Category: IHC-Antibodies

Keratins are cytoplasmic intermediate filament proteins expressed by epithelial cells. Cytokeratin 7 is a type II keratin that is found in most ductal and glandular epithelia including the urinary tract, lung, breast and female genital tract. There is no expression in most gastrointestinal epithelia, prostate, hepatocyte and squamous epithelia, as well as in colon, prostate and squamous carcinomas. Restricted distribution of CK7 makes this antibody a useful marker in a panel with antibody Cytokeratin 20.

CD20 (Cluster of Differentiation 20) is 35/37 kDa non-glycosylated phosphoprotein expressed on the surface of all B-cells. It is involved in B-cell activation, proliferation and differentiation and therefore one of the most importantB-cell markers.

Keratins are cytoplasmic intermediate filament proteins expressed by epithelial cells. Cytokeratins, 5 & 6, are type II keratins that are in combination useful in differentiating mesothelioma (positive) from lung carcinoma (negative) or metastic carcinoma in the pleura (negative). It detects undifferentiated large cell carcinoma, squamous carcinoma, spindle cell squamous cell carcinoma of the skin, malignancies of prostate and breast and it helps to discriminate between ductal hyperplasia of the breast (strong staining) and solid papillary DCIS (negative).

CD56, also known as neural cell adhesion molecule (NCAM), is a part of the immunoglobulin superfamily of adhesion molecules and mediates homophilic interactions through its extracellular region. It is used as a marker fordetection of T-LGL (T-Large Granular Lymphocyte) lymphoproliferative disorders and NK cells. CD56 is also known as a marker of neural lineage due to its discovery site. For example, astrocytoma, neuroblastoma or small cell carcinoma of lung are CD56-positive. [1-6]

CD171 (Cluster of Differentiation), also known as L1 cell adhesion molecule isoform 1 precursor (L1CAM), is a transmembrane protein and a member of the immunoglobulin superfamily. This cell adhesion molecule has an important role in the development of the nervous system, including neuronal migration and differentiation.CD171 is involved in neuron-neuron adhesion, neurite fasciculation, outgrowth of neuritis, and others.

CD99 is an O-glycosylated transmembrane protein and the gene product of MIC2 [1]. It is expressed on Ewing’s sarcoma/primitive neuroectodermal tumor (ES/PNET) cells, Sertorli cells, pancreatic islet cells, thymocytes and other hematopoietic cells. CD99 plays a role in the T-cell adhesion, differentiation of primitive neuroectodermal cells and leukocyte migration.

Calretinin is a calcium binding protein abundantly expressed in neurons. Outside the nervous system, calretinin is found in mesothelial cells, steroid producing cells, testicular Sertoli cells, rete testis, ovarian surface epithelium, some neuroendocrine cells, breast glands, eccrine sweat glands, hair follicular cells, thymic epithelial cells, endometrial stromal cells and fat cells.

Keratins are cytoplasmic intermediate filament proteins expressed by epithelial cells. Cytokeratin 14 is a type I keratin that is found in basal cells of squamous epithelia, some glandular epithelia, myoepithelium and mesothelial cells in various tissues including prostate and breast. A cocktail of CK14, its corresponding partner CK5 and p63 is useful to detect the basal-like phenotype of breast carcinoma and to differentiate normal and prostate cancer.

CD31 is an integral membrane glycoprotein located on the surface of endothelial cells, platelets and some hematopoietic cells. It plays a key role in removing aged neutrophils from the body. CD31 is often used as an endothelial cell marker. The antibody recognizes cells from arteries, arterioles, venules, veins, non-sinusoidal capillaries of various tissues as well as tumors of endothelial origin and vascular invasions of tumors. CD31 reacts with normal, benign and malignant endothelial cells that form the lining of the blood vessels. The extent of CD31 expression can help determine the degree of tumor angiogenesis.

CD21 (Cluster of Differentiation 21) is a transmembrane protein involved in the complement system. It is the complement receptor for C3d and the Epstein-Barr virus. This antibody recognizes follicular dendritic cells, mature marginal and mantle B-cells as well as neoplasms derived from follicular dendritic cells.

CD138, also known as syndecan-1, is a transmembrane heparan sulfate proteoglycan and is a member of the syndecan proteoglycan family, which mediate cell binding, cell signaling and cytoskeletal organization. The syndecan 1 protein participates in cell proliferation, cell migration and cell-matrix interactions. This antibody is a useful marker for labeling normal mature plasma cells and early pre B-cells, while other haematolymphoid cells are negative. Various types of epithelial cells are also CD138 positive. Among haematolymphoid neoplasms, CD138 is expressed in practically all cases of plasma cell malignancies. Among non-haematolymphoid neoplasms, the expression of CD138 is found in various types of carcinomas.

CD5, also known as Lymphocyte Antigen T1/Leu-1, is a transmembrane glycoprotein involved in regulation of Tcell proliferation. CD5 is a pan T-cell marker that is also found on a subset of B cells, but not on the majority of peripheral blood B cells. Furthermore, T cell malignancies, B cell chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma(SLL) and mantle-cell lymphomas are CD5 positive.