Prostate cancer is the most common type of noncutaneous cancer diagnosed in men in the United States and the second leading cause of cancer-related death. African American (AA) men are more likely to be diagnosed with and are more than twice as likely to die from prostate cancer compared to white men. The reasons for this difference are complex. While socio-economic factors and access to care may have some influence, they cannot fully explain this disparity. There is evidence of genetic factors as well as environmental, diet, and lifestyle factors being important contributors to the higher rate of prostate cancer and prostate cancer deaths in AA men. Inflammation has emerged as a potential contributory factor in both the initiation and progression of prostate cancer. Furthermore, previous studies indicate that inflammation and the overexpression of genes involved in inflammatory pathways may be more prevalent in the prostates of AA men versus white men. We hypothesize that prostatic inflammation may contribute to the increase in prostate cancer mortality rates in AA men and that the stimulus for the overexpression of genes involved in inflammatory pathways may be infectious agents. Infections, including sexually transmitted infections (STIs), can cause inflammation and, indeed, our previous studies have detected the presence of microorganisms in prostate tissue. Past infection with an STI as well as increased numbers of sexual partners are both associated with an increased risk of prostate cancer. With the advent of “metagenomic” sequencing technologies (i.e., the determination of all microbial species present in a sample using next-generation sequencing), we are now able to fully determine the variety of microbial species present in a prostate tissue sample. As an initial strategy, we are currently utilizing 16S ribosomal RNA (rRNA) sequencing to comprehensively evaluate the presence of bacterial rRNA in post-surgical prostatectomy tissue specimens from both AA and white men. The results of these analyses will be compared to presence, type, and extent of inflammation in the corresponding surgical tissue specimen and we will be developing strategies to localize microorganism(s) of interest in prostate tissues. The results of our studies stand to provide a wealth of information regarding the prostate tumor microenvironment in AA men and will begin to allow for a mechanistic understanding of the role of inflammation and infections in this prostate cancer racial disparity.
Citation Format: Corey M. Porter, Shu-Han Yu, Karen Sfanos. Metagenomic studies of bacterial agents in prostate cancer racial disparities. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr A71.
- ©2015 American Association for Cancer Research.