Due to limited information on the clinical impact of ATM mutations on MCL and although ATM has been repeatedly proven to be the most commonly mutated gene, followed by CDKN2A and TP53, the latest publications consistently show no statistically significant difference in the OS of patients with wild-type vs. mutated ATM, which is in sharp contrast to TP53 defects [3, 83]. The gene discussed is ATM; the disease is mantle cell lymphoma.