P16(INK4a) correlates to human papillomavirus presence, response to radiotherapy and clinical outcome in tonsillar carcinoma.

Abstract

BACKGROUND: Human papillomavirus (HPV) in tonsillar carcinoma is correlated with favourable clinical outcome. Here, p16(INK4A), in situ HPV DNA hybridisation (ISH) and HPVL1 capsid detection were evaluated in tonsillar carcinoma to predict the response to radiotherapy (RT) and prognosis. MATERIALS AND METHODS: Fifty-one pre-treatment paraffin-embedded tonsillar cancer biopsies were analysed. Immunohistochemistry (IHC) was used for p16(INK4A) and HPVL1 capsid analysis and PCR and ISH for HPV detection. RESULTS: High-risk HPV DNA was detected by PCR in 49% of the tumours. P16(INK4a) staining was correlated to HPV In the high-grade p16(INK4a) staining group, 94% had a complete RT response. High p16(INK4a) staining as well as the HPV PCR-positive cases had a favourable prognosis. HPV DNA ISH and L1 IHC could not predict RT response or clinical outcome. CONCLUSION: P16(INK4a) overexpression was correlated to HPV in tonsillar carcinoma and is useful for predicting RT response and prognosis in tonsillar carcinoma patients.