GSTM1-null genotype as a risk factor for sporadic colorectal cancer in a Romanian population. Association with the NAT2-rapid-acetylator phenotype and exposure to environmental factors.

We evaluated the association between the presence of the GSTM1-null genotype and the combined presence of the GSTM1-null genotype/NAT2 rapid acetylator phenotype and the risk of developing sporadic colorectal cancer (CRC), as well as their interaction with environmental risk factors. One hundred and fifty patients with sporadic CRC and 162 controls were genotyped using PCR-RFLP analysis. For testing and quantification of the simple effect (main effect) and of the gene-gene and gene-environment interaction (modification effect), univariate and multivariate logistic regression was used. In the multiplicative model, from the genetic factors, GSTM1-null and NAT2*6B had a statistically significant influence on the risk for CRC, while from the environmental factors, smoking and diet had similar effects. The combination of GSTM1-null/NAT2 rapid acetylator phenotype/smoking behavior or GSTM1-null/NAT2 rapid acetylator phenotype/diet rich in fried red meat was not found to influence the sporadic CRC risk in Romanians, but the GSTM1-null genotype, NAT2 rapid acetylator phenotype influenced the sporadic CRC risk differently depending on the gender of the patient.