Patent No. 598031 Disclosed is the use of a pharmaceutical composition in the manufacture of a medicament fortreating a solid tumor in a subject characterized by excessive or misregulated cellular proliferation of at least one targeted cell type selected from the group consisting of a targeted tumor stem cell and a targeted tumor progenitor cell, the pharmaceutical composition comprising a therapeutic amount of at least one agent selected from the group consisting of a Leukemia Inhibitory Factor (LIF) preparation and a Leukemia Inhibitory Factor (LIF) mimetic that is effective to increase LIF receptor (LIFR)- mediated signaling in the targeted tumor stem cell or targeted tumor progenitor cell.