ABCB1 and cancer: Several studies which investigate the association of activated canonical Wnt signaling pathway and overexpression of ABC family transporter proteins in other types of cancer, such as colon cancer and neuroblastoma, have suggested that MDR1, also known as ABCB1, a subfamily B of ABC family transporter proteins, is a protein product from one of the direct target genes in the pathway (Yamada et al., 2000; Flahaut et al., 2009; Chikazawa et al., 2010).