耳鼻咽喉科: オープンアクセス

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Worldwide Prevalence of Human Papillomavirus in Tonsillar Squamous Cell Carcinoma and Tumor-Free Tonsillar Tissue

Maria Rusan*,Therese Ovesen

Human Papillomavirus (HPV) is the etiological agent in cervical cancer and a significant proportion of anogenital cancers. It appears to also be associated with a subset of head and neck cancers, in particular tonsillar squamous cell carcinoma (TSCC). The overall prevalence of HPV and the type-specific prevalence at the cervical level vary geographically. It is unclear whether this is also the case in tonsillar infection with HPV and in HPV-associated TSCC. This review provides an overview of the current literature with regards to the prevalence and types of HPV found in TSCC, and in tumor-free tonsillar tissue, globally. The HPV prevalence in TSCC is highly variable from region to region, ranging from 0 to 100%. The majority of studies from Europe, however, report an HPV prevalence of 40-60%. A similar prevalence of 35-65% is reported in North America. The only study from Australia reports a comparable prevalence of 46%. In contrast, the prevalence in China and Taiwan is between 0 and 13%. No data is available from Latin America, Africa, Eastern Europe, and other parts of Asia. The predominant type identified is HPV 16, with the majority of studies detecting HPV 16 in over 80% of HPV-positive samples. HPV 33 is the second most frequent type. Other high-risk and low-risk types are only rarely isolated. Co-infections with multiple types are also rare. Several Western European countries, USA and Australia, have reported an increase in the incidence of TSCC cases. There is evidence that this is attributable to an increase in HPV- associated TSCC cases. In tumor-free tissue the overall HPV prevalence ranges between 0 and 9%, and the most frequent type identified is HPV 16. HPV 11 has also occasionally been isolated. The interpretation of these results is complicated by the small sample size of many studies and by heterogeneous methodology.