JAK2V617F mutation distribution in hematologic malignancies

In this study we have examined the deviation of JAK2V617F mutation among the patients who applied to the departments of child health and disease and pediatric hematology of Çukurova University Medicine Faculty between September 2009 and September 2011. 216 patients in the pediatric group that were diagnosed with acute leukemia by cytomorphological and immunohistochemical studies have been examined. In addition, 176 adults -PV, ET, CML and PMF patients- who applied to Hematology clinic between the dates September 2009 and 2011 have been studied. In order to identify the JAK2V617F mutation, DNA has been isolated from the whole blood. DNA isolation has been carried out with manual methodology, using the High Pure PCR Template Preparation Kit (Roche), and the extracted DNAs have been preserved at -80ºC. Gene mutations have been identified by analyzing the Tm curves obtained throughout the RealTime PCR. The mutant JAK2617F/F Tm value is 53ºC, the wild type JAK2617V/V Tm value is 62ºC, and heterozygosis allels JAK2617V/F Tm values are 53ºC and 62ºC. As a result, the rates of the identified JAK2V617F mutation are as follows: none (0%) among the 164 ALL patients, 1 (1,92%) among the 52 AML patients, 71 (89,8%) among the 79 PV patients, 22 (43,1%) among the 51 ET patients, 1 (4,5%) among the 22 CML patients, 15 (62,5%) among the 24 PMF patients. Although no significant relation has been detected between the platelet value and JAK2V617F mutation for the CML, PV and PMF adult patient groups, a significant relation has been detected between the platelet value and JAK2V617F mutation for the ET patients -as expected- because of thrombocytosis, which is the main pathogenomic sign of the disease. A significant statistical difference (p=0,000) has been found between the allele and genotype distribution. T allele is identified as a risk for the disease according to allele distribution (p<0,0001). No statistical difference (p>0.05) has been found for hemoglobin (Hb), hematocrit (Hct), white blood cell (WBC) values for the PV and ET patients with and without JAK2V617F mutation. It is concluded that the JAK2V617F mutation at the hematological malignancies is very little or negligible in the childhood leukemia when compared to the adults. This study examines the highest number of patients in pediatric age group in Turkey and in the literature. The results obtained are in accordance with the literature. Moreover, this is the first study to evaluate the relationship between JAK2V617F mutation and flowcytometric findings for the immunophenotypic examination, which is an important classification tool of leukemia. It is once again shown that determination of the JAK2V617F mutation with Realtime PCR is a useful screening test for definitive diagnosis of hematologic malignancies especially PV and ET and follow-up of patients? response to therapy as reported in the literature. A medicine has been recently developed consisting of JAK1/2 inhibitor to cure MPDs patients. This reveals the importance of examination of JAK2V617F mutation.