The prevalence of different human papillomavirus types and p53 mutations in laryngeal carcinomas: is there a reciprocal relationship?
This study investigates whether a reciprocal association occurs between HPV infection and somatic mutation of the tumour suppressor gene p53 in laryngeal carcinomas. Using immunohistochemical techniques, 87 tumours were examined for expression of the mutant form of p53 phosphoprotein using the monoclonal antibody PAB 1801. The prevalence of different HPV types in these tumours was determined by using the polymerase chain reaction and restriction enzyme analysis. Over-expression of p53 was noted in 50/87 (57.5%) of the tumours investigated but not in any of the non-neoplastic laryngeal mucosa (controls). There was no statistical correlation between p53 immunoreactivity and the clinicopathological parameters of laryngeal carcinomas. HPV DNA was detected in 8/36 (22.2%) of the tumours: HPV-6 in three, HPV-11 in one, HPV-16 in two, and unknown HPV type in two. In p53-mutant tumours, HPV was present in 4/20 tumours but none of these were high risk HPV types. In p53-normal tumours, on the other hand, HPV was present in 4/16 tumours but two of these were definitely high risk HPV-16. These results imply the reciprocal association between HPV and somatic mutations of p53 found in the case of cervical carcinoma.