CALR and acquired polycythemia vera: The MPN include clonal disorders of hemopoietic stem cells such as polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (MF) that are driven by mutations in Janus kinase 2 (JAK2), myeloproliferative leukemia (MPL), or calreticulin (CALR) genes [30]; however, none of these could be detected in 2–15% of the patients (triple-negative patients, TN).