TGFB1 and neoplasm: The tumor-derived cell lines maintained robust Smad4 restorability (Fig. 1e), mounted an expected Smad4-dependent cytostatic response to TGFβ in vitro (Extended Data Fig. 2a,b) and produced metastases with remarkably similar histopathology to those emerging in the GEMMs and in PDAC patients23 (Extended Data Fig. 2c).