TGF-β1 could negatively regulate Cited2 in breast cancer cells, epithelial cells, and leiomyoma cells (26, 32, 33), and TGF-β1 expression is up-regulated in hypoxia, which is related to pulmonary vascular remodeling and the PH development (22, 34). Here, TGFB1 is linked to leiomyoma.