TGFB1 and metastatic neoplasm: Furthermore, with TGF-β1 stimulation, PPM1A knockdown led to a significant reduction in the expression of epithelial markers and increased expression of mesenchymal markers in both cell lines, and these effects were prevented by treatment with SB431542, suggesting that upon activation of TGF-β signaling induced by loss of PPM1A, cells exhibit a more overt EMT, which may contribute to the formation of more aggressive and metastatic tumors.