Prostate cancer screening by prostate-specific antigen (PSA); a relevant approach for the small population of the Cayman Islands

Evaluation of a multigenomic liquid biopsy (PROSTest) for prostate cancer detection and follow-up in a Caribbean population

INTRODUCTION

The PROSTest is a novel machine learning-based liquid biopsy assay that functions as a diagnostic and prognostic tool in prostate cancer (PCa). The algorithm outcome (scored 0-100) has a cutoff of >50 to indicate PCa. In this study, we evaluated the screening utility of the test in comparison with the commonly used PSA test.

MATERIALS AND METHODS

509 men (median age: 62 [40-88]), predominantly Afro-Caribbean (n=449, 88.2 %) were enrolled in this study at a referral centre for prostatic cancer screening and management. These included 417 symptomatic patients with urinary tract (UT) problems, of which 12 were diagnosed with PCa, 53 with benign prostatic hyperplasia (BPH) and 352 were free from prostatic diseases, prior to PROSTest (Cohort 1). The remaining 92 of the 509, with relatively young age (median 49 and range 40-75 years) were screened with the PROSTest first and included 28 with UT symptoms and 64 asymptomatic but with a family history of cancer (Cohort 2). PROSTest and PSA was performed on all subjects.

RESULTS

In Cohort 1, the PROSTest was positive in 11 (91.7 %) PCa, 9 (17.0 %) of BPH, and 29 (8.2 %) of subject with UT symptoms but no disease. In Cohort 2, PROSTest was positive in 4 of 28 (14.3 %) symptomatic patients and in 5 of 64 (7.8 %) asymptomatic subjects. A total of 111 individuals (from both cohorts) were identified as "at risk" (PSA >4 ng/mL). Sixteen of 111 (14.4 %) were PROSTest-positive. Thirty-nine percent (43/111) have completed a 1-year follow-up. Of the 43 with elevated PSA, 2 out of 2 (100 %) who were also PROSTest-positive, were diagnosed with PCa.

CONCLUSION

PROSTest is a more sensitive and specific biomarker than PSA in the diagnosis and, potentially, screening for PCa. The seemingly false positive PROSTest results in BPH or symptomatic UT require a longer follow-up of these patients.

Qi Ling Inhibits Progression of Androgen-Independent Prostate Cancer via Negative Regulation of TRIM66/HP1γ/AR Axis

AIM

This study aimed to understand the molecular mechanism underlying the therapeutic effect of Qi Ling (QL) against androgen-independent prostate cancer.

METHODS

The relative expression of TRIM66 in prostate tumor was interrogated by microarray. Real-time polymerase chain reaction and Western blotting were performed to determine the transcript abundances and protein expressions of TRIM66, HP1γ, AR, c-Myc, and GAPDH. Cell proliferation and apoptosis were analyzed by cell counting kit-8 method and flow cytometry. The regulatory action of c-Myc on TRIM66 was interrogated with luciferase reporter plasmid and the direct binding was demonstrated by chromatin immunoprecipitation. The secretory prostate-specific antigen was quantified by enzyme-linked immunosorbent assay.

RESULTS

TRIM66 was aberrantly overexpressed in prostate cancer and associated with unfavorable prognosis. TRIM66/HP1γ/AR was upregulated during the androgen-independent transition in hormone-deprived medium. The TRIM66 level positively linked to cell proliferation and negatively linked to cell apoptosis in androgen-independent prostate cancer cells. QL treatment specifically inhibited c-Myc and therefore directly downregulated TRIM66 via binding to its promoter. Ectopic introduction of TRIM66 significantly reversed the anti-tumor effects of QL against androgen-independent prostate cancer.

CONCLUSION

Our study uncovered the importance of downregulated TRIM66/HP1γ/AR signaling in mediating the anti-tumor properties of QL.