GSTM3 is a cytosolic enzyme involved in prostaglandin and leukotriene synthesis and in the metabolization of toxic compounds, such as chemotherapeutic drugs, insecticides, herbicides, carcinogens, and by-products of oxidative stress. GSTM3 is expressed in testis, brain, lung, and lymphocytes. GSTM3 have been reported to be dysregulated in cancers like prostate cancer and colon cancer.