HIF1A and systemic sclerosis: Of note, PH associated with pulmonary fibrosis is the major cause of mortality in individuals suffering from fibrotic disease, such as SSc, and accumulating evidence has revealed that HIF-1α is implicated in producing excessive ECM which was the underlying cause of fibrosis (Distler et al., 2007; Higgins et al., 2007; Halberg et al., 2009; Ueno et al., 2009; Zhou et al., 2009; Gilkes et al., 2013; Nayak et al., 2016).