HMOX1 and prostate neoplasm: It is worth noting that the transcription of HO1 was maximally induced in the presence of parthenolide after 4 h stimulation in all normoxic and hypoxic prostate tumor cells, both in wt and in HIF1α knockdown cells, whereas in parthenolide untreated cells HO1 appeared stimulated under chronic hypoxia only when HIF1α signaling was intact.