口腔黏膜癌变过程中Fas与FasL表达的相互关系

The Relationship of Fas and Fas L Protein Expression in Oral Carcinogenesis

目的 初步探讨Fas和FasL蛋白在口腔黏膜癌前损害发生发展过程中的作用及变化规律。方法 分别选出正常口腔黏膜、上皮单纯增生、上皮轻度异常增生、上皮中度异常增生、上皮重度异常增生与原位癌、鳞状细胞癌标本 ,共 6 4例 ,采用免疫组织化学染色技术———酶标链亲和素生物素法 (LsAB)染色并进行光镜下观察。结果 多数口腔鳞癌显示Fas表达的下调和FasL表达的上调 ,同样的结果见于口腔癌前损害黏膜组织。结论 Fas和FasL的表达参与了口腔癌变过程 ,且可能是癌细胞逃避宿主免疫攻击的机制。Fas FasL系统有望成为判定口腔癌前损害预后的生物标志。

Objective The purpose of the study is to investigate the mechanism of immune escape and the expression of Fas and Fas L in oral premalignant lesions (OPLs) and oral squamous cell carcinomas (OSCCs).Methods 64 samples, including normal oral mucosa(7), hyperkeratosis(9), premalignant lesions(24) and squamous cell carcinomas(24), were studied. The cells in the test specimens, which demonstrate granular staining, were considered as positive. The expression of Fas and Fas L was evaluated semi-quantitatively as follows: -,no expression; +(mild),<5% positive cells; ++(moderate),6%～25% positive cells; +++(intense),26%～50% positive cells; or ++++(very intense),>50% positive cells.Results In the process of oral carcinogenesis, each stage had Fas expression. The positive staining appeared essentially on cell membrane. Various degrees of Fas expression were seen in the diseased tissues. The number of positively stained cells in the moderately and severely dysplastic tissues appeared higher than that in the normal control (P<0.05). In the OSCC group, the level of expression of Fas antigen decreased significantly by comparison with the normal controls (P<0.05). Fas L expression was discovered in each stage of the process of oral carcinogenesis. The positive staining appeared in cytoplasm. In hyperkeratotic tissues and OPLs, the number of Fas L expression cells was significantly higher than that in the normal controls. The number of Fas L expression cells of OSCCs increased by comparison with both normal controls and OPLs.Conclusion The results indicate that the expression of Fas and Fas L is involved in oral carcinogenesis and this may be directly related to the mechanism by which the cancer cells evade the host immune assault. Perhaps, Fas/Fas L system may be used as a prognostic biomarker in predicting the behavior of oral premalignant lesions in the near future.