Abstract

Mutations in the p53 gene seem to be the most common genetic changes in human malignancies. Mutation or altered p53 expression is a common occurrence in many solid neoplasms, including head and neck carcinomas. Recent studies have also shown p53 alterations in several premalignant conditions of the colon, esophagus, lung, and brain. Preliminary data have suggested that p53 mutations may be involved in tumor progression. This study was performed to determine the incidence of p53 mutations in histologically 27 squamous cell carcinomas, 19 basal cell carcinomas, 18 Schneiderian papillomas, 3 Schneiderian papillomas with malignant transformation, and 15 pleomorphic adenomas of the head and neck region. The degree of p53 gene overexpression was also evaluated according to differentiation, histologic type of tumor, and tumor progression in the head and neck carcinomas. The results were as follows; 1) Eighteen of 27 squamous cell carcinomas, and 4 of 27 dysplasias adjacent to the squamous cell carcinoma of the head and neck expressed p53 protein, but none of the normal control specimens expressed detectable p53 protein. There was no relationship between differentiation of squamous cell carcinoma and p53 protein expression. 2) Twelve of 19 basal cell carcinomas expressed p53 protein; the adenoid type especially overexpressed p53 protein. 3) Nine of 15 pleomorphic adenomas expressed p53 protein especially in the epithelial components. 4) Thirteen of 18 Schneiderian papillomas and all Schneiderian papillomas with malignant transformation expressed p53 protein. The above results indicate that the p53 protein expression is a useful tool for the prediction of tumor progression in the head and neck tumor, but there was no relationship between the differentiation of the tumor and p53 protein expression.

• Keywords: p53;Squamous cell carcinoma;Basal cell carcinoma;Pleomorphic adenoma;Schneiderian papilloma