ESRP1 and neoplasm: Although the EMT is thought to be critical for the early transition of cells to a more invasive and metastatic phenotype, the MET is important for the late stage of metastasis, that is, tumor formation in metastatic sites.3 Accordingly, our in vitro observation that ESPR1 promotes switching from mesenchymal to epithelial phenotypes suggests that this factor contributes to formation of metastatic tumors, thus explaining the association of ESRP1 with poor outcome in OC.