BMI1 and ovarian carcinoma: On the other hand, ectopic expression of BMI1 can also reduce γH2AX in IR-treated normal human keratinocytes [96], while knockdown of BMI1 significantly increases γH2AX in cisplatin-treated ovarian cancer cell lines A-2780 and CP-70 [97], suggesting that BMI1 might compromise DSB-elicited checkpoint activation.