Chen et al. (2012) have indicated that the ABCG2421C>A (rs2231142) polymorphism, resulting in a Glu141Lys substitution, is aprotective factor for developing cancer. Additionally, ABCG2 34G>A (rs2231137),resulting in a Val12Met substitution, is also well studied and is related to theadverse effect of many drugs that are transported by ABCG2 (Imai et al., 2002). This evidence concerns the gene ABCG2 and cancer.