Interestingly, the p-DNA-PKcs at S2056 for non-homologous end joining (Figure 3B) and the ubiquitination of Fanconi anaemia complementation group D2 (FANCD2) for FA repair (Figure 3C) showed higher endogenous expression levels and were activated in CL1-0 cells but not in CL1-5 cells after MMC treatment. This evidence concerns the gene FANCD2 and Fanconi anemia.