Our study with AUY922 and prostate cancer cells suggests that it may indeed impart radiosensitization through multiple mechanisms: (1) reassortment of prostate cancer cells into G2-M; (2) downregulation of the PI3K-AKT-mTOR radioresistance pathway; and (3) downregulation of the ATR-Chk1 DDR pathway. Here, CHEK1 is linked to prostate carcinoma.