Cancer stem cells exhibit different metabolic profiles from other cancer cells such that they do not readily respond to treatment using conventional chemotherapeutic agents. Studies disclosed herein now demonstrate that the glycylcycline antibiotic tigecycline (a tetracycline derivative) exhibits anti-cancer activity including activity against cancer stem cells. This anti-neoplastic activity appears to be due to inhibition of mitochondrial protein synthesis in the cancer cells. In preferred embodiments the cancer to be treated is a hematological cancer such as leukemia lymphoma or myeloma. Figure 1 is the representative figure.
