DNMT1 and pulmonary arterial hypertension: Moreover, treatment with a demethylation agent such as 5-aza-2′-deoxycytidine or genetic inhibition of enhancer of zeste homolog 2, which functions in the methylation of CpG islands by recruiting DNMT, restored the expression of BMPR1B in human glioblastoma tumor-initiating cells.60 Collectively, these epigenetic regulations of BMPR1 genes may also be involved in PAH pathogenesis, and require further elucidation, as these biological phenomena have not yet been described in the cardiovascular system.