CD138 (Plasma Cell Marker)

CD138 positive indicates that cells express the CD138 (syndecan‑1) surface protein, a marker characteristic of mature plasma cells. Immunohistochemical CD138 positivity helps identify and quantify plasma cell populations in tissue or bone marrow and supports diagnosis of plasma‑cell disorders (e.g., multiple myeloma). It is not diagnostic alone — results must be interpreted with clinical findings and additional tests (flow cytometry, protein electrophoresis, imaging).

CD138 (syndecan‑1) is a cell‑surface proteoglycan commonly used as a marker of plasma cells. It helps identify and quantify plasma cells in bone marrow and is widely used in diagnosing and monitoring multiple myeloma and plasmacytoma. CD138 is also expressed on many epithelial cells and certain carcinomas, where it can aid pathological classification and tumor studies.

CD138 stains plasma cells; positivity indicates plasma-cell presence. Low, scattered CD138 reflects reactive plasma cells; a high percentage or dense clusters suggest plasma-cell proliferation or myeloma. Clonality (kappa/lambda restriction) and co-markers (CD38, CD19, CD56) guide interpretation. Results must be correlated with morphology, clinical findings and laboratory tests (SPEP/UPEP, bone marrow) and discussed with a pathologist.

CD138 (syndecan‑1) is a cell‑surface heparan sulfate proteoglycan found on normal and malignant plasma cells. In multiple myeloma it’s used as a diagnostic and monitoring marker by immunohistochemistry or flow cytometry. CD138 mediates cell adhesion and signaling; a shed soluble form can be measured in blood and often correlates with tumor burden and prognosis, aiding disease assessment.

Plasma cell myeloma (multiple myeloma) is a malignant plasma‑cell cancer that ranges from slow‑growing to aggressive. It commonly causes bone pain, fractures, anemia, kidney damage, high calcium and infection risk. Treatments often control disease and prolong survival, but it is generally considered incurable with relapses common; prognosis depends on stage, age, organ damage and treatment response.

A CD138 biopsy refers to immunohistochemical staining of biopsy or bone marrow samples for the CD138 (syndecan‑1) protein, a plasma cell marker. It highlights and quantifies plasma cells to diagnose and monitor plasma‑cell disorders such as multiple myeloma or plasmacytoma, guide treatment decisions, and assess residual disease. Results are interpreted alongside morphology, other markers, and clinical findings.