Besides chronic alcoholism and smoking, the oral Human Papiloma Virus (HPV) infection is an etiological factor in oral squamous cell carcinoma, and is related to the oncologically high-risk HPV16 in 90% of the cases. Based on current literature data, we investigated the gene inactivation mechanisms of the two possible etiological factors in 17 head and neck carcinoma cases, looking for the degree to which the oral HPV infection is a predictive factor of head and neck squamous cell carcinomas. We investigated 17 cases of squamous cell carcinoma in young and middle aged patients, namely the expression of the p16, p53 and Ki-67 proteins with the immunohistochemical method, as well as the presence of HPV-DNA in the cases of HPV-16, HPV-18 and HPV-33 genotypes with Polymerase Chain Reaction method (PCR). Comparing the immunofenotypes of the tumor cells with the presence of HPV-DNA, we found, that the 3 HPV positive tumors don’t always follow the p16 route of inactivation: along with the p16+/ Ki67+/p53- fenotype, which would suggest a viral etiology, the p16+/Ki67-/p53- fenotype is also present in the case of the HPV-16 genotype, at the same time the HPV-33 genotype characterises the p16-/Ki67-/p53+ fenotype. The viral etiology of the tumor can be regarded as a prognostic factor only when the mechanisms of cancerogenesis are precisely mapped, it can not be regarded as having a predictive value on its own.
Keywords: head and neck squamous cell carcinoma, HPV virus, p16 protein