophagectomy mortality and worsens the long-term survival in resected esophageal cancer patients. Moreover, preoperative treatments such as chemotherapy or chemoradiotherapy (which have recently been applied worldwide) might affect the bacterial flora of the sputum. To investigate the association among preoperative treatments, the bacterial flora of sputum, and the clinical and pathological features in resected esophageal cancer patients, this study newly investigates the effect of preoperative treatments on the bacterial flora of sputum. We investigated the association among preoperative treatments, the bacterial flora of sputum, and clinical and pathological features in 163 resected esophageal cancer patients within a single institution. Pathogenic bacteria such as Candida (14.1%), Staphylococcus aureus (6.7%), Enterobacter cloacae (6.1%), Haemophilus parainfluenzae (4.9%), Klebisiella pneumoniae (3.7%), Methicillin-resistant Staphylococcus aureus (MRSA) (3.7%), Pseudomonas aeruginosa (2.5%), Escherichia coli (1.8%), Streptococcus pneumoniae (1.8%), and Haemophilus influenzae (1.2%) were found in the sputum. The pathogen detection rate in the present study was 34.3% (56/163). In patients with preoperative chemotherapy and chemoradiotherapy, the indigenous Neisseria and Streptococcus species were significantly decreased (P= 0.04 and P= 0.04). However, the detection rates of pathogenic bacteria were not associated with preoperative treatments (all P> 0.07). There was not a significant difference of hospital stay between the sputum-monitored patients and unmonitored patients (35.5 vs. 49.9 days; P= 0.08). Patients undergoing preoperative treatments exhibited a significant decrease of indigenous bacteria, indicating that the treatment altered the bacterial flora of their sputum. This finding needs to be confirmed in large-scale independent studies or well-designed multicenter studies.

Fibroblast growth factor receptor 2 expression, but not its genetic amplification, is associated with tumor growth and worse survival in esophagogastric junction adenocarcinoma

Background

Fibroblast growth factor receptor 2 (FGFR2) genetic alterations lead to tumor cell proliferation in various types of cancer. We hypothesized that FGFR2 amplification is associated with FGFR2 expression, resulting in tumor growth and poorer outcome in esophagogastric junction (EGJ) adenocarcinoma.

Patients and Methods

A total of 176 consecutive chemo-naive patients with EGJ adenocarcinoma were enrolled from two academic institutions. FGFR2 amplification was examined by real-time PCR (N = 140) and FGFR2 expression with immunohistochemical staining (N = 176), and compared against clinicopathological factors and patient outcomes. The effects of FGFR2 inhibition or overexpression on cell proliferation, cell cycle, and apoptosis assays were investigated in EGJ adenocarcinoma cell lines. Downstream FGFR2, AKT and ERK were also examined.

Results

Based on the correlation between FGFR2 levels and FGFR2 overexpression in vitro, FGFR2 amplification was defined as copy number > 3.0. In clinical samples, FGFR2 amplification and FGFR2 IHC expression were 15% and 61%, respectively. Although these two statuses were significantly correlated (P < 0.05), only FGFR2 IHC expression was significantly associated with tumor depth (multivariate P < 0.001) and overall survival of patients (univariate P = 0.007). Supporting these findings, FGFR2 overexpression was associated with tumor cell proliferation, cell cycle progression, and anti-apoptosis. Selective inhibition of FGFR2 sufficiently suppressed tumor cell proliferation through de-phosphorylation of AKT and ERK.

Conclusions

FGFR2 amplification was significantly associated with FGFR2 expression. FGFR2 expression (but not FGFR2 amplification) was associated with tumor growth and patient outcomes. Our findings support FGFR2 as a novel therapeutic target for EGJ adenocarcinoma.

CXCL9, CXCL10, CXCL11/CXCR3 axis for immune activation - A target for novel cancer therapy

Chemokines are proteins which induce chemotaxis, promote differentiation of immune cells, and cause tissue extravasation. Given these properties, their role in anti-tumor immune response in the cancer environment is of great interest. Although immunotherapy has shown clinical benefit for some cancer patients, other patients do not respond. One of the mechanisms of resistance to checkpoint inhibitors may be chemokine signaling. The CXCL9, -10, -11/CXCR3 axis regulates immune cell migration, differentiation, and activation, leading to tumor suppression (paracrine axis). However, there are some reports that show involvements of this axis in tumor growth and metastasis (autocrine axis). Thus, a better understanding of CXCL9, -10, -11/CXCR3 axis is necessary to develop effective cancer control. In this article, we summarize recent evidence regarding CXCL9, CXCL10, CXCL11/CXCR3 axis in the immune system and discuss their potential role in cancer treatment.

Colorectal cancer: epigenetic alterations and their clinical implications

Colorectal cancer (CRC) is a heterogeneous disease with distinct molecular and clinical features, which reflects the wide range of prognostic outcomes and treatment responses observed among CRC patients worldwide. Our understanding of the CRC epigenome has been largely developed over the last decade and it is now believed that among thousands of epigenetic alterations present in each tumor, a small subgroup of these may be considered as a CRC driver event. DNA methylation profiles have been the most widely studied in CRC, which includes a subset of patients with distinct molecular and clinical features now categorized as CpG island methylator phenotype (CIMP). Major advances have been made in our capacity to detect epigenetic alterations, providing us with new potential biomarkers for diagnostic, prognostic and therapeutic purposes. This review aims to summarize our current knowledge about epigenetic alterations occurring in CRC, underlying their potential future clinical implications in terms of diagnosis, prognosis and therapeutic strategies for CRC patients.

Comparison of systemic inflammatory and nutritional scores in colorectal cancer patients who underwent potentially curative resection

BACKGROUND

Various systemic inflammatory and nutritional scores have been reported to predict postoperative outcomes. This study aimed to investigate the best systemic inflammatory and nutritional scores in colorectal cancer (CRC) patients who underwent potentially curative resection.

METHOD

We evaluated 468 consecutive CRC patients in this study. Comparisons of systemic inflammatory and nutritional scores, including the neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), prognostic index (PI), prognostic nutritional index (PNI), and modified Glasgow prognostic score (mGPS), were performed using univariate/multivariate analyses for patient survival.

RESULTS

The PNI and mGPS, but not the NLR, PLR, and PI, were significantly associated with overall and relapse-free survival. The mGPS, but not the PNI, was strongly correlated with TNM stage (P < 0.001). Cox multivariate analysis showed that both the PNI and mGPS were exclusive independent prognostic factors for both overall and relapse-free survival (P < 0.001). Furthermore, the PNI status predicted patient survival more clearly than the mGPS in combination with TNM stage.

CONCLUSIONS

This study suggests that the PNI and mGPS are useful predictive scores in CRC patients who undergo potentially curative resection, especially the PNI in combination with TNM stage. Routine evaluation of the host status using the scores may be useful in CRC treatment.

CONUT: a novel independent predictive score for colorectal cancer patients undergoing potentially curative resection

BACKGROUND

Controlling nutritional status (CONUT) score, calculated from serum albumin and total cholesterol concentrations and total lymphocyte count, is reportedly valuable for nutritional assessment. This study investigated whether CONUT score was predictive of outcomes in colorectal cancer (CRC) patients undergoing surgical resection.

METHODS

Preoperative CONUT scores were retrospectively evaluated in 417 CRC patients who underwent potentially curative resection at Kumamoto University Hospital from March 2005 to August 2014. Patients were divided into four groups based on preoperative CONUT scores: normal, light, moderate, and severe. The associations of CONUT score with clinicopathological factors, patient survival, and postoperative complications were examined.

RESULTS

CONUT score correlated significantly with age (P < 0.001), body mass index (P = 0.005), carcinoembryonic antigen (P = 0.002), and carbohydrate antigen 19-9 (P = 0.005) concentrations. Overall survival (OS) rate was significantly lower in patients with moderate/severe than light or normal CONUT scores. CONUT score was independently prognostic of OS [moderate/severe vs. normal, hazard ratio = 5.92, 95 % confidence interval (CI) 2.30-14.92; P < 0.001)]. Patients with moderate/severe CONUT scores were at greater risk for complications, especially for severe complications. Multivariate analysis showed that CONUT score was independently predictive of severe complications (moderate/severe vs. normal, odds ratio = 4.51, 95 % CI 1.89-10.74; P < 0.001).

CONCLUSIONS

CONUT score may predict survival and postoperative severe complications in CRC patients undergoing potentially curative resection. Management of CRC patients may need consideration of host nutritional status.

Cancer-related multiple brain infarctions caused by Trousseau syndrome in a patient with metastatic colon cancer: a case report

Thromboembolism that occurs in association with a malignant tumor is known as Trousseau syndrome. We herein present a case of Trousseau syndrome during systemic chemotherapy for metastatic colon cancer. A 65-year-old man with multiple liver metastases underwent primary tumor resection and systemic chemotherapy. Multiple brain infarctions were detected by magnetic resonance imaging immediately after first-line chemotherapy, which was deemed ineffective. There was no evidence of cardioembolic stroke or carotid atherosclerosis. Although the patient was initially asymptomatic, he subsequently developed paralysis. Despite anticoagulant treatment, he developed repeated recurrences of the infarction, and the area of the infarction spread as the liver metastases progressed. The patient's condition showed no response to an alternative treatment regimen for advanced colon carcinoma. He died approximately 11 months after tumor discovery.

Prognostic and clinical impact of sarcopenia in esophageal squamous cell carcinoma

Recently, depletion of skeletal muscle mass (sarcopenia) has been linked to poor prognosis in several types of cancers, but has not been investigated in esophageal squamous cell carcinoma (ESCC). This retrospective study investigates the relationship between sarcopenia and clinical outcome in ESCC patients treated by surgical resection or definitive chemoradiation therapy (dCRT). The study was retrospectively conducted in a single academic hospital in Kumamoto, Japan, and involved 325 ESCC patients (256 surgical cases and 69 dCRT cases) treated between April 2005 and April 2011. Skeletal muscle mass was quantified by radiologic measures using standard computed tomography scans. The skeletal muscle tissue in the 325 ESCC patients was distributed as follows: mean: 47.10; median: 46.88; standard deviation (SD): 7.39; range: 31.48-71.11; interquartile range, 46.29-47.90. Skeletal muscle tissue was greater in male patients than in female patients (P < 0.0001), but was independent of other clinical and tumor features. Sarcopenia was not significantly associated with overall survival (log rank P = 0.54). Lymph node involvement significantly altered the relationship between sarcopenia and survival rate (P for interaction = 0.026). Sarcopenia significantly reduced the overall survival of patients without lymph node involvement (log rank P = 0.035), but was uncorrelated with overall survival in patients with lymph involvement (log rank, P = 0.31). The anastomosis leakage rate was significantly higher in the sarcopenia group than in the non-sarcopenia group (P = 0.032), but other surgical complications did not significantly differ between the two groups. Sarcopenia in ESCC patients without lymph node involvement is associated with poor prognosis, indicating sarcopenia as a potential biomarker for identifying patients likely to experience an inferior outcome. Moreover, sarcopenia was associated with anastomosis leakage but no other short-term surgical outcome.

Tumor/normal esophagus ratio in (18)F-fluorodeoxyglucose positron emission tomography/computed tomography for response and prognosis stratification after neoadjuvant chemotherapy for esophageal squamous cell carcinoma

BACKGROUND

Positron emission tomography (PET) response criteria in solid tumors were recently proposed as a standardized method for the metabolic and quantitative assessment of response to chemotherapy. However, use of these criteria is limited in many institutions because of the need for exclusive software. This study was designed to clarify whether tumor to normal esophageal (T/N) ratio on (18)F-fluorodeoxyglucose PET/computed tomography could predict response to neoadjuvant chemotherapy and stratify prognosis in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Clinicopathological data were collected for 73 patients with ESCC who received neoadjuvant chemotherapy with docetaxel, cisplatin, and 5-fluorouracil followed by curative resection. The right liver lobe and normal esophagus were utilized as reference tissues for diagnosing complete metabolic response (CMR). Statistical methods included Kaplan-Meier analysis and univariate and multivariate Cox proportional hazards regression analyses.

RESULTS

CMR was achieved in 24 patients on the basis of maximum standardized uptake value (SUVmax) and in 11 on the basis of SUVmax evaluation with T/N ratio. Although prognosis was poorer in patients who achieved CMR than partial metabolic response based on SUVmax, the responses were significantly correlated with disease-free survival (DFS) based on SUVmax evaluation with T/N ratio (P = 0.0011). Receiver operating characteristic curve analysis showed that SUVmax evaluation with T/N ratio was the best predictor of pGrade 3. Multivariate analysis showed that SUVmax evaluation with T/N ratio was an independent predictor of DFS in patients with pGrade 1 pathologic response.

CONCLUSIONS

SUVmax evaluation with T/N ratio is useful for evaluating the effects of neoadjuvant chemotherapy in patients with ESCC.

Abstract 5158: The change of EZH2 expression in development of colorectal cancer from adenoma

[Background]Colorectal cancer has been revealed to develop from adenoma through mutation and deletion of various genes such as FAP, KRAS, DCC and p53 in the process called adenoma-carcinoma sequence. Furthermore, proteins of the polycomb repressive complex 2 (PRC2) function as transcriptional repressors by trimethylating histone H3 at lysine 27, and this complex's activity is essential for cell proliferation and differentiation. The histone methyltransferase enhancer zeste homolog 2 (EZH2), a key member of PRC2, is associated with transcriptional repression of tumor suppressor gene. In our previous study, EZH2 expression was reported to increase as pathology worsened in pancreatic IPMN. Thus EZH2 expression was hypothesized to increase in the adenoma-carcinoma sequence as well.[Purpose]The purpose of this study was to investigate the change of EZH2 expression in progressing colorectal cancer. [Materials and Methods]63 patients with colorectal adenoma, 24 patients with carcinoma in adenoma and 14 patients with colorectal carcinoma who underwent surgical or endoscopic resection were enrolled in this study. The normal lesions of the clinical specimens were also examined. We evaluated the association between EZH2 expression, pathology and expression of tumor suppressor gene. Immunohistochemistry of EZH2, Ki-67, p21, p27 and p16 was performed.[Results]The Ki-67 expression increased parallel to the worsening of pathological findings (p = 0.009), and EZH2 expression showed a significantly positive association with Ki-67 expression (p = 0.02). There was a significant increase of EZH2 expression between normal and colorectal adenoma and carcinoma in adenoma. However, no significance between carcinoma in adenoma and colorectal cancer in EZH2 expression could be identified. Conversely, p21 expression decreased significantly between normal and adenoma lesion; however, p16 and p27 expression showed no major change. [Conclusion]EZH2 expression considerately increased parallel to pathological worsening and p21 expression showed a decrease between normal and colorectal adenoma. Thus EZH2 can contribute to development of colorectal cancer from adenoma via p21 suppression.

Citation Format: Mayuko Ohuchi, Yasuo Nakamoto, Ryuma Tokunaga, Kenichi Nakamura, Keisuke Kosumi, Kazuto Harada, Hironobu Shigaki, Junji Kurashige, Masaaki Iwatsuki, Yoshifumi Baba, Yuji Miyamoto, Naoya Yoshida, Hideo Baba. The change of EZH2 expression in development of colorectal cancer from adenoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5158.