Clonal architecture of chronic myelomonocytic leukemias

Raphaël Itzykson, Olivier Kosmider, Aline Renneville, Margot Morabito, Claude Preudhomme, Céline Berthon, Lionel Adès, Pierre Fenaux, Uwe Platzbecker, Olivier Gagey, Philippe Rameau, Guillaume Meurice, Cédric Oréar, François Delhommeau, Olivier A. Bernard, Michaela Fontenay, William Vainchenker, Nathalie Droin, Eric Solary

Key points

  • Early clonal dominance may distinguish chronic myelomonocytic leukemia from other chronic myeloid neoplasms with similar gene mutations

  • Early dominance of TET2 mutated cells in the hematopoietic tissue promotes myeloid differentiation skewing towards the granulomonocytic line


Genomic studies in chronic myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and MPN/MDS, have identified common mutations in genes encoding signaling, epigenetic, transcription and splicing factors. In the present study, we interrogated the clonal architecture by mutation-specific discrimination analysis of single-cell-derived colonies in 28 patients with chronic myelomonocytic leukemias (CMML), the most frequent MPN/MDS. This analysis reveals a linear acquisition of the studied mutations with limited branching through loss of heterozygosity. Serial analysis of untreated and treated samples demonstrates a dynamic architecture on which most current therapeutic approaches have limited effects. The main disease characteristics are early clonal dominance, arising at the CD34+/CD38- stage of hematopoiesis, and granulomonocytic differentiation skewing of multipotent and common myeloid progenitors. Comparison of clonal expansions of TET2 mutations in MDS, MPN and CMML, together with functional invalidation of TET2 in sorted progenitors, suggests a causative link between early clonal dominance and skewed granulomonocytic differentiation. Altogether, early clonal dominance may distinguish CMML from other chronic myeloid neoplasms with similar gene mutations.

  • Submitted June 28, 2012.
  • Accepted November 28, 2012.