The APC gene rs41115 polymorphism is associated with survival in Iranian colorectal cancer patients

Abstract

Introduction: The onset of colorectal cancer is a complex process caused by numerous genetic pathways. APC functions as a ``"gatekeeper" and its mutations occur at the initiation stage of the colorectal tumorigenesis. The main aim of this study was to investigate common somatic mutations of exon 15 APC genes in patients with colorectal cancer in East Azerbaijan, Iran.

Methods: This study was designed and performed as a cross-sectional and case-only study. Tissue biopsies were obtained during colonoscopy and confirmed colorectal carcinoma cases were evaluated. Two hotspot regions of exon 15 for APC mutations were evaluated using PCR amplification and Sanger sequence analysis.

Results: The synonymous (p.Thr1475Thr) polymorphism was observed in all patients; 35 patients (61.4%) had AG genotype and 22 patients (38.6%) had AA genotype. Also, a missense mutation and two deletions were found. Pearson's correlation test showed a significant correlation between the stage of the disease (rho = 0.23, P =< 0.05), and anatomical subsite of the tumor with rs41115 polymorphism (rho = 0.31, P =< 0.05). Overall comparison of survival function in the different genotypes of the APC gene showed significant differences between groups, and CRCs with AG genotype had 3.24-fold higher hazard of mortality than CRCs with AA genotype (HR = 3.24; 95% CI: 1.21 - 8.68, P = 0.020).

Conclusion: APC mutation plays an important predictive role in overall survival. However, the pattern and type of APC gene have a diverse impact on clinical outcomes in the Asian population. Moreover, in CRC patients the APC mutations were reported to be diverse variants.