Abstract: Objective To explore the association of genetic variants of decay-accelerating factor (DAF)rs150046210 with the risk of colorectal cancer. Methods DAF rs150046210 was genotyped by Polymerase Chain Reaction in 380 patients with colon cancer and 380 normal controls, 450 patients with rectal cancer and 450 normal controls, respectively. Logistic regression was used to investigate the association between rs150046210 and colorectal. Results Compared with DAF rs150046210 DD genotype carriers,Ⅱ genotype carriers had 0.764 times (95%CI: 1.763-2.675, P=0.008) and 0.789 times (95%CI: 1.227-2.608, P=0.003) higher risk of colon cancer and rectal cancer, respectively. When stratified by sex, women with genotype Ⅱ had a 1.015-fold increased risk of colon cancer (95%CI: 1.085-3.742, P=0.026), and men with genotype Ⅱ had a 1.041-fold increased risk of rectal cancer (95%CI: 1.290-3.228, P=0.002),comparing with DAF rs150046210 DD carriers. In the age stratification, this genetic variation affected the risk of colon cancer (OR=2.355, 95%CI: 1.273-4.356,P=0.006) in the low age group (≤60 years old) who carried Ⅱ gene, also affected the risk of rectal cancer (OR=1.757,95%CI:1.106-2.789,P=0.017),(OR=2.313, 95%CI:1.334-4.012,P=0.003) in the high age group (>60 years old) with DI or Ⅱ genotype. Compared with DAF rs150046210 DD genotype carriers, Ⅱ genotype of not smoking, not drinkers had a 0.791(95% CI: 1.106-2.900, P=0.018) and 0.714 (95% CI: 1.086-2.704, P= 0.021)-fold increased risk of colon cancer incidence, type Ⅱ gene carriers who didn′t smoke or drink wine showed increased risk of rectal cancer(OR=2.395, 95%CI:1.514-3.788,OR=1.923, 95%CI: 1.221-3.030, respectively). Conclusions DAF rs150046210 polymorphism can increase the risk of colorectal cancer in the elderly patients.

Key words: decay-accelerating factor, complement regulatory protein, polymorphism, colorectal cancer