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National Cancer Institute U.S. National Institutes of Health www.cancer.gov
Viral Epidemiology Branch

Research into Lung Cancer

Bacterial Infections and Inflammation

Six case-control studies have reported a significant but modest association between lung cancer and infection with C. pneumoniae. A causal relationship is plausible, because C. pneumonia can cause chronic lung infection and inflammation, which might increase cancer risk. In FY2007, IIB approved, nested case-control study within the NCI's PLCO cancer screening trial will evaluate whether serologic evidence of chronic C. pneumonia infection is associated with an increased risk of lung cancer. Markers of lung inflammation and an extensive panel of polymorphisms in genes related to innate immunity will also be evaluated. These polymorphism analyses will complement a nearly completed IIB-led analysis of candidate susceptibility genes in a lung cancer case-control study.

Using extant data from PLCO, SEER Medicare, and a cohort study in China, IIB is mentoring an epidemiology PhD dissertation on three closely related analyses of the relationship of lung cancer to tuberculosis, pneumonia and radiographic evidence of pulmonary scarring. These are expected to be completed in FY07.

Novel Cancer-Associated Infections

Jaagsiekte sheep retrovirus (JSRV) causes ovine pulmonary adenocarcinoma, a lethal neoplasm that is histologically indistinguishable from human bronchioalveolar carcinoma (BAC). In FY2006, IIB organized and leads a collaboration with the laboratory that reported detection of JSRV CA antigen in some 30% of human BAC and adenocarcinoma tumor tissues, as well as with an independent academic laboratory. A masked immunohistochemistry study to assess reproducibility of JSRV CA detection in BAC, adenocarcinomas and squamous cell carcinomas will be completed in FY2007. In FY2006, the Branch also supported development of reagents suitable to facilitate the immunohistochemistry analysis and ultimately for serologic studies. During and beyond FY2007, effort to detect JSRV in human tissues or anti-JSRV in human sera will be expended only if JSRV is reproducibly detected in the lung cancer tissues.

In FY2007, IIB plans to conduct a pilot study, using prediagnostic sera from cases and controls in the ATBC cohort study. This would estimate the risk of lung cancer associated with antibodies against pertussis and against a panel of mycobacterial antigens, as well as with inflammation markers and antibodies against C. pneumoniae.