The present study aimed to test (i) whether preventing the up-regulation of Hsp90 and Hsp70 by PI-103, an inhibitor of PI3K and mTOR, can enhance the radiosensitizing effect of NVP-AUY922 in cancer cell lines, and (ii) what is the optimum drug-IR treatment schedule for radiosensitization of tumor cells. Here, MTOR is linked to neoplasm.