THE DETECTION OF HUMAN PAPILLOMAVIRUS (HP V) DNA IN FORMALIN-FIXED INVASIVE SQUAMOUS-CELL CANCERS OF THE LARYNX BY POLYMERASE CHAIN-REACTION (PCR)

Approximately 67 different subtypes of HPV's have now been described. Regularly most of the cervical cancers are positive for HPV 16/18. Cur rent research also indicates that HPVs may be involved in the developm ent of benign tumours and also squamous cell cancers of head and neck. Studies establishing the presence of different HPV subtypes in oral c ancers and precancers suggest the possibility of the virus as etiologi cal factor in oral carcinogenesis too. In this study the prevalence of HPV 6/11, 16 and 18 infection and other exogenous risk factors like n icotine and alcohol in laryngeal cancers were studied. A total of 100 formalin-fixed and paraffin-embedded cancers, 41 glottic and 59 suprag lottic, in patients aged 58 years, were detected by use of the E6 spec ific PCR for HPV DNA. Significantly more glottic cancers, 26 of 41 (63 .4%), were positive for the investigated HPV's. HPV 16 was found in al l positive cancers. This predominance of HPV 16 was also present in th e supraglottic carcinomas, but only 10.2% (6 of 59) of these groups we re HPV positive. In both groups the patients with HPV 16 and/or 18 pos itive cancers, the exogenous risk factor was higher thay with in HPV 1 6/18 negative tumours. Following infection, the virus either remains d ormant or else undergoes active replication resulting in the synthesis of infectious virus. The integration of virus DNA into the host cell DNA may be the result of action of nicotine and/or alcohol. The integr ation event is the key of the carcinogenesis. The level of the risk fa ctor in the patients with supraglottic tumours was significantly highe r. The results this paper show the possible role of HPV 16/18 in the p athogenesis of laryngeal cancers. There may be a second important way of carcinogenesis in supraglottic carcinomas.