Recent analyses of head and neck squamous cell carcinomas revealed frequent infections by oncogenic human papillomavirus (HPV) type 16 in tonsillar carcinomas. Concerning involvement of risk factors, clinical course of the disease, and prognosis there are strong indications arguing that the HPV-positive tonsillar carcinomas may represent a separate tumor entity. Looking for a surrogate marker, which in further epidemiological studies could replace the laborious and expensive HPV detection and typing we analyzed p16 protein expression in 34 tonsillar carcinoma for correlation to HPV status and load of viral DNA. p16 has been shown to be of diagnostic value for clinical evaluation of cervical dysplasia. We found 53% of the tested tonsillar carcinomas to be HPV-positive. Fifty-six percent of all tumors tested were immunohistochemically positive for the p16 protein. In 16 of 18 of the HPV-positive carcinomas diffuse p16 expression was observed. In contrast, only one of the HPV-negative carcinomas showed focal p16 staining (P < 0.001). As determined by laser-assisted microdissection and quantitative real-time polymerase chain reaction, p16 expression correlated with the presence of HPV-DNA in the individual tumor specimens. Clinical outcome analysis revealed significant correlation of p16 expression with increased disease-free survival (P = 0.02). These data indicate that p16 is a technically simple immunohistological marker, applicable for routine pathological histology, and its prognostic value for survival is fully equivalent to HPV-DNA detection.

Our recent analysis of papillomavirus (HPV) DNA in different malignant head and neck tumors revealed that HPV infections occurred most frequently in tonsillar carcinomas (58%) and that 84% of positive cases contained the highly oncogenic HPV type 16. We could also present data in favor of the hypothesis that in view of their clinical behavior and the involved risk factors HPV-positive and HPV-negative tonsillar carcinomas may represent two separate tumor entities. Looking for a surrogate marker, which in further epidemiological studies could replace the laborious and expensive HPV detection/typing we analyzed p16 protein expression in 34 tonsillar carcinomas for their correlation with HPV status. p16 is an inhibitor of cyclin-dependent kinases 4 and 6 which activate the negative cell cycle regulator protein pRB which in turn downregulates p16 expression. It could be shown that in neoplastic cells of the cervix uteri E7 protein of the high-risk HPVs can interfere with this regulatory circuit by its virtue to inactivate pRB and thus lead to the overexpession of p16. We found 53% of the tested tonsillar carcinomas to be HPV positive. 56% of all tumors tested were immunohistochemically positive for the p16 protein. In 16 of 18 of the HPV-positive carcinomas diffuse p16 expression was observed. In contrast, only 1 of the HPV-negative carcinomas showed focal p16 staining (p < 0.001). Clinical outcome analysis revealed a significant correlation of p16 expression with increased disease-free survival (p = 0.02). These data indicate that p16 is a technically simple immunohistological marker, applicable for routine pathological histology, and its prognostic value for survival is fully equivalent to HPV DNA detection.

Introduction:The jaw can be affected by several lesions that manifest in the oral cavity, but little is known about their distribution patterns in various populations.Aims and Objectives:This study presents the frequency and distribution of biopsied jaw lesions recorded in Faculty of Dentistry and gathers the information including provisional and final diagnosis of the lesions.Material and Methods:Biopsy of 1938 lesions (2008–2013) was reviewed and 1473 lesions were included in this study. The provisional diagnosis and histopathological validations of lesions were compared. Data on the location of the lesion, as well as patient demographics, were also evaluated. The lesions were divided into three major groups as 1 - developmental/reactive and inflammatory lesions of the jaw, 2 - cystic lesion and 3 - tumor and tumor-like lesions.Statistical Analysis:The variables were recorded and analysed using descriptive statistics.Results and Observations:Three hundred and ninety-six lesions were in Group 1 and periapical granuloma was the most frequent diagnosis. Seven hundred and eighty-nine lesions were in Group 2 and the radicular cyst was the most frequent diagnosis. Two hundred and eighty-eight lesions were in Group 3 and the keratocystic odontogenic tumor was the most frequent. Two hundred and ninety-one biopsied lesions were in disagreement with respect to the diagnoses on clinical and histopathological examination.Conclusion:Consequently, a provisional diagnosis of some of the malignant lesions was reactive, inflammatory, cystic or benign lesions, therefore the importance of evaluation of the specimen is emphasized.

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