TGFB1 and breast cancer: During extravasation, TGFβ induces angiopoietin-like 4 (ANGPTL4) expression via the Smad signaling pathway; the increased levels of ANGPTL4 enhance the retention of cancer cells in the lungs by disrupting vascular endothelial cell–cell junctions, thus increasing the permeability of lung capillaries to facilitate trans-endothelial passage of breast cancer cells (52).