Despite being described in tumor cells, ABC transporters are expressed in prokaryotes as well as eukaryotes, being associated to detoxification (Descoteaux et al., 1995; Raj et al., 2009; Boncoeur et al., 2012), efflux of inflammatory molecules (Leslie et al., 2005), and lipid translocation (Araujo-Santos et al., 2005; Aye et al., 2009). This evidence concerns the gene ABCG2 and neoplasm.