HGF and neoplasm: Breast cancer cells secrete soluble factors leading to adipocyte “dedifferentiation” and these adipocytes secrete soluble factors (interleukin-6 [IL-6] and hepatocyte growth factor [HGF]), exosomes, and extracellular matrix components (matrix metalloproteinase-11 [MMP-11] and collagen IV), and then promote tumor cell invasiveness.78