Using ChIP assays by pulling down overexpressed myc-tagged PITX2C[42] or endogenous PITX2[43], PITX2 was evidenced to bind to both sites in chemoresistant colon and renal cancer cell lines and was supported by RNAi studies wherein PITX2 downregulation resulted in attenuated ABCB1 mRNA and ABCB1 protein as well as chemoresistance[42,43]. This evidence concerns the gene ABCB1 and renal carcinoma.