Polymorphisms in the ABCB1 gene have been found to be associated with a susceptibility to ulcerative colitis [20,21,22,23,24,25], Parkinson’s disease [26,27,28], Alzheimer’s disease [29,30], cancer [31,32,33,34,35], bullous pemphigoid [36,37], the osteonecrosis of the femoral head [38,39], major depressive disorder [40,41,42] and ischemic strokes [43]. The gene discussed is ABCB1; the disease is cancer.