Identification of novel, clonally stable, somatic mutations targeting transcription factors PAX5 and NKX2-3, the epigenetic regulator LRIF1, and BRAF in a case of atypical B-cell chronic lymphocytic leukemia harboring a t(14;18)(q32;q21).

Fiche publication

Date publication

février 2021

Journal

Cold Spring Harbor molecular case studies

Auteurs

Membres identifiés du Cancéropôle Est :
Pr BASTIE Jean-Noël , Dr CAILLOT Denis , Dr CASASNOVAS Olivier , Dr CHAPUSOT Caroline , Dr DELVA Laurent , Pr MARTIN Laurent , Pr MAYNADIE Marc , Pr CALLANAN Mary , Dr CHRETIEN Marie-Lorraine , Dr AUCAGNE Romain , Dr ROSSI Cédric , Dr ALBUISSON Juliette

Tous les auteurs :
Burlet B, Ramla S, Fournier C, Abrey-Recalde MJ, Sauter C, Chrétien ML, Rossi C, Duffourd Y, Ragot S, Buriller C, Tournier B, Chapusot C, Nadal N, Racine J, Guy J, Bailly F, Martin L, Casasnovas O, Bastie JN, Caillot D, Albuisson J, Broccardo C, Thieblemont C, Delva L, Maynadié M, Aucagne R, Callanan MB

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/33608382

Résumé

Diagnosis of B-cell chronic lymphocytic leukemia (B-CLL) is usually straightforward, involving clinical, immunophenotypic (Matutes score), and (immuno)genetic analyses (to refine patient prognosis for treatment). CLL cases with atypical presentation (e.g., Matutes ≤ 3) are also encountered, and for these diseases, biology and prognostic impact are less clear. Here we report the genomic characterization of a case of atypical B-CLL in a 70-yr-old male patient; B-CLL cells showed a Matutes score of 3, chromosomal translocation t(14;18)(q32;q21) (), mutated , deletion 17p, and mutations in , (subclonal), and (subclonal). Quite strikingly, a novel mutation that was predicted to be loss of function was also seen. Exome sequencing identified, in addition, a potentially actionable mutation, together with novel somatic mutations affecting the homeobox transcription factor , known to control B-lymphocyte development and homing, and the epigenetic regulator , which is implicated in chromatin compaction and gene silencing. Neither nor mutations, predicted to be loss of function, have previously been reported in B-CLL. Sequencing confirmed the presence of these mutations together with , , and mutations, with the t(14;18)(q32;q21) translocation, in the initial diagnostic sample obtained 12 yr prior. This is suggestive of a role for these novel mutations in B-CLL initiation and stable clonal evolution, including upon treatment withdrawal. This case extends the spectrum of atypical B-CLL with t(14;18)(q32;q21) and highlights the value of more global precision genomics for patient follow-up and treatment in these patients.