Twenty-one candidate miRNAs were obtained firstly by the first search in PubMed (https://pubmed.ncbi.nlm.nih.gov/) and Cochrane Library (https://www.cochranelibrary.com/) using the keywords of miRNA, PAH, SSc, TGF-ß, and BMPR2 (Fig. 1). Here, BMPR2 is linked to systemic sclerosis.