JAK2 V617F Mutation in Adult Taiwanese Patients with Essential Thrombocythemia: More Prevalent in Old Patients and Correlated with Higher Hemoglobin Level and Higher Leukocyte Count

Abstract

Background: Essential thrombocythemia (ET) is classified as a chronic myeloproliferative neoplasm. JAK2 V617F mutation is found in about 50–60% patients with ET. We aim to determine the prevalence of JAK2 V617F mutation and its association with phenotype in adult Taiwanese patients with ET. Methods: In this combined retrospective and prospective study, adult ET patients, at least 18 years of age, were enrolled between November 2007 and September 2011. Genomic DNA was extracted from unsorted bone marrow and/or peripheral blood samples for the detection of JAK2 V617F mutation by allele-specific polymerase chain reaction. The clinical and laboratory characteristics of all patients at the time of diagnosis or referral were determined retrospectively by chart review. Results: A total of 82 patients were enrolled, and JAK2 V617F mutation was detected in 55 patients (67.1%). JAK2 V617F mutation was significantly more prevalent in old patients (36.4% vs. 14.8%, p=0.044), and associated with higher hemoglobin level (median 13.7 vs. 12.8 g/dL p=0.012) and higher white blood cell count at diagnosis (12.1×103 vs. 8.8×103/μL p=0.015). ET patients with the mutation also tend to have lower platelet count (median 902×103 vs. 1078×103/μL p=0.051). In a binary logistic regression model, only higher hemoglobin concentration was significantly associated with JAK2 V617F mutational status (odds ratio 1.2 95% confidence interval 1.0–1.5; p=0.047). Conclusion: JAK2 V617F mutation in Taiwanese adult patients with ET has a high prevalence of 67.1% and is associated with old age, higher hemoglobin level, and higher leukocyte count.

Keywords

• essential thrombocythemia
• JAK2
• mutation
• prevalence