<原著>免疫組織化学的にみた扁平上皮癌の分化 <ORIGINAL ARTICLE>Immunohistochemical Evaluation of Differentiation of Oral Squamous Cell Carcinomas
口腔領域の悪性腫瘍で最も発症頻度の高い扁平上皮癌は,角化性扁平上皮癌や非角化性扁平上皮癌に大別されるほか,数種に細分されている.このような組織型は腫瘍細胞の分化の状態と深く関連していることが考えられる.そこで今回,正常口腔粘膜上皮,白板症上皮を対照として,扁平上皮癌の各種について細胞増殖抗原と分化抗原の発現の有無と程度を検討した.その結果,今回検索に供した細胞抗原のほとんどはいずれの組織にも発現される点で共通し,その発現細胞種が異なることが明らかになった.但し,細胞接着性タンパクのE-cadherin, α-およびβ-cateninは扁平上皮癌にはほとんど発現せず,同タンパクのCD44ファミリーも他の組織に比べて著しい減少傾向を示した.しかし,CD44v6は扁平上皮癌で増加傾向を示し,角化性扁平上皮癌では, over expressionの特徴があった.以上から,上皮細胞に特異的な発現物質は,扁平上皮癌でreduced,逆のincreased expression,時にover exoressionし,その結果として異なった分化形態が現れることが強く示唆された.
Oral squamous cell carcinomas (SCO) can be histologically classified as keratinized, non-keratinized, basal cell, basaloid, spindle cell and undifferentiated type. These variants of oral SCC are considered to arise due to different in degrees of tumor cell differentiation. The present study was performed to determine the difference between keratinized and non-keratinized oral SCC by immunohistopathological methods using normal oral mucosa and leukoplakia as control materials. Although almost cellular antigens (cytokeratin AE1/AE3, epithelial membrane antigen(EMA), proliferating cell nuclear antigen (PCNA), epidermal growth factor receptor (EGFR), CD44 families excepting for E-cadherin, α- and 0-catenin) were immunoreactive to all epithelium supplied to the present investigation, the intensity of immunoreactivity and the value of immunopositive cells for specific antibodies to the cellular antigens exhibited a tendency to decrease as the lesions were more malignant. E-cadherin, α- and P-catenin were detected in the tissue of oral SCC. The difference in immunoreactivity between keratinized and non-keratinized oral SCC could not be distinguished, however, CD44v6, a kind of CD family, was characterized by the specific finding that the antigen is over expressed in some cases of keratinized type oral SCC. These results obtained from the present study suggest that the difference in the degree of expression of epithelium specific cellular antigens, such as reduced, increased and/or over expressions depends much on the cellular differentiation of variants of oral SCC.