p53 Tumor supressor gene in laryngeal squamous cell carcinomas

Abstract

Purpose: Mutations in the p53 tumor supressor gene have been shown to be one of the most common genetic abnormalities in human cancers. Using p53 avidin-biotin- complex immunohistochemical method on fixed, embedded specimens, the frequency of presence of mutant p53 protein was investigated to understand the role of the p53 gene mutations in tumorigenesis of the laryngeal carcinomas. Methods: Forty formalin fixed, paraffin embedded tumor specimens of squamous cell carcinoma of larynx comprised the patient group and 13 biopsy specimens of benign laryngeal nodule were used as controls. Immunohistochemical staining was applied to all specimens. Results: Abnormal expression of p53 protein was found in 19 of 40 laryngeal carcinomas (47.5 %). Mutant p53 protein was not found in any of the 13 cases with benign laryngeal nodules. There was no correlation between tumor size, nodal involvement, stage and abnormal expression of the p53 protein. However, a significant correlation was found between tumor grade and p53 expression. In all cases immunostaining of p53 within the malignant tumor cells was confined to the nuclei, and dysplastic epithelial areas also showed positive immunostaining in the nuclei of four cases. Conclusion: This study may indicate that p53 gene mutation could have a role in laryngeal carcinoma, but the stage at which p53 has its effect on initiation or progression of this disease still remains unclear.