Provided herein are methods for treating myeloproliferative neoplasm-associated myelofibrosis in a subject, comprising administering to the subject an ActRIIB signaling inhibitor. Also provided herein are methods for treating myeloproliferative neoplasm-associated myelofibrosis in a subject in need thereof, wherein the method comprises administering to the subject a pharmaceutically effective amount of an ActRIIB signaling inhibitor, and wherein said treating reduces or palliates one or more symptoms of said myeloproliferative neoplasm-associated myelofibrosis in said subject. Also provided herein is a method for treating anemia in a subject in need thereof, comprising administering to the subject a pharmaceutically effective amount of an ActRIIB signaling inhibitor, wherein the subject has myeloproliferative neoplasm-associated myelofibrosis.
