Clinical utility of the PCA3 urine assay in European men scheduled for repeat biopsy

Prospective multicentre evaluation of PCA3 and TMPRSS2-ERG gene fusions as diagnostic and prognostic urinary biomarkers for prostate cancer

BACKGROUND

Prostate cancer antigen 3 (PCA3) and v-ets erythroblastosis virus E26 oncogene homolog (TMPRSS2-ERG) gene fusions are promising prostate cancer (PCa) specific biomarkers that can be measured in urine.

OBJECTIVE

To evaluate the diagnostic and prognostic value of Progensa PCA3 and TMPRSS2-ERG gene fusions (as individual biomarkers and as a panel) for PCa in a prospective multicentre setting.

DESIGN, SETTING, AND PARTICIPANTS

At six centres, post-digital rectal examination first-catch urine specimens prior to prostate biopsies were prospectively collected from 497 men. We assessed the predictive value of Progensa PCA3 and TMPRSS2-ERG (quantitative nucleic acid amplification assay to detect TMPRSS2-ERG messenger RNA [mRNA]) for PCa, Gleason score, clinical tumour stage, and PCa significance (individually and as a marker panel). This was compared with serum prostate-specific antigen and the European Randomised Study of Screening for Prostate Cancer (ERSPC) risk calculator. In a subgroup (n=61) we evaluated biomarker association with prostatectomy outcome.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariate and multivariate logistic regression analysis and receiver operating curves were used.

RESULTS AND LIMITATIONS

Urine samples of 443 men contained sufficient mRNA for marker analysis. PCa was diagnosed in 196 of 443 men. Both PCA3 and TMPRSS2-ERG had significant additional predictive value to the ERSPC risk calculator parameters in multivariate analysis (p<0.001 and resp. p=0.002). The area under the curve (AUC) increased from 0.799 (ERSPC risk calculator), to 0.833 (ERSPC risk calculator plus PCA3), to 0.842 (ERSPC risk calculator plus PCA3 plus TMPRSS2-ERG) to predict PCa. Sensitivity of PCA3 increased from 68% to 76% when combined with TMPRSS2-ERG. TMPRSS2-ERG added significant predictive value to the ERSPC risk calculator to predict biopsy Gleason score (p<0.001) and clinical tumour stage (p=0.023), whereas PCA3 did not.

CONCLUSIONS

TMPRSS2-ERG had independent additional predictive value to PCA3 and the ERSPC risk calculator parameters for predicting PCa. TMPRSS2-ERG had prognostic value, whereas PCA3 did not. Implementing the novel urinary biomarker panel PCA3 and TMPRSS2-ERG into clinical practice would lead to a considerable reduction of the number of prostate biopsies.

Correlation of urine TMPRSS2:ERG and PCA3 to ERG+ and total prostate cancer burden

ERG rearrangements (most commonly transmembrane protease, serine 2 [TMPRSS2]:ERG [T2:ERG] gene fusions) have been identified in approximately 50% of prostate cancers . Quantification of T2:ERG in postdigital rectal examination urine, in combination with PCA3, improves the performance of serum prostate-specific antigen for prostate cancer prediction on biopsy. Here we compared urine T2:ERG and PCA3 scores with ERG+ (determined with immunohistochemical analysis) and total prostate cancer burden in 41 mapped prostatectomies. Prostatectomies had a median of 3 tumor foci (range, 1-15) and 2.6 cm of summed linear tumor dimension (range, 0.6-7.1 cm). Urine T2:ERG score correlated most with summed linear ERG+ tumor dimension and number of ERG+ foci (r(s) = 0.68 and 0.67, respectively, both P < .001). Urine PCA3 score showed weaker correlation with both number of tumor foci (r(s) = 0.34, P = .03) and summed linear tumor dimension (r(s) = 0.26, P = .10). In summary, we demonstrate a strong correlation between urine T2:ERG score and total ERG+ prostate cancer burden at prostatectomy, consistent with high tumor specificity.

The current status of active surveillance for prostate cancer

The occurrence of low-risk, localized prostate cancer (PCa) has increased in the prostate-specific antigen era. A significant amount of low-risk PCas progress slowly and may not impact patient survival. Thus, these patients may be subjected to unnecessary interventions that result in physical and psychological complications. The active surveillance (AS) protocol has been used over the few past decades. It was designed so that patients with low-risk PCa can be monitored for a period of time, during which they are free from complication of interventions, and can be treated with curative intention on evidence of disease progression. Institutions have developed different selection criteria and follow-up schedules for suitable patients with PCa. Recently, long-term data have emerged suggesting that AS is a reasonable option for appropriately selected patients with low-risk PCa who have a life expectancy of < 10 years. Subsequently, the AS protocol has been recognized by various guidelines as part of the treatment strategy for PCa. However, the challenges that remain for AS are the risk of under-staging of PCa and the low uptake and high attrition rate of AS, and questions remain regarding its long-term efficacy. Recent advances in AS for PCa, such as better imaging modality, combining AS with limited local therapy, as well as the role of AS in association with chemoprevention, are discussed.

Combination of real-time elastography and urine prostate cancer gene 3 (PCA3) detects more than 97% of significant prostate cancers

OBJECTIVE

The prostate cancer gene 3 (PCA3) score in urine is a promising biomarker for prostate cancer. Real-time elastography (RTE) is a well-documented ultrasound modality. The objective of this study was to evaluate the ability to detect significant cancer foci in the prostate with these methods alone and in combination.

MATERIAL AND METHODS

From September 2009 to September 2010, 40 patients planned for radical prostatectomy underwent a PCA3 urine test and RTE before operation. A Hitachi EUB-8500 with prostate end-fire transrectal probe was used. The PCA3 score was evaluated with a standard cut-off value of 35. RTE was evaluated in correlation with whole-mount section pathology. Three patients fulfilled the criteria for insignificant prostate cancer and were excluded from the study.

RESULTS

The PCA3 score was increased in 26 patients (70%). RTE identified at least one tumour in 33 out of 37 patients (89%). RTE detected the largest tumour in 27 out of 37 patients (73%). More than one cancer was present in 29 patients and RTE identified more than one tumour in 13 of these. The RTE was false positive in four patients. The PCA3 score was increased in three out of four false-negative RTE patients. By combining both methods, 36 out of 37 patients (97%) with significant prostate cancer were detected.

CONCLUSIONS

The combination of PCA3 score and RTE detected 97% of significant prostate cancers. The combinative use of RTE and PCA3 will be further investigated in an unselected series of men with suspected prostate cancer.

Beyond prostate-specific antigen - future biomarkers for the early detection and management of prostate cancer

Prostate-specific antigen is currently commonly used as a screening biomarker for prostate cancer, but it has limitations in both sensitivity and specificity. The development of novel biomarkers for early cancer detection has the potential to improve survival, reduce unnecessary investigations and benefit the health economy. Here we review the use and limitations of prostate-specific antigen and its subtypes, urinary biomarkers including PCA3, alpha-methylacyl-CoA racemase, the TMPRSS2-ERG fusion gene and microseminoprotein-beta, and other novel markers in both serum and urine. Many of these biomarkers are at early stages of development and require evaluation in prospective trials to determine their potential usefulness in clinical practice. Genetic profiling may allow for the targeting of high-risk populations for screening and may offer the opportunity to combine biomarker results with genotype to aid risk assessment.

Biomarkers for the diagnosis of new and recurrent prostate cancer

Prostate cancer is the most prevalent cancer in men and can be managed effectively if diagnosed early and monitored. Currently, prostate-specific antigen testing in conjunction with a digital rectal exam has been utilized for screening at-risk men. However, the lack of specificity of prostate-specific antigen as a marker for prostate cancer combined with the asymptomatic and slow-growing nature of prostate tumors has resulted in many men being overdiagnosed and subjected to surgery or treatment with adverse side effects. The focus in the research community currently has been on discovering noninvasive surrogate markers such as proteins, circulating tumor cells and nucleic acids in the blood or urine of patients with prostate cancer. These markers, in combination with prostate-specific antigen, are providing promise that a personalized multiparametric approach to prostate cancer diagnosis and monitoring will aid in managing this disease.

Beyond PSA: the next generation of prostate cancer biomarkers

Since the introduction of serum prostate-specific antigen (PSA) screening 25 years ago, prostate cancer diagnosis and management have been guided by this biomarker. Yet, PSA has proven controversial as a screening assay owing to several inherent limitations. The next wave of prostate cancer biomarkers has emerged, introducing new assays in serum and urine that may supplement or, in time, replace PSA because of their higher cancer specificity. This expanding universe of biomarkers has been facilitated, in large part, by new genomic technologies that have enabled an unbiased look at cancer biology. Such efforts have produced several notable success stories that involve rapidly moving biomarkers from the bench to the clinic. However, biomarker research has centered on disease diagnostics, rather than prognosis and prediction, which would address disease management. The development of biomarkers to stratify risk of prostate cancer aggressiveness at the time of screening remains the greatest unmet clinical need in prostate cancer. We review the current state of prostate cancer biomarker research, including the PSA revolution, its impact on early cancer detection, the recent advances in biomarker discovery, and the future efforts that promise to improve clinical management of this disease.

Is PCA3 score useful in preoperative staging of a single microfocus of prostate cancer diagnosed at saturation biopsy?

OBJECTIVE

To evaluate prostate cancer gene 3 (PCA3) score accuracy in preoperative staging of cases of single microfocus of prostate cancer (PCa; less than 5% with Gleason score ≤6) diagnosed after repeat saturation biopsy (median 30 cores).

METHODS

From January 2009 to March 2012, 38 patients (median 64 years) with a microfocus of PCa, median PSA of 9.1 ng/ml and T1c clinical stage underwent radical retropubic prostatectomy. PCA3 score (cut-off of 20 vs. 35) was evaluated in predicting insignificant PCa (pIPCa: cancer volume <0.5 ml and Gleason score ≤6) versus organ-confined (OC) versus non-OC PCa.

RESULTS

Median PCA3 score results were equal to 10 versus 53 (p < 0.05) versus 108 (p < 0.05) in the presence of pIPCa (13.2%), versus OC (65.8%) versus non-OC PCa (21%), respectively. PCA3 scores were significantly correlated with tumor volume.

CONCLUSIONS

A PCA3 score cut-off >20 in the presence of a microfocus of PCa is highly predictive of significant PCa (diagnostic accuracy equal to 86.8%) at definitive specimen.

Systematic, evidence-based discovery of biomarkers at the NCI

In the past decade, biomarker discovery has become ubiquitous in cancer research. However, despite this interest in biomarker research, few newly-characterized biomarkers have emerged as clinically-used entities. Here, we review the current state of biomarker research in cancer and identify challenges that stall many biomarker discovery efforts. We outline a model for systematic biomarker discovery, exemplified by recent efforts in prostate cancer, in which bioinformatics plays a central role in identifying promising new candidate biomarkers. Finally, we review the role of the National Cancer Institute's Early Detection Research Network (EDRN) in biomarker studies and the importance of EDRN-led efforts to establish a research standard for more effective biomarker discovery efforts.

The epigenetic promise for prostate cancer diagnosis

BACKGROUND

Prostate cancer is the most common cancer diagnosis in men and a leading cause of death. Improvements in disease management would have a significant impact and could be facilitated by the development of biomarkers, whether for diagnostic, prognostic, or predictive purposes. The blood-based prostate biomarker PSA has been part of clinical practice for over two decades, although it is surrounded by controversy. While debates of usefulness are ongoing, alternatives should be explored. Particularly with recent recommendations against routine PSA-testing, the time is ripe to explore promising biomarkers to yield a more efficient and accurate screening for detection and management of prostate cancer. Epigenetic changes, more specifically DNA methylation, are amongst the most common alterations in human cancer. These changes are associated with transcriptional silencing of genes, leading to an altered cellular biology.

METHODS

One gene in particular, GSTP1, has been widely studied in prostate cancer. Therefore a meta-analysis has been conducted to examine the role of this and other genes and the potential contribution to prostate cancer management and screening refinement.

RESULTS

More than 30 independent, peer reviewed studies have reported a consistently high sensitivity and specificity of GSTP1 hypermethylation in prostatectomy or biopsy tissue. The meta-analysis combined and compared these results.

CONCLUSIONS

GSTP1 methylation detection can serve an important role in prostate cancer managment. The meta-analysis clearly confirmed a link between tissue DNA hypermethylation of this and other genes and prostate cancer. Detection of DNA methylation in genes, including GSTP1, could serve an important role in clinical practice.

Initial prostate biopsy: development and internal validation of a biopsy-specific nomogram based on the prostate cancer antigen 3 assay

BACKGROUND

Urinary prostate cancer antigen 3 (PCA3) assay in combination with established clinical risk factors improves the identification of men at risk of harboring prostate cancer (PCa) at initial biopsy (IBX).

OBJECTIVE

To develop and validate internally the first IBX-specific PCA3-based nomogram that allows an individual assessment of a man's risk of harboring any PCa and high-grade PCa (HGPCa).

DESIGN, SETTING, AND PARTICIPANTS

Clinical and biopsy data including urinary PCA3 score of 692 referred IBX men at risk of PCa were collected within two prospective multi-institutional studies.

INTERVENTION

IBX (≥ 10 biopsy cores) with standard risk factor assessment including prebiopsy urinary PCA3 measurement.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

PCA3 assay cut-off thresholds were investigated. Regression coefficients of logistic risk factor analyses were used to construct specific sets of PCA3-based nomograms to predict any PCa and HGPCa at IBX. Accuracy estimates for the presence of any PCa and HGPCa were quantified using area under the curve of the receiver operator characteristic analysis and compared with a clinical model. Bootstrap resamples were used for internal validation. Decision curve analyses quantified the clinical net benefit related to the novel PCA3-based IBX nomogram versus the clinical model.

RESULTS AND LIMITATIONS

Any PCa and HGPCa were diagnosed in 46% (n=318) and 20% (n=137), respectively. Age, prostate-specific antigen, digital rectal examination, prostate volume, and PCA3 were independent predictors of PCa at IBX (all p<0.001). The PCA3-based IBX nomograms significantly outperformed the clinical models without PCA3 (all p<0.001). Accuracy was increased by 4.5-7.1% related to PCA3 inclusion. When applying nomogram-derived PCa probability thresholds ≤ 30%, only a few patients with HGPCa (≤ 2%) will be missed while avoiding up to 55% of unnecessary biopsies. External validation of the PCA3-based IBX-specific nomogram is warranted.

CONCLUSIONS

The internally validated PCA3-based IBX-specific nomogram outperforms a clinical prediction model without PCA3 for the prediction of any PCa, leading to the avoidance of unnecessary biopsies while missing only a few cases of HGPCa. Our findings support the concepts of a combination of novel markers with established clinical risk factors and the superiority of decision tools that are specific to a clinical scenario.

Defining prostate cancer risk before prostate biopsy

Prostate cancer is the most commonly diagnosed cancer in men. At present, patients are selected for prostate biopsy on the basis of age, serum prostate specific antigen (PSA), and prostatic digital rectal examination (DRE) findings. However, due to limitations in the use of PSA and DRE, many patients undergo unnecessary prostate biopsy. A further problem arises as many patients are diagnosed and treated for indolent disease. This review of the literature highlights the strengths and weaknesses of existing methods of prebiopsy risk stratification and evaluates promising serum, urine, and radiologic prostate cancer biomarkers, which may improve risk stratification for prostate biopsy in the future.

PCA3 sensitivity and specificity for prostate cancer detection in patients with abnormal PSA and/or suspicious digital rectal examination. First Latin American experience

INTRODUCTION

Prostate Cancer Gene 3 (PCA3) is a recently described and highly specific urinary marker for prostate cancer (CaP). Its introduction in clinical practice to supplement low specificity of prostate specific antigen (PSA) can improve CaP diagnosis and follow-up. However, before its introduction, it is necessary to validate the method of PCA3 detection in distinct geographic populations.

OBJECTIVES

Our aim was to describe for the first time in Latin America, the application of the PROGENSA PCA3 assay for PCA3 detection in urine in Chilean men and its utility for CaP diagnosis in men with an indication of prostate biopsy.

MATERIALS AND METHODS

Sixty-four Chilean patients (mean age, 64 years) with indication of prostate biopsy because of elevated PSA and/or suspicious digital rectal examination (DRE) were prospectively recruited. PCA3 scores were assessed from urine samples obtained after DRE, before biopsy, and compared with PSA levels and biopsy outcome.

RESULTS

The median PSA value and mean PCA3 score were 5.8 ng/ml and 31.7, respectively. Using a cutoff PCA3 score of 35, the sensitivity and specificity for detecting CaP were 52% and 87%, respectively. The receiver operating characteristic (ROC) curve analysis showed an area under the curve of 0.77 for PCA3 and 0.57 for PSA, for the same group of patients. In patients with previous negative biopsy, PCA3 specificity increased by 2.2%.

CONCLUSIONS

This is the first report in Latin America on the use of PCA3 in diagnosing CaP. Our results are comparable to those reported in other populations in the literature, demonstrating the reproducibility of the test. PCA3 score was highly specific and we specially recommend its use in patients with persistent elevated PSA and prior negative biopsies.

The role of genetic markers in the management of prostate cancer

CONTEXT

Despite widespread screening for prostate cancer (PCa) and major advances in the treatment of metastatic disease, PCa remains the second most common cause of cancer death for men in the Western world. In addition, the use of prostate-specific antigen testing has led to the diagnosis of many potentially indolent cancers, and aggressive treatment of these cancers has caused significant morbidity without clinical benefit in many cases. The recent discoveries of inherited and acquired genetic markers associated with PCa initiation and progression provide an opportunity to apply these findings to guide clinical decision making.

OBJECTIVE

In this review, we discuss the potential use of genetic markers to better define groups of men at high risk of developing PCa, to improve screening techniques, to discriminate indolent versus aggressive disease, and to improve therapeutic strategies in patients with advanced disease.

EVIDENCE ACQUISITION

PubMed-based literature searches and abstracts through January 2012 provided the basis for this literature review. We also examined secondary sources from reference lists of retrieved articles and data presented at recent congresses. Cited review articles are only from the years 2007-2012, favoring more recent discussions because of the rapidly changing field. Original research articles were curated based on favoring large sample sizes, independent validation, frequent citations, and basic science directly related to potentially clinically relevant prognostic or predictive markers. In addition, all authors on the manuscript evaluated and interpreted the data acquired.

EVIDENCE SYNTHESIS

We address the use of inherited genetic variants to assess risk of PCa development, risk of advanced disease, and duration of response to hormonal therapies. The potential for using urine measurements such as prostate cancer antigen 3 (PCA3) RNA and the transmembrane protease, serine 2 v-ets erythroblastosis virus E26 oncogene homolog (avian) (TMPRSS2-ERG) gene fusion to aid screening is discussed. Multiple groups have developed gene expression signatures from primary prostate tumors correlating with poor prognosis, and attempts to improve and standardize these signatures as diagnostic tests are presented. Massive sequencing efforts are underway to define important somatic genetic alterations (amplifications, deletions, point mutations, translocations) in PCa, and these alterations hold great promise as prognostic markers and for predicting response to therapy. We provide a rationale for assessing genetic markers in metastatic disease for guiding choice of therapy and for stratifying patients in clinical trials, and discuss challenges in clinical trial design incorporating the use of these markers.

CONCLUSIONS

The use of genetic markers has the potential to aid disease screening, improve prognostic discrimination, and prediction of response to treatment. However, most markers have not been prospectively validated for providing useful prognostic or predictive information or improvement upon clinicopathologic parameters already in use. Significant efforts are underway to develop these research findings into clinically useful diagnostic tests in order to improve clinical decision making.

Emerging critical role of molecular testing in diagnostic genitourinary pathology

CONTEXT

The unprecedented advances in cancer genetics and genomics are rapidly affecting clinical management and diagnostics in solid tumor oncology. Molecular diagnostics is now an integral part of routine clinical management in patients with lung, colon, and breast cancer. In sharp contrast, molecular biomarkers have been largely excluded from current management algorithms of urologic malignancies.

OBJECTIVE

To discuss promising candidate biomarkers that may soon make their transition to the realm of clinical management of genitourologic malignancies. The need for new treatment alternatives that can improve upon the modest outcome so far in patients with several types of urologic cancer is evident. Well-validated prognostic molecular biomarkers that can help clinicians identify patients in need of early aggressive management are lacking. Identifying robust predictive biomarkers that will stratify response to emerging targeted therapeutics is another crucially needed development. A compiled review of salient studies addressing the topic could be helpful in focusing future efforts.

DATA SOURCES

A PubMed (US National Library of Medicine) search for published studies with the following search terms was conducted: molecular , prognostic , targeted therapy , genomics , theranostics and urinary bladder cancer , prostate adenocarcinoma , and renal cell carcinoma . Articles with large cohorts and multivariate analyses were given preference.

CONCLUSIONS

Our recent understanding of the complex molecular alterations involved in the development and progression of urologic malignancies is yielding novel diagnostic and prognostic molecular tools and opening the doors for experimental targeted therapies for these prevalent, frequently lethal solid tumors.

Predicting prostate biopsy outcome: prostate health index (phi) and prostate cancer antigen 3 (PCA3) are useful biomarkers

Indication for prostate biopsy is presently mainly based on prostate-specific antigen (PSA) serum levels and digital-rectal examination (DRE). In view of the unsatisfactory accuracy of these two diagnostic exams, research has focused on novel markers to improve pre-biopsy prostate cancer detection, such as phi and PCA3. The purpose of this prospective study was to assess the diagnostic accuracy of phi and PCA3 for prostate cancer using biopsy as gold standard. Phi index (Beckman coulter immunoassay), PCA3 score (Progensa PCA3 assay) and other established biomarkers (tPSA, fPSA and %fPSA) were assessed before a 18-core prostate biopsy in a group of 251 subjects at their first biopsy. Values of %p2PSA and phi were significantly higher in patients with PCa compared with PCa-negative group (p<0.001) and also compared with high grade prostatic intraepithelial neoplasia (HGPIN) (p<0.001). PCA3 score values were significantly higher in PCa compared with PCa-negative subjects (p<0.001) and in HGPIN vs PCa-negative patients (p<0.001). ROC curve analysis showed that %p2PSA, phi and PCA3 are predictive of malignancy. In conclusion, %p2PSA, phi and PCA3 may predict a diagnosis of PCa in men undergoing their first prostate biopsy. PCA3 score is more useful in discriminating between HGPIN and non-cancer.

Chronic prostatitis does not influence urinary PCA3 score

BACKGROUND

The influence of chronic prostatitis on serum PSA level is well known. Whether it also influences potential new biomarkers of prostate cancer (PCa) has to be determined. We conducted a prospective study to evaluate the effect of chronic prostatitis on the PCa urinary marker PCA3.

METHODS

Included were 38 patients, mean-aged of 37.5 years, with clinical suspicion of chronic prostatitis. A simplified version of the Meares-Stamey four-glass localization test was performed and urine specimens were collected for cytological analysis and culture. A postprostatic massage urine sample was used for the urinary PCA3 test.

RESULTS

Four patients had an eventual diagnosis of urethritis and all had a PCA3 score less than 5. Among the remaining 34 patients, 7 had bacterial chronic prostatitis (NIH II prostatitis), 11 had abacterial chronic prostatitis (NIH IIIa), and 16 had non inflammatory prostatodynia (NIH IIIb). All these patients had a PCA3 score less than 28, that is, under the cutoff of 35, which is commonly used for prostate cancer diagnosis. Patients with NIH category IIIa prostatitis had significantly higher number of leukocytes and red cells as well as prostate cells in urine samples but their PCA3 scores did not differ from those of other prostatitis patients.

CONCLUSION

In this study, NIH II and III chronic prostatitis did not influence the PCA3 score. Our results suggest that increased PCA3 score is unlikely to be explained by the sole chronic prostatitis and warrants prostate biopsies to eliminate prostate cancer.

An overview of prostate diseases and their characteristics specific to Asian men

In this paper, we reviewed the features of common prostate diseases, such as benign prostatic hyperplasia (BPH), prostate cancer (PCa) and chronic prostatitis (CP) that are specific to Asian men. Compared to the Westerners, Asians exhibit particular characteristics of prostate diseases. Through summarizing the epidemiology, symptomatology, diagnostics and therapeutics of these diseases, we find that Asians have a lower incidence of PCa than whites, but the incidences of BPH and CP are similar. Asian men with CP often suffer from fewer disease sites, but have a higher frequency of pain during urination rather than after sexual climax. Prostate-specific antigen (PSA) is a widely used marker for the diagnosis of PCa in both Asian and Western countries. Although the PSA level may be lower in Asians, the threshold used is based on whites. After reviewing the treatments available for these diseases, we did not find a fundamental difference between Asians and whites. Furthermore, the selection for the most appropriate treatment based on the individual needs of patients remains a challenge to urologists in Asia. After considering the traits of prostate diseases that are specific to Asian men, we hope to pave the way for the development of specific diagnostic and therapeutic strategies targeted specifically to Asian men.

Molecular diagnosis of prostate cancer: PCA3 and TMPRSS2:ERG gene fusion

PURPOSE

Widespread prostate specific antigen screening together with the increase in the number of biopsy cores has led to increased prostate cancer incidence. Standard diagnostic tools still cannot unequivocally predict prostate cancer progression, which often results in a significant overtreatment rate. We present recent findings on PCA3 and TMPRSS:ERG fusion, and describe their clinical implications and performance.

MATERIALS AND METHODS

The PubMed® database was searched for reports on PCA3 (130 articles), TMPRSS:ERG and ETS fusion (180 publications) since 1999.

RESULTS

In recent years advances in genetics and biotechnology have stimulated the development of noninvasive tests to detect prostate cancer. Serum and urine molecular biomarkers have been identified, of which PCA3 has already been introduced clinically. The identification of prostate cancer specific genomic aberrations, ie TMPRSS2:ERG gene fusion, might improve diagnosis and affect prostate cancer treatment.

CONCLUSIONS

Although several recently developed markers are promising, often showing increased specificity for prostate cancer detection compared to that of prostate specific antigen, their clinical application is limited. The only 2 true prostate cancer specific biomarkers identified to date remain PCA3 and TMPRSS2:ERG gene fusion.

A three-gene panel on urine increases PSA specificity in the detection of prostate cancer

BACKGROUND

Several studies have demonstrated the usefulness of monitoring an RNA transcript, such as PCA3, in post-prostate massage (PM) urine for increasing the specificity of prostate-specific antigen (PSA) in the detection of prostate cancer (PCa). However, a single marker may not necessarily reflect the multifactorial nature of PCa.

METHODS

We analyzed post-PM urine samples from 154 consecutive patients, who presented for prostate biopsies because of elevated serum PSA (>4 ng/ml) and/or abnormal digital rectal exam. We tested whether the putative PCa biomarkers PSMA, PSGR, and PCA3 could be detected by quantitative real-time PCR in post-PM urine sediment. We combined these findings to test if a combination of these biomarkers could improve the specificity of actual diagnosis. Afterwards, we specifically tested our model for clinical usefulness in the PSA diagnostic "gray zone" (4-10 ng/ml) on a target subset of 82 men with no prior biopsy.

RESULTS

By univariate analysis, we found that the PSMA, PSGR, and PCA3 scores were significant predictors of PCa. Using a multiplex model, the area under the multi receiver-operating characteristic curve was 0.74 versus 0.82 in the diagnostic "gray zone." Fixing the sensitivity at 96%, we obtained a specificity of 34% and 50% in the gray zone.

CONCLUSIONS

Taken together, these results provide a strategy for the development of a more accurate model for PCa diagnosis. In the future, a multiplexed, urine-based diagnostic test for PCa with a higher specificity, but the same sensitivity as the serum-PSA test, could be used to determine better which patients should undergo biopsy.

[Outcomes of expanded use of PCA3 testing in a Spanish population with clinical suspicion of prostate cancer]

OBJECTIVES

DD3(PCA3) (PCA3) gene expression is prostate cancer-specific. Routine use of this biomarker has resulted in a 35-67% reduction in the number of required biopsies. The aim of this study is to evaluate our outcomes in its routine use and to establish in which group of patients this is the most efficient, depending on the number of previous PCA3 biopsies.

MATERIAL AND METHODS

A total of 474 consecutive patients who had previously undergone a biopsy (group A, n=337) or not (group B, n=134) for whom a PCA3 was requested were analyzed. We subdivided group A into A(1) (a previous biopsy, n=182) and A(2) (<1 previous biopsy, n=155). The recommendation of whether to perform a biopsy or not was made independently by each of the 11 clinicians and guided by prostatic specific antigen (PSA) levels and digital rectal examination.

RESULTS

Median age was 65 years (range 38 to 84). PCA3 score had an informative ratio of 99.6%, with a median of 29 (range 1-3245). The percentage of biopsy sparing was 49% of the cases. ROC analysis demonstrated an AUC for PSA and PCA3 of 0.532 (P=.417) and 0.672 (P<.0001), respectively. Sensitivities of PSA≥ 4 and PCA3≥ 35 were 87% vs. 85%, with specificities of 12% vs. 33%, PPV 34% vs. 39% and NPV 63% vs. 81%, respectively. The PCA3 score showed direct correlation with the percentage of positive biopsies (P<.0001).

CONCLUSIONS

Routine use of PCA3, due to its high NPV, results in a significant reduction in the number of biopsies. PCA3 appears to be more efficient in biopsy-naive patients. Among patients already biopsied, the results are superior in those biopsied only once.

Utility of PCA3 in patients undergoing repeat biopsy for prostate cancer

BACKGROUND

Men with persistently elevated and/or rising PSA levels after negative prostate biopsy often undergo multiple repeat biopsies. Prostate cancer antigen 3 (PCA3) has emerged as a predictor of prostate cancer.

METHODS

We sought to define the utility of PCA3 in combination with other clinical data in predicting the risk of prostate cancer on repeat biopsy. We retrospectively obtained PCA3, PSA, PSA density (PSAD), digital rectal examination (DRE) and transrectal ultrasound (TRUS) findings from 103 patients at a single institution who had at least one prior negative prostate biopsy. The sensitivity and specificity of PCA3 in detecting prostate cancer was determined. Receiver operating characteristics curves were produced for each variable individually and in multivariable analysis, controlling for PCA3, PSAD, TRUS, PSA and DRE. A nomogram was created, internally validated and compared to another recently published nomogram.

RESULTS

Of the 103 patients, 37 (31%) had prostate cancer on repeat biopsy. The sensitivity and specificity of PCA3 (using a cut point of 25) was 0.67 and 0.64, respectively. In multivariable analyses, PCA3 was independently associated with prostate cancer (odds ratio: 1.02, 95% confidence interval: 1.01-1.04), with area under the curve (AUC) of 0.64. A multivariable model containing PCA3, PSAD, PSA, DRE and TRUS findings showed the most diagnostic accuracy (AUC: 0.82).

CONCLUSIONS

In the setting of prior negative biopsies, PCA3 was independently associated with prostate cancer in a multivariable model. In combination with other clinical data, PCA3 is a valuable tool in assessing the risk of prostate cancer on repeat biopsy.

Prostate cancer gene 3 score predicts prostate biopsy outcome in men receiving dutasteride for prevention of prostate cancer: results from the REDUCE trial

OBJECTIVES

To examine the ability of the urinary prostate cancer gene 3 (PCA3) assay to predict biopsy-detected cancers in men receiving dutasteride in the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) study cohort.

METHODS

Urine and serum samples from 930 men in the active arm were acquired at years 2 and 4 of the biopsy visits. In addition to univariate logistic regression and receiver operating characteristic analysis, multivariate analysis for association with biopsy outcome was performed for PCA3 score in the presence of serum prostate-specific antigen (PSA), age, prostate volume, and family history of prostate cancer.

RESULTS

At year 2, the univariate PCA3 score area under the receiver operating characteristic curve (AUC) was 0.668 versus 0.603 for PSA. At year 4, the PCA3 assay significantly predicted the biopsy outcome (AUC 0.628, 95% confidence interval 0.556-0.700), and the PSA level was not predictive (AUC 0.556, 95% confidence interval 0.469-0.642). The year 2 multivariate model yielded an AUC of 0.712. Removing the PCA3 score decreased the AUC to 0.660 (P = .0166 vs the full model). The median PCA3 scores in the dutasteride arm were not different from those in the 1072 men in the placebo arm (16.2 and 17.2 at year 2, P = .1755; and 18.8 and 18.1 at year 4, P = .2340, respectively). However, the PSA values were reduced >50% in the dutasteride arm at both visits (both P < .0001 vs placebo). At a PCA3 score cutoff of 35, the sensitivity and specificity were equivalent between the 2 arms.

CONCLUSIONS

In the present study, the PCA3 assay outperformed PSA for cancer detection in men undergoing dutasteride treatment and improved the diagnostic accuracy when combined with the PSA level and other clinical variables. In addition, no adjustment in PCA3 score was needed to yield equivalent clinical performance between the dutasteride and placebo arms. These findings are particularly important in light of the potential role of dutasteride for prostate cancer chemoprevention.

A comparative performance analysis of total prostate-specific antigen, percentage free prostate-specific antigen, prostate-specific antigen velocity and urinary prostate cancer gene 3 in the first, second and third repeat prostate biopsy

Study Type - Diagnosis (exploratory cohort) Level of Evidence 2b What's known on the subject? and What does the study add? Risk factor assessment in the repeat biopsy setting is affected by a decreasing diagnostic accuracy of each single risk factor (e.g. DRE, tPSA, %fPSA, complexed PSA, PSA density or PSAV] with increasing number of prostate biopsy sessions. PCA3 shows impressive diagnostic performance in the initial and early repeat biopsy settings. In a head-to-head comparison we demonstrate the concept that the number of previous repeat biopsy session strongly influences performance characteristics of biopsy risk factors, including PCA3. While the novel diagnostic marker would have avoided a considerable number of unnecessary biopsies in the first repeat biopsy scenario, its effects dissipated at second and ≥ third repeat biopsies.

OBJECTIVE

To compare the performance characteristics of prostate cancer risk factors such as total prostate-specific antigen (tPSA), percentage free PSA (%fPSA), PSA velocity (PSAV) and urinary prostate cancer gene 3 (PCA3) at first, second and ≥ third repeat biopsy session.

PATIENTS AND METHODS

Patients (n= 127) aged ≤70 years, with suspicious digital rectal examination (DRE) and/or persistently elevated age-specific total PSA levels (2.5-6.5 ng/mL) and/or suspicious prior histology (atypical small acinar proliferations [ASAPs]≥ two cores affected by high-grade prostatic intra-epithelial neoplasia [HGPIN]) undergoing either a first, second, or ≥ third repeat biopsy were investigated using a 12- or 24-core biopsy scheme. PSAV (≥ three values collected over ≥12 months) was calculated using the log-slope method. PCA3 scores were assessed using the Progensa assay®. After stratification according to the number of previous biopsies (first, second and ≥ third), calculation of specificity, positive and negative predictive values (PPV, NPV) and the proportion of avoided unnecessary repeat biopsies (PAB) compared with tPSA at fixed sensitivity thresholds (75, 85 and 95%) were performed. Finally, accuracy estimates (area under the curve [AUC]) were quantified for each repeat biopsy scenario.

RESULTS

At repeat biopsy, overall prostate cancer (PCa) detection was 34.6%. At first repeat biopsy, PCA3 predicted PCa best (AUC = 0.80) and would have avoided 72.2% of repeat biopsies (75% sensitivity) compared with tPSA. At second repeat biopsy, %fPSA demonstrated the highest accuracy (AUC = 0.82) and would have avoided 66.7% of repeat biopsies (75% sensitivity) compared with tPSA. At ≥ third repeat biopsy, again %fPSA demonstrated the highest accuracy (AUC = 0.70) and would have avoided 45.0% of repeat biopsies (75% sensitivity) compared with tPSA. The main limitation of our study resides in its small sample size.

CONCLUSIONS

The findings of the present study promote the concept that the number of previous repeat biopsy sessions strongly influences the performance characteristics of biopsy risk factors. Total PSA was no significant risk factor in the entire analysis. By contrast, %fPSA performed best at second and ≥ third repeat biopsy. PSAV's diagnostic potential was reserved to patients at second and ≥ third repeat biopsy. Finally, PCA3 demonstrated the highest diagnostic accuracy and potential to reduce unnecessary biopsies at first repeat biopsy. However, this advantage dissipated at second and ≥ third repeat biopsy.

Age-specific PCA3 score reference values for diagnosis of prostate cancer

PURPOSE

We evaluated the impact of age on PCA3 score and the utility of age-specific reference values in predicting initial prostate biopsy (pBx) outcomes.

PATIENTS AND METHODS

This single-center, retrospective study included 205 men who underwent an initial 14-core TRUS-guided pBx due to PSA > 3.0 ng/ml or suspicious digital-rectal examination (DRE). PCA3 scores were measured with the Progensa assay. Linear regression models were fit to identify factors that impact PCA3 score and to determine age-specific reference values. Predictive accuracies of logistic regression models predicting presence of prostate cancer (PCa) were analyzed.

RESULTS

The positive biopsy rate was 37%. In multivariable linear regression, age (P < 0.001), presence of PCa (P < 0.001), and multifocal HG-PIN (P = 0.012) were independent predictors of PCA3 score. Age showed the strongest impact on PCA3 score (T = 4.77). The upper 95% confidence interval of PCA3 score in each age category was defined as the age-specific limit. A PCA3-score over the age-specific limit (PCA3-age) was associated with an 4.17-fold increased odds of being diagnosed with PCa (P < 0.001). In multivariable logistic regression models predicting the presence of PCa, predictive accuracy of a base model (age, DRE, PSA, volume) increased from 69.6 to 75.4% (P = 0.037) by adding the continuous PCA3 score, to 73.9% (P = 0.098) with the 35 cutoff (PCA3-35) and to 77.1% (P = 0.008) with PCA3-age.

CONCLUSIONS

PCA3 score increases with age, independent of PCa presence. Age-specific PCA3 score reference values are superior to PSA, continuous PCA3 score, and PCA3-35 in predicting initial pBx outcome. Therefore, an age-adjusted PCA3 score should be used for interpretation of the results.

The relationship between Prostate CAncer gene 3 (PCA3) and prostate cancer significance

OBJECTIVE

To evaluate the relationship between Prostate CAncer gene 3 (PCA3) and prostate cancer significance.

PATIENTS AND METHODS

Clinical data from two multi-centre European open-label, prospective studies evaluating the clinical utility of the PCA3 assay in guiding initial and repeat biopsy decisions were analysed. First-catch urine was collected after digital rectal examination (three strokes per lobe) and the PCA3 score was determined using the PROGENSA(®) PCA3 assay. Transrectal ultrasound-guided biopsy (≥8 cores) and radical prostatectomy (RP) specimens were analysed by the local pathologist. The relationship between biopsy and RP outcomes with the PCA3 score was assessed.

RESULTS

Of the 1009 men enrolled, 348 (34%) had a positive biopsy. The median and mean PCA3 scores were statistically significantly lower in men with biopsy Gleason score <7 vs ≥7, with clinical stage T1c vs T2a-T2c, T3a cancers, with ≤33% vs >33% positive biopsy cores and with 'biopsy indolent' vs 'biopsy significant' prostate cancer (indolent prostate cancer defined by biopsy Epstein criteria). In all, 175 men with a positive biopsy had a RP: median and mean PCA3 scores were statistically significantly lower in men with pathological Gleason score <7 vs ≥7, and with pathological stage T2a-T2c vs T3a-T3b cancers.

CONCLUSIONS

The PCA3 score may combined with traditional tools aid in identifying men with clinically insignificant prostate cancer, as shown by biopsy and RP pathological features including biopsy Epstein criteria, who could be candidates for active surveillance. Treatment selection should be based on a combination of clinical and pathological variables. If one wants to use a threshold point to guide treatment decisions in clinical practice, a PCA3 score threshold of 20 may have the highest utility for selecting men with clinically insignificant prostate cancer in whom active surveillance may be appropriate; a PCA3 score threshold of 50 may be used to identify men at high risk of harbouring significant prostate cancer who are candidates for RP. Although the association between the PCA3 score and prostate cancer aggressiveness needs further evaluation, the inclusion of the PCA3 score into patient management strategies may provide clinicians with another tool to more accurately determine the course of treatment.

Contemporary role of prostate cancer antigen 3 in the management of prostate cancer

CONTEXT

Newly discovered biomarkers ideally should prove clinical usefulness, provide additional detection, staging, and prognosis information to improve individual risk assessment, and potentially permit targeted cancer therapy.

OBJECTIVE

To review, display, and evaluate the current evidence regarding the biologic and analytic approach of urinary prostate cancer gene 3 (PCA3) in prostate cancer (PCa) detection, staging, and prognosis, and its therapeutic potential.

EVIDENCE ACQUISITION

A systematic and comprehensive Medline search was performed using the Medical Subject Headings search terms PCA3, DD3, UPM3, prostate cancer, cell-lines, prostate tissue, prostate biopsy, detection, diagnosis, radical prostatectomy, staging, grading, progression, and gene therapy. Results were restricted to English-language papers published within the period 1999-2011.

EVIDENCE SYNTHESIS

The PCA3 gene is highly overexpressed in specific PCa cell lines and prostatic tumours. In 2006, a simple and robust urine test (Progensa) became commercially available. Despite its costs, prostate cancer antigen 3 (PCA3) is superior to prostate-specific antigen (PSA) and percent free PSA in the early detection of PCa. PCA3 improves the diagnostic accuracy of externally validated nomograms among men with an elevated PSA undergoing biopsy. PCA3 independently predicts low-volume disease and pathologically insignificant PCa but is not associated with locally advanced disease and is limited in the prediction of aggressive cancer. Preliminary data demonstrate that combining PCA3 with other new biomarkers further improves diagnostic and prognostic accuracy. Finally, findings of the first PCA3-Gene-ViroTherapy study suggest therapeutic potential by exploiting PCA3 overexpression.

CONCLUSIONS

PCA3, integrated in novel biopsy nomograms or risk stratification tools, can be used to counsel or confirm biopsy indications. If confirmed in further studies, using PCA3 together with established staging risk factors could assist clinicians in specific pretreatment decision making. So far no evidence for the usefulness of PCA3 in active surveillance programs has been presented.

Quadriplex model enhances urine-based detection of prostate cancer

BACKGROUND

The major advantages of urine-based assays are their non-invasive character and ability to monitor prostate cancer (CaP) with heterogeneous foci. While the test for the prostate cancer antigen 3 (PCA3) is commercially available, the aim of our research was to test other putative urine markers in multiplex settings (AMACR (α-methylacyl-CoA racemase), EZH2 (enhancer of zeste homolog 2), GOLM1 (golgi membrane protein 1), MSMB (microseminoprotein, β), SPINK1 (serine peptidase inhibitor) and TRPM8 (transient receptor potential cation channel, subfamily M, member 8)).

METHODS

Expression of the candidate biomarkers was studied in sedimented urine using quantitative reverse transcriptase polymerase chain reaction in two sets of patients with and without restriction on serum PSA levels.

RESULTS

We confirmed that PCA3 is an independent predictor of cancer in the patients without restriction of serum PSA values (set 1, n=176, PSA=0.1-587 ng ml(-1)). However, AMACR was the only parameter that differentiated CaP from non-CaP patients with serum PSA between 3 and 15 ng ml(-1) (set 2, n=104). The area under curve (AUC) for this gene was 0.645 with both sensitivity and specificity at 65%. Further improvement was achieved by multivariate logistic regression analysis, which identified novel duplex (TRPM8 and MSMB), triplex (plus AMACR) and quadriplex (plus PCA3) models for the detection of early CaPs (AUC=0.665, 0.726 and 0.741, respectively).

CONCLUSIONS

Novel quadriplex test could be implemented as an adjunct to serum PSA or urine PCA3 and this could improve decision making for diagnostics in the case of 'PSA dilemma' patients.

Biopsy and treatment decisions in the initial management of prostate cancer and the role of PCA3; a systematic analysis of expert opinion

PURPOSE

The Prostate CAncer gene 3 (PCA3) assay may guide prostate biopsy decisions and predict prostate cancer (PCa) aggressiveness. This study explored the appropriateness of (1) PCA3 testing; (2) biopsy; (3) active surveillance (AS) and the value of the PCA3 Score for biopsy and AS decisions.

METHODS

Using the RAND/UCLA appropriateness method, 12 urologists assessed the appropriateness of PCA3, biopsy and AS for theoretical patient profiles, constructed by combining clinical variables. They individually scored the appropriateness for all profiles using a 9-point scale. Based on the median score and extent of agreement, the appropriateness for each profile was calculated.

RESULTS

The PCA3 Assay was mainly considered appropriate in men with ≥1 negative biopsy, PSA ≥ 3 ng/mL and life expectancy (LE) ≥10 years. A LE < 10 years, ≥2 negative biopsies and PCA3 Score <20 decreased biopsy appropriateness, while PSA ≥ 3 ng/mL and PCA3 Score >50 increased it. In men without a prior biopsy, LE ≥ 10 years and a suspicious DRE, PCA3 did not affect biopsy appropriateness. In other men, a PCA3 Score <20 discouraged biopsy, while a value ≥35 supported biopsy. AS was mainly considered appropriate if LE < 10 years, T1c PCa, ≤20% positive cores and PSA < 3 ng/mL. A PCA3 Score <20 pleads for and higher scores (particularly >50) against AS.

CONCLUSIONS

These findings illustrate in which men PCA3 can be of additional value when taking biopsy and treatment decisions in clinical practice.

[How to select the best candidates for prostate biopsies? The role of traditional tools and contribution of new biomarkers in prostate cancer]

In 2010, early detection of prostate cancer continues to rely on digital rectal examination and serum total PSA. However, selecting patients for prostate biopsy requires taking into account the prostate volume and the evolution of PSA over time. PSA derivatives such as PSA density, PSA velocity and the ratio free PSA / total PSA are useful supplements. However, the choice of the threshold value is not well defined and depends on the relative sensitivity and specificity desired. The real innovations come from basic research that has found potential markers of aggressiveness of prostate cancer and molecular biology tools used routinely as the PCA-3 score and the pro-PSA. The role of these new markers for diagnosis and prognosis of prostate cancer remains unclear.

Role of histopathology and molecular markers in the active surveillance of prostate cancer

Surgery or radiation therapy remain the standard curative treatments for newly diagnosed prostate cancer patients. Nonetheless, these aggressive treatments are associated with decreased quality of life with altered sexual and urinary functions. The objective was a systematic review of active surveillance protocols to investigate the role of histopathology and molecular markers in the active surveillance of prostate cancer. Medline was searched using the following terms: prostate cancer, active surveillance and expectant management. Selection criteria, follow-up strategies and outcomes. Using modern risk stratification, several centres have gained significant experience in identifying patients with a low risk of prostate cancer progression and have adopted an active surveillance program with delayed curative therapy. Interestingly, only limited numbers of patients under active surveillance require additional treatment. Recent data suggest that delayed treatment does not appear to alter the clinical outcome among those highly selected patients. The future and conclusions. A better understanding of the molecular determinants of prostate cancer behaviour would not only enable healthcare professionals to identify which cases need aggressive treatment but, perhaps more importantly, would also indicate potential targets for the development of novel therapeutic strategies.

Tumour markers in prostate cancer III: biomarkers in urine

The serum PSA test still is the most important biomarker for the detection and follow-up of prostate cancer. PSA-based screening can reduce disease specific mortality but coinciding unnecessary testing and overdiagnosis warrant further research for more specific biomarkers. Numerous studies of both serum and urine-based prostate cancer biomarker candidates have been presented the last ten years. However, biomarkers for identifying the most aggressive subsets of this malignancy are still missing. Being non-invasive, urine-based tests might be suitable for both clinical and (mass) screening purposes, but also for prediction and to gain prognostic information. Protein-based, DNA-based and RNA-based urine biomarkers have been developed and tested.

PROTEIN MARKERS IN URINE

Data on protein-based urine biomarkers (i.e. Annexin A3, matrix metalloproteinases and the urinary:serum PSA ratio) show up to now contradictory results and further studies are warranted to be able to assess their clinical value in which the cost aspect should not be overlooked. DNA markers in urine. Studies on DNA-based urine biomarkers focus on hypermethylation of gene panels with GSTP1 hypermethylation being the most promising individual marker. Larger prospective clinical studies of single markers and gene panels are however needed to validate their clinical utility.

RNA MARKERS IN URINE

RNA-based urine biomarkers are by far the most developed. The PCA3 test, the TMPRSS2-ERG fusion gene, transcript expression levels of GOLPH2, SPINK1 and their combination have been subject of many studies showing encouraging results.

CONCLUSION

Up to now urine-based biomarkers represent a promising alternative or addition to serum-based biomarkers. Prospective studies in a multivariate setting, including larger sample sizes and avoiding attribution bias caused by preselection on the basis of serum PSA are however required.

[Variation of urinary PCA3 following transrectal ultrasound-guided prostate biopsy]

INTRODUCTION

Serum PSA is known to rise slightly following an attentive digital rectal examination (DRE) and dramatically following prostatic biopsy. The aim of this study was to evaluate the PCA3 response in these situations.

PATIENTS AND METHODS

In 15 consecutive men undergoing transrectal ultrasound-guided needle biopsy of the prostate and who gave their informed consent, urinary PCA3 was determined twice: at a first consultation, urine being sampled immediately after an attentive DRE and second within 2 hours after the biopsy. The mean interval between the two samplings was 14 days (median 15). PCA3 measurements were centralized and performed by the same biologist. At least twelve cores were taken using a biopsy gun with an 18-gauge needle. Changes in PCA3 levels were studied.

RESULTS

Mean age of the 15 men was 67.3 years (range 50.9-79.1). Mean (median) pre-biopsy total and %free PSA were respectively 6.6 ng/ml (5.7) and 15.8% (15.5). Mean prostate volume was 43.6 cm(3). Seven patients complained of mild LUTS. DRE was suspicious in eight patients. Of the 15 men, 6 (40%) had adenocarcinoma on biopsy (all clinically confined to the prostate). Median (range) Gleason score was 6 (6-7). Median PCA3 score (range) before and after prostatic biopsy were respectively 36 (9-287) and 27 (5-287) with no significant difference between the two groups (sign test for matched series p > 0.05). The median variation between pre- and post-biopsy PCA3 was -18%. When considering a PCA3 cut-off of 35, two patients changed group: one patient had 51 before and 31 after (PSA 4.6; no cancer on prostate biopsy) and the second had 36 before and 27 after (PSA 5.6; low-risk PCa). The figure represents the PCA3 values for each case (squares for the pre-biopsy and diamonds for the post-biopsy). When considering only the six patients with PCA, median (mean) PCA3 score before and after prostatic biopsy were respectively 51.5 (60.8) and 44.5 (54.8) with no significant difference between the two groups (sign test for matched series p > 0.5) and a median variation between pre- and post-biopsy PCA3 of 1.5%.

CONCLUSIONS

Prostate biopsy did not alter significantly urinary PCA3 value. This confirms what was theoretically expected.

A multiplex model of combining gene-based, protein-based, and metabolite-based with positive and negative markers in urine for the early diagnosis of prostate cancer

BACKGROUND

Multiplex urine-based assay emerged outperforms single biomarker (e.g., prostate-specific antigen, PSA) for predicting prostate cancer (CaP), whereas its combined mode has to be fully optimized. Our aim is to determine whether a strategy of combining gene-based, protein-based, metabolite-based with positive, negative makers in urine could optimize a multiplex model for detecting CaP.

METHODS

Using quantitative PCR, Western blot, and liquid chromatography-mass spectrometry, expression patterns of PCA3, TMPRSS2: ERG, Annexin A3, Sarcosine, and urine PSA were evaluated in urine samples from 86 untreated patients with CaP and 45 patients with no evidence of malignancy. Multivariate logistic regression analysis was used to generate a final model and receiver-operating characteristic (ROC) analysis and special bootstrap software to assess diagnostic performance of tested variables.

RESULTS

The expression patterns of PCA3, TMPRSS2: ERG, Annexin A3, Sarcosine, and a panel including these biomarkers were significant predictors of CaP both in patients with PSA 4-10 ng/ml and in all patients (all P < 0.05). Employing ROC analysis, the area under the curves of the panel in these both cohorts were 0.840 and 0.856, respectively, which outperform that of any single biomarker (PCA3: 0.733 and 0.739; TMPRSS2: ERG: 0.720 and 0.732; Annexin A3: 0.716 and 0.728; Sarcosine: 0.659 and 0.665, respectively).

CONCLUSIONS

Compared with single biomarker, the multiplex model including PCA3, TMPRSS2: ERG, Annexin A3 and Sarcosine adds even more to the diagnostic performance for predicting CaP. Further validation experiments and optimization for the strategy of constructing this model are warranted.