FGFR1 and cancer: By contrast, downregulation of miR-133b and miR-214 in human cancers (Wen et al., 2013; Wang et al., 2013b) and that of miR-424 and miR-503 in pulmonary artery epithelial cells of patients with pulmonary arterial hypertension (Kim et al., 2013b) de-repress FGFR1 and promote proliferation of tumor cells and endothelial cells, respectively, through FGF signaling activation.