['This study investigated the status of the p53 tumor suppressor gene in patients less than 40 years of age who had squamous cell carcinoma of the tongue develop with no known risk factors.', 'Histologic sections from 21 patients were prepared from formalin-fixed, paraffin-embedded tissue and were processed for standard immunohistochemistry for detection of the p53 protein. In addition, tumors were evaluated by single-strand conformation polymorphism and by DNA sequencing to identify potential mutations in the conserved exons (5-9) of the p53 gene.', 'Eighty-one percent (17 of 21) of the patients overexpressed p53 by immunohistochemical analysis. However, none of these patients demonstrated mutations in exons 5-9 of the gene.'] Is overexpression of p53 in squamous cell carcinoma of the tongue in young patients with no known risk factors associated with mutations in exons 5-9?