Previous studies have found that SMAD3 could bind to the SBE in the promotor of MET to induce the expression of MET in epithelial cells and also triggers systemic sclerosis fibroblasts.24, 25 To further explore whether SMAD3 could regulate MET in BCa in the same manner, western blot and qRT-PCR analysis were performed but the results suggested no significant reduction of MET in SMAD3 knockdown BCa cells, which indicated that SMAD3 could not regulate MET directly binding to its promotor. This evidence concerns the gene SMAD3 and systemic sclerosis.