EXPRESSION OF P53 IN ESOPHAGEAL SQUAMOUS EPITHELIUM FROM SURGICAL SPECIMENS RESECTED FOR SQUAMOUS-CELL CARCINOMA OF THE ESOPHAGUS, WITH SPECIAL REFERENCE TO UNINVOLVED MUCOSA

Accumulation of p53 protein has been considered an intermediate biomar ker in multistage oesophageal carcinogenesis. The aim of the present s tudy was to investigate p53 expression by immunohistochemistry in 13 t horoughly sampled oesophagectomy specimens from a geographical area wi th a high oesophageal cancer incidence (Basse Normandie, France). Expr ession of p53 was looked for in tissue samples of cancer, intraepithel ial neoplasia, and uninvolved mucosa. The streptavidin biotin peroxida se complex method was used for p53 immunostaining. p53 expression was found in invasive squamous cell carcinoma in 8 out of 11 cases and in intraepithelial neoplasia in 10 out of 11 cases. In all 13 cases, in u ninvolved oesophageal mucosa, expression of p53 was focally present in areas of chronic oesophagitis. Chronic oesophagitis has been regarded by epidemiologists as a precursor lesion for squamous cell carcinoma of the oesophagus. Since oesophageal carcinogenesis is a multistage pr ocess, the study of precursor lesions could provide information on the timing of p53 gene abnormalities during oesophageal carcinogenesis. T hese preliminary data require to be confirmed by molecular analysis of the p53 gene.