Abstract. HPV involvement in head and neck (HN) cancer is still under active investigation. Fresh frozen and archival clinical samples from 115 patients affected by HN carcinomas were analysed by PCR-based methods and direct sequencing. HPV types, intra-type variants, physical status, viral load and viral transcript presence were determined. HPV positivity was correlated with the main clinical-pathological features, including smoker and drinker status, and the clinical outcome. Twenty-one tumours were HPV positive (18.3%) with HPV16 being the most frequent type (n=14) followed by HPV6 (n=4), HPV33, HPV35, and HPV58 (n=1, each type). Tonsil carcinomas contained more high-risk HPV types (6/8; 75%) than all other sites (p=0.0004). HPV16 genome was integrated in all analysed tumours, as pure integrated form or mixed with concomitant episomal forms (4 cases). The viral load showed a wide variability (range, 0.7-485 copies per cell) with the highest value detected in a larynx tumour and the lowest one in a case of cancer of the oral cavity. In 9 HPVpositive samples where mRNA was available, transcripts of viral early oncogenes originating by integrated, episomal or mixed forms of the viral genome were found. A statistically significant correlation was evidenced between HPV and tumour differentiation, being the virus more associated with tumour grade G3/G4. Multivariate Cox regression analysis revealed that lymph-node and grade status were significant independent factors for a worse disease-free survival and overall survival, whereas the HPV status was associated with a better overall survival (OR, 0.33; 95% CI, 0.13-0.81; p=0.01). Taken together these results indicate that distinct pathological mechanisms for the malignant transformation in each single HN subsite should be taken in account; HPV molecular analyses should be considered a valid tool to distinguish subsets of oropharyngeal tumours and HPV presence could be useful for the prognostic assessment of HNSCC.
IntroductionTumours of the oral cavity and pharynx have been estimated at 643,000 cases for 2002, with 349,000 deaths (1). The incidence of these cancers is traditionally found to be very high in some areas of the world (e.g., France and South India), but in the last decade other areas (e.g., Eastern Europe and Japan) reported an increasing incidence of head and neck (HN) squamous cell carcinomas (SCC) (2). HN cancer constitutes one of the most difficult pathologies to eradicate. Recurrences are frequent and about a half of patients die (1). The heterogeneity of treatment response and the lack of prognostic factors could be the main causes of the adverse clinical outcome. Moreover, the behaviour variability of each individual tumour has also emphasized the difficulties of managing these tumours.Life habits such as the intake of toxic agents present in tobacco smoke, alcohol drink and betel chewing, or poor hygiene remain major risk factors for these tumours. However, the fraction of HN cancers attributable to these risk factors is close to 80-90%, while the...