Expression of EGFR and HPV-associated p16 in head and neck cancer: correlation and influence on prognosis after radiotherapy in 1088 patients from the randomised DAHANCA 5, 6 & 7 trials

Background: Expression of p16 is highly correlated to infection with Human Papillomavirus in squamous cell carcinoma of the head and neck (HNSCC). Previous reports have demonstrated an inverse correlation between expression of epidermal growth factor receptor (EGFR) and p16 in HNSCC. The aim of this study was to examine the correlation between EGFR and p16 and to asses their influence on response to radiotherapy (RT) and survival in a large cohort of HNSCC patients treated with RT alone in the randomised DAHANCA 5, 6& 7 trials.Material and Methods: Between January 1986 and December 1999 The Danish Head and Neck Cancer group (DAHANCA) conducted the nationwide DAHANCA 5, 6& 7 randomised trials, focusing on overcoming the disadvantages of tumour cell hypoxia and accelerated tumour cell proliferation in relation to RT. In the present study 1088 pre-treatment tumour tissues from patients in these trials were examined by immunohistochemistry for EGFR-expression (high/low) and p16 status (pos/neg).Results: In total 258 of 1088 (24%) tumours were p16pos and 885 (81%) had high EGFR-expression. The correlation between EGFR and p16 was found to be inverse with p16pos tumours tending to have lower EGFR-expression (27%) compared to p16neg tumours (16%, pppp