Siebren Dijkstra

Clinical use of novel urine and blood based prostate cancer biomarkers: A review

In the era of upcoming techniques for molecular profiling, breakthroughs led to new discoveries in the field of prostate cancer (PCa) biomarkers. Since the early 1990s a tremendous increase in PCa incidence is seen, dedicated to the introduction of prostate specific antigen (PSA) testing. However, due to its lack of specificity many men undergo unnecessary biopsies, resulting in a rising incidence of clinically insignificant PCa. To overcome this drawback, cancer specific biomarkers are needed to identify patients who are at high risk of harbouring PCa and to distinguish patients with aggressive disease from patients with insignificant cancer. The most non-invasive, easy to obtain substrate for biomarker measurement is urine. The most promising markers to date are PCA3 and TMPRSS2-ERG. Both markers demonstrate to have a higher specificity and diagnostic accuracy for PCa outcome compared to serum PSA. This might better predict the presence of PCa and therefore reduce the number of unnecessary biopsies. Combining both markers in a panel might result in an even higher diagnostic accuracy, given the heterogeneity of the disease. In PCa management, circulating tumour cells (CTCs) detected in the blood seem a promising tool to predict treatment response and survival benefit. Although results appear to be encouraging, the biggest challenge about new markers in PCa is to validate them in large clinical trials and subsequently implement these markers into clinical practice. In this review we discuss the clinical usefulness of novel, non-invasive tests in PCa management.

Prostate Cancer Biomarker Profiles in Urinary Sediments and Exosomes

PURPOSE Urinary biomarker tests for diagnosing prostate cancer have gained considerable interest. Urine is a complex mixture that can be subfractionated. We evaluated 2 urinary fractions that contain nucleic acids, ie cell pellets and exosomes. The influence of digital rectal examination before urine collection was also studied and the prostate cancer specific biomarkers PCA3 and TMPRSS2-ERG were assayed. MATERIALS AND METHODS Urine samples were prospectively obtained before and after digital rectal examination from 30 men scheduled for prostate biopsy. Cell pellet and exosomes were isolated and used for biomarker analysis. Analytical and diagnostic performance was tested using the Student t-test and ROC curves. RESULTS Unlike the exosome fraction, urinary sediment gene expression analysis was compromised by amorphous precipitation in 10% of all specimens. Digital rectal examination resulted in increased mRNA levels in each fraction. This was particularly relevant for the exosomal fraction since after digital rectal examination the number of samples decreased in which cancer specific markers were below the analytical detection limit. Biomarker diagnostic performance was comparable to that in large clinical studies. In exosomes the biomarkers had to be normalized for prostate specific antigen mRNA while cell pellet absolute PCA3 levels had diagnostic value. CONCLUSIONS Exosomes have characteristics that enable them to serve as a stable substrate for biomarker analysis. Thus, digital rectal examination enhances the analytical performance of biomarker analysis in exosomes and cell pellets. The diagnostic performance of biomarkers in exosomes differs from that of cell pellets. Clinical usefulness must be prospectively assessed in larger clinical cohorts.

Detection of High-grade Prostate Cancer Using a Urinary Molecular Biomarker-Based Risk Score.

BACKGROUND To reduce overdiagnosis and overtreatment, a test is urgently needed to detect clinically significant prostate cancer (PCa). OBJECTIVE To develop a multimodal model, incorporating previously identified messenger RNA (mRNA) biomarkers and traditional risk factors that could be used to identify patients with high-grade PCa (Gleason score ≥7) on prostate biopsy. DESIGN, SETTING, AND PARTICIPANTS In two prospective multicenter studies, urine was collected for mRNA profiling after digital rectal examination (DRE) and prior to prostate biopsy. The multimodal risk score was developed on a first cohort (n=519) and subsequently validated clinically in an independent cohort (n=386). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The mRNA levels were measured using reverse transcription quantitative polymerase chain reaction. Logistic regression was used to model patient risk and combine risk factors. Models were compared using the area under the curve (AUC) of the receiver operating characteristic, and clinical utility was evaluated with a decision curve analysis (DCA). RESULTS AND LIMITATIONS HOXC6 and DLX1 mRNA levels were shown to be good predictors for the detection of high-grade PCa. The multimodal approach reached an overall AUC of 0.90 (95% confidence interval [CI], 0.85-0.95) in the validation cohort (AUC 0.86 in the training cohort), with the mRNA signature, prostate-specific antigen (PSA) density, and previous cancer-negative prostate biopsies as the strongest, most significant components, in addition to nonsignificant model contributions of PSA, age, and family history. For another model, which included DRE as an additional risk factor, an AUC of 0.86 (95% CI, 0.80-0.92) was obtained (AUC 0.90 in the training cohort). Both models were successfully validated, with no significant change in AUC in the validation cohort, and DCA indicated a strong net benefit and the best reduction in unnecessary biopsies compared with other clinical decision-making tools, such as the Prostate Cancer Prevention Trial risk calculator and the PCA3 assay. CONCLUSIONS The risk score based on the mRNA liquid biopsy assay combined with traditional clinical risk factors identified men at risk of harboring high-grade PCa and resulted in a better patient risk stratification compared with current methods in clinical practice. Therefore, the risk score could reduce the number of unnecessary prostate biopsies. PATIENT SUMMARY This study evaluated a novel urine-based assay that could be used as a noninvasive diagnostic aid for high-grade prostate cancer (PCa). When results of this assay are combined with traditional clinical risk factors, risk stratification for high-grade PCa and biopsy decision making are improved.

Comparative analysis of prostate cancer specific biomarkers PCA3 and ERG in whole urine, urinary sediments and exosomes.

Abstract Background: PCA3 and ERG are mRNA-based prostate cancer (PCa) specific biomarkers that can be detected in urine. However, urine is a complex substrate that can be separated in several fractions. In this study we compared the levels of PCa-specific biomarkers (PCA3 and ERG) and KLK3 as prostate-specific reference gene in three urine substrates–whole urine, urinary sediment (cell pellet) and exosomes–and evaluated the influence of performing a digital rectal examination (DRE) prior to urine sampling. Methods: First-voided urine samples were prospectively obtained before and after DRE from 29 men undergoing prostate biopsies. The urine was separated in whole urine, cell pellet and exosomes and the biomarker levels were measured with RT-qPCR. Results: PCa was identified in 52% (15/29) of men. In several samples the mRNA levels were below the analytical limit of detection (BDL). The biomarker levels were highest in whole urine and significantly higher after DRE in all substrates. In PCa patients higher levels of PCA3 and ERG were found in all urine substrates after DRE compared to non-PCa patients. Conclusions: This is the first study in which urinary PCa-specific biomarker levels were compared directly in three separate urine fractions. These results suggest that whole urine could be the urine substrate of choice for PCa-diagnostics based on analytical sensitivity, which is reflected directly in the high informative rate. Moreover, the significant positive effect of performing a DRE prior to urine sampling is confirmed. These findings could be of influence in the development of PCa-diagnostic urine tests.

KLK3, PCA3, and TMPRSS2‐ERG expression in the peripheral blood mononuclear cell fraction from castration‐resistant prostate cancer patients and response to docetaxel treatment

To monitor systemic disease activity, the potential of circulating tumor cells (CTCs) bears great promise. As surrogate for CTCs we measured KLK3, PCA3, and TMPRSS2‐ERG messenger RNA (mRNA) in the peripheral blood mononuclear cell (PBMC) fraction from a castration‐resistant prostate cancer (CRPC) patient cohort and three control groups. Moreover, biomarker response to docetaxel treatment was evaluated in the patient group.

Cost‐effectiveness of a new urinary biomarker‐based risk score compared to standard of care in prostate cancer diagnostics – a decision analytical model

To assess the cost‐effectiveness of a new urinary biomarker‐based risk score (SelectMDx; MDxHealth, Inc., Irvine, CA, USA) to identify patients for transrectal ultrasonography (TRUS)‐guided biopsy and to compare this with the current standard of care (SOC), using only prostate‐specific antigen (PSA) to select for TRUS‐guided biopsy.

A urinary biomarker-based risk score correlates with multiparametric MRI for prostate cancer detection

Prostate cancer (PCa) diagnostics would greatly benefit from more accurate, non‐invasive techniques for the detection of clinically significant disease, leading to a reduction of over‐diagnosis and over‐treatment. The aim of this study was to determine the association between a novel urinary biomarker‐based risk score (SelectMDx), multiparametric MRI (mpMRI) outcomes, and biopsy results for PCa detection.

Potential utility of cancer-specific biomarkers for assessing response to hormonal treatments in metastatic prostate cancer

Prostate cancer is the second leading cause of cancer death in men and there is an urgent clinical need to improve its detection and treatment. The introduction of prostate-specific antigen (PSA) as a biomarker for prostate cancer several decades ago represented an important step forward in our ability to diagnose this disease and offers the potential for earlier and more effective treatment. PSA measurements are now routinely conducted alongside digital rectal examination, with raised PSA levels leading to biopsy. PSA is also used to monitor disease and assess therapeutic response. However, there are some important limitations to its use, not least its lack of specificity for prostate cancer, and increased PSA screening may have resulted in overdiagnosis and overtreatment of early, low-risk prostate cancer. Therefore, there is a need for more specific and sensitive biomarkers for the diagnosis and monitoring of prostate cancer and treatment response; in particular, biomarkers of response to hormonal treatments in prostate cancer and predictive biomarkers to identify who is most likely to respond to these treatments. Here we review the current utilization of PSA and data on potentially more specific and sensitive biomarkers for the diagnosis and monitoring of prostate cancer: prostate cancer antigen 3 (PCA3) and the TMPRSS2-ERG fusion gene. A description of the design of an ongoing study of the 6-month extended release formulation of leuprorelin acetate (Eligard® 45 mg) will provide preliminary data on the potential utility of these new biomarkers for detecting therapeutic response after hormonal therapy.

Epigenetic markers in circulating cell-free DNA as prognostic markers for survival of castration-resistant prostate cancer patients

: Noninvasive biomarkers to guide personalized treatment for castration‐resistant prostate cancer (CRPC) are needed. In this study, we analyzed hypermethylation patterns of two genes (GSTP1 and APC) in plasma cell‐free DNA (cfDNA) of CRPC patients. The aim of this study was to analyze the cfDNA concentrations and levels of the epigenetic markers and to assess the value of these biomarkers for prognosis.

18 Een directe vergelijking van prostaatkankerbiomarkers in drie urinefracties: onbewerkte urine, sediment en exosomen

SamenvattingHet prostaatspecifiek antigeen (PSA) wordt gebruikt als tumormarker voor prostaatkanker, maar heeft als belangrijk nadeel dat het niet specifiek is. PCA3 en TMPRSS2-ERG zijn prostaatkankerspecifieke biomarkers die gedetecteerd kunnen worden in urine. Urine is een complex substraat en bestaat uit meerdere fracties.