P53 PROTEIN EXPRESSION IN LARYNGEAL SQUAMOUS-CELL CARCINOMAS BEARING WILD-TYPE AND MUTATED P53 GENE

We performed an immunohistochemical analysis to investigate the expres sion of p53 protein in a panel of 18 laryngeal squamous cell carcinoma s, 15 primary tumours and three in relapse, previously analysed by us for the presence of p53 gene mutations, Dysplastic and/or normal surro unding mucosa was evaluated in 15 different tumours, The results of ou r study are the following: (1) expression of p53 protein was observed in one out of five tumours positive for p53 gene mutations (20%) and i n 10 out of 13 (80%) negative cases; (2), p53 protein overexpression w as frequently observed in normal and/or dysplastic mucosa surrounding either wild-type (7/11) or mutated p53 tumours (2/4); (3), p53 immunor eactive cells showed a pattern of distribution in normal and mildly/mo derately dysplastic mucosa (basal layers), different from that in seve rely dysplastic mucosa (whole thickness), These data further support t he hypothesis that p53 protein over-expression may be a marker of the earliest phases of multistep tumorigenesis in laryngeal squamous cell carcinoma.