Clinical and Hematological Relevance of JAK2V617F, CALR, and MPL Mutations in Vietnamese Patients with Essential Thrombocythemia

Abstract

Background: The picture of Vietnamese patients with essential thrombocythemia (ET) remains mostly undetermined.<br />Our study intended to determine the frequency of JAK2V617F, CALR exon 9, and MPL exon 10 mutations as well as<br />to analyze clinical characteristics associated with different mutational status in Vietnamese ET patients. Methods: We<br />explored mutations of JAK2V617F, MPL, and CALR from 395 patients using allele specific oligonucleotide – polymerase<br />chain reaction and Sanger sequencing techniques; then, the clinical and hematological features were compared according<br />to mutation patterns. Results: We found that JAK2V617F, CALR exon 9, and MPL exon 10 mutations were present in<br />56.2%, 27.6%, and 1% of the 395 patients with ET, respectively. Twelve different types of CALR mutation were detected<br />in 109 patients, with the CALR type 1 mutation (c.1099_1150del; L367fs*46) was the most common, followed by<br />CALR type 2 mutation (c.1154_1155insTTGTC; K385fs*47). The JAK2V617F-positive patients had older age, higher<br />white blood cell counts and higher hemoglobin levels but lower platelet counts than patients with CALR mutations<br />or patients negative for triple tests. There was no significant difference regarding sex ratio, white blood cell counts,<br />platelet counts and hemoglobin levels among CALR mutation subtypes. Conclusion: we reported high frequency of<br />JAK2V617F, CALR, and MPL mutations in Vietnamese patients with ET and underscored the importance of combined<br />genetic tests for diagnosis and classification of ET into different subtypes.