Prostate Cancer Gene 3 Research Articles

The Role of PCA3 Testing in Patients with a Raised Prostate-Specific Antigen Level After Greenlight Photoselective Vaporization of the Prostate

Greenlight(®) photoselective vaporization of the prostate (PVP) is an effective method for treating men with lower urinary tract symptoms. A rise in prostate specific antigen (PSA) levels, however, may be noticed in some patients during follow-up. The aim of this study was to determine whether the prostate cancer gene 3 (PCA3) urinary test would help identify patients who were in need of a prostate biopsy. The PSA of all patients undergoing PVP were analyzed. Patients with an elevated (above reference range) or rising PSA level (defined as > 0.75 ng/mL/year if the PSA was between 4.1 and 10 or a doubling time of less than 2 years) were offered a transrectal ultrasonography (TRUS) guided prostate biopsy. Before the biopsy procedure, all patients had a PCA3 test. The relationships between PSA, PCA3, and TRUS prostate biopsy findings were analyzed to determine sensitivity and specificity for the PCA3 test in this setting. 50 patients were identified. The mean age was 69.97 (range 57-83) years. The mean PSA level was 10.1 ng/mL (range 3.03-44.2 ng/mL). Six patients were found to have prostate cancer. Of those, five patients had a positive PCA3 test. One patient had a negative PCA3 test but positive biopsy findings. This gives a sensitivity of 83.3%, and a positive predictive value of 21.7%. The negative predictive value was 96%. The results suggest that a negative PCA3 test in our group of patients is a good predictor of negative biopsy results. The low positive predictive value may be an artefact of the group size. This will need further investigation and greater patient numbers to determine.

The diagnostic value of PCA3 gene-based analysis of urine sediments after digital rectal examination for prostate cancer in a Chinese population

Prostate cancer gene 3 (PCA3) encodes a prostate-specific mRNA that has shown promise as a prostate cancer (PCa) diagnostic tool and is detectable in prostate cancer cells shedding into urine after digital rectal examination (DRE). In our earlier studies, a tissue test for PCA3 appeared to have greater specificity for PCa. There, we performed a clinical evaluation of PCA3 mRNA assay in urine sediments after DRE enriched with prostate cells in a Chinese population. PCA3 mRNA was detected by real-time fluorescent quantitative reverse transcription–polymerase chain reaction (FQ-RT–PCR) in the urine sediments. PSA mRNA detected also by real-time FQ-RT–PCR was used to confirm the yield of prostate cells in the urine sediments beforehand and normalize PCA3 mRNA signals. The data were summarized in a receiver operating characteristic (ROC) curve to visualize the efficacy of ratio PCA3/PSA mRNA as a marker; sensitivity and specificity were calculated also. We also correlated the ratio PCA3/PSA mRNA to the biopsy results (including the presence or absence of malignancy and the Gleason score of the malignancy cases) and to the bone metastasis to evaluate its clinical value. The PCA3 mRNA expression (PCA3/PSA mRNA) in the PCa group was significantly higher than that in the BPH group. The AUC-ROC was 0.786 (95% CI: 0.683–0.889). When the cutoff value was set as 0.107, the sensitivity and specificity were 62.9% and 90.6%, respectively. The positive predictive value and negative predictive value of the PCA3 urine test was 78.6% and 81.7%, respectively. No significant correlation was found between urine PCA3 expression and Gleason score or bone metastasis. Results indicated the clinical usefulness of the PCA3/PSA mRNA of urine sediments after DRE as a molecular marker in the early diagnosis of prostate cancer, which appears to be highly specific for PCa. As a non-invasive and sample accessible assay, the PCA3/PSA mRNA may therefore be useful as an aid in the diagnosis of PCa.

PSGR and PCA3 as biomarkers for the detection of prostate cancer in urine

Several studies have demonstrated the usefulness of monitoring an RNA transcript in urine, such as PCA3, for prostate cancer (PCa) diagnosis. PCa screening would benefit from additional biomarkers of higher specificity and could be used in conjunction with prostate-specific antigen (PSA) testing, in order to better determine biopsy candidates. We used urine sediments after prostate massage (PM) from 215 consecutive patients, who presented for prostate biopsy. We tested whether prostate-specific G-protein coupled receptor (PSGR), a biomarker previously described to be over-expressed in PCa tissue, could also be detected by quantitative real-time PCR in post-PM urine sediment. We combined these findings with prostate cancer gene 3 (PCA3), the current gold standard for PCa diagnosis in urine, to test if a combination of both biomarkers could improve the sensitivity of PCA3 alone. By univariate analysis we found that PSGR and PCA3 were significant predictors of PCa. Receiver operator characteristic curve analysis and its multivariate extension, multivariate ROC (MultiROC), were used to assess the outcome predictive values of the individual and the paired biomarkers. We obtained the following area under the curve values: PSA (0.602), PSGR (0.681), PCA3 (0.656), and PSGRvPCA3 (0.729). Then, we tested whether a combination of PSGR and PCA3 could improve specificity by fixing the sensitivity at 95%. We obtained specificities of 15% (PSGR), 17% (PCA3), and 34% (PSGRvPCA3). A multiplexed model including PSGR and PCA3 improves the specificity for the detection of PCa, especially in the area of high sensitivity. This could be clinically useful for determining which patients should undergo biopsy.

Behavior of the PCA3 gene in the urine of men with high grade prostatic intraepithelial neoplasia

An ideal marker for the early detection of prostate cancer (PCa) should also differentiate between men with isolated high grade prostatic intraepithelial neoplasia (HGPIN) and those with PCa. Prostate Cancer Gene 3 (PCA3) is a highly specific PCa gene and its score, in relation to the PSA gene in post-prostate massage urine (PMU-PCA3), seems to be useful in ruling out PCa, especially after a negative prostate biopsy. Because PCA3 is also expressed in the HGPIN lesion, the aim of this study was to determine the efficacy of PMU-PCA3 scores for ruling out PCa in men with previous HGPIN. The PMU-PCA3 score was assessed by quantitative PCR (multiplex research assay) in 244 men subjected to prostate biopsy: 64 men with an isolated HGPIN (no cancer detected after two or more repeated biopsies), 83 men with PCa and 97 men with benign pathology findings (BP: no PCa, HGPIN or ASAP). The median PMU-PCA3 score was 1.56 in men with BP, 2.01 in men with HGPIN (p = 0.128) and 9.06 in men with PCa (p = 0.008). The AUC in the ROC analysis was 0.705 in the subset of men with BP and PCa, while it decreased to 0.629 when only men with isolated HGPIN and PCa were included in the analysis. Fixing the sensitivity of the PMU-PCA3 score at 90%, its specificity was 79% in men with BP and 69% in men with isolated HGPIN. The efficacy of the PMU-PCA3 score to rule out PCa in men with HGPIN is lower than in men with BP.

787 An evaluation of prostate cancer gene 3 (PCA3) in patients with suspected prostate cancer

Instability in the repeat size of microsatellite sequences has been described in both hereditary nonpolyposis and sporadic colorectal cancers. Tumors expressing microsatellite instability are identified through the comparison of the repeat sizes at multiple microsatellite loci between tumor and matched normal tissue DNA. The use of a five-marker panel including two mononucleotide repeat microsatellites, BAT-25 and BAT-26, has recently been suggested for the clinical determination of tumor microsatellite instability. The BAT-25 and BAT-26 loci included in this panel have both demonstrated sensitivity to microsatellite instability and normal quasimonomorphic allelic patterns, which has simplified the distinction between normal and unstable alleles. However, in this study, we identified allelic variations in the size of the poly(A) tract at BAT-26 in 12.6% of 103 healthy African-Americans screened. In addition, 18.4% exhibited allelic size variations in the poly(T) tract at BAT-25. Finally, 2.9% showed variant alleles at both BAT-25 and BAT-26 loci. Screening a small population of Nigerians confirmed the polymorphic nature of both loci and the ethnic origin of alleles not identified in other populations studied thus far. Our results dispute the quasimonomorphic nature of both BAT-25 and BAT-26 in all populations and support the need for thorough population studies to define the different allelic profiles and frequencies at microsatellite loci.

Proteomics Analysis of Bladder Cancer Exosomes

Exosomes are nanometer-sized vesicles, secreted by various cell types, present in biological fluids that are particularly rich in membrane proteins. Ex vivo analysis of exosomes may provide biomarker discovery platforms and form non-invasive tools for disease diagnosis and monitoring. These vesicles have never before been studied in the context of bladder cancer, a major malignancy of the urological tract. We present the first proteomics analysis of bladder cancer cell exosomes. Using ultracentrifugation on a sucrose cushion, exosomes were highly purified from cultured HT1376 bladder cancer cells and verified as low in contaminants by Western blotting and flow cytometry of exosome-coated beads. Solubilization in a buffer containing SDS and DTT was essential for achieving proteomics analysis using an LC-MALDI-TOF/TOF MS approach. We report 353 high quality identifications with 72 proteins not previously identified by other human exosome proteomics studies. Overrepresentation analysis to compare this data set with previous exosome proteomics studies (using the ExoCarta database) revealed that the proteome was consistent with that of various exosomes with particular overlap with exosomes of carcinoma origin. Interrogating the Gene Ontology database highlighted a strong association of this proteome with carcinoma of bladder and other sites. The data also highlighted how homology among human leukocyte antigen haplotypes may confound MASCOT designation of major histocompatability complex Class I nomenclature, requiring data from PCR-based human leukocyte antigen haplotyping to clarify anomalous identifications. Validation of 18 MS protein identifications (including basigin, galectin-3, trophoblast glycoprotein (5T4), and others) was performed by a combination of Western blotting, flotation on linear sucrose gradients, and flow cytometry, confirming their exosomal expression. Some were confirmed positive on urinary exosomes from a bladder cancer patient. In summary, the exosome proteomics data set presented is of unrivaled quality. The data will aid in the development of urine exosome-based clinical tools for monitoring disease and will inform follow-up studies into varied aspects of exosome manufacture and function.

Interpretation of the Prostate Cancer Gene 3 in Reference to the Individual Clinical Background: Implications for Daily Practice

Introduction: The prostate cancer gene 3 (PCA3) urine assay for the diagnosis of prostate cancer was introduced into clinical practice at the end of 2006. We report our experience with the test in a routine clinical setting and discuss the interpretation of the test results in the context of the individual patient history. Material and Methods: We retrospectively reviewed the data of all patients who received PCA3 determination during a visit to our outpatient clinic between January and June 2008. Prostate volume, prostate-specific antigen (PSA) and (in cases where a biopsy was performed) the biopsy results were collected. Results: The PCA3 score was independent of prostate volume and serum PSA. In our study population, 56 men had a negative (<35) and 47 a positive score (≧35). Thirty-two patients were subsequently biopsied, 18 of which were diagnosed with prostate cancer (51%). Patients with a positive biopsy showed significantly higher PCA3 values (p < 0.05). Sensitivity was 94%, specificity was 36% and the negative predictive value was 83%. The area under the curve in the receiver operating characteristics was 0.81 for the PCA3 score and 0.61 for the serum PSA. Conclusion: The PCA3 value correlates with the probability of a positive prostate biopsy. The high negative predictive value can facilitate the decision for or against a prostate biopsy. However, the low specificity and the comparably high costs hamper the routine use for prostate cancer screening purposes. To increase specificity, in daily practice the PCA3 score should be interpreted carefully with reference to the absolute PSA value and clinical history.

The prostate cancer gene 3 (PCA3) urine test in men with previous negative biopsies: does free‐to‐total prostate‐specific antigen ratio influence the performance of the PCA3 score in predicting positive biopsies?

to determine the performance characteristics of the prostate cancer gene 3 (PCA3) score on the outcome of biopsy relative to different ranges of free-to-total prostate-specific antigen (PSA) ratio (f/tPSA) in men with a previous negative biopsy and a PSA level of 2.5-10 ng/mL, as urine tests like PCA3 are currently under investigation in order to improve prostate cancer diagnosis and to decrease the rate of unnecessary rebiopsies. data from the previous prospective European multicentre study were reviewed. Only patients with a PSA level of 2.5-10 ng/mL were included in the present study. In all, 301 patients had complete data. The diagnostic accuracy of the PCA3 score for predicting a positive biopsy outcome was studied using sensitivity, specificity, negative and positive predictive values. The PCA3 performance was evaluated relative to three different subgroups of f/tPSA, as follows: >20% (group 1), 10-20% (group 2) and <10% (group 3). the prostate cancer detection rates were 18.8%, 23.9% and 34.8% in groups 1, 2 and 3, respectively. The area under the receiver operating characteristic curve of the PCA3 score, total PSA and f/tPSA was 0.688, 0.553 and 0.571, respectively. The percentage of men with positive biopsies was 30.6%, 37.0% and 44.4% in those with a PCA3 score of >30, vs 10.3%, 15.5% and 28.6% when the PCA3 score was <30, in groups 1, 2 and 3, respectively. The difference was significant only in groups 1 and 2. In men with a f/tPSA of ≤ 10% the difference in detection rates relative to the PCA3 score was not statistically significant regardless of which PCA3 threshold was used. A high PCA3 score was significantly associated with age, clinical T2 stage and positive biopsy (P < 0.001, 0.013 and <0.001, respectively). In bivariate analysis accounting for the PCA3 score and the f/tPSA, a PCA3 score of >30 was a significant independent predictor of positive biopsies (odds ratio 3.01; 95% confidence interval 1.74-5.23; P < 0.001). PCA3 remained a better predictor of prostate cancer than f/tPSA. In men with a f/tPSA of >10%, the use of the PCA3 score was highly correlated with the risk of having cancer on re-biopsy, and could prevent unnecessary prostate biopsies if the value is low.

The Prostate Cancer gene 3 assay: indications for use in clinical practice

The Prostate CAncer gene 3 (PCA3) assay is a novel tool that might aid in the diagnosis of prostate cancer and that might indicate the significance of the disease. In this review we discuss five clinical cases in which the PCA3 assay can be considered, based on scientific evidence and key patient cases from real-life clinical practice. The PCA3 assay might be used to guide biopsy decisions in: (i) Men with an elevated serum total prostate specific antigen (tPSA) level and one or more previous negative biopsies; (ii) men with a normal tPSA level and a family history of prostate cancer; (iii) men with an elevated tPSA level (2.5-10 ng/mL) and no previous biopsy; (iv) men with an elevated tPSA level and a concomitant urinary condition. In addition, in men diagnosed with prostate cancer, the PCA3 assay could aid in the decision of whether active therapy is needed or active surveillance is appropriate.

A Gender Transformation in Urology

A Gender Transformation in Urology

The use of PCA3 in the diagnosis of prostate cancer

Although the routine use of serum PSA testing has undoubtedly increased prostate cancer detection, one of its main drawbacks has been its lack of specificity, which results in a high negative biopsy rate. Consequently, a large population of men with chronically elevated serum PSA and one or more negative biopsies has emerged. More accurate tests are needed that can help identify which patients are at high risk of developing prostate cancer, and for whom repeat prostate biopsies are mandatory. To improve the specificity of prostate cancer diagnosis, prostate-cancer-specific markers, such as prostate cancer gene 3 (PCA3), are needed. The strong association between PCA3 mRNA overexpression and malignant transformation of prostate epithelium indicates its potential as a diagnostic biomarker. Quantification of PCA3 mRNA levels in urine was found to help predict the outcome of prostate biopsies. The intensive and time-consuming reverse-transcriptase polymerase chain reaction PCA3 urine test has been translated successfully into the fast and easy transcription-mediated amplification (TMA)-based PCA3 test. This test is the first RNA-based molecular diagnostic assay in body fluids for prostate cancer that is available to urologists. This Review describes the translation of the molecular marker PCA3 from the research laboratory to clinical practice.

Prostate Cancer Gene 3 (PCA3): Development and Internal Validation of a Novel Biopsy Nomogram

Urinary prostate cancer gene 3 (PCA3) represents a promising novel marker of prostate cancer detection. To test whether urinary PCA3 assay improves prostate cancer (PCa) risk assessment and to construct a decision-making aid in a multi-institutional cohort with pre-prostate biopsy data. PCA3 assay cut-off threshold analyses were followed by logistic regression models which used established predictors to assess PCa-risk at biopsy in a large multi-institutional data set of 809 men at risk of harboring PCa. Regression coefficients were used to construct four sets of nomograms. Predictive accuracy (PA) estimates of biopsy outcome predictions were quantified using the area under the curve of the receiver operator characteristic analysis in models with and without PCA3. Bootstrap resamples were used for internal validation and to reduce overfit bias. The extent of overestimation or underestimation of the observed PCa rate at biopsy was explored graphically using nonparametric loss-calibration plots. Differences in PA were tested using the Mantel-Haenszel test. Finally, nomogram-derived probability cut-offs were tested to assess the ability to identify patients with or without PCa. PCA3 was identified as a statistically independent risk factor of PCa at biopsy. Addition of a PCA3 assay improved bootstrap-corrected multivariate PA of the base model between 2% and 5%. The highest increment in PA resulted from a PCA3 assay cut-off threshold of 17, where a 5% gain in PA (from 0.68 to 0.73, p=0.04) was recorded. Nomogram probability-derived risk cut-off analyses further corroborate the superiority of the PCA3 nomogram over the base model. PCA3 fulfills the criteria for a novel marker capable of increasing PA of multivariate biopsy models. This novel PCA3-based nomogram better identifies men at risk of harboring PCa and assists in deciding whether further evaluation is necessary.

Prostate cancer diagnosis in the new millennium: strengths and weaknesses of prostate‐specific antigen and the discovery and clinical evaluation of prostate cancer gene 3 (PCA3)

The decision to take a prostate biopsy is traditionally guided by a digital rectal examination and measurement of serum total prostate-specific antigen (tPSA). However, both techniques are subject to inherent weaknesses. The prostate cancer gene 3 (PCA3), a gene-based marker, specific for prostate cancer, supplements the predictive power of tPSA to improve diagnosis of disease. Including this new marker in the standard of care for men at risk of prostate cancer should be considered, as it presents marked potential for better decision making for a prostate biopsy and for improving overall patient care.

PCA3 Urine mRNA Testing for Prostate Carcinoma: Patterns of Use by Community Urologists and Assay Performance in Reference Laboratory Setting

Multiple trials have shown the high specificity of urine prostate cancer gene 3 (PCA3) compared with serum prostate-specific antigen (PSA) for biopsy detection of prostate carcinoma. We characterized the patterns of use of PCA3 by community urologists and determined the performance of PCA3 testing as a laboratory-developed test in a reference laboratory setting. The urine PCA3 and PSA mRNA levels after digital rectal examination were determined using transcription-mediated amplification. The cutoff for a positive PCA3 score (PCA3/PSA mRNA x 10(3)) were pre-established at > or = 35. The PCA3 results were correlated with the serum PSA level, previous biopsy history, and the prostate biopsy findings. A total of 278 PCA3 tests were performed from December 2006 to June 2007. Of the PCA3 tested patients, 55.5% had previously undergone > or = 1 prostate biopsy; 92.7% had a PSA level > or = 2.5 ng/mL. The PCA3 test informative rate was 97.5%. For 50 samples that were also analyzed at a separate laboratory, concordance was achieved in 94%. The mean and median PCA3 score was 44.3 and 21.1, respectively. No correlation was found with the serum PSA level. The PCA3 test was negative in 16 of 19 patients with negative concurrent biopsy findings and positive in 8 of 11 with positive concurrent biopsy findings (sensitivity 72.7% and specificity 84.2%). Of 32 patients (70% with previous biopsy) who had undergone biopsy an average of 56 days after positive PCA3 test results, prostate carcinoma was detected in 41%. Urine PCA3 testing on the transcription-mediated amplification platform performed well as a laboratory-developed test. The high specificity of PCA3 was confirmed. In patients with elevated PSA levels and negative biopsy findings, PCA3 testing might be useful in choosing between repeat biopsy and more conservative follow-up.

Clinical Utility of the PCA3 Urine Assay in European Men Scheduled for Repeat Biopsy

BackgroundThe Prostate CAncer gene 3 (PCA3) assay has shown promise as an aid in prostate cancer (pCA) diagnosis in identifying men with a high probability of a positive (repeat) biopsy. ObjectiveThis study evaluated the clinical utility of the PROGENSA PCA3 assay. Design, setting, and participantsThis European prospective, multicentre study enrolled men with one or two negative biopsies scheduled for repeat biopsy. MeasurementsAfter digital rectal examination (DRE), first-catch urine was collected to measure PCA3 mRNA concentration and to calculate the PCA3 score. The PCA3 score was compared to biopsy outcome. The diagnostic accuracy of the PCA3 assay was compared to percent of free prostate-specific antigen (%fPSA). Results and limitationsIn 463 men, the positive repeat biopsy rate was 28%. The higher the PCA3 score, the greater the probability of a positive repeat biopsy. The PCA3 score (cut-off of 35) had a greater diagnostic accuracy than %fPSA (cut-off of 25%). The PCA3 score was independent of the number of previous biopsies, age, prostate volume, and total prostate-specific antigen (PSA) level. Moreover, the PCA3 score was significantly higher in men with high-grade prostate intraepithelial neoplasia (HGPIN) versus those without HGPIN, clinical stage T2 versus T1, Gleason score ≥7 versus <7, and “significant” versus “indolent” (clinical stage T1c, PSA density [PSAD] <0.15ng/ml, Gleason score in biopsy ≤6, and percent positive cores ≤33%) pCA. ConclusionsThe probability of a positive repeat biopsy increases with rising PCA3 scores. The PCA3 score was superior to %fPSA for predicting repeat prostate biopsy outcome and may be indicative of clinical stage and significance of pCa.

Editorial Comment on: Preliminary Results of a Novel Method to Estimate the Probability of Prostate Cancer in Men with Elevated Serum PSA Values

The advent of prostate-specific antigen (PSA) testing in combination with digital rectal examination (DRE) has revolutionized early prostate cancer detection and consequently resulted in a stage migration at radical prostatectomy [1]. The majority of patients are currently being diagnosed at a localized stage. However, PSA represents an organ-specific but not disease-specific test, resulting in an ‘‘unnecessary’’ biopsy in approximately 60–70% of all men subjected to prostate biopsy [2]. This fact coined the term ‘‘PSA dilemma.’’ Fortunately, numerous efforts are under investigation and have already been made in improving PSA’s specificity, eg, percent free PSA (%fPSA), ( 5, 7) proPSA, proenzyme prostate-specific antigen prostate cancer gene 3 (PCA3), early prostate cancer antigen-2 (EPCA2) [3,4]. Spyropoulos and Dellis [5] present an interesting novel statistical approach to estimating an individual’s risk of prostate cancer putting a ratio relative to the acknowledged positive predictive value (PPV) of a PSA value of 50 ng/ml. Specifically, the authors derive three different ratios consisting of PSA, age, prostate volume, and %fPSA. These ‘‘individual’’ ratios are compared to the PSA value of 50 ng/ml ratios to derive the probability of a positive biopsy outcome. Despite this intriguing concept, some considerations need to be acknowledged regarding its statistical and clinical approach. First, it is limited by the relatively small sample size of only 146 men. Clearly, validation in larger Tel. +3

PCA3 Molecular Urine Assay Correlates With Prostate Cancer Tumor Volume: Implication in Selecting Candidates for Active Surveillance

Prostate cancer gene 3 (PCA3) has shown promise as a molecular marker in prostate cancer detection. We assessed the association of urinary PCA3 score with prostatectomy tumor volume and other clinical and pathological features. Urine specimens were collected after digital rectal examination from 59 men scheduled for prostate biopsy and 83 men scheduled for radical prostatectomy. Prostatectomy findings were evaluable for 96 men. PCA3 and prostate specific antigen mRNAs were quantified with Gen-Probe DTS 400 System. The PCA3 score was defined as the ratio of PCA3 mRNA/prostate specific antigen mRNA x10(3). The PCA3 score in men with negative biopsies (30) and positive biopsies (29) were significantly different (median 21.1 and 31.0, respectively, p = 0.029). The PCA3 score was significantly correlated with total tumor volume in prostatectomy specimens (r = 0.269, p = 0.008), and was also associated with prostatectomy Gleason score (6 vs 7 or greater, p = 0.005) but not with other clinical and pathological features. The PCA3 score was significantly different when comparing low volume/low grade cancer (dominant tumor volume less than 0.5 cc, Gleason score 6) and significant cancer (p = 0.007). On multivariate analysis PCA3 was the best predictor of total tumor volume in prostatectomy (p = 0.001). Receiver operating characteristic curve analysis showed that the PCA3 score could discriminate low volume cancer (total tumor volume less than 0.5 cc) well with area under the curve of 0.757. The PCA3 score appears to stratify men based on prostatectomy tumor volume and Gleason score, and may have clinical applicability in selecting men who have low volume/low grade cancer.

A multicenter evaluation of the PCA3 molecular urine test: Pre-analytical effects, analytical performance, and diagnostic accuracy

BackgroundMeasurement of prostate cancer gene 3 (PCA3) mRNA normalized to prostate-specific antigen (PSA) mRNA in urine has been proposed as a marker for prostate cancer. MethodsWe investigated pre-analytical effects, analytical performance, and diagnostic accuracy of a quantitative assay for PCA3. ResultsUrine specimens collected without prostate manipulation demonstrated low informative rates. However, specimens collected following digital rectal examinations of 3 or 8 strokes per prostate lobe demonstrated informative rates >94%. Across all urine specimen types, median PCA3 results did not show statistically significant differences (P>0.8). Measurements of controls of known mRNA content demonstrated percent recoveries of 100±15% for both PCA3 and PSA mRNAs. PCA3 mRNA total, intra-assay, inter-assay, and inter-site CVs were ≤17.1%, ≤14.0%, ≤9.9%, and ≤3.2%, respectively. Corresponding CVs for PSA mRNA assay were ≤11.5%, ≤8.6%, ≤7.9%, and ≤8.3%. Blinded assay of urines from 72 men with known prostate biopsy outcomes yielded areas under the curve from receiver-operating characteristic analysis of 0.7 at both research sites. Deming regression of individual PCA3 results between sites yielded slope=0.94, intercept=0.48, R=0.9677 (P<0.0001). ConclusionsThe PCA3 assay is insensitive to pre-analytical factors, performs well analytically and correctly classifies a high percent of subjects with known prostate cancer status across research sites.

POD-08.04: PCA3 molecular urine assay predicts tumor volume in prostatectomy

Prostate cancer gene 3 (PCA3) has shown promise as a molecular marker in prostate cancer detection. We assessed the correlation of the urinary PCA3 score to tumor volume determined in prostatectomy specimens as well as to other clinical and pathological features.

PCA3 Molecular Urine Assay for Prostate Cancer in Men Undergoing Repeat Biopsy

Men with elevated serum prostate-specific antigen (PSA) levels and negative prostate biopsy findings present a dilemma because of the lack of an accurate diagnostic test. We evaluated the potential utility of the investigational prostate cancer gene 3 (PCA3) urine assay to predict the repeat biopsy outcome. Urine was collected after digital rectal examination (three strokes per lobe) from 233 men with serum PSA levels persistently 2.5 ng/mL or greater and at least one previous negative biopsy. The specimens were collected from April 2004 to January 2006. The PCA3 scores were determined using a highly sensitive quantitative assay with transcription-mediated amplification. The ability of the PCA3 score to predict the biopsy outcome was assessed and compared with the serum PSA levels. The RNA yield was adequate for analysis in the urine samples from 226 of 233 men (ie, the informative specimen rate was 97%). Repeat biopsy revealed prostate cancer in 60 (27%) of the of 226 remaining subjects. Receiver operating characteristic curve analysis yielded an area under the curve of 0.68 for the PCA3 score. In contrast, the area under the curve for serum PSA was 0.52. Using a PCA3 score cutoff of 35, the assay sensitivity was 58% and specificity 72%, with an odds ratio of 3.6. At PCA3 scores of less than 5, only 12% of men had prostate cancer on repeat biopsy; at PCA3 scores greater than 100, the risk of positive biopsy was 50%. In men undergoing repeat prostate biopsy to rule out cancer, the urinary PCA3 score was superior to serum PSA determination for predicting the biopsy outcome. The high specificity and informative rate suggest that the PCA3 assay could have an important role in prostate cancer diagnosis.