For example, homozygous CDKN2A and CDKN2B deletions in two patients with B-cell acute lymphoblastic leukemia (B-ALL), which confers a poor prognosis in adult B-ALL [27], and heterozygous PAX5 deletions in two B-ALL patients (Figure 5) were not detected by traditional chromosome studies, but were revealed by aCGH analysis. The gene discussed is CDKN2A; the disease is B-cell acute lymphoblastic leukemia.