Abstract LB-181: CD133 as a disparity stem cell biomarker in African Americans with late-stage prostate cancer
Authors: Adu-Addai Benjamin , Salam Ahmad B. , Amin Ruksana , Wang Honghe , Lin Huixian , Ghebremedhin Anghesom , White Jason , Jaynes Jesse M. , Yates Clayton 
Published: August 2019

Background: Prostate cancer (PCa) is higher among African American (AA) than Caucasian Americans (CA). AAs are more frequently diagnosed with PCa with worse prognoses than CAs. Support of a genetic component to the high incidence and mortality rate in AA men is based on epidemiologic studies of men with similar genetic backgrounds. For instance, men in Ghana and Nigeria also have a high incidence of prostate cancer, as do men of African descent in the Caribbean islands and in the United Kingdom. Multiple reports indicate that PCa aggressiveness is the result of cancer stem cells (CSC). Furthermore, people of African Ancestry have been reported to have increased stemness gene signature in multiple tumor types. CD133, which is a well-known progenitor/stem cells marker, and is associated with prostate tumor relapse and metastasize due to the existence of prostate cancer stem cells (PCaCSC) has been well characterized, however, its role in prostate cancer racial disparity is unknown. Therefore, our objective is to analyze the significance of CD133 as a disparity stem cell biomarker in AA and CA patients with late-stage PCa.

Methods: TGCA Prostate Dataset was used for patient data. The R and R studio statistical software was used for the analysis, and for the survival analysis, Log-Rank test was used to determine survival. H & E was used to determine the presence of prostate cancer and tumors were scored using Gleason grading. CD133 protein location and expression was determined by IHC, and quantified using Aperio imaging software.

Results: We analyzed genomic data in TGCA for correlation between CD133 over-expression and worst patient survival outcome. Survival analysis indicated a poorer survival outcome in the AA with high CD133 expression during late-stage PCa compare to the CA with the same stage of PCa. Furthermore, the addition of CD44 furthermore increased the significant difference between the stem cell population (p= 0.04) between AA and CA patients. To confirm these results, we evaluated CD133 expression in (Gleason =7) PCa tumor from AA and CA patients and compared them to BPH. As in the TCGA data, we observed increased CD133 expression in AA patients.

Conclusion: Elevated CD133 shows an association with patients with African Ancestry. Further studies are necessary on a larger series of cases to elucidate the role of CD133 in the development and progression of prostate cancer and its suitability as a prognostic biomarker.

Citation Format: Benjamin Adu-Addai, Ahmad B. Salam, Ruksana Amin, Honghe Wang, Huixian Lin, Anghesom Ghebremedhin, Jason White, Jesse M. Jaynes, Clayton Yates. CD133 as a disparity stem cell biomarker in African Americans with late-stage prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-181.