BRCA1 and idiopathic pulmonary arterial hypertension: An attenuation of BRCA1 can be detected both in human primary pulmonary microvascular endothelial cells in which BMPR2 has been downregulated and in endothelium from idiopathic pulmonary arterial hypertension patients, indicating a link between deregulation of the BMPR2 signaling pathway and the level of BRCA123.