Our studies demonstrate that depletion of HGFL or RON decreases the mammosphere formation, self-renewal, and numbers of both human and murine BCSCs, resulting in reduced tumor formation and growth as evidenced by our in vivo syngeneic transplantation experiments and the use of two clinically-relevant models of breast cancer [6, 17, 18]. The gene discussed is MST1R; the disease is neoplasm.