BioProject

The tumoral clone of Waldenström’s macroglobulinemia (WM) shows a wide morphological heterogeneity which ranges from B-lymphocytes (BL) to plasma cells (PC). More...

The tumoral clone of Waldenström’s macroglobulinemia (WM) shows a wide morphological heterogeneity which ranges from B-lymphocytes (BL) to plasma cells (PC). By means of genome-wide expression profiling we have been able to identify genes exclusively deregulated in BL and PC from WM, but with a similar expression pattern in their corresponding cell-counterparts from CLL and MM, as well as normal individuals. The differentially expressed genes have important functions in B-cell differentiation and oncogenesis. Thus, two of the genes down-regulated in WM-BL were IL4R, which plays a relevant role in CLL B cell survival, and BACH2 that participates in the development of class-switched PC. Interestingly, one of the up-regulated genes in WM-BL was IL6. A set of 4 genes was able to discriminate clonal B-lymphocytes from WM and CLL: LEF1 (WNT/ßcatenin pathway), MARCKS, ATXN1 and FMOD. We also found deregulation of genes involved in plasma cell differentiation such as PAX5 which was overexpressed in WM-PC, and IRF4 and BLIMP1 which were underexpressed. In addition, three of the target genes activated by PAX5 -CD79, BLNK and SYK- were up-regulated in WM-PC. In summary, these results indicate that both PC and BL from WM are genetically different from the MM and CLL cell-counterpart. Keywords: Waldenström’s macroglobulinemia, expression profiling, microarrays, Affymetrix. Overall design: Bone marrow (BM) samples from 10 patients with Waldenström’s macroglobulinemia (WM), 12 with multiple myeloma (MM) and 11 with chronic lymphocytic leukemia (CLL) were included in the study. All samples corresponded to newly diagnosed untreated patients. In addition, 8 normal B lymphocytes samples (NBL) from peripheral blood and 5 normal plasma cells (NPC) from bone marrow of healthy donors were also selected in order to relate the deregulation of GEP of clonal populations to normal condition. The study was approved by the local research ethics committee and written informed consent was obtained from all patients and healthy donors. Less...