Presence of human papillomavirus (HPV) in variable proportions in tonsillar
squamous cell carcinoma tissues has been demonstrated by several worldwide studies. Some reports emphasized the significance of HPV in predicting a better prognosis, as well as ethnic differences between Chinese and Caucasians. In order to understand the
biological role of HPV and find out clinically accessible methods to determine its prognostic significance in primary tonsillar
squamous cell carcinoma, we collected 92 patients with primary tonsillar
squamous cell carcinoma diagnosed or treated in National Taiwan University Hospital, for whom archival
tumor tissue were available. Immunohistochemical stains of
p16(INK4A), high-risk HPV in situ hybridization, and nested polymerase chain reaction (PCR)-based genechips were performed to detect
HPV infection and determine its genotype. Clinical data were compared with
HPV infection detected by the different methods mentioned above. Real-time PCR was also performed on the HPV16-positive [HPV16(+)] lesions to understand viral integration status. The positive rates of nested PCR-based genechips, overexpression of
p16(INK4A), and high-risk HPV in situ hybridization were 75% (69/92), 53% (49/92), and 44% (40/92), respectively. Both overexpression of
P16(INK4A) and high-risk HPV in situ hybridization positivity were associated with favorable prognoses (P=0.004 and 0.001, respectively) and also independent prognostic factors in multivariate analyses (P=0.01 and 0.01, respectively). The positivity of nested PCR-based genechips was not statistically significant. From our data, primary tonsillar
squamous cell carcinoma with positive immunohistochemical stains of
p16(INK4A) and/or high-risk HPV in situ hybridization is associated with a better outcome, and both methods may serve as clinically accessible markers.