Localization of p53 protein and human papillomavirus in laryngeal squamous lesions

The p53 tumour suppressor protein can be ineffective because of mutations in the p53 gene or interactions with proteins synthesized by specific subtypes of HPV. We investigated the localization of p53 protein in association with HPV in paraffin sections of 10 dysplastic and 12 malignant laryngeal squamous epithelium specimens by using immunohistochemical and in situ hybridization techniques. Viral HPV type 16 or 18 related sequences were identified only in a squamous cell carcinoma (SCC) specimen. p53 was detected in 64% of cases studied. All p53+ specimens showed no HPV related sequences; the only HPV+ case was p53 negative. In our study, the increased p53 expression in the process from dysplastic to invasive SCC indicates that p53 overexpression is an early event in laryngeal carcinogenesis. Moreover, the systemic susceptibility to HPV infection suggests the need for an accurate evaluation of SCC risk not only in the genital tract in female patients shown to be positive for transforming HPV types (16 or 18).