CDKN1A and small cell lung carcinoma: To investigate whether cESRP1 is also involved in the negative regulation of TGF-β signalling in SCLC, we first treated chemosensitive cells with TGF-β1 (Fig. S4e) and observed that the TGF-β1 treatment efficiently increased the expression of cESRP1, Smad7, and p21(CDKN1A) (Fig. 4b; Fig. S4f).