Although this might simply reflect greater abundance of HIF-2α versus HIF-1α in RCC versus non-RCC cells (Maxwell et al, 1999; Krieg et al, 2000), or, as illustrated here, the presence of abnormal forms of HIF-1α protein in some RCC, there appeared to be a disproportion, for instance between modestly greater HIF-2α/HIF-1α protein levels in RCC4 versus Hep3B cells, and more striking differences in dependence of PHD3 on HIF-2α. Here, EGLN3 is linked to renal cell carcinoma.