伴 JAK2 重排的急性淋巴细胞白血病的临床病理特征、遗传学特征与治疗选择——10 例病例研究及文献综述

JAK2 rearrangement (JAK2-R) in acute lymphoblastic leukemia (ALL) is rare and often categorized as B-ALL with BCR::ABL1-like features based on the World Health Organization classification.

We report 10 patients with JAK2-R ALL, 9 males and 1 female, with a median age 40. 5 years. Eight patients presented with marked leukocytosis (median WBC, 63 10 9 /L) and hypercellular (>95%) bone marrow with increased lymphoblasts (72%-95%). There was no evidence of bone marrow fibrosis or hypereosinophilia.

Immunophenotypic analysis showed 9 B-cell and 1 T-cell neoplasms. Using fluorescence in situ hybridization (FISH) and RNA sequencing analysis, JAK2 partners were identified for 7 cases and included PCM1 (n = 4), ETV6 (n = 2) and BCR (n = 1). All patients received upfront polychemotherapy.

Additionally, 2 patients received ruxolitinib, 2 received allogeneic stem cell transplant, and 1 received CAR-T therapy. The 1- and 3-year overall survival rates were 55. 6% and 22. 2%, respectively. A literature review identified 24 B-ALL and 4 T-ALL cases with JAK2-R reported, including 16 males, 6 females and 6 gender not stated. Many JAK2 partner-genes were reported with the most common being PAX5 (n = 7), ETV6 (n = 5), BCR (n = 4) and PCM1 (n = 2).

Survival data on 13 reported cases showed 1- and 3-year overall survival rates of 41. 7% and 41. 7%, respectively. In summary, JAK2-R ALL occurs more often in adult males, are mostly of B-cell lineage, and associated with an aggressive clinical course. Absence of eosinophilia and bone marrow fibrosis and no evidence of preexisting/concurrent JAK2-R myeloid neoplasms distinguish JAK2-R ALL from other myeloid/lymphoid neoplasms with eosinophilia and JAK2-R.