Human papillomavirus (HPV) is an important factor for the development of tonsillar squamous cell carcinoma (TSCC). In addition, patients with HPV-positive TSCC have a better clinical outcome than patients with HPV-negative TSCC. Although, HPV is an important prognostic marker, additional biomarkers are needed to better predict clinical outcome to individualize treatment. Hence, we examined if classical HLA HLA-A,B,C and nonclassical HLA-E,G could serve as such marker. Formalin-fixed paraffin-embedded TSCC from 150 patients diagnosed 2000-2006, earlier analyzed for HPV DNA and p16(INK4a), and treated with intention to cure were evaluated for the expression of HLA-A,B,C and HLA-E,G by immunohistochemistry. For HPV-positive TSCC a low expression of HLA-A,B,C, whereas for HPV-negative TSCC, a normal expression of HLA-A,B,C was significantly correlated to a favorable clinical outcome. These correlations were more pronounced for membrane staining of HLA-A,B,C when compared with cytoplasmatic staining. No significant correlation was found between HLA-E,G and HPV status or clinical outcome. The unexpected contrasting correlation between HLA-A,B,C expression, and clinical outcome depending on HPV, indicates essential differences between HPV-positive and HPV-negative TSCC. Furthermore, our data demonstrate that for both HPV-positive and HPV-negative TSCC, the expression of HLA-A,B,C together with HPV may serve as a useful biomarker for predicting clinical outcome.
Copyright © 2012 UICC.