Abstract C40: A biopsy-focused approach to molecular studies of prostate cancer in African Americans: the Birmingham Alabama Prostate Cancer Consortium (BAPrCa)

Abstract

Cancer health disparities can arise from research studies in which the study subjects are not representative of the populations affected by the disease. In prostate cancer (PrCa) biorepositories, most of the frozen samples collected for molecular analyses are obtained from radical prostatectomy (RP) specimens. However, tissue collections based on RP specimens do not include patients who are diagnosed with relatively advanced disease and treated with first-line hormonal and/or radiation therapy rather than surgery; African Americans (AA) are more likely than European Americans (EA) to be diagnosed with this type of advanced prostate cancer. With support from the DOD Prostate Cancer Research Program, our research team has established the Birmingham Alabama Prostate Cancer Consortium (BAPrCa) with a major focus on studies that use prostate biopsies for the molecular analysis of PrCa in AAs. To ensure that there is no compromise of biopsy diagnosis, we use innovative tissue print technologies to obtain snap frozen nitrocellulose blots from each of the prostate biopsy cores. These biopsy tissue prints provide high quality RNA and DNA for molecular and genetic studies. Our biopsy-based analysis of high risk cancers has revealed PrCa subtypes that were either unrecognized or significantly underestimated in previous prostatectomy-based studies.

As of June 2016 more than 250 prostate biopsy patients have been prospectively enrolled in the BAPrCa prostate biopsy tissue print study; just under half (48%) of these study subjects self-identify as AA. Each biopsy from each study subject was tissue printed to generate more than 3000 unique pairs of high quality RNA and DNA samples. AA men were enrolled from two study sites in Birmingham Alabama, an academic medical center (University of Alabama at Birmingham, UAB) and a large urology private practice (Urology Centers of Alabama, UCA). The prevalence of prostate cancer diagnosed in our AA study subjects undergoing standard biopsies was 51%, with 30% showing cancer of Gleason 7 or more. A higher proportion of AA subjects were diagnosed with PrCa at UAB (61% cancer positive; 45% with Gleason 7 or more) compared to UCA (44% cancer positive; 20% with Gleason 7 or more). The difference between AA cancer diagnoses observed between our two study sites may in part result from differences in the criteria for biopsy; pre-biopsy PSA was less than 4 ng/ml for 25% of UCA subjects but for only 2% of UAB subjects.

PSA criteria for prostate biopsy may have a significant and unrecognized impact on the detection of prostate cancer in contemporary AA populations. The BAPrCa study cohort provides a unique opportunity to evaluate the PrCa subtypes diagnosed in AAs using different PSA criteria for biopsy, especially in a deep south AA population.

Citation Format: Sandra M. Gaston, Dennis Otali, James Kearns, Kerry Dehimer, George W. Adams, Soroush Rais-Bahrami, Jeffrey Nix, James E. Bryant, Peter Kolettis, William E. Grizzle. A biopsy-focused approach to molecular studies of prostate cancer in African Americans: the Birmingham Alabama Prostate Cancer Consortium (BAPrCa). [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr C40.