Role of cytokine receptors in the oncogenic properties of JAK2V617F and CALR mutants. (A) JAK2V617F activates signaling through the 3 main homodimeric receptors EPOR, MPL, and G-CSFR, which are involved in erythrocytosis, thrombocytosis, and neutrophilia, respectively. (B) The CALR mutants mainly activate MPL and at a low level the G-CSFR but not the EPOR, explaining the thrombocytosis associated with these mutants. Professional illustration by Somersault18:24.