JAK2 V617F and exon 12 genetic variations in Korean patients with BCR/ABL1-negative myeloproliferative neoplasms

Background : JAK2 genetic variations have been described in a high proportion of patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN). This study was designed to analyze the frequencies of JAK2 V617F and exon 12 variations, and their correlations with clinical characteristics of Korean patients with BCR/ABL 7-negative MPN. Methods : We examined a total of 154 patients with BCR/ABL 1-negative MPN that included 24, 26, 89, and 15 patients with polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (FT), and unclassified myeloproliferative neoplasms (MPNU), respectively. We performed allele-specific PCR to detect V617F in all BCR/ABL 1-negative patients, and performed direct sequencing to detect exon 12 variations in 47 V617F-negative MPN patients. JAK2c.1641+179-183del5 variation was detected by restriction fragment length polymorphism assay in 176 healthy subjects. Results : JAK2 V617F was detected in 91 patients (59.1%): PV (91.6%), PMF (46.2%), ET (52.8%), and MPNU (66.7%). In V617F-negative MPN patients, no mutations were found in exon 12. The c.1641+179-183del5 was detected in 68.1% of V617F-negative MPN patients and 45.4% of healthy subjects (P=0.008). JAK2 V617F was closely correlated with age and leukocytosis in BCR/ABL 1-negative MPN patients (P<0.05). However, c. 1641+179-183del5 was not related to age, sex, or complete blood cell count parameters in V617F-negative MPN patients and healthy subjects. The c.1641+179-183del5 was associated with an increased odds ratio for MPN (odds ratio, 2.6; 95% confidences interval, 1.3-5.1; P=0.007). Conclusions : Frequencies of V617F are similar to reported results. JAK2 exon 12 mutations may be rare and c.1641+179-183del5 may influence the occurrence of MPN in Korean patients with V6 17F-negative MPN.