Waldenstrom's Macroglobulinemia patients: expression and aCGH data

Waldenström’s macroglobulinemia (WM) is a distinct clinicobiological entity defined as a B-cell neoplasm characterized by a lymphoplasmacytic infiltrate in the bone marrow and immunoglobulin M paraprotein production. Cytogenetic analysis is limited by the difficulty in obtaining tumor metaphases and the genetic basis of the disease remains poorly defined. We performed a comprehensive analysis in 42 WM patients by using high-resolution array-based comparative genomic hybridization with the Human Genome 244A microarray. Overall, 83% of samples have chromosomal abnormalities, with a median of three abnormalities per patient (range 0 to 27). The most common abnormality was 6q deletion (40%) and four non-overlapped minimal deleted regions (MDR) were identified. Gain of 6p was the second most common abnormality (17%) and its presence was always concomitant with 6q loss. An interstitial MDR was delineated at 13q14 including MIRN15A and MIRN16-1 in 10% of patients. Other recurrent deletions were 7q22, 8p, 11q22-q23, 11q23-q24 and 17p11-p13 (7% each). Copy gains were identified in chromosomes 18 (17%), 4 (12%), 3 (10%), 8q (10%) and Xq27.1-q28 (10%). To note, we reported biallelic deletions and/or inactivating mutations with uniparental disomy in TRAF3 and TNFAIP3, two negative regulators of the NF-kB signaling pathway. Furthermore, we confirmed the association between TRAF3 inactivation and increased transcriptional activity of NF-kB target genes. Mutational activation of the NF-kB pathway, which is normally activated by ligand-receptor interactions within the bone marrow microenvironment, highlight its biologic importance, and suggest a therapeutic role for inhibitors of NF-KB pathway activation in the treatment of Waldenström’s macroglobulinemia. Keywords: gene expression profiling; array comparative genomic hybridization Expression data: Samples GSM318148-GSM318169. We included 22 samples from WM patients. Tumor clone population was selected by CD19+ or concomitant CD19+ and CD138+ sorting. aCGH data: Samples GSM318356-GSM318397. We included samples from 42 WM patients. Tumor DNA samples were selected by CD19+ or concomitant CD19+ and CD138+ sorting.