Incidence of human papilloma virus in lung cancer.

HPV has been identified not only in gynaecological carcinomas but also in tumors of other organs, especially of the oropharynx and upper aero-digestive tract. In this study we focused on the available literature on HPV in lung carcinomas. In total, 53 publications reporting on 4508 cases were reviewed and assessed for the following parameters: continent and region of the study, number of cases, detection method, material type, HPV type, histological subtype and number of the HPV-positive cases. Overall, the mean incidence of HPV in lung cancer was 24.5%. While in Europe and the America the average reported frequencies were 17% and 15%, respectively, the mean number of HPV in asian lung cancer samples was 35.7%. There was a considerable heterogeneity between certain countries and regions. Particular high frequencies of up to 80% were seen in Okinawa (Japan) and Taichung (Taiwan). However, there were also discrepant results within the same region pointing to methodological differences and the need for validation. All lung cancer subtypes were affected and especially the high risk types 16, 18, 31 and 33 as well as the low risk types 6 and 11 were found, the later mainly in association with squamous cell carcinomas. The data suggest that HPV is the second most important cause of lung cancer after cigarette smoking and strongly argues for additional research on this issue.