High resolution melting analysis: a rapid and accurate method to detect CALR mutations

Area of Science:

• Hematology
• Molecular Diagnostics
• Oncology

Background:

• Calreticulin (CALR) mutations are key in diagnosing myeloproliferative neoplasms (MPN) like essential thrombocythemia (ET) and primary myelofibrosis (PMF), particularly in JAK2/MPL-wild-type cases.
• Accurate molecular diagnosis is crucial for patient stratification and treatment selection in MPNs.

Purpose of the Study:

• To evaluate the feasibility and efficiency of high-resolution melting (HRM) as a rapid screening tool for detecting CALR mutations.
• To assess the prevalence of CALR mutations in ET and other thrombocytosis subtypes.

Main Methods:

• CALR gene analysis was performed using HRM and Sanger sequencing on patients with ET, persistent thrombocytosis, and suspected secondary thrombocytosis, all wild-type for JAK2/MPL.
• Comparative analysis of clinical features between CALR-mutated and JAK2/MPL-mutated ET patients was conducted.

Main Results:

• HRM accurately identified 18 CALR mutations and 1 polymorphism among 19 distinct melting patterns, with a detection limit of 3%.
• CALR mutations were found in 44% of ET patients and 14% of persistent thrombocytosis suggestive of MPN, but none in secondary thrombocytosis.
• The HRM method demonstrated high reproducibility, with no false positives or negatives observed.

Conclusions:

• High-resolution melting (HRM) provides a sensitive, reliable, and rapid method for screening CALR mutations.
• This HRM-based approach significantly aids in the molecular diagnosis of MPNs, especially in JAK2/MPL-negative cases.