ABSTRACT
Myeloproliferative neoplasm (MPN) is a kind of clone hematopoietic stem cell disease characterized by one or more myeloid cell lines hyperproliferation, including bcr-abl gene positive chronic myeloid leukemia (CML) and bcr-abl negative MPN, the later representing polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). A big stride has been made since the discovery of JAK2 and MPL gene mutations. However, the exact genetic basis of JAK2/MPL mutation double negative in MPN patients is still unclear. It has been reported recently that a new CALR mutation is discovered in the JAK2/MPL unmutated MPN patients who show unique clinical presentations, which provides a new diagnostic and prognosis-accessing criteria. The paper reviews CALR mutation and genetic mechanism mediating MPN.