EPAS1 and clear cell renal carcinoma: Notably, in the study of Petra Miikkulainen (Miikkulainen et al., 2019), a strong positive correlation between HIF-prolyl hydroxylase 3 (PHD3) and HIF-2α mRNA expression in renal clear cell carcinomas (RCCs) is observed, in contrast to the expected accumulation of HIF-2α after PHD3 knockdown in non-RCC cells, which also indicates the aggressiveness and poor prognosis of RCC.