B4GALT5 and leukemia: Meanwhile, two members of the B4GALT gene family, B4GALT1 (beta-1,4-galactosyltransferase 1) and B4GALT5 (beta-1,4-galactosyltransferase 5), have been reported to be involved in the development of MDR (multidrug resistance) of human leukemia cells by regulating the Hh (hedgehog) signaling and the expression of P-gp (p-glycoprotein) and MRP1 (MDR-associated protein 1) (Zhou et al., 2013).