Related Experiment Video
Updated: Jul 4, 2026
Transduction-Transplantation Mouse Model of Myeloproliferative Neoplasm
Published on: December 22, 2016
Characteristics and clinical correlates of MPL 515W>L/K mutation in essential thrombocythemia
Alessandro M Vannucchi1, Elisabetta Antonioli, Paola Guglielmelli
1Unita Funzionale di Ematologia, Dipartimento di Area Critica Medico-Chirurgica, Università degli Studi, Florence, Italy. amvannucchi@unifi.it
Abstract:
Among 994 patients with essential thrombocythemia (ET) who were genotyped for the MPLW515L/K mutation, 30 patients carrying the mutation were identified (3.0%), 8 of whom also displayed the JAK2V671F mutation. MPLW515L/K patients presented lower hemoglobin levels and higher platelet counts than did wild type (wt) MPL; these differences were highly significant compared with MPLwt/JAK2V617F-positive patients. Reduced hemoglobin and increased platelet levels were preferentially associated with the W515L and W515K alleles, respectively. MPL mutation was a significant risk factor for microvessel disturbances, suggesting platelet hyperreactivity associated with constitutively active MPL; arterial thromboses were increased only in comparison to MPLwt/JAK2wt patients. MPLW515L/K patients presented reduced total and erythroid bone marrow cellularity, whereas the numbers of megakaryocytes, megakaryocytic clusters, and small-sized megakaryocytes were all significantly increased. These data indicate that MPLW515L/K mutations do not define a distinct phenotype in ET, although some differences depended on the JAK2V617F mutational status of the counterpart.
Insights
The MPLW515L/K mutation in essential thrombocythemia (ET) is linked to lower hemoglobin and higher platelets. While not defining a distinct ET phenotype, it increases microvessel disturbance risk.
Area of Science:
- Hematology
- Molecular Biology
- Oncology
Background:
- Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by elevated platelet counts.
- The MPLW515L/K mutation is a known driver mutation in a subset of ET patients.
- Understanding the clinical and biological impact of MPL mutations is crucial for patient management.
Purpose of the Study:
- To investigate the clinical phenotype and biological characteristics of ET patients with MPLW515L/K mutations.
- To compare MPLW515L/K mutated patients with wild-type MPL and JAK2V617F co-mutated patients.
- To assess the association of MPLW515L/K mutations with thrombotic events and bone marrow morphology.
Main Methods:
- Genotyping of 994 ET patients for MPLW515L/K and JAK2V617F mutations.
- Comparative analysis of clinical parameters (hemoglobin, platelet count) between different mutational groups.
- Evaluation of bone marrow cellularity, megakaryocyte counts, and microvessel disturbances.
Main Results:
- MPLW515L/K mutation identified in 3.0% of ET patients; 8 also carried JAK2V617F.
- MPLW515L/K patients exhibited significantly lower hemoglobin and higher platelet counts compared to MPLwt/JAK2V617F patients.
- MPL mutation was a risk factor for microvessel disturbances; arterial thromboses increased compared to MPLwt/JAK2wt patients.
- Bone marrow showed reduced erythroid cellularity but increased megakaryocytes and megakaryocytic clusters.
Conclusions:
- MPLW515L/K mutations in ET are associated with specific hematological and morphological changes.
- These mutations increase the risk of microvessel disturbances, suggesting enhanced platelet reactivity.
- The phenotype associated with MPLW515L/K mutations can be influenced by the co-existence of JAK2V617F mutation.
