Whole-exome sequencing of primary plasma cell leukemia discloses heterogeneous mutational patterns.

Abstract

Primary plasma cell leukemia (pPCL) is a rare and aggressive form of plasma cell dyscrasia and may represent a valid model for high-risk multiple myeloma (MM). To provide novel information concerning the mutational profile of this disease, we performed the whole-exome sequencing of a prospective series of 12 pPCL cases included in a Phase II multicenter clinical trial and previously characterized at clinical and molecular levels. We identified 1, 928 coding somatic non-silent variants on 1, 643 genes, with a mean of 166 variants per sample, and only few variants and genes recurrent in two or more samples. An excess of C > T transitions and the presence of two main mutational signatures (related to APOBEC over-activity and aging) occurring in different translocation groups were observed. We identified 14 candidate cancer driver genes, mainly involved in cell-matrix adhesion, cell cycle, genome stability, RNA metabolism and protein folding. Furthermore, integration of mutation data with copy number alteration profiles evidenced biallelically disrupted genes with potential tumor suppressor functions. Globally, cadherin/Wnt signaling, extracellular matrix and cell cycle checkpoint resulted the most affected functional pathways. Sequencing results were finally combined with gene expression data to better elucidate the biological relevance of mutated genes. This study represents the first whole-exome sequencing screen of pPCL and evidenced a remarkable genetic heterogeneity of mutational patterns. This may provide a contribution to the comprehension of the pathogenetic mechanisms associated with this aggressive form of PC dyscrasia and potentially with high-risk MM.

• Authors: Ingrid Cifola, Marta Lionetti, Eva Pinatel, Katia Todoerti, Eleonora Mangano, Alessandro Pietrelli, Sonia Fabris, Laura Mosca, Vittorio Simeon, Maria Teresa Petrucci, Fortunato Morabito, Massimo Offidani, Francesco Di Raimondo, Antonietta Falcone, Tommaso Caravita, Cristina Battaglia, Gianluca De Bellis, Antonio Palumbo, Pellegrino Musto, Antonino Neri
• Journal: Oncotarget (Oncotarget) Vol. 6 Issue 19 Pg. 17543-58 (Jul 10 2015) ISSN: 1949-2553 [Electronic] United States
• PMID: 26046463 (Publication Type: Clinical Trial, Phase II, Journal Article, Multicenter Study, Research Support, Non-U.S. Gov't)

Topics

• Cluster Analysis
• DNA Mutational Analysis (methods)
• Exome
• Humans
• Leukemia, Plasma Cell (genetics)