MAGE-A antigens in lesions of the oral mucosa.

Oral squamous cell carcinoma develops continuously out of predamaged oral mucosa. For the physician and pathologist, difficulties arise in distinguishing precancerous from cancerous lesions. MAGE-A antigens are tumor antigens that are found solely in malignant transformed cells. These antigens might be useful in distinguishing precancerous from cancerous lesions. The aim of this study was to verify this assumption by comparing MAGE-A expression in benign, precancerous, and cancerous lesions of the oral mucosa. Retrospectively, biopsies of different oral lesions were randomly selected. The lesions that were included are 64 benign oral lesions (25 traumatic lesions (oral ulcers), 13 dental follicles, and 26 epulis), 26 oral lichen planus, 123 epithelial precursor lesions (32 epithelial hyperplasia found in leukoplakias, 24 epithelial dysplasia found in leukoplakias, 26 erythroplasia with oral epithelial dysplasia, and 41 carcinomas in situ in erythroleukoplakias). The lesions were immunohistochemically stained with the poly-MAGE-A antibody 57B, and the results were compared. Biopsies of oral lichen planus, oral ulcers, dental follicles, epulis, and leukoplakia without dysplasia showed no positive staining for MAGE-A antigens. Leukoplakia with dysplasia, dysplasia, and carcinomata in situ displayed positive staining in 33%, 65%, and 56% of the cases, respectively. MAGE-A antigens were not detectable via immunohistochemistry in benign lesions of the oral mucosa. The staining rate of dysplastic precancerous lesions or malignant lesions ranged from 33% to 65%. The MAGE-A antigens might facilitate better differentiation between precancerous and cancerous lesions of the oral mucosa.

Reactivity of monoclonal antibodies 17.13 and 63.12 with oral epithelial dysplasia and hyperkeratosis.

Monoclonal antibodies (MAbs) 17.13 and 63.12 exhibit characteristic reactivity patterns in normal stratified squamous epithelium, as well as highly sensitive and specific altered reactivity patterns in squamous cell carcinoma. The purpose of this study was to critically evaluate the patterns of reactivity of MAbs 17.13 and 63.12 in 43 biopsies of clinical oral leukoplakia or erythroleukoplakia with microscopic diagnoses of hyperkeratosis or epithelial dysplasia. Altered carcinoma-like reactivity patterns were seen in 72% of hyperkeratoses and in all cases of epithelial dysplasia, but varied in the level of epithelial strata exhibiting altered reactivity. Increased frequency of altered reactivity within the epithelial strata was associated with the presence, but not the grade of, epithelial dysplasia, as well as with the presence, intensity; and pattern of submucosal inflammation. The results of this study suggest that altered reactivity patterns of MAb 17.13 are associated with epithelial dysplasia and may be of assistance in detecting precancerous changes in hyperkeratoses before morphologically identifiable epithelial dysplasia. The association of submucosal inflammation with altered MAbs 17.13 and 63.12 reactivity may indicate either a decrease in specificity of these antibodies for precancerous change or an increased significance of inflammation in precancerous lesions.

Expression of mucin type carbohydrates may supplement histologic diagnosis in oral premalignant lesions.

Recent studies have shown that changes within membrane bound carbohydrates may be essential for cellular differentiation and malignant transformation. We have therefore, by means of immunohistochemistry, studied the expression of T/Tn related (Thomsen-Friedenrich) carbohydrates in 13 oral lesions with squamous cell dysplasia. The epithelial grade of dysplasia was graded as mild, moderate or severe. The following carbohydrate structures were studied: Tn, T, mucintype 3 chain H, and the sialylated derivates, sialosyl-Tn and sialosyl-T. In general, short structures were detected on the basal cells and longer structures on the more mature spinous cells. In many cases, this sequential expression was more disturbed with increasing grade of epithelial dysplasia. However, our results also showed that some lesions with the same grade of epithelial dysplasia showed different carbohydrate expression. These findings indicate that expression of carbohydrates may supplement histologic diagnosis in the evaluation of the prognosis of premalignant lesions.