Presentation Authors: Michael Liss*, Eric Stutz, Teresa Johnson-Pais, Ian Thompson, Robin Leach, San Antonio, TX
Introduction: Some Hispanic populations may have increased risk in BRCA mutations which would indicate an increased prostate cancer risk. We utilized the SABOR study, a large 18-year San Antonio community-based screening program to investigate the risk of prostate cancer in Hispanic men with a first degree relative with prostate cancer and additional risk of breast cancer family history.
Methods: SABOR has a total of 4,174 men enrolled of which 398 men were Hispanic with a history of prostate cancer. We further identified a total of 278 Hispanic men with a first-degree relative diagnosed with prostate cancer. Once the group was identified we attempted to update their family history records with a questionnaire. The questionnaire also included race, ethnicity, mortality, and any cancer the study subject may have encountered. Information about relatives included cancer type, age at diagnosis if the family member passed away from cancer, and the age at which he or she passed away. We isolated DNA from stored serum samples and sent for genetic testing using the Color platform. The test is designed to assess clinically relevant mutations in 30 genes associated with hereditary cancer risk. Next Generation Sequencing libraries compatible with the Illumina platform are generated and enriched for the 30 genes via a custom designed Agilent SureSelect bait library. DNA fragments enriched from these genes are retrieved and analyzed using 2x150 paired-end sequencing with an Illumina NextSeq 500 instrument. After alignment to reference genome, low quality and duplicate reads are removed and variants are detected with GATK Haplotypecaller
Results: Of the 278 participants which met selection criteria 28 had expired, 29 had been lost to follow-up, and 36 had withdrawn from the study. Participants were contacted and tracked via an excel spreadsheet to update our long-term data. The overall prostate cancer rate in our cohort was 14.4%. Men with a first degree relative with prostate cancer had an 11.7% (n=26/222). We identified 38 men who also had a first degree relative with breast cancer had a 36.8% (14/36) risk of cancer (p < 0.001). We identified 12 BRCA mutations out of 253 evaluable participants (4.7%), of which 41% (5/12) had both first-degree relatives with prostate and breast cancer. Additional mutations included MSH6 (n=15, 5.8%), ATM (n=9 3.5%) and APC (n=8, 3.1%).
Conclusions: Hispanic men with both a family history of prostate cancer and breast cancer are at a significant risk of future development of prostate cancer. These patients also have a higher risk of BRCA mutations and are good candidates for genetic testing.
Source of Funding: Color Foundation