CD44 and neoplasm: To this end, they have labeled primary pancreatic cancer cells with an anti-c-met antibody and separated the cells into a c-methigh and a c-metlow population: c-methigh, but not c-metlow, cells are able to induce tumor sphere formation in vitro; c-met inhibitors significantly reduced tumor-sphere formation in vitro; c-methigh and, particularly, c-methigh/CD44+ cells have an increased tumorigenicity potential when inoculated into immunodeficient mice [152].