Cellular manifestations of human papillomavirus infection in laryngeal tissues

Although epidemiologic studies have suggested human papillomavirus (HPV) to be an etiological agent in laryngeal carcinogenesis, little is known on the cellular manifestations of HPV infection in these tumors. In this study, we investigated the frequency of HPV infection in various neoplastic and non-neoplastic laryngeal tissue and its association with expression of the proliferating cell nuclear antigen (PCNA) and the tumor suppressor protein p53.

Tissues were analyzed by polymerase chain reaction (PCR) for the presence of HPV and by immunocytochemistry for the expression of p53 and PCNA.

None of the six normal laryngeal tissues showed the presence of HPV. Thirteen out of the 16 papillomas were positive for HPV, while 15 out of the 44 invasive cancers were HPV positive. PCNA expression increased as the lesion progressed through increasing histological abnormality (r = 0.64400, P = 0.00000). The correlation between the type of laryngeal neoplasm and p53 accumulation was significant (r = 0.54839, P = 0.00000). Significant correlation was also evident between presence of HPV and p53 accumulation (r = 0.34259, P = 0.00424) and PCNA expression (r = 0.036024, P = 0.00266) indicating that HPV positive tumors showed significant p53 accumulation and increased proliferation. There was also correlation between p53 and PCNA expression (r = 0.67475, P = 0.00000) indicating that in all tumors with p53 accumulation, there was a corresponding increase in PCNA expression.

The results suggests that changes in p53 and PCNA expression may be associated with HPV infection, and could play a role in laryngeal carcinogenesis.