Investigation of biomarkers in bioarchive prostate cancer samples collected from a historically underserved patient population
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Abstract
Prostate cancer is the second most frequent cancer diagnosis and one of the leading causes of cancer death for American men. In the US, Black men have higher rates of prostate cancer with worse outcomes. We seek to investigate known biomarkers of prostate cancer in the diverse population at our urban safety net hospital and to establish any link between location of cancer occurrence and the differential prognosis between two cohorts, Black men and non-Black men. A variety of archival specimens for the Black cohort were selected with varying Gleason scores and patient ages; specimens for the non-Black cohort specimens were then matched based on age. Clinical slides were reviewed by a pathologist and marked for cancerous and benign regions. Tissue microarrays (TMAs) were made from the corresponding formalin-fixed paraffin-embedded (FFPE) blocks. Each TMA included 30 cases, 15 from each cohort, from the same approximate time period, but varied in patient age and Gleason score of the subjects. The TMAs were sectioned and stained, both manually and with an auto-stainer, with H&E, PTEN and ERG. Pathologists reviewed the slides. We pulled demographic and prognostic data from a total of 607 and found that the Black cohort had a higher percentage of men under the age of 55. For the TMAs we reviewed a total of 302 specimens. No association was found between PTEN staining and cohort. Significant association (p= < 6.7e-5) was found between ERG staining and cohort. No association was found between age group and location of tumor. Significant association (p =0.005) was found between descent and location of the tumor. Of the 302 patients, 14 were positive for both PTEN and ERG staining. Our results demonstrate no correlation between PTEN staining and cohort or age group and location of tumor; however, there is significant association between ERG staining and cohort and cohort and location of the tumor. As seen in previous studies there were more younger men in the Black cohort. In the future we hope to further validate our results by using fresh tissue along with archival specimens from the last 6 years. Next steps are to investigate additional markers on the TMAs made and determine if there is correlation between the findings in metadata for known and developing biomarkers of prostate cancer. Should correlations occur between biomarkers, zone, and biochemical recurrence, this could be used to guide treatment options.