Genetic deletions of GSTM1 and GSTT1 in head and neck cancer: review of the literature from 2000 to 2012.

Head and neck cancer is one of the leading causes of deaths worldwide. Two genes GSTM1 and GSTT1 involved in phase II of carcinogen detoxification have been frequently studied in the literature. Their null genotypes are thought to be associated with increased head and neck cancer risk. However, the published reviews are not up to date and many important papers have been skipped. The current literature review was restricted to the null genotypes of the GSTM1 and GSTT1 genes with special emphasis on the genotypic status. We found that the size of study sample varied greatly and the oral cavity cancer was more influenced by GSTM1 and GSTT1 gene deletions. With respect to ethnicity Asians are more prone to head and neck cancers with these null genotypes as compared to Europeans and Americans. The current review showed significant associations (OR=9.0, 95%CI; 1.4-9.5; OR=3.7, 95%CI; 1.4-9.5) of GSTM1 and GSTT1 null genotypes with head and neck cancers. Review confirms the data of previous reviews that GSTM1 and GSTT1 gene polymorphisms may be risk factors for cancer initiation.