JAK2 in pediatric leukemia: mechanisms of pathogenesis and drug development - a narrative review.

Pediatric leukemia is one of the most prevalent childhood malignancies, and its pathogenesis involves complex molecular and genetic mechanisms. Among the critical players in leukemogenesis, the Janus kinase 2 (JAK2) gene has garnered significant attention due to its role in aberrant signal transduction and hematopoietic dysregulation. Mutations such as JAK2 V617F, while more commonly associated with myeloproliferative neoplasms, have also been implicated in pediatric leukemia subtypes, including acute lymphoblastic leukemia and acute myeloid leukemia. These mutations result in constitutive activation of the JAK-STAT pathway, promoting unchecked cell proliferation, survival, and resistance to apoptosis. The dysregulation of the JAK2 signaling pathway not only drives malignant transformation but also facilitates interactions with the bone marrow microenvironment, creating a niche that supports leukemia cell survival and immune evasion. Therapeutic advancements have focused on JAK2 inhibitors such as ruxolitinib and fedratinib, which show promise in preclinical and early clinical settings. However, challenges such as drug resistance and off-target effects limit their efficacy, necessitating the exploration of combination therapies and novel drug formulations. Current strategies include combining JAK2 inhibitors with chemotherapy, immune checkpoint inhibitors, or epigenetic modulators to achieve synergistic effects.