Polymorphism of glutathione S-transferase loci GSTM1 and GSTT1 and susceptibility to colorectal cancer in Egypt

Egypt has an unusually high proportion of early-onset colorectal cancer und er age 40 years. Environmental exposures and low DNA repair capacity are am ong the risk factors. Because GSTM1 and GSTT1 gene deficiencies may act as risk modifiers for colorectal cancer risk, we investigated the relationship between genetic polymorphism in these genes and colorectal cancer risk in Egyptians. Sixty-six patients and 55 controls were included. Genotyping for GSTM1 and GSTT1 was conducted using PCR techniques and the results were re lated to epidemiologic and clinical information. No overall association was observed between GSTM1 or GSTT1 null genotypes and colorectal cancer risk. However, the data suggest a possible role for GSTM1 genotype in influencin g tumor site. Furthermore, GSTM1 and GSTT1 genotypes, in conjunction with g ender and place of residence, may play a role in modifying disease risk. Fu rther studies on a larger population in Egypt are needed to generalize the results of this study. (C) 1999 Published by Elsevier Science Ltd. All righ ts reserved.