Category: IHC-Antibodies

Cadherins are calcium dependent cell adhesion proteins that play a role in cell recognition and segregation, morphogenetic regulation, and tumor suppression. Cadherin 17 may have a role in the morphological organization of liver and intestine and may be involved in intestinal peptide transport. Expression is found in the gastrointestinal tract and pancreatic duct.

Keratins are cytoplasmic intermediate filament proteins expressed by epithelial cells. Cytokeratin 8 is a type II keratin that is expressed in early embryogenesis. It is found in simple epithelia in respiratory, gastrointestinal and reproductive tract as well as thyroid. This antibody detectsmost non-squamous epithelial tumors andadenocarcinomas of the breast, ovary, gastrointestinal tract, thyroid, pancreas, bile duct and salivary glands. It is often co-expressed with cytokeratin 18, and the major keratin pair in simple-type epithelia, as found in the liver, pancreas, and intestine.

CD30 is a cell membrane protein, that regulates activation of NF-kappa B and apoptosis. It is expressed by Reed-Sternberg cells of classical Hodgkin’s disease. CD30 is a member of the tumor necrosis factor receptor (TNF-R)superfamily, which comprises more than 10 different members. CD30 has an extra cytoplasmic domain, transmembrane region, and a cytoplasmic domain. The protein is heavily glycosylated within the Golgi apparatus(120 kDa). This antibody detects Hodgkin‘s lymphoma, anaplastic large cell lymphomas, primary cutaneousCD30+ T-cell lymphoproliferative disorders and embryonal carcinomas.

Epidermal growth factor is a growth factor that stimulates cell growth, proliferation, and differentiation by binding to its receptor EGFR. EGFR is a receptor tyrosine kinase activating several signaling cascades. It is ubiquitously expressed and observed in tumors of head and neck, brain, bladder, stomach, breast, lung, endometrium, cervix, vulva, ovary, esophagus, stomach, and in squamous cell carcinoma. Overexpression of EGFR in tumors indicates poor prognosis.

Factor XIII is activated in the blood coagulation cascade by thrombin and calcium to a transglutaminase stabilizing the fibrin clot. This antibody detects the coagulation factor XIIIa subunit. Defects in factor XIIIa cause factor XIII subunit a deficiency an autosomal recessive disorder characterized by a lifelong bleeding tendency, defective wound healing, and habitual abortion.

Estrogen receptor (ER) is a nuclear hormone receptor that activates transcription of various genes, especially in reproductive tissues, regulated by its ligand estrogen. ER is expressed in approximately 70% of all breast cancer cases. It is reported that patients with ER-positive tumors have better prognosis than patients with ER-negative tumors.

Glial fibrillary acidic protein is an intermediate filament protein that is expressed by numerous cell types of the central nervous system. In the central nervous system, GFAP is expressed in astrocytes and ependymal cells but not in other glial cells. However, immature oligodendrocytes and immature choroid plexus cells may be GFAP positive. In the peripheral nervous system enteric Schwann cells and satellite cells of human sensory ganglia express GFAP. Outside the nervous system, GFAP is seen in myoepithelial cells and chondroblasts, in the former coexpressed with cytokeratin, in the latter coexpressed with vimentin. Astrocytoma, ependymoma, glioblastoma, and oligodendroglioma are almost always positive. Plexus carcinoma, ganglioglioma and primitive neuroectodermal tumours (PNET: neuroblastoma a.o.) express GFAP to a varying extent. Schwannoma and neurofibroma frequently express GFAP. Chondroma, chondrosarcoma and pleomorphic adenoma are also GFAP positive in most cases. A few carcinomas (especially from lung and breast) may express GFAP. in paraganglioma GFAP may be detected in sustentacular cells. This marker is mainly used to distinguish neoplasms of astrocytic origin from other neoplasms in the central nervous system.

Glucose transporters are a wide group of membrane proteins that facilitate the transport of glucose over a plasma membrane. GLUT1 is a membrane-associatederythrocyte glucose transport protein that is a major glucose transporter in the mammalian blood-brain barrier. GLUT1 is expressed in many human tissues like colon, lung, stomach, esophagus, and breast. It is over expressed in malignant cells and in a variety of tumors (breast, pancreas, cervix, endometrium, lung, mesothelium, colon, bladder, thyroid, bone, soft tissues, and oral cavity).

Glutamine synthetase (GS) converts ammonia and glutamate to glutamine. Glutamine synthetase has multiple metabolic functions. Two of them are detoxification of ammonia, and regulation of glutamate in neurons. Synthesis and catalytic activity of glutamine synthetase are highly regulated.

HSP70 is a heat shock protein of 70kDa. It prevents aggregation of other proteins in conjunction with other heat shock proteins and mediates folding of new proteins during synthesis.

Helicobacter pylori (H. pylori) is a spiral-shaped, gram negative rod bacterium that is found in human stomach, despite there is an extreme acidic pH. Infections of gastric mucosa lead to gastric diseases like stomach ulcers or chronic gastritis. Furthermore, an infection with H. pylori is linked with the formation of gastric cancer and MALT lymphoma (MALT = Mucosa Associated Lymphoid Tissue). The antibody is useful for detecting the bacterial infection in gastric and duodenal epithelial cells.

Isocitrate dehydrogenase 1/ IDH1 is an enzyme that catalyzes the third step of the citric acid cycle, which involves the oxidative decarboxylation of isocitrate, forming alpha-ketoglutarate and CO2 in a two-step reaction. The IDH1 protein is localized in the cytoplasm and in peroxisomes. It is expressed in a wide range of species and also in organisms that lack a complete citric acid cycle. Gliomas are the most frequent primary CNS malignancy.
The two common types of gliomas are astrocytomas and oligodendrogliomas. Three pathways of glioma development have been identified: primary glioblastomas that arise de novo without lower grade precursors, astrocytomas that start as grade II or III and then transform into secondary glioblastoma, or oligodendrogliomas that can transform into anaplastic oligodendroglioma.
IDH1 R132H point mutation is shown in more than 70 % of gliomas, frequently in WHO grade II and III gliomas and secondary grade IV glioblastomas.
The antibody QM002 is highly specific for the R132H point mutation allowing a diagnosis of astrocytomas or oligodendrogliomas.
The high rates of IDH1 mutations in oligodendroglial tumors make this mutation especially helpful for the differentiation of oligodendrogliomas from other tumors with clear cell appearance. IDH1 mutations have been shown to dominantly inhibit IDH1 catalytic activity.
Assessment of the IDH1 status may be performed by immunohistochemical detection of the mutated protein. In cases with negative or inconclusive immunostaining result further analysis by DNA-based methods is necessary. Testing of the IDH1 status is relevant for diagnostic and prognostic considerations in primary brain tumors. Mutated tumors generally show a better prognosis.