TGFB1 and breast carcinoma: Incubation of three-dimensional cultures with a TGFβ type I receptor kinase inhibitor (KI) reversed the ability Smurf2KdR and PIAS3CS to induce invasive growth of MDA-MB-231 breast cancer-derived organoids, suggesting that Smurf2KdR and PIAS3CS promote invasiveness of breast cancer cells via basal TGFβ signaling (Figure 5A, 6A: third row).