Prevalence of human papillomavirus in squamous cell carcinoma of the head and neck determined by polymerase chain reaction and Southern blot hybridization: proposal for optimized diagnostic requirements.

Human papillomaviruses (HPV) are discussed as cofactors in the carcinogenesis of squamous cell carcinoma of the head and neck (SCCHN). The prevalence of HPV infection in SCCHN is the subject of controversy since reported HPV prevalences range from less than 10% to almost 100%, depending mainly on the detection method employed. This study presents a realistic approximation to the real prevalence of HPV in SSCHN by applying polymerase chain reaction (PCR) and Southern blot hybridization (SBH), which are the most sensitive and specific HPV detection methods. Diagnostic procedures were optimized by applying a "hot-start" PCR protocol followed by a confirmatory SBH of the PCR products to reactions using both type-specific and consensus primers and probes. DNA of 75 tumour samples and 22 normal mucosa samples of the same patients were investigated. In 14 cases genomic SBH using complete HPV genomes as probes was performed additionally. HPV DNA was detected in 17/75 (22.7%) SCCHN specimens. HPV 16 was identified in four cases, HPV 45 in three cases, and HPV 6 and 18 in one case each. Hot-start PCR and SBH are the most reliable HPV detection methods, as they minimize both false-positive and false-negative results. With these methods, a HPV prevalence of 23% was achieved, which can be assumed to be representative for comparable study populations. The significant number of positives detected only by consensus primer PCR, along with the identification of HPV 45, indicate that further HPV types may play an important role in the genesis of SCCHN.