Prospective study to evaluate the relevance of CALR allele burden monitoring as a molecular marker of disease progression.

A first local study on 45 patients showed the prognostic impact of CALR mutation quantification in follow-up, independently of the European LeukemiaNet (ELN) prognostic score validated in this group of patients.

This study aims to evaluate a multicenter cohort of 260 patients, including all types of CALR-mutated MPNs and several follow-up samples, to model the temporal evolution of CALR allele burden.

Blood of MPN patients will be collected, at the time of diagnosis and for 3 years (max 1 sample/year), for the quantification of the CALR allele burden. During follow-up, a clinicobiological score to define the progression or not of the disease for each patient will be evaluated in Essential Thrombocythemia (ET) and MyeloFibrosis (MF).

Inclusion Criteria:

• adults (age ≥18 years),
• affiliated to the national social security system,
• with CALR mutated myeloproliferative neoplasm diagnosed between 2006 - 2020,
• for which at least one sample is available at the time of diagnosis or before cytoreductive treatment,
• who signed the consent to participate in the study,
• included, or consenting to be included, in the national clinical-biological database of France Intergroupe Syndrome Myéloprolifératifs (FIM).

Exclusion Criteria:

• patient with another active hematological disease or cancer at the time of diagnosis,
• person subject to legal protection scheme or incapable of giving consent.