H2AX and mantle cell lymphoma: Cotreatment of mantle cell lymphoma (MCL) cells with AF and ABT-888 (PARPi) increases synergistically the apoptosis of ATM-proficient MCL cells, with increased γ-H2AX foci induction in the DNA and depletion of p-Chk1 (a downstream target of ATR signaling) [192].