More than 50 polymorphisms of the MDR-1 gene have been described; a subset of these has been shown to play a pathophysiological role in the development of inflammatory bowel disease, femoral head osteonecrosis induced by steroids, lung cancer and renal epithelial tumors.
In an explorational case-control study, constitutional genotype frequencies were established at MDR1(C3435T) of 537 healthy control subjects and compared with those of 212 patients with renal epithelial tumors.