Risk factors (excluding hormone therapy) for endometrial hyperplasia: a systematic review.

ABC genes, especially ABCB1 (ATP-binding cassette, sub-family B (MDR/TAP), member 1; Doxorubicin resistance; Multidrug resistance 1; Multidrug resistance protein 1; P-glycoprotein 1; P glycoprotein 1/ multiple drug resistance 1;P-gp) (7q21.12), ABCC1 (9q31.1), ABCG2 (White1) (21q22.3), and other genes of this family encode proteins which are essential for drug metabolism and transport. The multidrug efflux transporters P-gp, multidrug-resistance associated protein 4 (MRP4) and breast cancer resistance protein (BCRP), located on endothelial cells lining brain vasculature, play important roles in limiting movement of substances into and enhancing their efflux from the brain. Transporters also cooperate with Phase I/Phase II metabolism enzymes by eliminating drug metabolites. Their major features are their capacity to recognize drugs belonging to unrelated pharmacological classes, and their redundancy, by which a single molecule can act as a substrate for different transporters. This ensures an efficient neuroprotection against xenobiotic invasions. The pharmacological induction of ABC gene expression is a mechanism of drug interaction, which may affect substrates of the up-regulated transporter, and over expression of MDR transporters confers resistance to anticancer agents and CNS drugs [1,2]. Mutations in ABC transpo