Therefore, following our promising results demonstrating reduced GM-CSF hypersensitivity and proliferation of GOF Shp2-expressing murine cells and primary JMML cells in vitro, we assessed the effect of PI3K p110δ inhibition on GOF Shp2-expressing mice in vivo as the next step in exploring p110δ inhibition as a potential treatment strategy for JMML. The gene discussed is PTPN11; the disease is juvenile myelomonocytic leukemia.