Up-regulation of POM121 is linked to prostate cancer aggressiveness and serves as a prognostic biomarker.

PURPOSE: Nucleoporins as components of the nuclear pore complex (NCP) are known for regulating nuclear-cytoplasmatic transport. Recently, the nucleoporin POM121 was found to have an important impact on intranuclear translocation of prostate cancer (PCa)-specific tumor drivers including the androgen receptor (AR). The aim of our study was to assess the potential of POM121 as a prognostic biomarker. METHODS: Therefore, we performed immunohistochemistry (IHC) for POM121 on a large clinically, well characterized PCa tissue cohort comprising benign prostatic samples, radical prostatectomy (RPE) samples, lymph node metastases, local recurrent tumors and distant metastases of 289 patients. Using a semi automated tissue image analysis software we evaluated POM121 protein expression level based on IHC. RESULTS: We could show that POM121 expression increases during tumor progression. Expression levels were significantly higher in primary tumors compared to benign samples (P = 0.001), and substantially higher in advanced tumors (P < 0.001) and in distant metastases (P = 0.006) compared to primary tumors. Furthermore, POM121 expression predicts biochemical recurrence free survival (BFS) after surgery independent of the WHO group and other clinicopathological markers. 5-years BFS with primary tumors lacking POM121 and expressing POM121 was 88.8% and 68.9%, respectively. CONCLUSION: Our study reveals the potential of POM121 as a potential biomarker for PCa, predicting BFS independent of other common clinicopathological parameters. Furthermore, POM121 might be a new targetable structure for patients suffering from advanced PCa.

Increased mediator complex subunit CDK19 expression associates with aggressive prostate cancer.

The Mediator complex is a transcriptional regulator interacting with transcription factors and RNA-polymerase-II. Recently, we identified its subunit CDK19 to be specifically expressed in prostate cancer (PCa) and to be functionally implicated in PCa aggressiveness. Aim of our study was to comprehensively characterize the protein expression of CDK19 and its paralog CDK8 in PCa. We performed immunohistochemistry (IHC) for CDK19/CDK8 on a large cohort including needle biopsies from 202 patients, 799 primary tumor foci of radical prostatectomy specimens from 415 patients, 120 locally advanced tumor foci obtained by palliative transurethral resection, 140 lymph node metastases, 67 distant metastases and 82 benigns. Primary tumors were stained for the proliferation marker Ki67, androgen receptor (AR) and ERG. For 376 patients, clinic-pathologic data were available. Primary endpoint was disease-recurrence-free survival (DFS). Nuclear CDK19 and CDK8 expression increases during progression showing the highest intensity in metastatic and castration-resistant tumors. High CDK19 expression on primary tumors correlates with DFS independently from Gleason grade and PSA. Five-year-DFS rates of patients with primary tumors expressing no, moderate and high CDK19 are 73.7, 56.9 and 30.4%, respectively. CDK19 correlates with Gleason grade, T-stage, Ki67 proliferation-index, nuclear AR expression and ERG-status. Therapeutic options for metastatic and castration-resistant PCa remain limited. In the current study, we confirmed an important role of the Mediator subunit CDK19 in advanced PCa supporting current developments to target CDK19 and its paralog CDK8. Furthermore, CDK19 protein expression has the potential to predict disease recurrence independently from established biomarkers thus contributing to individual management for PCa patients.

TRIM24 as an independent prognostic biomarker for prostate cancer.

INTRODUCTION: Simply applicable biomarkers for prostate cancer patients predicting the clinical course are urgently needed. Recently, TRIM24 has been identified to promote androgen receptor signaling and to correlate with an aggressive prostate cancer phenotype. Based on these data, we proofed TRIM24 as a prognostic biomarker for risk stratification. MATERIALS AND METHODS: We performed TRIM24 immunohistochemistry on 2 independent cohorts including a total of 806 primary tumors, 26 locally advanced/recurrent tumors, 30 lymph node metastases, 30 distant metastases, and 129 benign prostatic samples from 497 patients as well as on 246 prostate needle biopsies. Expression data were correlated with clinic-pathological data including biochemical recurrence-free survival (bRFS) as endpoint. RESULTS: Benign samples show no or low TRIM24 expression in 94%, while tumor tissues demonstrate significant higher levels. Strongest expression is observed in advanced and metastatic tumors. In multivariate analyses, TRIM24 up-regulation on radical prostatectomy specimens correlates with shorter bRFS independent of other prognostic parameters. 5-(10-) year bRFS rates for TRIM24 negative, low, medium and high expressing tumors are 93.1(93.1)%, 75.4(68.5)%, 54.9(47.5)% and 43.1(32.3)%, respectively. Of interest, tumors diagnosed as indolent disease, TRIM24 expression stratifies patients into specific risk groups. Increased TRIM24 expression associates with higher grade group, positive nodal status and extraprostatic tumor growth. TRIM24 assessment on prostate needle biopsies taken prior to treatment decision at time of initial diagnosis significantly correlates with recurrence after surgery. CONCLUSION: Using 2 large independent radical prostatectomy specimen cohorts, we found that TRIM24 expression predicts patients' risk to develop disease recurrence with high accuracy and independent from other established biomarkers. Further, this is the first study exploring TRIM24 expression on prostate needle biopsies which represents the clinically relevant tissue type on which biomarkers guide treatment decisions. Thus, we strongly suggest introducing TRIM24 evaluation in prostate needle biopsies in clinical routine as an inexpensive and simple immunohistochemical test.

Expression of Prostate-Specific Membrane Antigen (PSMA) on Biopsies Is an Independent Risk Stratifier of Prostate Cancer Patients at Time of Initial Diagnosis.

Background: Stratifying prostate cancer (PCa) patients into risk groups at time of initial diagnosis enabling a risk-adapted disease management is still a major clinical challenge. Existing studies evaluating the prognostic potential of PSMA (prostate-specific membrane antigen) for PCa were performed on radical prostatectomy specimens (RPE), i.e., decision making for disease management was already completed at time of sample analysis. Aim of our study was to assess the prognostic value of PSMA expression for PCa patients on biopsies at time of initial diagnosis. Methods: PSMA expression was assessed by immunohistochemistry on 294 prostate biopsies with corresponding RPE, 621 primary tumor foci from 242 RPE, 43 locally advanced or recurrent tumors, 34 lymph node metastases, 78 distant metastases and 52 benign prostatic samples. PSMA expression was correlated with clinico-pathologic features. Primary endpoint was recurrence free survival. Other clinicopathologic features included WHO/ISUP grade groups, PSA serum level, TNM-stage, and R-status. Chi-square test, ANOVA-analyses, Cox-regression, and log-rank tests were performed for statistical analyses. Results: High PSMA expression on both biopsy and RPE significantly associates with a higher risk of disease recurrence following curative surgery. The 5-year-recurrence free survival rates were 88.2, 74.2, 67.7 and 26.8% for patients exhibiting no, low, medium, or high PSMA expression on biopsy, respectively. High PSMA expression on biopsy was significant in multivariate analysis predicting a 4-fold increased risk of disease recurrence independently from established prognostic markers. PSMA significantly increases during PCa progression. Conclusion: PSMA is an independent prognostic marker on biopsies at time of initial diagnosis and can predict disease recurrence following curative therapy for PCa. Our study proposes the application of the routinely used IHC marker PSMA for outcome prediction and decision making in risk-adapted PCa management on biopsies at time of initial diagnosis.

Prognostic Value of the New Prostate Cancer International Society of Urological Pathology Grade Groups.

Gleason grading is the best independent predictor for prostate cancer (PCa) progression. Recently, a new PCa grading system has been introduced by the International Society of Urological Pathology (ISUP) and is recommended by the World Health Organization (WHO). Following studies observed more accurate and simplified grade stratification of the new system. Aim of this study was to compare the prognostic value of the new grade groups compared to the former Gleason Grading and to determine whether re-definition of Gleason Pattern 4 might reduce upgrading from prostate biopsy to radical prostatectomy (RP) specimen. A cohort of men undergoing RP from 2002 to 2015 at the Hospital of Goeppingen (Goeppingen, Germany) was used for this study. In total, 339 pre-operative prostatic biopsies and corresponding RP specimens, as well as additional 203 RP specimens were re-reviewed for Grade Groups according to the ISUP. Biochemical recurrence-free survival (BFS) after surgery was used as endpoint to analyze prognostic significance. Other clinicopathological data included TNM-stage and pre-operative PSA level. Kaplan-Meier analysis revealed risk stratification of patients based on both former Gleason Grading and ISUP Grade Groups, and was statistically significant using the log-rank test (p < 0.001). Both grading systems significantly correlated with TNM-stage and pre-operative PSA level (p < 0.001). Higher tumor grade in RP specimen compared to corresponding pre-operative biopsy was observed in 44 and 34.5% of cases considering former Gleason Grading and ISUP Grade Groups, respectively. Both, former Gleason Grading and ISUP Grade Groups predict survival when applied on tumors in prostatic biopsies as well as RP specimens. This is the first validation study on a large representative German community-based cohort to compare the former Gleason Grading with the recently introduced ISUP Grade Groups. Our data indicate that the ISUP Grade Groups do not improve predictive value of PCa grading and might be less sensitive in deciphering tumors with 3 + 4 and 4 + 3 pattern on RP specimen. However, the Grade Group system results less frequently in an upgrading from biopsy to the corresponding RP specimens, indicating a lower risk to miss potentially aggressive tumors not represented on biopsies.