USP7 and neoplasm: Our results provide a unique model of converting post-translational modification into epigenetic regulation and further implicate the role of HAUSP in the field of hypoxia-induced tumour progression since the other two deubiquitinases that could deubiquitinate HIF-1α, USP8 and UCHL1, are either involved in ciliogenesis under normoxia or does not modulate HIF-1α-induced gene transcription through regulating chromatin modification49, 50.