Aim: To investigate the role of the -347G-->GA polymorphism in the progression of colorectal cancer (CRC).
Methods: We designed a case-control study based on a population of CRC patients in China and normal healthy controls with no history of tumors or inherited diseases. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses were used to genotype the variants, and immunohistochemical staining was performed to measure the expression of E-cadherin in different allele cases among the CRC patients and normal controls.
Results: The GA-allele (G/GA heterozygous and GA/GA homozygous) did not increase the risk of CRC compared with the G-allele (OR=1.232, 95% CI=0.898-1.691). However, the frequencies of the GA-allele were higher in poorly differentiated (P=0.002) and proximal (P=0.019) CRC patients than in normal controls. We also observed that E-cadherin expression was lower in poorly differentiated CRC patients than in well differentiated CRC patients (P=0.001). Furthermore, E-cadherin expression was lower for the GA-allele than for the G-allele (G/G heterozygous) in CRC patients (P=0.018). In contrast, there was no significant difference in E-cadherin expression for the G-allele and GA-allele in normal controls (P=0.292).
Conclusion: The -347G-->GA promoter polymorphism in E-cadherin gene is associated with specific CRC features, and may be a prognostic factor rather than a susceptibility factor during the progression of CRC.