EPAS1 and renal cell carcinoma: In keeping with this, HIF-1α and HIF-2α show clear transcriptional selectivity, with studies to date defining at least two types of isoform-specific responses; certain genes appear exclusively responsive to HIF-1α in both RCC and non-RCC cells, whereas others respond to both HIF-1α and HIF-2α in non-RCC cells, and are dominantly regulated by HIF-2α in RCC cells (Hu et al, 2003; Sowter et al, 2003; Raval et al, 2005).