In the renal carcinoma cell line, 786-O cells, HIF2α expression is increased by Irp1 knockdown but not Irp2 knockdown, suggesting that Irp1 probably plays a major function in repressing HIF2α translation by binding to its 5′IRE in these particular cells (Zimmer et al., 2008). This evidence concerns the gene EPAS1 and renal carcinoma.