OBJECTIVETo explore the association between the polymorphisms of oncogenes H-ras and L-myc and colorectal cancer risk, and the interaction of those genes.

METHODSThe genotypes of H-ras and L-myc genes were determined by polymerase chain reaction-based restriction fragment length polymorphism analysis. Stratified analysis and logistic model were used to detect the gene-gene interaction. The gene-gene interaction was validated by multifactor dimensionality reduction (MDR) analysis.

RESULTSThe single SNP model showed that the polymorphisms of H-ras and L-myc genes were not significantly related with colorectal cancer risk (P > 0.05). Stratified analysis revealed that among the L-myc LS + SS genotype carriers, those with H-ras TC + CC genotype showed significantly increased risk of rectal cancer than those with TT genotype (OR = 1.81, P = 0.005). The positive interaction between L-myc and H-ras was detected by logistic regression model. The OR of the interaction effect was 2.74 (P = 0.024). This result was confirmed in the MDR model, with 54.83% testing balanced accuracy and 10/10 cross-validation consistency, and the model was still significant after the 1000 times permutation test (P = 0.001).

CONCLUSIONOur findings suggest that the polymorphism of H-ras and L-myc genes is not related to colorectal cancer risk, but there is a synergy between H-ras and L-myc polymorphisms in the development of rectal cancer.