This gene encodes a member of the membrane-spanning 4A gene family. Members of this nascent protein family are characterized by common structural features and similar intron/exon splice boundaries and display unique expression patterns among hematopoietic cells and nonlymphoid tissues. This gene encodes a B-lymphocyte surface molecule which plays a role in the development and differentiation of B-cells into plasma cells. This family member is localized to 11q12, among a cluster of family members. Alternative splicing of this gene results in two transcript variants which encode the same protein. [provided by RefSeq, Jul 2008],caution:Epitope 1, mapped in PubMed:16785532, is predicted to be buried in the membrane. Its accessibility to the extracellular space, and thus to antibody recognition, is not explained.,function:This protein may be involved in the regulation of B-cell activation and proliferation.,online information:CD20 entry,pharmaceutical:Monoclonal antibodies(mAb) against CD20 are used to treat B-cell non-Hodgkin’s lymphoma (NHL). These antibodies include Rituximab (Mabthera), Britumomab (Zevalin) and Tositumomab (Bexxar). CD20 engaged by mAb can generate transmembrane signals capable of directly controlling cell growth and triggering cell death in certain tumors. Alternatively, mAb can mediate complement-dependent cytotoxicity.,PTM:Phosphorylated. Might be functionally regulated by protein kinase(s).,similarity:Belongs to the MS4A family.,tissue specificity:Expressed on B-cells.,