Comparative genomic hybridization analysis of tonsillar cancer reveals a different pattern of genomic imbalances in human papillomavirus-positive and -negative tumors.

Our aim was to map and compare genomic imbalances in human papillomavirus (HPV)-positive and -negative squamous cell carcinomas of the tonsil. Twenty-five primary carcinomas were analyzed by comparative genomic hybridization. Fifteen (60%) were found to be HPV-positive by PCR, and the majority were HPV-16. There were statistically significant differences in the distribution of DNA gains and losses between the HPV-positive and -negative samples. Eleven of 15 HPV-positive samples (73%) showed gain on chromosome 3q24-qter, while only 4/10 (40%) HPV-negative samples had the same gain (p = 0.049). Furthermore, 4/10 (40%) HPV-negative samples but no HPV-positive samples had gain on chromosome 7q11.2-q22 (p = 0.017). As expected, and similar to previous studies, patients with an HPV-positive tumor had a statistically significantly better disease-specific survival than patients with an HPV-negative tumor (p = 0.002). The most common changes, e.g., gain on 3q or 8q, loss on 11q or 13 and loss on chromosome 7q in HPV-negative tumors, did not have any influence on prognosis. However the number of cases in each subgroup was limited.