On the other hand, it is also reported that H2AX is phosphorylated by activation of ATM in response to DNA damage induced by MTZ in human lung carcinoma A549 cells, therefore, it plays a key role in DNA damage response, as well as it is additionally required either for the assembly of DNA repair proteins at those sites containing damaged chromatin that for activation of checkpoint proteins, which arrest the cell cycle progression [42]. This evidence concerns the gene XRCC6P5 and lung carcinoma.