Coexpression of cytokeratins, involucrin, and blood group antigens in oral squamous cell carcinomas

Expression of E-cadherin and involucrin in leukoplakia and oral cancer: an immunocytochemical and immunohistochemical study

To assess the immunocytochemical and immunohistochemical correlation of adhesion (E-cadherin) and cell differentiation (involucrin) molecules in oral leukoplakia and oral squamous cell carcinoma. Cytological samples and biopsies were obtained from male and female patients aged over 30 years with oral leukoplakia (n = 30) and oral squamous cell carcinoma (n = 22). Cell scrapings and the biopsy were performed at the site of the lesion and histological slides were prepared for the immunocytochemical analysis of exfoliated oral mucosal cells and for the immunohistochemical analysis of biopsy tissues using E-cadherin and involucrin. Spearman's correlation and kappa coefficients were used to assess the correlation and level of agreement between the techniques. Immunostaining for E-cadherin and involucrin by both techniques was similar in the superficial layers of the histological sections compared with cell scrapings. However, there was no statistical correlation and agreement regarding the immunocytochemical and immunohistochemical expression of E-cadherin and involucrin in oral leukoplakia (R = 0.01, p = 0.958) (Kappa = 0.017, p = 0.92) or in oral squamous cell carcinoma (R = 0.26, p = 0.206) (Kappa = 0.36, p = 0.07). The immunoexpression of E-cadherin and involucrin in tissues is consistent with the expression patterns observed in exfoliated oral mucosal cells, despite the lack of a statistically significant correlation. There is an association of the histopathological characteristics of leukoplakia with the expression E-cadherin and of the microscopic aspects of oral squamous cell carcinoma with immunohistochemical expression of involucrin.

Analysis of salivary secretor status in patients with oral submucous fibrosis: a case-control study

AIM

Many individuals have various tobacco-related habits, yet only some develop clinical manifestation of lesions. This raises the question of whether there any inherent or host risk factors involved in the pathogenesis which need to be further investigated. The aim of the present study was to analyze the ABO antigen, secretor status, and blood groups of patients.

METHODS

The study consisted of 99 participants, with 33 patients allocated to three groups: (a) patients with a tobacco-related habit and oral submucous fibrosis (OSF); (b) patients with a tobacco-related habit, but no lesions; and (c) healthy controls. A total of 1 mL unstimulated saliva was collected in a sterile test tube, and the Wiener agglutination test was performed to analyze the ABO antigen in all three groups.

RESULTS

All of the OSF patients were non-secretors, whereas 84.8% were non-secretors in the group of individuals with habits as compared to 15.2% in the healthy group. A statistically-significant difference was observed between the OSF and healthy groups. The patients in the OSF group were predominantly blood-group A, followed by groups O, B, and AB.

CONCLUSION

There is a correlation between salivary secretor status and the development of OSF. Thus, non-secretors are at greater risk of and more prone to the development of oral lesions. Blood-groups A and O predominate over the B and AB blood groups.

Modulating expression of LAMPs and ABH histo-blood group antigens in normal and neoplastic human skin

Although the precise biological role of lysosomal membrane-associated glycoproteins (LAMPs) and ABH histo-blood group antigens (HBGAs) remains somewhat unclear, they are thought to be related to cell differentiation, cellular adhesion, and tumorigenesis. Here, we present the first comparative immunohistochemical study of both LAMPs and HBGAs in normal and neoplastic skin. Their localization is compared to that of high molecular weight cytokeratin and cytokeratin MNF 116. LAMPs and HBGA were differentially expressed in the normal stratified squamous epithelium, suggesting that they are involved in the initial steps of the differentiation process, whereas HBGAs are characteristic of terminal keratinocyte differentiation. No change in the reactivity for HBGA was detected in the stratified epithelium overlying squamous cell or basal cell carcinomas, whereas a considerable loss of LAMPs was detected. LAMPs were overexpressed in tumor cells, whereas HBGAs were lost in tumor zones of basocellular carcinomas. In spinocellular carcinomas, HBGAs were detected in tumor keratinocytes and in keratin pearls. These results provide new evidence for the differential expression of LAMPs and HBGAs in the normal stratified squamous epithelium, as well as the presence of a modulating reactivity in basocellular and spinocellular carcinomas, suggesting that these glycoproteins are involved in differentiation and tumorigenesis of human skin.

Cytokeratins and dermatology

Cytokeratins are fibrous intermediate-filament protein polymers present in almost all animal cells. Their function is related to epithelium structural maintenance, protection from mechanical trauma, and possibly communication between adjacent cells or cytoplasm components. Today there are 20 known cytokeratins, classified according to their molecular weight and pH as type I or acidic (cytokeratins 9-20) and type II or neutral-basic (cytokeratins 1-8). Cytokeratins are always expressed in specific pairs for each type of tissue, composed of one unit of type I and one unit of type II. Primary structural defects of cytokeratins are associated with various keratinization impairments. Two of the better characterized defects are bullous epidermolysis and epidermolytic hyperkeratosis. Anti-cytokeratin monoclonal antibodies are being used for diagnostic purposes to characterize the origin of poorly differentiated tumors and metastatic solid tumors.

Loss of basement membrane components laminin and type IV collagen parallels the progression of oral epithelial neoplasia

AIMS

To determine the immunohistochemical localization of basement membrane components laminin and type IV collagen in premalignant and malignant lesions of the oral epithelium.

METHODS AND RESULTS

Formalin-fixed tissue sections of 12 epithelial hyperplasias with no dysplasia and 30 dysplasias, clinically diagnosed as leukoplakia and/or erythroplakia, as well as 50 invasive squamous cell carcinomas, were stained with mouse monoclonal antibodies to human laminin and type IV collagen. Statistical analysis showed that there was a linear trend for discontinuous distribution of laminin from epithelial hyperplasia to epithelial dysplasia and invasive squamous cell carcinoma (P < 0.001). Laminin staining showed a linear trend for discontinuity with increasing grade of dysplasia (P < 0.05) and was more frequently discontinuous in areas of deep tumour invasion than in central or superficial areas (P < 0.05). Brush-shaped thickening and reduplication of the basement membrane were also identified.

CONCLUSIONS

Alterations in the distribution of laminin and type IV collagen in oral premalignant and malignant lesions indicate that the loss of continuity of the subepithelial basement membrane parallels the progression of the neoplastic transformation process in oral epithelium.

Langerhans cell density in normal human oral mucosa and skin: relationship to age, smoking and alcohol consumption

The immune function of skin has been studied extensively and it has been suggested that epidermal Langerhans cell (LC) density and function decreases with increasing age. Little is known, however, about the effect of age on oral mucosal LC. Cryostat sections from biopsies of buccal mucosa, lip, hard palate, lateral border of tongue, floor of mouth and abdominal skin, obtained from 91 subjects (aged 16-96 yr), were reacted immunocytochemically with a monoclonal antibody against CD1a and then LC density was expressed as LC/mm epithelial surface length. No significant effect of age on mucosal or skin LC density was found, whilst a history of smoking was associated with an increase in LC density in lateral border of tongue and in biopsies of labial mucosa taken from men (P < 0.05). There was no significant difference between LC density in men and women in oral mucosa. Oral mucosal LC may therefore form a relatively stable population in the adult and thus the increased incidence of mucosal disease in the elderly may be the result of subtle changes in cell mediated immune function rather than changes in LC density.

Keratin and keratinization

A flood of new knowledge and discoveries in the basic science of keratins and keratinization has appeared in the past several years. This review summarizes this recent information with a focus on the epithelial keratin polypeptides, keratin intermediate filaments, keratohyaline granule proteins, cell envelope formation and cell envelope proteins, "soft" keratinization, true disorders of keratinization (i.e., epidermolysis bullosa simplex and epidermolytic hyperkeratosis), and disease and drug effects on keratinization.

Tissue markers of potentially malignant human oral epithelial lesions

Tissue markers of potential malignancy have been sought for many years. Cell surface markers, particularly blood group and histocompatibility antigens, have shown great promise and several squamous carcinoma antigens have been identified--but not fully studied in potentially malignant lesions. Growth factors and receptors also need further study. Cytoplasmic markers of potential malignancy have been examined and, of these, keratins, filaggrin, and some carcinoma antigens show most promise. Nuclear analyses have promise but are time-consuming and expensive. Image cytometric analyses appear to be sensitive and predictive: oncogene and tumour suppressor analyses remain to be fully evaluated. New investigative techniques at the cellular and molecular level show increasing promise at defining potentially malignant oral epithelial lesions but more prospective studies are required.

Monoclonal antibody G6K12 specific for membrane-associated differentiation marker of human stratified squamous epithelia and squamous cell carcinoma

Monoclonal antibody (G6K12) specific for differentiated keratinocytes was developed using in vitro immunization against the SCC-25 cell line. G6K12 only recognized stratified portions of cultured SCC-25 cells. Immunohistochemical examination using normal human oral mucosa showed that specific G6K12-reactivity was limited to the lower spinous-cell layers, while this antibody weakly bound to cells in basal-cell layers as well as in the upper spinous, granular and cornified-cell layers. G6K12 was also reactive to keratinocytes in most moderately- and well-differentiated SCC tissues. Immunoelectron microscopic examination further demonstrated that the G6K12-immunoreactive area was at the outer surface of the entire plasma membrane, including the microvilli of stratified SCC-25. G6K12-binding was reduced 50% by the treatment of native cells with glycoendoceramidase for 2 h. These results suggest that G6K12 recognizes a plasma membrane-anchored glycoconjugate which is specific for differentiated keratinocytes.

Loss of epithelial L1 expression is associated with cellular invasion of oral squamous cell carcinomas

Recent studies have suggested that the epithelial expression of two leukocyte-related proteins, human class II HLA-DR antigen and myelomonocytic L1 antigen, depends on a certain state of cellular maturation and differentiation. We have studied HLA-DR and L1 expression in oral squamous cell carcinomas. The epithelial distribution of these proteins was evaluated in relation to differentiation alterations by two-color immunofluorescence staining with cytokeratins (K14 and K13) as a baseline. HLA-DR was infrequently expressed in oral carcinomas, apparently being unrelated to the degree of differentiation and the subepithelial leukocyte infiltration. L1 was generally present in oral epithelium but disappeared in the most invasive cells of carcinomas. These cells were also K14 and K13 negative suggesting an abnormal state of differentiation. L1 has been suggested to have an inhibitory effect on casein kinases I and II, enzymes possibly associated with cell proliferation; it might therefore exert an inhibitory effect on tumor growth. Its absence could be an interesting aspect of the invasiveness of oral carcinoma cells.

Prognostic value of various molecular and cellular features in oral squamous cell carcinomas: a review

Recent findings of prognostic value for oral squamous cell carcinomas (OSCCs) which may supplement clinical staging are reviewed. Many reports show that histopathologic grading, measurements of tumor-thickness and DNA-content have independent prognostic value and may thus be of clinical value. Features regarding cells at the invading margins of the tumors are probably of higher prognostic value than features within other parts of the tumors. Reportedly, various other cellular and serum markers have prognostic associations worthwhile further research.

Aberrant glycosylation in oral malignant and premalignant lesions

Cell surface carbohydrates serve as differentiation and developmental markers characteristic of different cell and tissue types. The expression of these carbohydrate antigens is often significantly altered in tumors, particularly in those arising from epithelial tissues. Analysis of cell surface carbohydrates in oral epithelium have shown that in normal epithelium they are expressed in a way that shorter carbohydrates are found on basal cells and that these carbohydrate structures are elongated parallel to terminal differentiation. The carbohydrate expression is altered in oral carcinomas and in some oral premalignant lesions. The change in carbohydrate expression can at present be explained by the lack of synthesis of specific glycosyltransferases. We have found mosaicism in the expression of carbohydrate antigens in all tumors and have found that the expression of a specific carbohydrate in the deep invasive parts of the tumor correlates with tumor prognosis.