MAPK3 and myeloproliferative neoplasm: Also in Jak2V617F settings, ruxolitinib/MK-8353 showed comparable effects in normalizing erythrocytosis and splenomegaly as seen with ruxolitinib/LTT462 (Supplementary Fig. 12A-H), thus credentialing combined JAK2/ERK1/2 inhibition as a valid approach to enhance the corrective potential of JAK2 inhibitor therapy for MPN.