STUDY ON MOLECULAR DIAGNOSIS OF ORAL PREMALIGNANT LESION EXPECTED TO BE TRANSFORMED INTO SQUAMOUS CELL CARCINOMA

鳞状细胞癌（squamous cell carcinoma，SCC）是口腔恶性肿瘤的主要类型。口腔鳞状细胞癌的手术治疗会导致严重的术后功能障碍或毁容。为了尽量减少这些问题，重要的是要立即治疗的病人，根据准确的诊断。本研究检测了p53抑癌基因在口腔鳞状细胞癌癌前病变中的表达情况，发现2/3的口腔鳞状细胞癌中p53抑癌基因发生突变，以及p53的改变是否可以作为癌前病变的诊断标志物，这些癌前病变以后可能转化为SCC。免疫组化结果显示，p53蛋白在口腔白斑癌变过程中呈高表达，提示p53基因的改变可能发生在癌变之前。提示p53蛋白的改变可能是口腔粘膜病变的诊断指标。p53基因在口腔鳞癌发生发展中的作用与口腔鳞癌的病理恶性程度、复发率及生存率无明显相关性，提示p53基因可能在口腔鳞癌的发生发展中起重要作用。

Squamous cell carcinoma (SCC) constitutes vast majority of the oral malignancy. The surgical treatment of oral SCC causes severe postoperative disfunction or, disfigurement. To minimize these problems, it is important to trea the patients immediately, based on the accurate diagnoses. It is well understood that some oral SCCs are developed from its premalignant lesions such as leukoplakia or erythroplakia, which give us hints to understand the mechanism of oral SCC carcinogenesis.In this study, we examined the status of p53 tumor suppressor gene in these oral premalignant lesions, which we showed to be mutated in 2/3 of oral SCCs, and if the p53 alteration could be used as a diagnostic marker of the premalignant lesions expected to be transformed into SCC later. Immunohistochemical analysis showed that p53 protein was highly expressed in many cases of the oral leukoplakia which were found to be subsequently transformed into SCC, suggesting that p53 gene alteration may possibly occur prior to malignant transformation. This result indicate that p53 alteration may possibly serve as a diagnostic marker of oral. SCC premalignant lesions.In addition, p53 gene mutation and clinical prognosis of the patient was compared to know the role of the gene in the progression of oral SCC.We could not find obvious correlation between the status of p53 and pathological malignancy score, the rate of recurrence and survival rate, suggesthig that p53 may possibly play a role rather in the initiation than prpgression of oral SCC.