Regarding the association between del(11q) and other chromosomal abnormalities, such cases show an increased copy number alterations, thus indicating genomic instability [15, 48]. ATM gene mutations have been largely studied in CLL patients with del(11q); however, they have been found in only 8–30% of 11q- patients [49], indicating that other genes could play a role in the pathobiology of 11q deletions in CLL. The gene discussed is ATM; the disease is B-cell chronic lymphocytic leukemia.