Our laboratory and others have extensively investigated the role and the contribution of estrogen, estrogen receptors and estrogen-metabolizing enzymes to the pathogenesis and progression of PAH (Chen et al., 2017b; Dean et al., 2018; Hood et al., 2017; Johansen et al., 2016; Mair et al., 2014; Wallace et al., 2015; White et al., 2012; Wright et al., 2015). This evidence concerns the gene ESR1 and pulmonary arterial hypertension.