EXPRESSION OF P53 PROTEIN IN ORAL SQUAMOUS-CELL CARCINOMAS AND ADJACENT NON-TUMOROUS MUCOSA OF THE FLOOR OF THE MOUTH - AN ARCHIVAL IMMUNOHISTOCHEMICAL STUDY USING WET AUTOCLAVE PRETREATMENT FOR ANTIGEN RETRIEVAL

Routinely formalin-fixed and paraffin-embedded material of 22 squamous cell carcinomas of the floor of the mouth (T2NoMo, Ro), together with adjacent dysplastic or normal mucosa, were immunohistochemically inve stigated using a panel of four anti-p53 antibodies (CM1, PAb1801, DO7, PAb240) subsequent to wet autoclave pretreatment for antigen retrieva l, p53 immunoreactivity was detected in 9/22 (40%) carcinomas with PAb 1801 and DO7 antibodies, and in 8/22 cases using CM1 and PAb 240. p53- positive tumour cells accumulated predominantly at the invasive front of the carcinomas. A focal or scattered p53 immunoreactivity was obser ved in the adjacent normal and/or dysplastic mucosa in 17/22 (77%) cas es using both CM1 and PAb1801 antibodies, in 10/22 with DO7, and in 8/ 22 with PAb240. This study has demonstrated examples of different p53 immunophenotypes in the non-tumorous and neoplastic oral mucosa of the same patient without significant correlation to the clinicopathologic al parameters studied.