Category: IHC-Antibodies

Myosin heavy chain 11 (MYH11) is a smooth muscle myosin and a subunit of a hexameric protein that consists of two heavy chain subunits and two light chain subunits. It functions as a major contractile protein, converting chemical into mechanical energy through the ATP hydrolysis. MYH has been a useful marker for myoepithelial cell as well as smooth muscle cell differentiation.

 NUT carcinoma (NC, formerly NUT midline carcinoma) is a rare, aggressive subtype of squamous cell carcinoma defined by a chromosomal rearrangement of the NUT gene (also known as NUTM1, nuclear protein in testis). It usually arises in the midline of the body including the thorax, mediastinum, lung (thoracic regions ~50 %) and head and neck area (~40 %), but has also been diagnosed arising outside the midline including salivary gland, pancreas, bladder, kidney, adrenal gland as well as various soft tissue and bone locations. NC is a nearly uniformly lethal cance with a reproducible 6.5 month median overall survival. Although NC can occur at any age, it affects primarily adolescents and young adults with median age of 24. In the majority of cases (~75 %), NUT is fused to BRD4. This results in a chimeric powerful BRD4 NUT oncoprotein. Variant NUT fusion partners, including BRD3, NSD3, ZNF532, and ZNF592, encode BRD4 interacting proteins that serve to link NUT with BRD4. Diagnosis of NC can be established by positive NUT nuclear immunohistochemical staining.

Programmed Death 1 (PD-1; CD279) is a transmembrane protein functioning as surface receptor for its ligands PD L1 and PD-L2. PD-1 is expressed mainly on activated T cells, B-cells and myeloid cells.
PD-1 is an immune checkpoint and plays a crucial role in down regulation of the immune system through inhibition of T-cell activation, which in turn reduces autoimmunity. Some tumor cells use this mechanism to prevent apoptosis by inhibiting T-cells directed to them. PD-1 is a useful marker for angioimmunoblastic lymphoma. Furthermore, increased expression of PD-1 has been found to be associated with poor prognosis in hepatocellular carcinoma and renal cell carcinoma. Treatments targeting PD-1 have shown encouraging results in breast cancer, non-small cell lung cancer (NSCLC) and melanoma.

Olig2 is a transcription factor involved in oligodendroglial specification. It is expressed in most glial tumors, such as oligodendrogliomas and astrocytomas, but has been not found in the non-glial tumors including neuroepithelial tumors, ependymomas, sub ependymomas, medulloblastomas, and nonneuroepithelial tumors, such as CNS lymphomas, meningiomas, schwannomas, atypical teratoid/rhabdoid tumor, and hemangioblastomas. Although more than half of glioblastomas are positive for Olig2, expression is very weak in terms of both percentage of labeled cells and intensity. Compared to the strong staining seen in glioma samples, a weak expression is observed in non-tumoral brain tissue.

Napsin A is a pepsin-like aspartate protease with a molecular weight of about 38 kDa. Napsin A is closely related to Napsin B. Napsin is expressed as a single-chain protein in type II pneumocytes and in adenocarcinomas of the lung and kidney. The high specificity of Napsin A in lung adenocarcinomas is useful in distinguishing such primary adenocarcinomas from adenocarcinomas of unknown origin.

PRAME is a tumor-associated antigen that is preferentially expressed on the nuclei of neoplastic melanocytes. In normal tissue, expression of this cancer testis antigen is largely restricted to testis.
Anti-PRAME can be used for differential diagnosis of melanoma with diffuse positive nuclear staining versus nevi which are negative or only focally positive for PRAME. Therefore, it can be a helpful additional examination for situations in which antibodies against Hmb-45, Melan A and SOX10 do not provide sufficient information to distinguish between benign and malignant melanocytic lesions.
Clear cell sarcoma is reported to give consistently negative staining in contrast to malignant melanomas and can therefore be used for differential diagnosis between clear cell sarcoma (negative) vs. malignant melanoma (positive). Most synovial sarcomas and myxoid liposarcomas are diffusely positive for PRAME. Literature using other clones documented that PRAME is expressed not only by melanoma but also by various non melanoma neoplasms including non-small cell lung cancer (NSCLC), breast carcinoma, renal carcinoma, ovarian carcinoma, and leukemia.

PAX8 is a member of the PAX family (Paired Box) of transcription factors. It is vital for organogenesis during the embryonic development of the kidneys, Müller organs and thyroid. Due to the restrictive expression in normal tissues, PAX8 is a sensitive and specific marker for primary tumors as well as for metastatic tumors from the above-mentioned organs and tissues. PAX8 is expressed in thyroid carcinoma (~90%), endometrial carcinoma (84-98%), ovarian carcinoma (71 99%) and renal cell carcinoma (~90%).

p63 is a transcription factor with significant structural similarity to p53 and p73. p63 plays a critical role in the growth and development of many epithelial organs.

p63 is highest expressed in squamous cell carcinoma irrespective of their origin (96-100%). Anti-p63 may be useful in the detection of squamous cell carcinoma of the head and neck (HNSCC), of the lung and skin. Prostate adenocarcinoma is almost always p63 negative, so p63 is used for the differentiation between prostate adenocarcinoma and benign prostate tissue.

Progesterone receptor (PR) is a nuclear hormone receptor that activates transcription of various genes, especially in reproductive tissues, regulated by its ligand progesterone. PR is predominantly expressed in female sex steroid responsive tissues such as the mammary gland, uterus and ovary. Two isoforms exist: PR-A (94 kDa) and PR-B (114 kDa). Ratio of these isoforms varies in reproductive tissues and during carcinogenesis. PR is expressed in about 65-75% of breast carcinomas. The expression of PR is usually closely linked to the expression of the estrogen receptor (ER), as both receptors are hormonally regulated. PR-positive status is often used as an indicator for a better prognosis and a better response to hormone therapies.

Anti-human antibody for in vitro diagnostic use. The primary antibody is intended for the qualitative detection of associated antigens as listed in the section ‘Summary and explanation’. It is intended to be used within an immunohistochemistry (IHC) procedure on formalin-fixed, paraffin-embedded (FFPE) tissue sections followed by light microscopy visualization to aid tumor diagnosis. The antibody may be used manually or with any automated staining platform. Authorized and skilled personnel may only use the product. The clinical interpretation of any test results should be evaluated within the context of the patient’s medical history and other diagnostic laboratory test results. A qualified pathologist must perform evaluation.

AMACR is an important enzyme for the b-oxidation of branched-chain fatty acids. High expression of the AMACR protein is found in prostate cancer (88-94%), but not in normal prostate and benign prostate diseases. The expression of AMACR is also detected in premalignant lesions of the prostate, in prostatic intraepithelial neoplasia (PIN) the positive rate of AMACR ranges from 13-72%. The p63 protein, a homolog of the tumor suppressor p53, is highly expressed in the basal or precursor layer of many epithelial tissues. p63 is detected in the basal cells of the prostate in normal prostate glands and PIN. Prostate adenocarcinoma is almost always negative for p63. The combination of AMACR and p63 can be extremely useful in the diagnosis of PIN and small focus adenocarcinomas, especially in difficult cases and cases with limited tissue. AMACR stains the cytoplasm of prostate adenocarcinomas and PIN, while p63 stains the basal cell nuclei of PIN and benign prostate glands.

PSA is a glycoprotein enzyme that is secreted by the epithelial cells of the prostate gland. PSA is produced for the ejaculate, where it liquefies semen in the seminal coagulum and allows sperm to swim freely. It is also believed to be instrumental in dissolving cervical mucus, allowing the entry of sperm into the uterus. PSA is present in small quantities in the serum of men with healthy prostates but is often elevated in the presence of prostate cancer or other prostate disorders. It is not uniquely an indicator of prostate cancer but may also detect prostatitis or benign prostatic hyperplasia.