Here we showed that the depletion of ESRP1 and ESRP2 in a non-invasive BC cell line RT4 rendered the cells from epithelial-like to mesenchymal-like, increased cell growth potential and increased cell invasiveness, likely through a substantial switch of the FGFR2 pre-mRNA from the epithelial IIIb form to the mesenchymal IIIc isoform. This evidence concerns the gene ESRP1 and breast cancer.