FOS and breast cancer: Using a 3D model of collagen-embedded spheroids of non-malignant, pre-malignant, and metastatic MCF10A human breast cancer cells, we found that TGFβRI kinase, Smad3, Smad4, and the AP-1 components cJun, JunB, cFos, and Fra1 co-operate in TGFβ-induced invasion in the presence of EGF; this co-operation induced the expression of various genes, including MMP10, SERPINE1, WNT7A, and WNT7B [37,38].