CD138/syndecan-1 (B-A38)

CD138, Syndecan 1, is expressed in the late stages of B-cell differentiation with progression towards plasma cells.1,2 It can be used to differentiate lymphoplasmacytic lymphoma from marginal zone lymphoma.1 ALK+ large B-cell lyphoma (LBCL) usually strongly expresses CD138 whereas lineage-associated markers such as anti-CD20 and anti-CD79a do not stain ALK+LBCL.3,7 Anti-CD138 is immunoreactive with HHV8-associated primary effusion lymphoma even though the lymphoma cells lack the expression of B-cell markers.5 Anti-CD138 is a good marker to identify and enumerate plasma cells, benign, reactive, or malignant, in bone marrow biopsy specimens.4,6 CD138 is also expressed in epithelial cells.6