Is hyperdiploidy a favorable cytogenetics in adults with B-lymphoblastic leukemia?

Hyperdiploidy (chromosomal number 51-65) is a common cytogenetic abnormality in pediatric patients with B-lymphoblastic leukemia (B-ALL) and belongs to the favorable cytogenetic subgroup. Hyperdiploidy in adult B-ALL is much less common and its clinical significance has not been well studied. Among the 1205 patients with B-ALL (1018 adults and 187 children) from our institution, 78 had a hyperdiploid karyotype, including 45 (4.4%) adults and 33 (17.6%) children (P < 0.0001). Among the patients with hyperdiploid B-ALL, the adult group had a significantly inferior survival (similar to the patients with a normal karyotype) compared with the pediatric group (median survival: 42 months vs undefined, P = 0.0029). Hyperdiploidy in adults B-ALL tended to more frequently harbor structural abnormalities (two or more) than children (53% vs 33%). Two or more structural abnormalities in a hyperdiploidy correlated with an adverse survival in adult patients (33 months vs undefined, P = 0.0008), similar to the survival of patients with a complex karyotype. We conclude that hyperdiploidy in adults with B-ALL is less favorable and more commonly contains structural abnormalities comparing to pediatric patients. We suggest that hyperdiploidy with two or more structural abnormalities are best considered as a complex karyotype in adults with B-ALL.