JAK2 and Splenomegaly: In their recent study, they demonstrated that TKI treatment was effective in CML patients with JAK2 V617 and CALR mutations, and patients achieved major molecular response; however, 3 of 4 such patients still showed thrombocytosis and/or splenomegaly, indicating that TKIs could not control all clinical symptoms of this type of atypical MPN.