JAK2 inhibition for the treatment of hematologic and solid malignancies

Introduction: Mutations in Janus kinase 2 (JAK2), and in particular JAK2 V617F, are common in Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs). In the past several years, JAK2 inhibitors have been rapidly developed as targeted therapies for MPNs. Areas covered: JAK2 mutations, including JAK2 V617F and unique fusion proteins, are critical for oncogenesis of some hematologic malignancies. Although JAK2 mutations are extremely rare in solid cancers, pathophysiological JAK2/STAT signaling can still promote tumor cell growth, proliferation, migration, invasion and angiogenesis. JAK2 inhibition can curtail malignant cellular behaviors and thus may be a promising therapeutic strategy. Expert opinion: The involvement of oncogenic JAK2 mutations in hematologic malignancies indicates that JAK2 inhibition has the potential to be a highly successful treatment option. The exact role of JAK2 signaling in solid cancers is unclear, but JAK2 inhibition may prevent disease progression by restricting malignant cell phenotypes. JAK2 inhibitors in development for the treatment of MPNs have demonstrated clinical activity with minimal toxicity. This class of agents should be investigated more rigorously for the treatment of other malignancies with aberrant JAK2 signaling with or without JAK2 mutations.