Mutations in the p53 and
retinoblastoma (pRb) pathways associated with the use of tobacco and alcohol are common in
squamous cell carcinoma (SCC) of the head and neck.
Cell cycle proteins are also affected by human papillomavirus (HPV), which may also have an aetiological role in
cancers at particular sites, most notably the tonsil. Attempts to identify prognostic molecular markers in head and
neck cancers have met with conflicting results, but few studies have been undertaken with tumours of known HPV status at a single anatomic site. In our study 86
tonsil cancers were analysed for HPV status by sequence analysis of polymerase chain reaction products and for the expression of
cell cycle proteins (p53, p21(CIP1/WAF1), pRb,
p16(INK4A),
cyclin D1 and p27(KIP1)) by immunohistochemistry. The HPV status could be established in 67 of the tumours. Thirty-one (46%) of these were HPV-positive, predominantly (28/31) for HPV16. Findings were related to tumour recurrence and patient survival. None of the
cell cycle proteins independently predicted recurrence or survival. Patients with HPV-positive tumours, however, were significantly less likely (p < 0.05) to have recurrence or to die of disease than those with HPV-negative tumours, after adjusting for the effects of the
cell cycle proteins, clinical stage, pathological node status, tumour grade, age, gender and treatment. These findings support the concept that HPV-positive
tonsil cancers may be a distinct
biological group with less aggressive characteristics. Screening of
tonsil cancers for HPV
DNA may help optimise treatment and provide more accurate prognostic information.