Prognostic Significance of Vascular Endothelial Growth Factor in Squamous Cell Carcinomas of the Tonsil in Relation to Human Papillomavirus Status and Epidermal Growth Factor Receptor

Abstract

Angiogenesis markers, vascular endothelial growth factor (VEGF) and microvessel density (MVD) have been associated with prognosis in squamous cell carcinomas (SCCs) of the head and neck. Other prognostic variables such as human papillomavirus (HPV) and epidermal growth factor (EGFR) may also be involved in tumour angiogenesis. This study determined relationships between VEGF, MVD, EGFR, HPV, response to radiotherapy and clinical outcome in 85 tonsillar SCCs. HPV status was determined by an HPV multiplex real-time polymerase chain reaction (PCR) assay/p16 immunohistochemistry. Expression of VEGF, CD31 (as marker of MVD) and EGFR was assessed by semiquantitative immunohistochemistry. Strong VEGF expressers were significantly more likely to have higher MVD than were weak expressers. There were no associations between VEGF or MVD and gender, patient age, TNM stage, EGFR expression or HPV status. Tumours with MVD of >15 per high-power field were significantly more likely to be poorly differentiated. There was a significant inverse relationship between EGFR and HPV status. HPV was a strong independent marker of loco-regional recurrence and death. VEGF and EGFR were risk factors for local recurrence and disease-specific death on univariate analysis but the associations weakened after adjustment for HPV. Among patients treated with radiotherapy, VEGF was associated with disease-specific death after adjusting for HPV and TMN stage. High-VEGF-expressing tumours positive for EGFR had a worse prognosis than all other groups combined after adjusting for HPV and TNM stage. HPV is a stronger prognostic marker than VEGF or EGFR in tonsillar SCCs. VEGF correlates with MVD in these tumours.