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

Document Type: Research Articles

Authors

1 Center for Molecular Biomedicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam.

2 Department of Hematology, Faculty of Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam.

3 Ho Chi Minh City Blood Transfusion and Hematology Hospital, Ho Chi Minh City, Vietnam.

4 Department of Medical Statistics and Informatics, Faculty of Public Health, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam.

Abstract

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

Keywords

Main Subjects