Risk of colorectal neoplasia associated with the adenomatous polyposis coli E1317Q variant.

Background: Reports of the risk of colorectal neoplasia associated with a variant of the adenomatous polyposis coli (APC E1317Q) gene are conflicting. Using a case-control design, we investigated this relationship within a clinic-based cohort followed through the Integrated Cancer Prevention Center and the Tel-Aviv Sourasky Medical Center.

Materials And Methods: All study subjects were tested for the APC E1317Q variant at enrollment. Subjects underwent colonoscopic evaluation (+/-biopsy and/or polypectomy) and had cancer history and colorectal neoplasia risk factors assessed. The crude and adjusted risks of neoplasia associated with the E1317Q variant were calculated.

Results: The prevalence of the E1317Q variant was 1.4% in the entire study sample and 3.2% in Sephardic Jews. E1317Q was more prevalent among cases: 15 of 458 (3.3%) cases were carriers compared with 11 of 1431 (0.8%) controls [odds ratio (OR) 4.4, 95% CI 2.0-9.6]. When stratified by neoplasia type, adenoma risk was significantly elevated in carriers (OR 4.1, 95% CI 1.8-9.4) but colorectal cancer risk was not (OR 2.1, 95% CI 0.8-5.3). After adjustment, the E1317Q variant remained a significant predictor of colorectal adenoma (OR 4.6, 95% CI 2.0-10.8).

Conclusions: The APC E1317Q variant is associated with colorectal neoplasia, particularly colorectal adenomas, but further studies are still needed. Variant prevalence is elevated in Sephardic Jews.