Proteomic Profiling of Diffuse Large B-Cell Lymphomas

Objective: The aim of this study was to identify differences in proteome profiles of diffuse large B-cell lymphoma (DLBCL) of nongerminal center (non-GC) versus GC type in the search for new markers and drug targets. Methods: Six DLBCL, with 3 repeats for each, were used for the initial study by proteomics: 3 non-GC and 3 GC DLBCL cases. For immunohistochemistry, tissue microarrays were made from 31 DLBCL samples: 16 non-GC de novo lymphomas and 15 GC cases (11 transformed from follicular lymphomas and 4 de novo GC lymphomas). Proteome profiling was performed by two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. Results: Ninety-one proteins were found differentially expressed in non-GC compared to GC type. The Cytoscape tool was used for systemic analysis of proteomics data, revealing 19 subnetworks representing functions affected in non-GC versus GC types of DLBCL. Conclusion: A validation study of 3 selected proteins (BiP/Grp78, Hsp90, and cyclin B2) showed the enhanced expression in non-GC DLBCL, supporting the proteomics data.