PTK2 and breast cancer: In addition to interacting with HIF-1, intracellular LOX can activate the transforming growth factor (TGF-β1)-mediated p38 mitogen-activated protein kinase (p38 MAPK) pathway and the focal adhesion kinase (FAK)/steroid receptor-coactivator (Src) pathway in a H2O2-dependent manner to promote EMT in breast cancer cells [30,31].