Abstract B81: Human papillomavirus-16 (HPV-16) detected in squamous cell lung cancer.

Abstract

Abstract B81 Background Human papillomavirus (HPV) is an epitheliotrophic double stranded DNA virus that has been found in lung cancer at variable frequencies around the world. The role of HPV in the etiology of this neoplasia and a specific association with histological type remain controversial. We previously reported HPV was associated with squamous cell lung carcinomas from Chile and HPV-16 was integrated into the host genome with low viral load. Material and Methods In order to study HPV presence and role in other countries, 60 lung carcinomas from Asia (China, Pakistan and Papua New Guinea) were analyzed using polymerase chain reaction (PCR). HPV-16 integration status and viral load was determined using real-time PCR and HPV-16 E6 protein expression was analyzed using immunohistochemistry. In order to determine the role of HPV-16 variants, L1 and E6 regions were sequenced in squamous lung carcinomas and cervical carcinomas from Chile. Results We detected high-risk HPV-16 in 8/60 (13%) specimens. According to histological type, HPV-16 was detected in 8/18 (44%) squamous cell carcinomas, 0/38 (0%) adenocarcinomas and in 0/4 (0%) small cell carcinomas and this difference was statistically significant (p<0.001). HPV-16 viral load was ranged between 411 to 2345 copies/100 ng of genomic DNA. We found that in 63% of positive samples, the HPV-16 genome was fully integrated into the host genome. HPV-16 E6 oncoprotein expression was detected in 1/8 (12.5%) HPV-16 positive cases. In addition, HPV-16 Asian-American (AA) variant with higher oncogenic potential was predominant in squamous cell carcinomas from Chile compared with European (E) variant that was predominant in cervical carcinomas. Conclusion Taken together, these findings suggest that HPV infection might be associated with a subset of squamous cell lung carcinomas and suggest a differential tropism of HPV-16 variants in bronchial and cervical epithelia. More studies about etiological role of HPV and the specific role of HPV-16 AA variant in squamous cell lung carcinomas development are warranted. This work was financed by Grants-in-Aid for Scientific Research on Priority Areas (12218231 and 17015037) of the Ministry of Education, Culture, Sports, Science and Technology, Japan. Citation Information: Cancer Prev Res 2008;1(7 Suppl):B81.