MYC and cancer: This phenomenon of the enhanced radiosensitization took place only in the cell cultures sensitive to the action of Hsp90 activity inhibitors, namely in MCF-7, HeLa, KTC-1, PC-3, Myc-CaP, HT 1080 and A549 cancer cell lines and actively proliferating endothelial cells but not in HBL-100, FRO and B16 or quiescent endothelial cells.