Polymorphisms of genes encoding for regulatory proteins in the coagulation cascade to predict outcome for stage II and III colon cancer.

Abstract

227 Background: In cancer patients, an activated coagulation cascade might promote tumor cell dissemination. There are preliminary data suggesting that fibrinogen in combination with platelets can build a meshwork that entraps cancer cells enabling them to escape from immunosurveillance. We therefore hypothesize that variations in genes encoding for regulatory proteins within the coagulation pathway may predict outcome in patients with stage II and III colon cancer. Methods: The impact of three functional single nucleotide polymorphisms (SNPs) within the FGB, SERPINC1 and ITGA2B genes on time to recurrence and overall survival was evaluated in 209 patients with stage II and III colon cancer. Genomic DNA was isolated from formalin-fixed paraffin embedded tissue and the SNPs were analyzed by PCR-based direct sequencing. Results: Baseline characteristics were as follows: median age = 70y (19-91); female/male ratio = 42.8% / 57.2%; 111 patients had stage II, and 98 stage III colon cancer. The FGB rs4220 SNP showed significant association with recurrence rate in the overall population. Patients harboring any A allele had a higher 3-years recurrence rate compared to those with a G/G genotype (28% vs 17%) in both univariate (HR 1.83, 95% confidence interval (CI) 0.99-3.36, p = 0.048) and multivariate analyses (HR 1.94, 95% CI 1.05-3.57, p = 0.034). This trend was most evident among pts with stage II and especially the subgroup of high-risk stage II colon cancer. Again, A allele carriers had a higher 3-years recurrence rate compared to those having a G/G genotype (24% vs 10% and 44% vs 15% respectively) in both univariate (HR 3.32, 95% CI 1.26-8.74, p = 0.010 and HR 5.34, 95% CI 1.38-20.68, p = 0.006) and multivariate analyses (HR 3.34, 95% CI 1.27-8.78, p = 0.015 and HR 5.44, 95% CI 1.40-21.15, p = 0.015). Conclusions: Here, we demonstrate that the FGB polymorphism rs4220 might serve as a prognostic biomarker in stage II colon cancer. Assessment of FGB rs4220 might help us to identify those stage II colon cancer patients who will derive the most benefit from adjuvant chemotherapy.