Jiang, Chen

Abstract Purpose: Irinotecan/5-fluorouracil (5-FU; FOLFIRI) or oxaliplatin/5-FU (FOLFOX), combined with bevacizumab or cetuximab, are approved, first-line treatments for metastatic colorectal cancer (mCRC). We aimed at identifying germline variants associated with survival in patients with mCRC treated with these regimens in Cancer and Leukemia Group B/SWOG 80405. Experimental Design: Patients with mCRC receiving either FOLFOX or FOLFIRI were randomized to either cetuximab or bevacizumab. DNA from peripheral blood was genotyped for approximately 700,000 SNPs. The association between SNPs and overall survival (OS) was tested in 613 patients of genetically estimated European ancestry using Cox proportional hazards models. Results: The four most significant SNPs associated with OS were three haplotypic SNPs between microsomal glutathione S-transferase 1 (MGST1) and LIM domain only 3 (LMO3, representative HR, 1.56; P = 1.30 × 10−6), and rs11644916 in AXIN1 (HR, 1.39, P = 4.26 × 10−6). AXIN1 is a well-established tumor suppressor gene in colorectal cancer, and rs11644916 (G>A) conferred shorter OS. Median OS for patients with the AA, AG, or GG genotypes was 18.4, 25.6, or 36.4 months, respectively. In 90 patients with stage IV colorectal cancer from The Cancer Genome Atlas (TCGA), rs11649255 in AXIN1 [in almost complete linkage disequilibrium (LD) with rs11644916], was associated with shorter OS (HR, 2.24, P = 0.0096). Using rs11648673 in AXIN1 (in very high LD with rs11644916 and with functional evidence), luciferase activity in three colorectal cancer cell lines was reduced. Conclusions: This is the first large genome-wide association study ever conducted in patients with mCRC treated with first-line standard treatment in a randomized phase III trial. A common SNP in AXIN1 conferred worse OS and the effect was replicated in TCGA. Further studies in colorectal cancer experimental models are required.

11011 Background: Beyond KRAS status, there are no validated markers for anti-EGFR therapy in mCRC. While expression of genes within the EGF signaling axis has been reported to correlate with benefit, most reports used data from non-randomized trials which cannot distinguish between general prognostic markers and markers that predict for benefit from C. CALGB 80203 was a 238-patient (pt), 4-arm, randomized phase II study of FOLFOX or FOLFIRI +/- C in mCRC pts. Formalin-fixed, paraffin-embedded (FFPE) tumor samples from CALGB 80203 were analyzed for gene expression of HER family ligands, receptors and regulators. Methods: FFPE tumor samples from consenting pts were analyzed for AREG, BTC, CD73, DUSP4, EGF, EGFR, EPGN, EREG, HB-EGF, HER2, HER3, HER4, PHLDA1 and TGFa by RT-qPCR. Interaction between baseline gene expression levels and treatment (C) with respect to progression-free survival (PFS) and overall survival (OS) was modeled using a multiplicative Cox proportional hazards model. Results: Baseline tumor tissue was available from 103 pts; 55% of tumors were KRAS wild type (WT). Two prognostic markers were identified; higher tumor mRNA levels of HER2 (HR=0.64, p=0.002) and EREG (HR=0.89, p=0.016) were associated with longer PFS across all pts. Potential predictive markers of benefit for C were identified. In KRAS WT tumors, lower HER3 expression was associated with longer OS from C treatment while higher HER3 expression was associated with shorter OS from C treatment (chemo + C: HR=1.15; chemo only: HR=0.48, interaction p=0.029). No association was observed for HER3 and outcome in KRAS mutant (MT) tumors. Interestingly, higher CD73 expression was associated with longer PFS in C-treated pts in both KRASWT (chemo + C: HR=0.91; chemo only: HR=1.57, interaction p=0.026) and MT tumors (chemo + C: HR=0.80; chemo only: HR=1.29, p=0.025). Conclusions: In one of the first reports using data from a randomized study, gene expression of HER3 and CD73 were identified as potential predictive markers for C. These data implicate not only HER axis signaling but also immune modulation as potential mechanisms of C action and sensitivity, and warrant confirmation in other large randomized trials.

Abstract Background and Aims: Cancer and Leukemia Group B 80303 was a randomized, phase III study in patients with advanced pancreatic cancer treated with gemcitabine plus either bevacizumab or placebo. We prospectively collected germline DNA and conducted a genome-wide association study (GWAS) using overall survival (OS) as the endpoint. Experimental Design: DNA from 351 patients was genotyped for more than 550,000 single-nucleotide polymorphisms (SNP). Associations between OS and SNPs were investigated using the log-linear 2-way multiplicative Cox proportional hazards model. The subset of 294 genetically European patients was used for the primary analysis. Results: A nonsynonymous SNP in interleukin (IL)17F (rs763780, H161R) and an intronic SNP in strong linkage disequilibrium (rs7771466) were associated with OS using genome-wide criteria (P ≤ 10−7). Median OS was significantly shorter (P = 2.61 × 10−8) for the rs763780 heterozygotes [3.1 months; 95% confidence interval (CI), 2.3–4.3] than for the patients without this variant (6.8 months; 95% CI, 5.8–7.3). After adjustment by stratification factors, the P value for the association was 9.51 × 10−7. Conclusions: The variant 161R form of IL-17F is a natural antagonist of the antiangiogenic effects of wild-type 161H IL-17F, and angiogenesis may play an important role in the metastatic spread of pancreatic cancer. In this preliminary study, we hypothesize that the angiogenetic potential of pancreatic cancers in patients with variant IL-17F is higher than that of tumors in patients with wild-type IL-17F, conferring worse prognosis. This exploratory GWAS may provide the foundation for testing the biology and clinical effects of novel genes and their heritable variants through mechanistic and confirmatory studies in pancreatic cancer. Clin Cancer Res; 18(2); 577–84. ©2011 AACR.