A method for treating a solid brain tumor comprising a population of tumor-propagating cells (TPCs) with stem-like characteristics in a subject, said method comprising administering to the subject a pharmaceutical composition comprising a therapeutic amount of a therapeutic agent and a pharmaceutically acceptable carrier, wherein the therapeutic agent is a t-butyloxycarbonyl peptide derivative of Wnt5a, selected from Peptide A (SEQ ID NO:
- 2), Peptide B (SEQ ID NO:
- 3), for a combination of Peptide A (SEQ ID NO:
- 2) and Peptide B (SEQ ID NO:
- 3), wherein the t-butyloxycarbonyl peptide derivative of Wnt5a is formulated per se or in salt form, and
- wherein the composition is administered orally, buccally, parenterally, intranasally, rectally, or topically.