TGFB1 and non-small cell lung carcinoma: For instance, downregulated in SCLC and chemo-resistant NSCLC cells, circRNA cESRP1 enhances drug sensitivity by directly binding to and repressing miR-93-5p, thereby up-regulating the expression of Smad7 and p21, forming a negative feedback loop to regulate EMT process dependent of transforming growth factor-β (TGF-β) (Huang W. et al., 2019).