Expression of Ki67 and P53 in primary squamous cell carcinoma of the larynx

Abstract

We studied a series of untreated laryngeal carcinomas in an attempt to determine the relationship between Ki67 and p53 expression and clinicopathological findings. The relationship between expression of these markers in non-tumoral tissue was also evaluated in order to investigate the possible role of immunohistochemistry as a diagnostic aid in evaluating laryngeal biopsies. Samples from 54 patients with laryngeal squamous cell carcinoma (SCC) were analyzed retrospectively. The uninvolved vocal cord was evaluated as a non-tumoral sample. Paraffin sections of tumors were immunohistochemically stained for p53 and Ki67 expression. Overall, p53 expression was found in 35 (64.8%) of the patients. There was a significant correlation among tumoral p53 expression and tumor location, tumor stage and lymph node involvement. Most grade I tumors had a Ki67 labeling index <50% and a labeling index ≥ 50 was found mainly in high-grade tumors. Tumoral Ki67 expression correlated significantly with tumor grade and mitotic count. There was no correlation between Ki67 labeling index and tumor region. In non-tumoral tissue, 95% of high-grade pre-neoplastic lesions revealed a high expression of Ki67. Non-tumoral p53 expression did not correlate with histological findings. p53 and Ki67 expression in tumoral tissue may be a prognostic marker in patients with laryngeal SCC. Evaluation of the proliferative index in biopsy samples of dysplastic laryngeal mucosa is potentially useful for predicting the progression toward carcinoma.