GSTM1 and ovarian carcinoma: Overall analysis showed that <i>GSTM1</i> and <i>GSTT1</i> null were not associated with the risk of ovarian cancer, subgroup analysis showed that <i>GSTM1</i> null was associated with an increased risk of OC in East Asia, and <i>GSTT1</i> null was associated with an increased risk of OC in South America.