Oncogenic human papillomavirus (HPV) is a causative agent in a subgroup of head and neck carcinomas, particularly tonsillar squamous cell carcinomas (TSCC). This study was undertaken because controversial data exist on the physical status of HPV-DNA and the use of p16INK4A overexpression as surrogate HPV marker, and to examine the impact of HPV and tobacco consumption on the clinical course of TSCC. Tissue sections of 81 TSCC were analyzed by HPV 16-specific fluorescence in situ hybridization (FISH) Head and neck squamous cell carcinomas (HNSCC) account for 4% of all malignancies in the Western world, for up to 50% of all malignancies in Southeast Asian countries and for 6.5% of all annual cancer cases worldwide.1 HNSCC is associated with severe disease-and treatment-related morbidity and because treatment has not improved greatly in recent years, the 5-year survival rate remains 50%. HNSCC develop in various anatomical defined regions, including the oral cavity, larynx and pharynx. These organ-specific tumors each show specific clinical presentations and outcome, and are treated by different strategies. 2,3 The median age at presentation is 60 years and approximately two-third of patients are male. Well-known risk factors in the etiology of HNSCC are cigarette smoking combined with alcohol consumption in Western countries, or with betel quid chewing in Asia. A history of tobacco use is present in 90% of patients who develop oral cavity cancers. 2,3Despite these evident associations, the exact mechanisms by which these factors cause tumor initiation and progression are not fully understood. Furthermore, the fact that most tobacco and alcohol users do not develop HNSCC and that in recent years more often individuals without a history of these traditional risk factors have been witnessed, 4 underlines the complexity of HNSCC pathogenesis and a role for additional factors in the disease process.Increasing evidence suggests that human oncogenic papillomaviruses (HPVs), known to cause uterine cervical and other anogenital cancers, may also be of importance in the pathogenesis of HNSCC. 5 The strongest association has been found for oropharyngeal carcinomas, especially tonsillar carcinomas.6-11 Sero-positive patients for HPV 16 or with a history of HPV-related anogenital cancer also show increased risk rates of developing oropharyngeal cancer.12,13 The prevalence of HPV-exhibiting HNSCC, however, varies broadly amongst several studies (2-76%) due to differences in the population, combination of histological subsites, type and number of specimens analyzed, and detection methods used. 7,14 Thus, besides determining the presence of HPV DNA it has been suggested to better define the biological association of oncogenic HPV with these tumors, e.g., by means of assessing the viral copy number per cell, the viral oncoprotein E6/E7 expression levels, perturbation of pRb-dependent cell cycle control, or the physical status of the virus (episomal or integrated). 15 In this way, several reports have shown that HPV 16 is predomi...

Head and neck squamous cell carcinomas (HNSCC) account for 6.5% of annual cancer cases worldwide. During the last decades, the incidence of HNSCC has increased in Western Europe. For example, the incidence of cancer of the mouth and pharynx increased from 26.8 to 33.8 per 100,000 from 1985 to 1990. 1,2 Recent data suggest that this increase in incidence is especially high in patients younger than 40 years of age. 3,4 Median age at presentation of HNSCC is 60 years, and 66.7% of the patients are men.Tobacco smoking, alcohol drinking and betel quid chewing are well-known risk factors in the etiology of HNSCC, responsible for 90% of the cases. 5,6 The age at smoking initiation appears to be inversely associated with a higher relative risk of developing a carcinoma. 5,7 Tobacco and alcohol use are independent risk factors, but when combined a synergistic effect is observed. 5 In addition, epidemiologic and molecular data suggest that human oncogenic papillomaviruses (HPVs), known to cause cervical and other anogenital cancers, may also promote head and neck carcinogenesis. 8 -10 Discrepancy exists with respect to the percentage of HNSCC harboring HPV, as the reported frequencies in head and neck lesions vary over a wide range (2-76%). 8,11 These differences may be due to the detection method used (Southern blot hybridization, polymerase chain reaction (PCR) or in situ hybridization), the anatomic location of tumors, the type of HPV detected and/or the number of tissue samples analyzed in the various studies. 8,11 Most studies have so far concentrated on the role of HPV in the etiology of uterine cervical cancer. 12 Particularly the high-risk oncogenic HPVs, such as HPV type 16 and 18, induce preneoplastic lesions with an increased risk of progression to cancer. The transition from dysplasia to invasive cancer appears to be associated with integration of the viral DNA into the host genome, most probably at fragile sites in chromosomes. [13][14][15] Molecular studies have shown that HPV integration results in upregulation of the viral oncoproteins E6 and E7. 8,12 The E6 protein contains zincbinding motifs and can complex with the host cell p53, thereby inducing p53 degradation through the ubiquitin-mediated pathway and thus preventing a cell cycle block and induction of apoptosis in DNA-damaged cells. The E7 protein forms complexes with hypophosphorylated forms of the retinoblastoma tumor suppressor protein (pRb), resulting in a decrease of the cellular pRb level and a release of E2F, a transcription factor involved in cell cycle progression. 16,17 Since HPV inactivates both p53 and pRb, it is expected that inactivating mutations in these genes do not play an important role in HPV-infected HNSCC. This is not only the case in cervical cancers 10,12 but also in half of the HNSCC. 6 Some studies on HNSCC, however, have reported the concomitant presence of HPV DNA and p53 overexpression and/or mutation. 9,18 -21 This gives rise to the question as to whether HPV is causally related to the development of a subgroup of HN...

Human papillomavirus is involved in the carcinogenesis of tonsillar squamous cell carcinomas. Here, we investigated the expression and the prognostic value of key cell cycle proteins in the pRb and p53 pathways in both human papillomavirus type 16-positive and -negative tonsillar squamous cell carcinomas. Using immunohistochemistry, 77 tonsillar squamous cell carcinomas with known human papillomavirus type 16 status and clinical outcome were analyzed for expression of Ki67, p16 INK4A, cyclin D1, pRb, p14 ARF , MDM2, p53, p21 Cip1/WAF1 , and p27 KIP1 . Results were correlated with each other and with clinical and demographic patient data. A total of 35% of tonsillar carcinomas harbored integrated human papillomavirus type 16 DNA and p16 INK4A overexpression, both being considered essential features for human papillomavirus association. These tumors also showed the overexpression of p14 ARF (Po0.0001) and p21 Cip1/WAF1 (P ¼ 0.001), and downregulation of pRb (Po0.0001) and cyclin D1 (P ¼ 0.027) compared with the human papillomavirus-negative cases. Univariate Cox regression analyses revealed a favorable survival rate for non-smokers (P ¼ 0.006), as well as for patients with T1-2 tumors (Po0.0001) or tumors showing low expression of cyclin D1 (P ¼ 0.028), presence of human papillomavirus and overexpression of p16 INK4A (P ¼ 0.01), p14 ARF (P ¼ 0.02) or p21 Cip1/WAF1 (P ¼ 0.004). In multivariate regression analyses, smoking and tumor size, as well as expression of cyclin D1 and p21 Cip1/WAF1 , were found to be independent prognostic markers. We conclude that human papillomavirus positivity in tonsillar squamous cell carcinomas strongly correlates with p21 Cip1/WAF1 and p14 ARF overexpression and downregulation of pRb and cyclin D1. In particular p21 Cip1/WAF1 overexpression is an excellent favorable prognosticator in tonsillar squamous cell carcinomas. Modern Pathology ( Head-and-neck squamous cell carcinoma is the sixth most prevalent malignancy in the world, contributing 6% of new cancer cases annually worldwide. 1,2 These tumors have a 5-year survival rate of approximately 50%, which has not improved in the last two decades. 3 Well-recognized risk factors in the etiology of head-and-neck squamous cell carcinomas are extensive tobacco and alcohol consumption in B90% of cases, as well as oncogenic human papillomaviruses (HPVs), predominantly HPV type 16. 3,4 Interestingly, the association of HPV is strongest for tonsillar squamous cell carcinoma with a prevalence up to 50%. [5][6][7][8]

Taken together, these data support the view that HPV-harbouring HNSCC can be considered a discrete tumour entity with, moreover, a favourable prognosis. Screening of patients, especially those with tonsillar cancers, for the presence of HPV may help to further optimize treatment protocols and to provide more accurate prognostic information.