HGF and neoplasm: Moreover, stressful signals that promote transcriptional activation of MET in cancer cells may also induce HGF upregulation in tumor stromal cells (42), feeding a positive stimulatory circuit of HGF-MET signaling that allows cancer cells to convert the anti-apoptotic and pro-migratory activities typically used in tissue regeneration and repair into pro-invasive and pro-metastatic behaviors (43).