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Turkish Journal of Medical Sciences

Abstract

Background/aim: Calreticulin (CALR) mutations in essential thrombocythemia (ET) are associated with younger age, higher platelet counts, and lower thrombosis rates. The present study analyzes the demographic, laboratory, and clinical features of the CALR mutation and its prognostic impact.

Materials and methods: The clinical impact of CALR mutations was assessed in 391 ET patients.

Results: CALR-mutation patients were more commonly male than JAK2 V617F-positive and triple-negative patients. Age at diagnosis was similar across all groups, although patients with type 2 CALR mutations were younger than those with nontype 1/nontype 2 mutations. Compared with JAK2 V617F-positive patients, CALR-mutation patients had lower leukocyte counts (9.6 × 10⁹/L vs. 10.9 × 10⁹/L), lower hemoglobin (Hb) and hematocrit (Hct) levels, higher platelet counts (1078.5 × 10⁹/L vs. 858.1 × 10⁹/L), and lower total thrombosis rates (20.8% vs. 37.8%), while the CALR-mutated and triple-negative patients had lower venous thrombosis rates than in the JAK2 V617F-positive patients. The arterial thrombosis rate before and at the time of diagnosis was lower in the CALR-mutation patients than in the JAK2 V617F-positive patients, and the total venous thrombosis rate in patients aged <60 years at the time of diagnosis was lower in the CALR-mutation and triple-negative patients than in the JAK2 V617F-positive patients. Multivariable analysis revealed cardiovascular (CV) risk to be the only independent predictor of total thrombosis. Female gender, absence of CV risk, and platelet count ≥1000 × 10⁹/L were associated with a lower incidence of arterial thrombosis. Age <60 years was associated with lower risks of arterial and venous thrombosis. Overall, thrombosis-free, and leukemia-free survival were similar across all groups, while myelofibrosis-free survival was longer in the type 2 CALR-mutation group.

Conclusion: The CALR mutation was lower among females, and was associated with lower leukocyte counts, and Hb and Hct levels, and with higher platelet counts. In multivariable analysis, the apparent protective association of CALR with thrombosis was not independent.

Author ORCID Identifier

GÖKHANGÖKHAN SAMİ AYDIN: 0009-0004-3043-6910

ELİF AKSOY: 0000-0002-3650-3043

İPEK YÖNAL HİNDİLERDEN: 0000-0003-1353-2367

AYNUR DAĞLAR ADAY: 0000-0001-8072-0646

EMİNE GÜLTÜRK: 0000-0003-2836-6162

MELİHA NALÇACI: 0000-0002-2555-5024

FEHMİ HİNDİLERDEN: 0000-0002-6297-9555

DOI

10.55730/1300-0144.6184

Keywords

CALR mutation, essential thrombocythemia, myeloproliferative neoplasm

First Page

497

Last Page

508

Publisher

The Scientific and Technological Research Council of Türkiye (TÜBİTAK)

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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