BioProject

The pathogenesis of classical Hodgkin lymphoma (cHL), the most common lymphoma in the young, is still enigmatic, largely because its Hodgkin and Reed-Sternberg (HRS) tumor cells are rare in the involved lymph node and therefore difficult to analyze. More...

The pathogenesis of classical Hodgkin lymphoma (cHL), the most common lymphoma in the young, is still enigmatic, largely because its Hodgkin and Reed-Sternberg (HRS) tumor cells are rare in the involved lymph node and therefore difficult to analyze. Here, by overcoming this technical challenge and performing for the first time a genome-wide transcriptional analysis of microdissected HRS cells in comparison to other B-cell lymphomas, cHL lines and normal B-cell subsets, we show that they differ extensively from the usually studied cHL cell lines, that the lost B-cell identity of cHLs is not linked to the acquisition of a plasma cell-like gene expression program, and that Epstein-Barr virus infection of HRS cells has a minor transcriptional influence on the established cHL clone. Moreover, although cHL appears a distinct lymphoma entity overall, HRS cells of its histological subtypes diverged in their similarity to other related lymphomas. Unexpectedly, we identified two molecular subgroups of cHL associated to differential strengths of the transcription factor activity of the NOTCH1, MYC and IRF4 proto-oncogenes. Finally, HRS cells display deregulated expression of several genes potentially highly relevant to lymphoma pathogenesis, including silencing of the apoptosis-inducer BIK and of INPP5D, an inhibitor of the PI3K-driven oncogenic pathway. Overall design: The present study complements the GSE12453 and GSE14879 records by adding the following 10 samples: 5 primary tumor samples and 5 cell line samples. The 5 primary tumor samples represent 1000-2000 neoplastic cells microdissected from frozen biopsies of 5 cases of primary mediastinal B-cell lymphoma (PMBL). The 5 cell line samples represent 500-1000 living neoplastic cells isolated by fluorescence-activated cell sorting from growing cultures of the classical Hodgkin lymphoma (cHL) cell lines L1236, L428, KMH2 and HDLM2 and the lymphocyte-predominant Hodgkin lymphoma (lpHL) cell line DEV. Less...