Mucin, staining

Unusual/uncommon types of mesothelioma should be mentioned because they can cause diagnostic confusion. Mucin-positive epithelial mesotheliomas are not uncommon." Between 1% and 5% of all moderately well to well differentiated epithelial mesotheliomas show mucicarmine and/or PAS-diastase staining (Fig. 12.59). Patterns of mucin staining have been extensively described by this author." Mucin-positive epithelial mesotheliomas most frequently express immunohistochemical markers that are negative in most epithelial mesotheliomas and usually positive in pulmonary adenocarcinomas (CEA, LeuMl, B72.3, BerEP4). Mucinpositive epithelial mesotheliomas express calretinin and... 

APOMUCiNS Overall, the various mucin stains may not be as helpful as one would like. The gastric mucin MUC5AC is positive, but only in 38% to 70% of... 

Histochemical demonstration of most of the O-acetylated sialic acids is possible because substituents on the side chain of Neu hinder periodate oxidation of this part of the molecule to an extent dependent on the number and position of the O-acetyl groups already mentioned. Correspondingly, removal of these ester groups by alkaline treatment (0.5% KOH in 70% ethanol91) may increase the staining reaction of a sialic acid. For example, the presence of O-acylated sialic acids has been demonstrated in colonic, epithelial mucin of man and various mammals (summarized in Ref. 91), in healthy and diseased, human small-intestine,188-190 in bovine submandibular gland,182 in mouse and rat erythrocyte-membranes,191 and in human lymphocytes.192... 

Fig. 4.5.10 Analysis of core-1 mucin type -linked glycans derived from apolipoprotein C-III (ApoC-III). Serum-derived ApoC-III from a control (lane 1, left) and a CDG-IIx patient (lane 2, right) was investigated by IEF followed by antibody staining with a polyclonal rabbit-a-human ApoC-III antibody. ApoC-IIfi ApoC-IIEand ApoC-III0 indicate the variability in the amount of sialic acid residues linked to ApoC-III...

A significant positive correlation has been observed between the levels of inflammatory cytokines in the conjunctival epithelium and the severity of ocular irritation symptoms and corneal fluorescein staining. The inflammatory cytokines and other inflammatory mediators also correlate positively to severity of conjimctival squamous metaplasia in Sjogren patients. These proin-flammatory cytokines also have been implicated in regulation of epithelial mucin expression, with several studies suggesting inflammation is central to the pathogenesis of meibomian gland dysfunction as well. 

M54. Mowry, R. W., The special value of methods that color both acidic and vicinal hydroxyl groups in the histochemical study of mucins. With revised directions for the colloidal iron stain, the use of alcian blue G8X and their combinations with the periodic acid-Schiff reaction. Ann. N. Y. Acad. Set. 106, 402-423 (1963). 

Use Microscopic stain and reagent for pectin, plant mucin, and gum. 

Encoded by the MUCI gene on chromosome I and a derivative human antigen, EMA is a transmembrane glycoprotein of the breast mucin complex, and its expression is increased in carcinomas.Unlike normal breast, in which EMA is present on the apical cell membrane, neoplasms demonstrate EMA on the entire circumference of the cell membrane. Increased amounts of the large glycoprotein interfere with cell-to-cell and cell-to-matrix adhesion in neoplastic cells. The utility of EMA antibody is in the detection of epithelial differentiation, as a supplement to the cytokera-tins. Spindle cell, small cell, and large cell neoplasms may on rare occasion be stained with EMA but may be only focally positive for cytokeratins. 437... 

Several EMA antibodies, each of which reacts to different epitopes of the large glycoprotein antigen, are available, including MAM-6, episialin, polymorphic epithelial mucin, (3AI5-3, DF3 antigen, and breast epithelial mucin.The EMA antibodies stain skin... 

Pure and mixed mucinous breast carcinomas may be WT1+ however, staining is rarely intense compared with serous ovarian carcinomas. 

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