ATM and familial pancreatic carcinoma: More importantly, RP Sahu et al found that H2AX (pSer-139), ATM (pSer-1981) and Chk1 (pSer-345) activations were concomitant with G2/M cell cycle arrest in curcumin-treated human pancreatic cancer cells, but they did not observed ATR (pSer-428) and Chk2 (pThr-68) activations [36].