Ph-like acute lymphoblastic leukemia in adults is characterized by IgH-CRFL2 and JAK2 mutations and poor prognosis [HG-U133A]

Philadelphia-like B-cell precursor acute lymphoblastic leukemia (Ph-like ALL) is characterized by distinct genetic alterations and inferior prognosis in children and younger adults. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults. Among 207 adult B-cell precursor ALL patients, 26 (13%) were classified as Ph-like using Affymetrix microarrays. The incidence of this subtype was 25% among 105 B-cell precursor ALL patients negative for BCR-ABL1 and MLL-translocations (B-other). All patients with IgH-CRLF2 translocation (38% vs 0%; p=0.002) or mutations in JAK2 (44% vs. 0%; p<0.001) were exclusively found in the Ph-like subgroup. Clinical and outcome analyses were restricted to patients treated within GMALL trials 06/99 and 07/03 (n=107). The complete remission (CR) rate after induction was 100% for Ph-like (n=19) and B-other patients (n=40). After induction, significantly fewer Ph-like patients reached molecular CR (33% vs 79%; p=0.01). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous CR (24% vs 62%; p<0.001) and overall survival (22% vs 64%; p=0.006) compared to B-other ALL patients. Subsequent analysis led to a clinically applicable algorithm identifying this patient subset with a specificity of 100%. Our study is the first to demonstrate that the profile of genetic events in adult Ph-like ALL resembles pediatric Ph-like ALL and differs from B-other ALL. The Ph-like phenotype associates with inferior outcomes in intensively treated adult ALL patients. Ph-like adult ALL should be recognized as a distinct, high-risk entity and further research on improved diagnostic and therapeutic approaches is needed.

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Herold T, Schneider S, Metzeler KH, Neumann M, Hartmann L, Roberts KG, Konstandin NP, Greif PA, Bräundl K, Ksienzyk B, Huk N, Schneider I, Zellmeier E, Jurinovic V, Mansmann U, Hiddemann W, Mullighan CG, Bohlander SK, Spiekermann K, Hoelzer D, Brüggemann M, Baldus CD, Dreyling M, Gökbuget N