Glutathione S-Transferase M1 (GSTM1) and Glutathione S-Transferase T1 (GSTT1) Null Polymorphisms, Smoking, and Their Interaction in Oral Cancer: A HuGE Review and Meta-Analysis

• Published in: American journal of epidemiology 2011-04, Vol.173 (8), p.847-857
• Main Authors: ZHANG, Zhi-Jiang, KE HAO, RONG SHI, GENMING ZHAO, JIANG, Guo-Xin, YIQING SONG, XIAOHUI XU, JIN MA
• Format: Article
• Language: English
• Subjects: Asian Continental Ancestry Group; Biological and medical sciences; Epidemiology; European Continental Ancestry Group; General aspects; Genetic Association Studies; Genetics; Genomes; Glutathione Transferase - genetics; Humans; Medical sciences; Meta-analysis; Miscellaneous; Mouth Neoplasms - enzymology; Mouth Neoplasms - genetics; Oral cancer; Otorhinolaryngology. Stomatology; Polymorphism; Polymorphism, Genetic; Public health. Hygiene; Public health. Hygiene-occupational medicine; Smoking - genetics; Tobacco, tobacco smoking; Toxicology; Tumors; Upper respiratory tract, upper alimentary tract, paranasal sinuses, salivary glands: diseases, semeiology
• ISSN: 0002-9262; 1476-6256
• DOI: 10.1093/aje/kwq480

The association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and oral cancer is not consistent across studies, and data on their interaction with smoking in oral cancer are lacking. The authors systematically searched PubMed and SciVerse Scopus for case-control studies examining the association between null genotypes of the GSTM1 and GSTT1 genes and oral cancer. Twenty-eight case-control studies published in English were identified. Summary odds ratios were derived via random-effects models. The summary odds ratio for the GSTM1 null genotype was 1.43 in Asians (95% confidence interval (CI): 1.14, 1.78; P < 0.01, I (2) = 73%) and 0.98 in Caucasians (95% CI: 0.76, 1.28; P = 0.91, I (2) = 0%). Case-only analysis of 6 studies (552 cases) showed an inverse multiplicative interaction between GSTM1 null polymorphisms and smoking (ever/high levels of smoking vs. never/low levels) (odds ratio (OR) = 0.51, 95% CI: 0.32, 0.82; P = 0.01, I (2) = 34%). The GSTT1 null genotype was not significantly associated with oral cancer in Asians (OR = 1.07, 95% CI: 0.82, 1.38; P = 0.63, I (2) = 65%) or Caucasians (OR = 1.04, 95% CI: 0.41, 2.65; P = 0.93, I (2) = 55%). In conclusion, the GSTM1 null genotype may be associated with a higher risk of oral cancer in Asians but not in Caucasians, and this effect may be modified by smoking status. The GSTT1 null genotype may not be associated with oral cancer.