NR1I2 and osteosarcoma: PXR has, additionally, a multi-factorial impact on cancer, either by directly affecting cell proliferation and apoptosis, or by inducing chemotherapy resistance in colon, breast, prostate, and endometrial cancer, and in osteosarcoma, suggesting that identification of novel PXR ligands, agonists and antagonists, might have relevance for the treatment of these disorders.