Sequential evaluation of CALR mutant burden in patients with myeloproliferative neoplasms

Chiara Cavalloni, Elisa Rumi, Virginia V. Ferretti, Daniela Pietra, Elisa Roncoroni, Marta Bellini, Michele Ciboddo, Ilaria C. Casetti, Benedetta Landini, Elena Fugazza, Daniela Troletti, Cesare Astori, Mario Cazzola

Research output: Contribution to journalArticlepeer-review


We investigated the variation of CALR-mutant burden during follow-up in 105 CALR-mutant MPN and compared it to the variation of JAK2-mutant burden in 226 JAK2-mutant MPN. The median allele burden at last evaluation was significantly higher than at first evaluation in essential thrombocythemia (ET) (49.5% vs 45%, P < .001) but not in primary myelofibrosis (PMF) (52% vs 51%, P 0.398). Median values of slope were positive both in ET (0.071) and in PMF (0.032). In CALR-mutant ET there was a difference between natural and therapy-related slope (P 0.006). In the JAK2-mutated cohort, the median allele burden at last evaluation was not different respect to that at first evaluation, neither in ET (22.9% vs 23.2%, P = 0.216) nor in PMF (50.5% vs 45.0%, P = 0.809), despite a positive slope. Multivariate analysis to evaluate the effect of mutation (CALR vs JAK2) on the slope of mutant burden in not treated pts with a positive slope adjusting for diagnosis (ET vs PMF) showed a trend toward a higher increase of mutant burden in CALR vs JAK2 (β = 0.19, P = 0.061) with no difference between diagnosis (β = 0.419). The findings of this study suggest that clonal expansion in CALR-mutant MPN is faster than that observed in JAK2-mutant MPN.

Original languageEnglish
Pages (from-to)33416-33421
Number of pages6
Issue number20
Publication statusPublished - Jan 1 2017
Externally publishedYes


  • Burden
  • CALR
  • JAK2
  • Myeloproliferative
  • Sequential

ASJC Scopus subject areas

  • Oncology


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