P^（53）　PROTEIN　OVEREXPRESSION　IN　PREMALIGNANT　AND　MALIGNANT　LESIONS　OF　ORAL　MUCOSA：IMMUNOHISTOCHEMICAL　OBSERVATION

Ｐ^（５３） ＰＲＯＴＥＩＮ ＯＶＥＲＥＸＰＲＥＳＳＩＯＮ ＩＮ ＰＲＥＭＡＬＩＧＮＡＮＴ ＡＮＤ ＭＡＬＩＧＮＡＮＴ ＬＥＳＩＯＮＳ ＯＦ ＯＲＡＬ ＭＵＣＯＳＡ：ＩＭＭＵＮＯＨＩＳＴＯＣＨＥＭＩＣＡＬ ＯＢＳＥＲＶＡＴＩＯＮＰ^（５３）ＰＲＯＴＥＩ...

In order to analyze the relationship between p53 protein and the progression of malignancy in epithelium of oral mucosa, carcinomas and epithelium immediately adjacent to carcinoma were studied by immunohistochemistry using wild-type p53 (Dako-p53, DO-7 ) monoclonal antibody to detect the level of p53 protein overexpression. A total of 36 cases of human squamous cellcarcinomas (SCC) including varied differentiated ) recurrent and metastatic SCC3 were investigated.19 cases of epithelium immediately adjacent to carcinoma (EAC) were also stained with the same antibody. A sensitive immunostaining method was established by using microwave oven heating to retLieve p53 antigen in the formalin-fixed and paraffin-embedded tissues. p53 protein overexpression was detected in 3 of 10 (30% ) well differentiated SCCs, in 13 of 12 (75. 47 % ) moderately and poorly differentiated SCCs and in 7 of 9 (77. 78%) of the metastatic and recurrent SCCs. The total percentage of p53-positive in all SCC was 63.89%. p53 protein was also found positive in 9 of 19 EACs (47.37%) and in 2 of 5 (40% ) leukoplakia. Authors conclude that overexpression of p53 protein involved both in the late stage of malignancies of oral mucosa and in the early stage of some premalignant lesions. Mutations in the p53 gene have been shown to be on of the most common genetic abnoumalities in a auide range of human Cancers and the published litrature also shows this to be the case in oral cancer[5-10].