[Analysis of CALR, JAK2 and MPL gene mutations in BCR-ABL negative myeloproliferative neoplasms].

OBJECTIVE: To explore the mutational status of CALR, JAK2 and MPL genes in BCR-ABL negative myeloproliferative neoplasms (MPN) patients and the clinical features of MPN patients with these mutations.

METHODS: A total of 246 patients with a definite diagnosis of BCR-ABL negative MPN were enrolled from January 2009 to January 2014 into this study. Among them, there were 48 cases of polycythemia vera (PV) patients, 171 cases of essential thrombocythemia (ET) patients and 27 cases of primary myelofibrosis (PMF) patients. And CALR, JAK2 V617F, 12 exons of JAK2 and MPL W515L/K genes were amplified by PCR and sequenced directly. Clinical features were also analyzed in patients.

RESULTS: Among 246 cases of BCR-ABL-negative MPN patients, 52 cases (21.1%) had CALR mutation, 121 cases (49.2%) JAK2 V617F mutation, 0 case (0) 12 exons of JAK2 mutation, and 2 cases (0.8%) MPL W515L/K mutation, respectively. These mutations were found existing exclusively. In PV patients, the white blood cell and platelet counts in JAK2 V617F mutated group were higher than those in wild-type JAK2 V617F group, while the level of hemoglobin was higher in wild-type JAK2 V617F group (all P<0.05). In ET patients, the white blood cell count, the level of hemoglobin, the frequency of thromboembolic events and risk stratification in JAK2 V617F mutated group were higher than those in CALR mutated group (all P<0.05). In PMF patients, the level of hemoglobin in JAK2 V617F mutated group were significantly higher than those in CALR mutated group (P<0.05).

CONCLUSIONS: The proliferative level of bone marrow, risk of thromboembolic events and stratification are lower in CALR mutated patients than those in JAK2 V617F mutated patients. The pathogenic mechanism of mutated gene should be further investigated in future.