GSTM1 and cancer: The GST M1 (GSTM1; BC036805, GenBank) and theta 1 (GSTT1; X79389, GenBank) genes have received much attention because of the high prevalence of homozygous deletions resulting in null genotypes with a decreased ability to detoxify carcinogenic compounds, placing null individuals at increased cancer risk (Bolufer et al. 2006; Bolt and Their 2006; Hiyama et al. 2008; Parl 2005; Shi et al. 2008; White et al. 2008).