The association of IGF1 rs35767 polymorphism with colorectal cancer risk in the Chinese Han population.

Insulin-like growth factor 1 (IGF1) plays an important role in the development and growth of colorectal cancer (CRC). Hence, potential functional polymorphisms of the IGF1 gene may be involved in CRC risk. This study mainly aimed to assess the association of IGF1 rs35767 polymorphism with CRC risk in the Chinese Han population by a case-control study and a pooled analysis. In a case-control study with 208 CRC patients and 312 healthy individuals, the rs35767 polymorphism was genotyped by DNA sequencing. Furthermore, a pooled analysis of two case-control studies was performed using Stata software. IGF1 rs35767 polymorphism was significantly associated with CRC risk in both a case-control study (AA vs. GG: OR = 2.26, 95% CI = 1.35-3.80, P  = 0.003; AA vs. (GG + GA): OR = 2.32, 95% CI = 1.44-3.74, P = 0.001; A vs. G: OR = 1.43, 95% CI = 1.11-1.85, P  = 0.007) and a pooled analysis [(GA + AA) versus GG: OR = 1.30, 95% CI = 1.03-1.63, P  = 0.03; A versus G: OR = 1.28, 95% CI = 1.08-1.53, P  = 0.01]. In addition, the IGF1 rs35767 polymorphism was also significantly associated with the stage of CRC. CRC patients with the rs35767 A allele were more likely to have a high tumor stage. These findings indicated that IGF1 rs35767 polymorphism was linked to CRC risk and tumor stage in the Chinese Han population, and might serve as a valuable biomarker.