Abstract 520: MYB exhibits racially disparate overexpression and clinicopathologic association in prostate cancer: significance as a predictor of biochemical recurrence

Abstract

Abstract Prostate cancer (PCa) is the most diagnosed non-cutaneous malignancy and the second leading cause of cancer-related death in American men. Significant racial disparities also exist in incidence and clinical outcome. African American (AA) men are nearly two times more likely to be diagnosed with PCa and have more than twice mortality rate than their Caucasian American (CA) counterparts. Despite an early diagnosis in majority of the cases, about one-third patients face biochemical recurrence following local therapy, with a likelihood of developing distant metastasis. Gleason score used as a prognosticator exhibits discrepancy between AA and CA men highlighting the need for better predictive markers. We previously demonstrated functional significance of MYB in PCa growth, aggressiveness, and castration-resistance. We also showed a role of MYB in sustained androgen receptor (AR) signaling under androgen-deprived condition and prostate-specific antigen (PSA) expression. Here, we studied the expression of MYB in PCa by immunohistochemistry and examined if it varied between AA and CA PCa cases and had any clinicopathological correlation. A total of 105 PCa [CA (n=50) and AA (n=55)] cases with available clinicopathologic data were included. MYB expression was also studied in adjacent benign prostatic hyperplasia (BPH) and high-grade prostate intraepithelial neoplastic (HGPIN) lesions. Stained slides were scanned and digitally analyzed for the measurement of percent positivity (0-100%) and staining intensity (1+, 2+ and 3+). Significant overexpression of MYB (p<0.0001) was reported in PCa relative to HGPIN and BPH. PCa predominantly exhibited moderate to strong staining, compared to weak to moderate staining with low precent positivity rate in HGPIN and weak MYB staining with low percent positivity in BPH. A significantly higher expression of MYB (p<0.0001) was noted in high Gleason score (8-9) PCa, compared to the low-medium Gleason score (≤7) PCa. Interestingly, MYB expression was significantly (p= 0.024) higher in AA PCa than CA PCa in overall and Gleason score wise comparisons. Correlation analysis of MYB showed its inverse association with time to BCR (r =-0.467, 95% CI=-0.675 to -0.190, p=0.002). Altogether, our findings establish MYB as a potentially useful biomarker for PCa diagnosis and prognosis and provide clinical support to our prior findings on the pathobiological role of MYB in PCa. Citation Format: Mohammad Aslam Khan, Srijan Acharya, Shashi Anand, Fnu Sameeta, James E. Carter, Oliver J. Semmes, Dean A. Troyer, Seema Singh, Santanu Dasgupta, Ajay P. Singh. MYB exhibits racially disparate overexpression and clinicopathologic association in prostate cancer: significance as a predictor of biochemical recurrence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 520.