The Investigation of JAK2 V617F Mutation in Chinese Patients with Hematological Malignancies.

Myeloproliferative Diseases (MPD) are a spectrum of pathogenetically related disorders of varying clinical manifestations, characterized by neoplastic expansion of relatively mature granulocyte, erythroid, megakaryocyte, or monocyte and eosinocyte lineage cells. Recently a novel point mutation affecting the Janus tyrosine kinase 2 (JAK2 V617F) was identified as pathogenetically mechanisms by multiple competing groups. To investigate its prevalence and clinical significance in Chinese patients with hematological malignancies, we introduced Allele-specific PCR (AS-PCR) combined with sequence analysis to screen JAK2 V617F mutation.

A total of 98 Chinese MPD patients and 120 additional hematological malignancies including AML, ALL, MDS were analyzed for the JAK2 V617F mutation. 98 MPD patients were referred for PV (n=57), ET (n=18), IMF (n=12), HES (n=2) and CML (n=9). 2 ml peripheral blood samples of MPD and 5–10 ml bone marrow samples of AML, ALL, MDS at the time of initial diagnosis were obtained with informed consent and genomic DNA was isolated presently. In addition, peripheral blood samples from 20 healthy donors were also collected as control. All samples were first screened by AS-PCR. The positive samples were subsequently confirmed by sequence analysis.

The results showed that JAK2 V617F mutation was detected in 43 of 57 PV patients (75.4%), 7 of 18 ET patients (38.9%) and 5 of 12 IMF patients (41.7%). None of the AML, ALL, MDS, CML was found JAK2 V617F. There is no statistical difference of JAK2 V617F positive ratio between PV, ET and IMF. Furthermore, the mutation was not detected in the HES patient and 20 healthy controls. There is no other mutations and polymorphisms throughout exon 12 of JAK2.

To our knowledge, this is the first report of JAK2 V617F mutation in a number of Chinese patients with hematological malignancies especially BCR/ABL-negative MPD. The incidence of JAK2 V617F of our study is a little lower compared with other publications especially in PV patients. The main reason may be firstly attributed to ethnic difference. In addition, with more MPD patients introduced and more sensitive methods such as ARMS-PCR or Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) applied, more JAK2 V617F mutation will be identified.