To further examine the role of IL-1β in MPN pathogenesis, we crossed our SclCreER;JAK2-V617F (VF)20,21 mice with IL-1β−/− mice22 and analyzed the resulting double mutant VF;IL-1β−/− mice after induction with tamoxifen. The gene discussed is IL1B; the disease is myeloproliferative neoplasm.