MAPK1 and myeloproliferative disorder: Stivala et al. [65], in fact, demonstrate that DUSP4/6 mRNA is not suppressed in splenocytes or bone marrow cells of an MPN mouse model treated with ruxolitinib or MEK inhibition, suggesting that a loss of DUSP4/6 expression is not contributing to enhanced ERK activity in response to JAK2 or MEK inhibition in such therapeutic model systems.