Molecular history of Richter syndrome: origin from a cell already present at the time of chronic lymphocytic leukemia diagnosis

Maurizio Martini, Luigi Maria Larocca, Davide Rossi, Valeria Spina, Francesco Forconi, Daniela Capello, Marco Fangazio, Silvia Rasi, Valter Gattei, Antonio Ramponi, Francesco Bertoni, Gianluca Gaidano

Risultato della ricerca: Contributo in rivistaArticolo in rivista

23 Citazioni (Scopus)

Abstract

Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia to aggressive lymphoma. We explored intraclonal diversification (ID) of immunoglobulin genes in order to (i) follow the evolutionary history of the RS clone (ii) compare the role of ID in clonally related RS vs. clonally unrelated cases. Most (10/11, 90.9%) clonally related RS stem from the predominant clone observed at CLL diagnosis. One single RS had a transformation pattern compatible with sequential evolution from a secondary CLL subclone. Once RS transformation had occurred, all secondary CLL subclones disappeared and were substituted by the dominant RS clone with its own descendants. These observations suggest that genetic lesions associated with RS transformation are acquired by a cell belonging to the original CLL clone, rather than being progressively accumulated by later CLL subclones. Accordingly, most (9/11, 81.1%) clonally related RS harbored a genetic lesion disrupting TP53 that was already present, though at subclonal levels, in 5/11 (45.5%) samples of the paired CLL phase. A fraction of clonally related RS switched off ID (4/11, 36.4%) or reduced the levels of ID (5/11, 45.4%) at transformation. Conversely, all clonally unrelated RS harbored ID and were characterized by a significantly higher mutation frequency compared to clonally related RS (median: 1.18 × 10(-3) vs. 0.13 × 10(-3); p =0.002). These data indicate that (i) clonally related RS stems from a cell that is already present within the initial CLL clone and (ii) clonally unrelated and clonally related RS are biologically distinct disorders also in terms of antigen affinity maturation.
Lingua originaleEnglish
pagine (da-a)3006-3010
Numero di pagine5
RivistaInternational Journal of Cancer
Volume130
DOI
Stato di pubblicazionePubblicato - 2012

Keywords

  • Cell Transformation, Neoplastic
  • Genes, Immunoglobulin
  • Genes, p53
  • Humans
  • Immunoglobulins
  • Leukemia, Lymphocytic, Chronic, B-Cell
  • Lymphoma
  • Mutation
  • Mutation Rate
  • Tumor Suppressor Protein p53

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