TAP1 and cancer: ABCB6 belongs to the ABCB subfamily, which includes P-glycoprotein (ABCB1/MDR1) causing multidrug resistance of cancer cells [3]; the TAP1/2 complex (ABCB2-3) mediating the translocation of immunogenic peptides from the cytosol into the endoplasmic reticulum [4]; ABCB4-MDR3 influencing the translocation of phosphatidylcholine [5], and ABCB11 involved in the secretion of bile acids [6].