HGF and non-small cell lung carcinoma: Expression of the receptor c-Met and its only known ligand HGF, has been observed in tumor biopsies of solid tumors, and the c-Met signaling has been documented in a wide range of human malignancies (for example in brain tumors and non-small cell lung cancer; medulloblastomas; gastric and esophageal carcinomas) [36–39].