SOCS1 and cancer: It may be expected that deleterious MIR142 mutations also affect other well-documented hematologic targets of miR-142-3p or miR-142-5p, including RAC1 (Rac Family Small GTPase 1)7, PROM1 encoding CD133 antigen8,9, TNFRSF13C encoding B cell-activating factor receptor (BAFF-R)10, SOCS1 (Suppressor of Cytokine Signaling 1)11,12, PTEN (Phosphatase And Tensin Homolog)13,14, IL6 (Interleukin 6)15 and CD274 encoding programmed death-ligand 1 (PD-L1)14,16,17 which is an important immune checkpoint molecule that is elevated in many cancers, including different types of MPNs18,19.