Association between GSTM1 and GSTT1 allelic variants and head and neck squamous cell cancinoma.
BACKGROUND
GSTM1 and GSTT1 are involved in the detoxification of carcinogens such as smoking by-products, and polymorphisms in these two genes with a result of loss of enzyme activity may increase risk of carcinogenesis. Although many epidemiological studies have investigated the association between GSTM1 or GSTT1 null genotype and head and neck squamous cell carcinoma (HNSCC), the results remain conflicting. To elucidate the overall association of GSTM1, GSTT1 and HNSCC, we included all available studies and performed this meta-analysis.


RESULTS
A dataset including 42 articles for GSTM1, 32 articles for GSTT1, and 15 articles for GSTM1 and GSTT1 in combination were identified by a search in PubMed. Associations beween HNSCC and polymorphisms of GSTM1 and GSTT1 alone and in combination were analysed by software RevMan 5.1. Stratification analysis on ethnicity and smoking status, sensitivity analysis, heterogeneity among studies and their publication bias were also tested. Association was found in overall analysis between HNSCC and GSTM1 and GSTT1 null genotype. Stratified by ethnicity, we found increased risks of HNSCC in carriers with GSTM1 null genotype in Asian, GSTT1 null genotype in South American, and dual null genotype in European and Asian. When stratified by smoking, a more significant association of GSTM1 null genotype with HNSCC risk was observed in smokers.


CONCLUSIONS
This meta-analysis presented additional evidence of the association between GSTM1 and GSTT1 polymorphisms and HNSCC risk.
Institute of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China.
Yang
Y
Zhang
Yuanyuan
Y
Ni
Hao
H
Zhang
Yongchu
Y
Pan
Junqing
J
Ma
Lin
L
Wang
D000483:Alleles; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000473:pathology; D005260:Female; D056726:Genetic Association Studies; D005982:Glutathione Transferase / Q000235:genetics*; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000473:pathology; D006801:Humans; D008297:Male; D012307:Risk Factors; D000077195:Squamous Cell Carcinoma of Head and Neck
D005982:Glutathione Transferase; C413545:glutathione S-transferase T1