The findings of a study presented at the 12th International Congress on Myeloproliferative Neoplasms suggest performing calreticulin mutations (CALR) analysis for the diagnosis of JAK2 negative myeloproliferative neoplasm (MPN).
In this prospective observational study, which was conducted between 2014 and 2018, researchers assessed 137 diagnosed with essential thrombocythemia (ET) or myleofibrosis (MF). All ET patients were categorized as either high or low risk based on the presence or absence of thrombosis at age 60 years and older. MF patients were categorized into low, intermediate-1, intermediate-2 and high-risk groups using a specialized scoring system. Molecular analysis was performed in all patients using primers for JAK2, CALR and MPL mutation via PCR and validated via sequencing.
Subsequently, they assessed response to therapy according to revised-response criteria published by the International Working Group-Myeloproliferative Neoplasms Research and Treatment. Any ET patient with no known history of contraindications was administered an antiplatelet agent, with hydroxyurea used as a first-line therapy followed by interferon alpha in patients either refractory or resistant to hydroxyurea. The researchers used erythropoietin and synthetic androgens to treat anemia in MF patients.
According to the results, CALR mutation was detected in 29.3% of ET and 30.7% of MF, whereas JAK2 mutation was detected in 37.3% of ET and 37.1% of MF patients. The authors wrote of their findings: “CALR mutation comprised of 32.4% of ET and 38.1% of MF with non-mutated JAK2 in our study group, therefore we strongly suggest performing CALR mutation analysis for the diagnosis of JAK2 negative MPN.”
They added that “long-term follow up is required to determine the clinical relevance and response to treatment in CALR mutated ET and PMF.”
Zaidi U, et al. Clinical and Prognostic Relevance of CALR Mutant Myeloproliferative Neoplasm in Pakistani Population. Presented at the 12th International Congress on Myeloproliferative Neoplasms; October 24-25, 2019; New York, NY.