Association of the Glutathione S-Transferase M1, T1 Polymorphisms with Cancer: Evidence from a Meta-Analysis

<div><p>Background</p><p>Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that are involved in the metabolism of many xenobiotics, including a wide range of environmental carcinogens. While the null genotypes in <i>GSTM</i>1 and <i>GSTT1</i> have been implicated in tumorigenesis, it remains inconsistent and inconclusive. Herein, we aimed to assess the possible associations of the <i>GSTM1</i> and <i>GSTT1</i> null genotype in cancer risks.</p><p>Methods</p><p>A meta-analysis based on 506 case-control studies was performed. Odds ratios (OR) with corresponding 95% confidence intervals (CIs) were used to assess the association.</p><p>Results</p><p>The null genotypes of <i>GSTM1</i> and <i>GSTT1</i> polymorphisms were associated with a significantly increased risk in cancer (for <i>GSTM1</i>: OR = 1.17; 95%CI = 1.14–1.21; for <i>GSTT1</i>: OR = 1.16; 95%CI = 1.11–1.21, respectively). When the analysis was performed based on their smoking history, the risk associated of <i>GSTM1</i> null and <i>GSTT1</i> null genotypes with cancer is further increased (for <i>GSTM</i>1: OR = 2.66; 95%CI = 2.19–3.24; for <i>GSTT1</i>: OR = 2.46; 95%CI = 1.83–3.32, respectively).</p><p>Conclusions</p><p>These findings indicate that <i>GSTM1</i> and <i>GSTT1</i> polymorphisms may play critical roles in the development of cancer, especially in smokers.</p>