These genetic variants of CYP1A1 genes, besides causing enhanced enzyme activity, are also known to play a major role in the pathogenesis of several cancers (Singh et al., 2007; Wright et al., 2010; Kristiansen et al., 2011; Singh et al., 2007; Wright et al., 2010; Kristensen et al., 2011). The gene discussed is CYP1A1; the disease is cancer.