BOB-1 (RBT-BOB1), RMab

The BOB-1 protein is a co-activator that interacts with OCT-1 and/or OCT-2 transcription factors, and is critical in germinal center formation and immunoglobulin production. The strongest expression of BOB-1 is found in the germinal center, mantle-zone B cells, and plasma cells. Because BOB.1/OBF.1 are germinal center derived, L&H cells in Nodular Lymphocyte Predominant Hodgkin’s Lymphoma are consistently immunoreactive for BOB-1. Conversely, the Hodgkin/Reed-Sternberg cells in classical Hodgkin’s Lymphoma either do not express both or express only one of the two proteins or neither.

In Diffuse Large B-cell Lymphomas, the highest expression levels for BOB-1 antibody are reported in Follicular Center Lymphomas, Diffuse Large B-cell Lymphomas, and Burkitt Lymphomas. B-CLL, MALT-type, and Mantle Cell Lymphomas score negative or display a heterogenous/weaker activity. The strong nuclear expression of BOB-1 antibody and Oct-2 by Germinal Center Derived Lymphomas makes these antibodies a novel class of broad spectrum B-lineage immunohistochemical markers in the differential diagnosis of Lymphomas, specifically between Primary Mediastinal B-cell Lymphoma from classical Hodgkin’s Disease.