28231 Results for: "Biotium"

Supplier: Biotium

Chromogranin A is present in neuroendocrine cells throughout the body, including the neuroendocrine cells of the large and small intestine, adrenal medulla and pancreatic islets. It is an excellent marker for carcinoid tumors, pheochromocytomas, paragangliomas, and other neuroendocrine tumors. Co-expression of chromogranin A and neuron specific enolase (NSE) is common in neuroendocrine neoplasms. Reportedly, co-expression of certain keratins and chromogranin indicates neuroendocrine lineage. The presence of strong anti-chromogranin staining and absence of anti-keratin staining should raise the possibility of paraganglioma. The co-expression of chromogranin and NSE is typical of neuroendocrine neoplasms. Most pituitary adenomas and prolactinomas readily express chromogranin.

Supplier: Biotium

Recognizes a protein of 40 kDa, identified as cytokeratin-19 (CK19), which is expressed in sweat gland, mammary gland ductal and secretory cells, bile ducts, gastrointestinal tract, bladder urothelium, oral epithelia, esophagus, and ectocervical epithelium. Anti-CK19 reacts with a wide variety of epithelial malignancies including adenocarcinomas of the colon, stomach, pancreas, biliary tract, liver, and breast. Perhaps the most useful application is the identification of thyroid carcinoma of the papillary type, although 50%-60% of follicular carcinomas are also labeled. Anti-CK19 is a useful marker for detection of tumor cells in lymph nodes, peripheral blood, bone marrow and breast cancer.

Supplier: Biotium

This monoclonal antibody is part of a new panel of reagents, which recognizes subcellular organelles or compartments of human cells. These markers may be useful in identification of these organelles in cells, tissues, and biochemical preparations. This MAb recognizes the double stranded DNA in human cells. It can be used to stain the nuclei in cell or tissue preparations and can be used as a nuclear marker in human cells. This MAb produces a homogeneous staining pattern in the nucleus of normal and malignant cells.,Double Stranded deoxyribonucleic acid (ds DNA) is the genetic material of all cells and many viruses and is a polymer of nucleotides. The monomer consists of phosphorylated 2-deoxyribose N-glycosidically linked to one of four bases, adenine, cytosine, guanine or thymine. These are linked together by 3',5'-phosphodiester bridges. In the Watson-Crick double-helix model, two complementary strands are wound in a right-handed helix and held together by hydrogen bonds between complementary base pairs.

Supplier: Biotium

Recognizes a protein of 40 kDa, identified as CD7 (Workshop IV; Code T155). CD7 is a member of the immunoglobulin gene superfamily. Its N-terminal amino acids 1-107 are highly homologous to Ig kappa-L chains whereas the carboxyl-terminal region of the extracellular domain is proline-rich and has been postulated to form a stalk from which the Ig domain projects. CD7 is expressed on the majority of immature and mature T-lymphocytes, and T cell leukemia. It is also found on natural killer cells, a small subpopulation of normal B cells and on malignant B cells. Cross-linking surface CD7 positively modulates T cell and NK cell activity as measured by calcium fluxes, expression of adhesion molecules, cytokine secretion and proliferation. CD7 associates directly with phosphoinositol 3'-kinase. CD7 ligation induces production of D-3 phosphoinositides and tyrosine phosphorylation.

Supplier: Biotium

Recognizes a protein of 40 kDa, identified as CD7 (also known as gp40, Leu9). CD7 is a member of the immunoglobulin gene superfamily. Its N-terminal amino acids 1-107 are highly homologous to Ig kappa-L chains whereas the carboxyl-terminal region of the extracellular domain is proline-rich and has been postulated to form a stalk from which the Ig domain projects. CD7 is expressed on the majority of immature and mature T-lymphocytes, and T cell leukemia. It is also found on natural killer cells, a small subpopulation of normal B cells and on malignant B cells. Cross-linking surface CD7 positively modulates T cell and NK cell activity as measured by calcium fluxes, expression of adhesion molecules, cytokine secretion and proliferation. CD7 associates directly with phosphoinositol 3'-kinase. CD7 ligation induces production of D-3 phosphoinositides and tyrosine phosphorylation.

Supplier: Biotium

This MAb reacts with a protein of 22 kDa, identified as beta subunit of HCG. It does not cross react with the alpha subunit. HCG is a glycoprotein, which is secreted in large quantities by normal trophoblasts. It is present only in trace amounts in non-pregnant urine and sera but rises sharply during pregnancy. HCG is composed of two non-identical, non-covalently linked polypeptide chains designated as the alpha and beta subunits. The alpha subunit is identical to that of thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH), and luteinizing hormone (LH). hCG MAb detects cells and tumors of trophoblastic origin such as choriocarcinoma. Large cell carcinoma and adenocarcinoma of the lung demonstrate anti-hCG positivity in 90% and 60% of cases respectively. 20% of lung squamous cell carcinomas are positive. hCG expression by non-trophoblastic tumors may indicate aggressive behavior.

Supplier: Biotium

This is a cocktail of four highly specific monoclonal antibodies (EGP40/826, EGP40/837, EGP40/1110, EGP40/1120) that recognize extracellular as well as intracellular domains of the epithelial cellular adhesion molecule (Ep-CAM). It is a 40-43 kDa transmembrane epithelial glycoprotein, identified as epithelial specific antigen (ESA), or Ep-CAM. Ep-CAM is expressed on baso-lateral cell surface in most simple epithelia and a vast majority of carcinomas. This epithelial antigen plays an important role as a tumor-cell marker in lymph nodes from patients with esophageal carcinoma otherwise classified as node-negative. Epithelial antigen has also been suggested as a discriminator between basal cell and baso-squamous carcinomas, and squamous cell carcinoma of the skin.

Supplier: Biotium

Recognizes a protein of 40 kDa, identified as CD7 (also known as gp40, Leu9). CD7 is a member of the immunoglobulin gene superfamily. Its N-terminal amino acids 1-107 are highly homologous to Ig kappa-L chains whereas the carboxyl-terminal region of the extracellular domain is proline-rich and has been postulated to form a stalk from which the Ig domain projects. CD7 is expressed on the majority of immature and mature T-lymphocytes, and T cell leukemia. It is also found on natural killer cells, a small subpopulation of normal B cells and on malignant B cells. Cross-linking surface CD7 positively modulates T cell and NK cell activity as measured by calcium fluxes, expression of adhesion molecules, cytokine secretion and proliferation. CD7 associates directly with phosphoinositol 3'-kinase. CD7 ligation induces production of D-3 phosphoinositides and tyrosine phosphorylation.

Supplier: Biotium

This MAb recognizes protein of 26 kDa-60 kDa, which is identified as CD63. Its epitope is different from that of MAb LAMP3/529. The tetraspanins are integral membrane proteins expressed on cell surface and granular membranes of hematopoietic cells and are components of multi-molecular complexes with specific integrins. The tetraspanin CD63 is a lysosomal membrane glycoprotein that translocates to the plasma membrane after platelet activation. CD63 is expressed on activated platelets, monocytes and macrophages, and is weakly expressed on granulocytes, T cell and B cells. It is located on the basophilic granule membranes and on the plasma membranes of lymphocytes and granulocytes. CD63 is a member of the TM4 superfamily of leukocyte glycoproteins that includes CD9, CD37 and CD53, which contain four transmembrane regions. CD63 may play a role in phagocytic and intracellular lysosome-phagosome fusion events. CD63 deficiency is associated with Hermansky-Pudlak syndrome and is strongly expressed during the early stages of melanoma progression.

Supplier: Biotium

This is a cocktail of four highly specific monoclonal antibodies (EGP40/826, EGP40/837, EGP40/1110, EGP40/1120) that recognize extracellular as well as intracellular domains of the epithelial cellular adhesion molecule (Ep-CAM). It is a 40-43 kDa transmembrane epithelial glycoprotein, identified as epithelial specific antigen (ESA), or Ep-CAM. Ep-CAM is expressed on baso-lateral cell surface in most simple epithelia and a vast majority of carcinomas. This epithelial antigen plays an important role as a tumor-cell marker in lymph nodes from patients with esophageal carcinoma otherwise classified as node-negative. Epithelial antigen has also been suggested as a discriminator between basal cell and baso-squamous carcinomas, and squamous cell carcinoma of the skin.

Supplier: Biotium

Protein phosphorylation is a fundamental event in the regulation of a large number of intracellular processes. Phosphorylation of specific tyrosine residues is the result of activation or stimulation of their respective protein tyrosine kinases. The phosphorylated proteins can be auto-phosphorylated kinases or certain cellular protein substrates. Tyrosine-phosphorylated proteins are involved in signal transduction and in the regulation of cell proliferation. Antibody to phosphotyrosine provides an excellent tool for the detection, characterization, and purification of phosphotyrosine containing proteins. This MAb shows no cross-reaction with other phosphoamino acids and is superb for multiple applications including staining of formalin/paraffin tissues.

Supplier: Biotium

Reacts with a 70 kDa membrane-bound isozyme (Regan and Nagao type) of Placental Alkaline Phosphatase (PLAP) occurring in the placenta during the 3rd trimester of gestation. It is highly specific for PLAP and shows no cross-reaction with other isozymes of alkaline phosphatase. Anti-PLAP reacts with germ cell tumors and can discriminate between these and other neoplasms. Somatic neoplasms e.g. breast, gastrointestinal, prostatic, and urinary cancers may also immunoreact with antibodies to PLAP. Anti-PLAP positivity in conjunction with anti-keratin negativity favors seminoma over carcinoma. Germ cell tumors are usually anti-keratin positive, but they regularly fail to stain with anti-EMA, whereas most carcinomas stain with anti-EMA. Anti-PLAP has been useful in the diagnosis of gestational trophoblastic disease.

Supplier: Biotium

Anti-CD57 marks a subset of lymphocytes known as natural killer (NK) cells. Follicular center cell lymphomas often contain many NK cells within the neoplastic follicles. Anti-CD57 also stains neuroendocrine cells and their derived tumors, including carcinoid tumor and medulloblastoma. Anti-CD57 can also be useful in separating type B3 thymoma from thymic carcinoma when combined with a panel that includes antibodies against GLUT1, CD5, and CEA.

Supplier: Biotium

This MAb recognizes protein of 26 kDa-60 kDa, which is identified as CD63. Its epitope is different from that of MAb LAMP3/529. The tetraspanins are integral membrane proteins expressed on cell surface and granular membranes of hematopoietic cells and are components of multi-molecular complexes with specific integrins. The tetraspanin CD63 is a lysosomal membrane glycoprotein that translocates to the plasma membrane after platelet activation. CD63 is expressed on activated platelets, monocytes and macrophages, and is weakly expressed on granulocytes, T cell and B cells. It is located on the basophilic granule membranes and on the plasma membranes of lymphocytes and granulocytes. CD63 is a member of the TM4 superfamily of leukocyte glycoproteins that includes CD9, CD37 and CD53, which contain four transmembrane regions. CD63 may play a role in phagocytic and intracellular lysosome-phagosome fusion events. CD63 deficiency is associated with Hermansky-Pudlak syndrome and is strongly expressed during the early stages of melanoma progression.

Supplier: Biotium

This MAb recognizes basic (Type II or HMW) cytokeratins, which include 67 kDa (CK1); 64 kDa (CK3); 59 kDa (CK4); 58 kDa (CK5); 56 kDa (CK6); 52 kDa (CK8). Twenty human keratins are resolved with two-dimensional gel electrophoresis into acidic (pI 6.0) subfamilies. The acidic keratins have molecular weights (MW) of 56.5, 55, 51, 50, 50 , 48, 46, 45, and 40 kDa. Many studies have shown the usefulness of keratins as markers in cancer research and tumor diagnosis.

Supplier: Biotium

Cytokeratin 8 (CK8) belongs to the type II (or B or basic) subfamily of high molecular weight cytokeratins and exists in combination with cytokeratin 18 (CK18). CK8 is primarily found in the non-squamous epithelia and is present in majority of adenocarcinomas and ductal carcinomas. It is absent in squamous cell carcinomas. Hepatocellular carcinomas are defined by the use of antibodies that recognize only cytokeratin 8 and 18. CK8 exists on several types of normal and neoplastic epithelia, including many ductal and glandular epithelia such as colon, stomach, small intestine, trachea, and esophagus as well as in transitional epithelium. Anti-CK8 does not react with skeletal muscle or nerve cells. Epithelioid sarcoma, chordoma, and adamantinoma show strong positivity corresponding to that of simple epithelia (with antibodies against CK8, CK18 and CK19). Reportedly, anti-CK8 is useful for the differentiation of lobular (ring-like, perinuclear) from ductal (peripheral-predominant) carcinoma of the breast.

Supplier: Biotium

This antibody recognizes proteins of 80-200 kDa, identified as different members of CEA family. CEA is synthesized during development in the fetal gut and is re-expressed in increased amounts in intestinal carcinomas and several other tumors. This MAb does not react with nonspecific cross-reacting antigen (NCA) and with human polymorphonuclear leucocytes. It shows no reaction with a variety of normal tissues and is suitable for staining of formalin/paraffin tissues. CEA is not found in benign glands, stroma, or malignant prostatic cells. Antibody to CEA is useful in detecting early foci of gastric carcinoma and in distinguishing pulmonary adenocarcinomas (60-70% are CEA ) from pleural mesotheliomas (rarely or weakly CEA ). Anti-CEA positivity is seen in adenocarcinomas from the lung, colon, stomach, esophagus, pancreas, gallbadder, urachus, salivary gland, ovary, and endocervix.

Supplier: Biotium

Anti-CD57 marks a subset of lymphocytes known as natural killer (NK) cells. Follicular center cell lymphomas often contain many NK cells within the neoplastic follicles. Anti-CD57 also stains neuroendocrine cells and their derived tumors, including carcinoid tumor and medulloblastoma. Anti-CD57 can also be useful in separating type B3 thymoma from thymic carcinoma when combined with a panel that includes antibodies against GLUT1, CD5, and CEA.

Supplier: Biotium

This antibody recognizes proteins of 80-200 kDa, identified as different members of CEA family. CEA is synthesized during development in the fetal gut and is re-expressed in increased amounts in intestinal carcinomas and several other tumors. This MAb does not react with nonspecific cross-reacting antigen (NCA) and with human polymorphonuclear leucocytes. It shows no reaction with a variety of normal tissues and is suitable for staining of formalin/paraffin tissues. CEA is not found in benign glands, stroma, or malignant prostatic cells. Antibody to CEA is useful in detecting early foci of gastric carcinoma and in distinguishing pulmonary adenocarcinomas (60-70% are CEA ) from pleural mesotheliomas (rarely or weakly CEA ). Anti-CEA positivity is seen in adenocarcinomas from the lung, colon, stomach, esophagus, pancreas, gallbadder, urachus, salivary gland, ovary, and endocervix.

Supplier: Biotium

This MAb recognizes a 21 kDa protein, identified as the p21WAF1 tumor suppressor protein. This MAb is highly specific to p21 and shows no cross-reaction with other closely related mitotic inhibitors. p21WAF1 is a specific inhibitor of cdk s and a tumor suppressor involved in the pathogenesis of a variety of malignancies. The expression of this gene acts as an inhibitor of the cell cycle during G1 phase and is tightly controlled by the tumor suppressor protein p53. Its expression is induced by the wild type, but not mutant, p53 suppressor protein. Normal cells generally display a rather intense nuclear p21 expression. Loss of p21 expression has been reported in many carcinomas (gastric carcinoma, non-small cell lung carcinoma, thyroid carcinoma). In ELISA, MAb WA-1 is useful either as a solid phase or for detection of p21 protein.

Supplier: Biotium

This MAb is specific for progesterone. It exhibits minimal cross reactivity with related compounds in ELISA. It reacts with Progesterone-11a-HMS-BSA: 100%; 5-beta-Pregnane-3,20-dione: 48%; 5-alpha-Pregnane-3,20-dione: 26.4%; 17-alpha-Hydroxyprogesterone: 2.5% and 20-alpha-Hydroxyprogesterone: 0.04%. Progesterone is a steroid hormone synthesized from the cholesterol derivative, pregnenolone, in the cortex of the adrenal gland. Progesterone is secreted by the corpus luteum and acts to prepare the endometrium for the implantation of a fertilized egg. During pregnancy, it is secreted by the placenta to prevent spontaneous abortion and to stimulate the development of mammary tissue to produce milk. Thus, progesterone plays a central role in the reproductive events associated with the establishment and maintenance of pregnancy. Luteinized theca cells of normal ovary secrete progesterone. The determination of progesterone concentrations in the body fluids is of great value for endocrinological investigations in women. This MAb may prove useful in identification of ovarian tumors.

Supplier: Biotium

The Pax gene family of nuclear transcription factors is comprised of nine members that function during embryogenesis to regulate the temporal and position-dependent differentiation of cells. In addition, the family is involved in a variety of signal transduction pathways in the adult organism. Mutations in the Pax family of proteins have been linked to disease and cancer in humans. Pax-7 is a protein specifically expressed in cultured satellite cell-derived myoblasts. In situ hybridization reveals that Pax-7 is also expressed in satellite cells residing in adult muscle. A chromosomal aberration in the gene encoding Pax-7 causes rhabdomyosarcoma 2 (RMS2) (also called alveolar rhabdomyosarcoma).

Supplier: Biotium

Recognizes a protein of 33-55 kDa, identified as CD53 (Workshop V; Code CD53.1). CD53 is expressed on monocytes, and macrophages, granulocytes, dendritic cells, osteoblasts and osteoclasts, NK cells, and on T- and B-cells from every stage of differentiation but is absent from platelets, erythrocytes, and non-haemopoietic cells. CD53 is a member of a family of tetraspan transmembrane proteins, including CD9, CD37, CD63, CD81, and CD82. It associates with integrins, MHC class II molecules, and a tyrosine phosphatase and plays a role in cellular activation as part of a signal transduction complex involving other membrane glycoproteins. Defects of CD53 expression on neutrophils appear to be related with recurrent infectious diseases. Cross-linking CD53 using CD53 antibodies led to cytoplasmic calcium fluxes in B cells, monocytes, and granulocytes and activation of the monocyte oxidative burst.

Supplier: Biotium

The onset of angiogenesis is believed to be an early event in tumorigenesis and may facilitate tumor progression and metastasis. Several growth factors with angiogenic activity have been described. These include Fibroblast Growth Factor (FGF), Platelet Derived Growth Factor (PDGF), Vascular Endothelial Growth Factor (VEGF) and Placenta Growth Factor (PLGF). Placenta growth factor (PLGF) is a secreted protein primarily produced by placental trophoblasts but also expressed in other endothelial cells and tumors. There are three isoforms, PLGF-1, PLGF-2, and PLGF-3. PLGF-2 is expressed up until week 8 in the placenta; the placental tissues continuously express PLGF-1 and PLGF-3 but only PLGF-1 is found in colon and mammary carcinomas. PLGF acts to stimulate angiogenesis, endothelial growth and migration. PLGF is a powerful promoter of tumor growth and is upregulated in some cancers, and PLGF is thought to aid in atherosclerotic lesions and neovascular growth surrounding the lesion. Also, PLGF appears to aid aldosterone mediated atherosclerosis. Serum levels of PLGF in some cases are used as a potential biomarker for disease or genetic defect. Recent research indicates that PLGF levels are lower in mothers with Down syndrome fetuses. Evidence has suggested VEGF to be an obligatory component in PLGF signaling. While VEGF homodimers and VEGF/PLGF heterodimers function as potent mediators of mitogenic and chemotactic responses in endothelial cells, PLGF homodimers are effectual only at extremely high concentrations. Indeed, many of the physiological effects attributed to VEGF may actually be a result of VEGF/PLGF. VEGF and PLGF share a common receptor, Flt-1, and may also activate Flk-1/KDR.

Supplier: Biotium

This antibody recognizes a polypeptide of 6.5 kDa, identified as pS2 estrogen-regulated protein. Its epitope is localized between aa57-84 of human pS2 protein. pS2 is a trefoil peptide. Trefoil peptides are protease resistant molecules secreted throughout the gut that play a role in mucosal healing. These peptides contain three intra-chain disulfide bonds, forming the trefoil motif, or P-domain. pS2 is known to form dimers and this dimerization is thought to play a role in its protective and healing properties. About 60% of breast carcinomas are positive for pS2. Staining is cytoplasmic, often with localization to the Golgi apparatus. pS2 is shown to be localized in normal stomach mucosa, gastric fluid, goblet cells in the colon and small intestine, and in ulcerations of the gastrointestinal tract. Several studies have shown that pS2 is primarily expressed in estrogen receptor-positive breast tumors and it may define a subset of estrogen-dependent tumors that displays an increased likelihood of response to endocrine therapy.

Supplier: Biotium

The onset of angiogenesis is believed to be an early event in tumorigenesis and may facilitate tumor progression and metastasis. Several growth factors with angiogenic activity have been described. These include Fibroblast Growth Factor (FGF), Platelet Derived Growth Factor (PDGF), Vascular Endothelial Growth Factor (VEGF) and Placenta Growth Factor (PLGF). Placenta growth factor (PLGF) is a secreted protein primarily produced by placental trophoblasts but also expressed in other endothelial cells and tumors. There are three isoforms, PLGF-1, PLGF-2, and PLGF-3. PLGF-2 is expressed up until week 8 in the placenta; the placental tissues continuously express PLGF-1 and PLGF-3 but only PLGF-1 is found in colon and mammary carcinomas. PLGF acts to stimulate angiogenesis, endothelial growth and migration. PLGF is a powerful promoter of tumor growth and is upregulated in some cancers, and PLGF is thought to aid in atherosclerotic lesions and neovascular growth surrounding the lesion. Also, PLGF appears to aid aldosterone mediated atherosclerosis. Serum levels of PLGF in some cases are used as a potential biomarker for disease or genetic defect. Recent research indicates that PLGF levels are lower in mothers with Down syndrome fetuses. Evidence has suggested VEGF to be an obligatory component in PLGF signaling. While VEGF homodimers and VEGF/PLGF heterodimers function as potent mediators of mitogenic and chemotactic responses in endothelial cells, PLGF homodimers are effectual only at extremely high concentrations. Indeed, many of the physiological effects attributed to VEGF may actually be a result of VEGF/PLGF. VEGF and PLGF share a common receptor, Flt-1, and may also activate Flk-1/KDR.

Supplier: Biotium

Recognizes a 53 kDa protein, which is identified as p53 suppressor gene product. It reacts with the mutant as well as the wild form of p53 under denaturing and non-denaturing conditions. Its epitope maps within the N-terminus (aa 20-25) of p53 oncoprotein. p53 is a tumor suppressor gene expressed in a wide variety of tissue types and is involved in regulating cell growth, replication, and apoptosis. It binds to MDM2, SV40 T antigen and human papilloma virus E6 protein. Positive nuclear staining with p53 antibody has been reported to be a negative prognostic factor in breast carcinoma, lung carcinoma, colorectal, and urothelial carcinoma. Anti-p53 positivity has also been used to differentiate uterine serous carcinoma from endometrioid carcinoma as well as to detect intratubular germ cell neoplasia. Mutations involving p53 are found in a wide variety of malignant tumors, including breast, ovarian, bladder, colon, lung, and melanoma.

Supplier: Biotium

Recognizes a 53 kDa protein, which is identified as p53 suppressor gene product. It reacts with the mutant as well as the wild form of p53 under denaturing and non-denaturing conditions. Its epitope maps within the N-terminus (aa 20-25) of p53 oncoprotein. p53 is a tumor suppressor gene expressed in a wide variety of tissue types and is involved in regulating cell growth, replication, and apoptosis. It binds to MDM2, SV40 T antigen and human papilloma virus E6 protein. Positive nuclear staining with p53 antibody has been reported to be a negative prognostic factor in breast carcinoma, lung carcinoma, colorectal, and urothelial carcinoma. Anti-p53 positivity has also been used to differentiate uterine serous carcinoma from endometrioid carcinoma as well as to detect intratubular germ cell neoplasia. Mutations involving p53 are found in a wide variety of malignant tumors, including breast, ovarian, bladder, colon, lung, and melanoma.

Supplier: Biotium

This antibody recognizes a protein of 40 kDa, identified as cytokeratin-19 (CK19), which is expressed in sweat gland, mammary gland ductal and secretory cells, bile ducts, gastrointestinal tract, bladder urothelium, oral epithelia, esophagus, and ectocervical epithelium. Anti-CK19 reacts with a wide variety of epithelial malignancies including adenocarcinomas of the colon, stomach, pancreas, biliary tract, liver, and breast. Perhaps the most useful application is the identification of thyroid carcinoma of the papillary type, although 50%-60% of follicular carcinomas are also labeled. Anti-CK19 is a useful marker for detection of tumor cells in lymph nodes, peripheral blood, bone marrow and breast cancer.

Supplier: Biotium

This antibody recognizes a protein of 40 kDa, identified as cytokeratin-19 (CK19), which is expressed in sweat gland, mammary gland ductal and secretory cells, bile ducts, gastrointestinal tract, bladder urothelium, oral epithelia, esophagus, and ectocervical epithelium. Anti-CK19 reacts with a wide variety of epithelial malignancies including adenocarcinomas of the colon, stomach, pancreas, biliary tract, liver, and breast. Perhaps the most useful application is the identification of thyroid carcinoma of the papillary type, although 50%-60% of follicular carcinomas are also labeled. Anti-CK19 is a useful marker for detection of tumor cells in lymph nodes, peripheral blood, bone marrow and breast cancer.