CD138 + Ki-67

CD138/syndecan-1 is an excellent marker for identifying plasma cells, as CD138 is a transmembrane heparin proteoglycan present on the surface membrane of plasma cells that remains active in formalin-fixed paraffin-embedded bone marrow sections. Other hematopoietic cells, endothelial cells and lymphoplasmacytoid lymphomas in bone marrow are CD138 negative (1). CD138 is also expressed in fibroblasts, keratinocytes and normal hepatocytes (1).

The Ki-67 antibody identifies a nuclear antigen, which is associated with cell proliferation. It is found throughout the cell cycle in the G1, S, G2, and M phases; but not in the GO phase. It is commonly used to grade the proliferation index of tumors (2).

As CD138 is localized to the cell membrane, it can be paired with nuclear prognostic markers, such as Ki-67, in double-marker immunostaining reactions without overlap of the chromogenic signals. In multiple myeloma, a CD138 + Ki-67 IHC double stain was shown to be more sensitive and accurate for myeloma cell proliferation assessment than cytogenetic methods (3).

1. Chilosi M, et al. CD138/syndecan-1: a useful immunohistochemical marker of normal and neoplastic plasma cells on routine trephine bone marrow biopsies. Mod Pathol. 1999 Dec;12(12):1101-6.
2. Xu JL, et al. Proliferation, apoptosis, and intratumoral vascularity in multiple myeloma: correlation with the clinical stage and cytological grade. J Clin Pathol. 2002 Jul;55(7):530-4.
3. Ely S, et al. Cost effectiveness of cell proliferation vs. cytogenetics for risk stratification in multiple myeloma. Mod Pathol 2016 Feb; 29 (supplement 2):343A.
4. Center for Disease Control Manual. Guide: Safety Management, NO. CDC-22, Atlanta, GA. April 30, 1976 “Decontamination of Laboratory Sink Drains to Remove Azide Salts.”
5. Clinical and Laboratory Standards Institute (CLSI). Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline-Fourth Edition CLSI document M29-A4 Wayne, PA 2014.