EPAS1 and neoplasm: VHL inactivation results in the stabilization of the alpha subunits of the hypoxia-inducible factor alpha (HIF) family of transcription factors of which HIF2α is thought to be a key oncogenic driver of ccRCC tumorigenesis, while emerging evidence suggests that HIF1α may be a tumour suppressor gene3, 8, 10, 11, 52, 53.