The knockdown of SCF with siRNA and inhibition of SCF signaling by anti-c-kit antibodies or with tyrosine kinase inhibitors like sunitinib and sorafenib have been demonstrated to reduce MDSC frequencies in the human bone marrow cells in vitro as well as in murine models of colon and Lewis lung carcinoma that was associated with enhanced anti-tumor reactivity, tumor regression and prolonged survival. The gene discussed is KITLG; the disease is neoplasm.