EPAS1 and neoplasm: Indeed, we found that our small molecule inhibitor of HIF signalling NSC-134754 [16, 18–20], which exhibits anti-tumour activity in vivo [18, 53] could significantly block tumour cell growth and HIF-α (HIF-1α and HIF-2α) protein in tumour cells expressing elevated CHCHD4, without mitochondrial respiratory chain involvement.