Cytokeratin patterns in the epidermis of human ovarian mature cystic teratomas

Cytokeratin expression in human thymus: immunohistochemical mapping

Cytokeratin expression in normal postnatal human thymus was studied immunohistochemically by using monoclonal antibodies against various cytokeratin polypeptides. An attempt was made to characterize cell populations giving rise to the cornified structures of Hassal's corpuscles. Monoclonal antibody KB-37, a marker of squamous epithelium basal cells, was applied to distinguish the earliest cells capable of undergoing squamous differentiation. Parts of the subcapsular epithelium were extensively stained with this reagent. This epithelium, like the basal layer of certain squamous epithelia, exhibited a high incidence of cytokeratins 13 and 14, and pronounced expression of cytokeratin 19. Simple epithelium cytokeratins 8, 18, and 19 were present in the cortex. Scattered cells reacted with KB-37 antibody. All stellate epithelial cells in the medulla were positive for cytokeratin 19. Most of the medullar epithelial cells were positive for cytokeratins 13, 14 and 17 of complex epithelium, in contrast to the cortex, where only a few cells were positive for these cytokeratins. A significant proportion of the medullar cells was positive for KB-37 antigen. Cytokeratins 8 and 18 were expressed in single cells and in groups of cells surrounding Hassal's corpuscles. The outermost cells of these corpuscles were positive for cytokeratin 19 and KB-37. In the peripheral parts of Hassal's corpuscles, simple epithelium cytokeratins 7, 8, 18, and cytokeratins 4, 13, 14, and 17, characteristic of stratified nonkeratinizing epithelia, were coexpressed with keratinization-specific cytokeratins 10/11. The inner parts of the swirls were uniformly positive for cytokeratins 10/11. However, the expression of other cytokeratins was reduced.

Epidermoid cyst of the spleen: a cytokeratin profile with comparison to other squamous epithelia

The stratified squamous epithelium of a splenic epidermoid cyst was studied with a battery of monoclonal antibodies to cytokeratin (CK) proteins. CKs 10 and 11 were found in the suprabasal layers of the stratified squamous epithelium, while staining for CK 13 was focal or diffuse throughout. CKs 18 and 19 decorated individual squamous cells or stained the entire thickness of the epithelium. These results were compared with those previously obtained by us in stratified squamous epithelia of ovarian mature cystic teratoma, fetal epidermis, adult epidermis and squamous metaplasia in a peritoneal cyst. From these comparisons it emerges that the epidermoid splenic cyst is either of teratomatous derivation or originates from inclusion of fetal squamous epithelium. Squamous metaplasia of mesothelium or inclusions of mature squamous epithelium appears to be an unlikely source of origin of these cysts.

Intermediate filament protein profiles of human testicular non-seminomatous germ cell tumors: correlation of cytokeratin synthesis to cell differentiation

The patterns of cytoskeletal differentiation were studied in 20 testicular non-seminomatous germ cell tumors by immunohistochemistry, using diverse monoclonal antibodies specific for different intermediate filament (IF) proteins and for desmoplakin. Immunofluorescence and immunoperoxidase methods on both formalin-fixed and frozen tissues were applied, in some cases together with a gel electrophoretic analysis of IF proteins. The tumors examined included embryonal carcinoma (EC), endodermal sinus tumor (EST), choriocarcinoma and teratoma. Nine of the tumors were composed of only one histological type, the others showed mixed components. Cytokeratins 8 and 18 were identified in all these neoplasms, but their immunostaining was weak in ECs. Cytokeratin 19 was absent or very scarce in ECs, but strongly expressed in ESTs, choriocarcinomas and teratomas, thus allowing the identification of small EST and choriocarcinoma elements in ECs even when they were morphologically not obvious. Occasionally, some cells in ECs and ESTs also stained for cytokeratins 4 and/or 17, indicating potential for epithelial stratification. The majority of the germ cell tumors showed varied amounts of vimentin, often in co-existence with cytokeratins. Neurofilaments were demonstrated in scattered tumor cells in a single case of EST. In the teratomas studied, each type of tissue component present showed the expected IF protein. However, in many germ cell tumors some stromal cells and blood vessels contained, in addition to vimentin and desmin, also cytokeratins 8 and 18. This heterogeneity of the cytoskeletal profile of germ cell tumors is indicative of the varied differentiation potential inherent in these neoplasms.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of cytokeratin 13, a component characteristic of internal stratified epithelia, is not induced in human epidermal tumors

Human cytokeratin 13 is one of the most abundant intermediate filament (IF) proteins of many internal stratified epithelia and occurs, at least in certain cell cultures, in an O-glycosylated form binding the lectin, wheat germ agglutinin (WGA). As other groups have reported that, in the mouse, the synthesis of mRNA encoding the 47-kDa cytokeratin corresponding to human cytokeratin 13 is induced in epidermal keratinocytes during malignant transformation, we have examined the synthesis of cytokeratin 13 mRNA and protein in human epidermis and epidermal tumors, using specific cDNA probes and cytokeratin 13 antibodies. We isolated two different cDNA clones from the vulvar carcinoma cell line A-431, in which this protein is abundant: One clone seems to represent the entire mRNA, whereas the other is only a minor component and encodes a truncated cytokeratin 13 lacking most of the carboxy-terminal tail domain, probably a product of alternative, "incorrect" splicing. Comparison of the amino acid sequences with those of other cytokeratins revealed a high degree of conservation with respect to several other human type I cytokeratins, notably cytokeratin 15, and to the murine 47-kDa cytokeratin. When human epidermis and a series of benign and malignant epidermal tumors were examined with these cDNA probes and cytokeratin-13-specific antibodies we did not find an induction of expression in keratinocytes, normal or malignantly transformed, except for some scattered, sparse cytokeratin-13-positive cells and very low levels of cytokeratin 13 mRNA, detectable only with the highly sensitive polymerase chain reaction (PCR). We conclude that the gene(s) encoding cytokeratin 13 are not induced in human keratinocytes during epidermal carcinogenesis, in apparent contrast to reports of murine epidermal tumors, and we discuss possible explanations for this interspecies difference.

Subtyping of epithelial cells of normal and metaplastic human uterine cervix, using polypeptide-specific cytokeratin antibodies

The aim of the present study was to explore the histogenesis of metaplastic cells in the human uterine cervix. In a previous study we demonstrated that squamous cervical metaplasia expresses a unique set of cytokeratin polypeptides different from that expressed by the various normal epithelial elements of both the exo- and endocervix. It was thus proposed that the formation of squamous metaplasia represented a new route of differentiation. In the present study we further investigated this aspect by expanding the battery of monoclonal antibodies directed against specific cytokeratin epitopes used for immunohistochemical labelling. The antibodies used were: KS-1 A3, which specifically stains cytokeratin polypeptide no. 13; antibody KS-2.1, which is an anti-cytokeratin reacting with pseudostratified transitional and some simple epithelia; and antibody KS-B17.2 reacting with cytokeratin polypeptide no. 18. Examination of the staining patterns obtained with these antibodies revealed specific staining of ciliated cells with antibody KS-2.1 and of endocervical reserve cells with antibody KS-1A3. In 6 out of 19 cases tested reserve cells were also stained with antibody KS-2.1. These results enabled us to distinguish between at least four types of cells residing within the simple epithelium of the endocervix, namely columnar nonciliated cells, ciliated cells, and two subpopulations of reserve cells. Since metaplasia was positively stained by antibodies KS-1A3 and KS-2.1, we propose that the endocervical reserve cells that express cytokeratin polypeptide no. 13 are most probably the cells from which endocervical metaplasia is derived.