Methods and compounds are described for treating solid tumors, and in particular, malignant, neoplastic solid tumors such as glioblastoma and medulloblastoma, by inhibiting protein kinase MRK/ZAK activity. Also provided are pharmaceutical composition containg a MRK/ZAK inhibitor compound and a pharmaceutically acceptable carrier and a method of sensitizing tumor cells to radiation therapy comprising administering an effective amount of the MRK/ZAK inhibitor compound.
