The mechanism through which ANGPTL-4 promotes breast cancer progression was described by Padua et al., where they found that the cytokine transforming growth factor-B (TGF-B) induces breast cancer cell metastasis to the lungs, and the key molecule in this process was the overexpressed ANGPTL-4 through SMAD signaling pathway [9] (Figure 1). Here, ANGPTL4 is linked to breast cancer.