Renin–angiotensin system gene polymorphisms and colorectal cancer risk: a meta-analysis

Objective: The renin–angiotensin system gene has been implicated in the progression of colorectal cancer. Nevertheless, the details of that role remain controversial. We performed a meta-analysis to investigate the correlation between renin–angiotensin system gene polymorphisms and colorectal cancer. Methods: We retrieved relevant studies from PubMed and Embase. Subsequently, fixed or random-effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (CIs). Results: We identified six studies of the angiotensin-converting enzyme insertion/deletion (I/D) polymorphism, and two studies of the angiotensinogen M235T polymorphism. The angiotensin-converting enzyme I/D polymorphism did not significantly correlate with colorectal cancer risk in the total population (DD vs. II: OR 0.77, 95% CI 0.39–1.50; DI vs. II: OR 1.05, 95% CI 0.85–1.30; dominant model: OR 0.94, 95% CI 0.68–1.31; recessive model: OR 1.01, 95% CI 0.80–1.27). Similarly, the angiotensinogen M235T polymorphism was not associated with colorectal cancer risk (TT vs. MM: OR 1.38, 95% CI 0.52–3.67; TM vs. MM: OR 1.19, 95% CI 0.96–1.47; dominant model: OR 1.28, 95% CI 0.77–2.14; recessive model: OR 1.17, 95% CI 0.53–2.59). Conclusion: Our findings suggest that the angiotensin-converting enzyme I/D and angiotensinogen M235T polymorphisms are unlikely to correlate with colorectal cancer.