Specific Antigen Serum Research Articles

Molybdenum disulfide-based aptamer sensor for high-precision detection of prostate specific antigen in serum

As a representative transition metal dichalcogenide, molybdenum disulfide (MoS2) has unique electronic, optical, and mechanical properties that exhibit advantages in the construction of biosensing interfaces. In this study, we explored the construction of a MoS2-based aptamer sensor and investigated its application for high-precision detection of prostate specific antigen (PSA) in serum. Carboxyl group-modified MoS2 was stably bonded to the surface of an aminated electrode as a substrate structure, and the electrode was further modified with biocompatible membrane polydopamine and PSA aptamers to form an aminated screen-printed electrode/carboxylated MoS2/polydopamine (SPE-NH2/MoS2-COOH/PDA)-based aptamer sensor, which achieved ultrasensitive detection of PSA at 0.001 pg/mL ∼ 1 ng/mL with a limit of detection (LOD) of 0.16 fg/mL. The detection results of related interfering substances, such as L-cysteine, alpha fetoprotein (AFP), carcinoembryonic antigen (CEA) and bovine serum albumin (BSA), proved that the sensor had good selectivity. Then, repeated test results of multiple sensors verified that the aptamer sensors had good reproducibility between sensors. Finally, the practical application of the aptamer sensor was evaluated by a blank spiking method, which demonstrated its great clinical application potential. In summary, our study has provided ideas for the application of MoS2 composite-based aptamer sensing interfaces for potential precision medicine needs.

Ex vivo γH2AX assay for tumor radiosensitivity in primary prostate cancer patients and correlation with clinical parameters

BackroundAccurate surrogate parameters for radio resistance are warranted for individualized radiotherapy (RT) concepts in prostate cancer (PCa). The purpose of this study was to assess intertumoral heterogeneity in terms of radio resistance using an ex-vivo γH2AX assay after irradiation of prostate biopsy cores and to investigate its correlation with clinical features of respective patients as well as imaging and genomic features of tumor areas.MethodsTwenty one patients with histologically-proven PCa and pre-therapeutic multiparametric resonance imaging and prostate-specific membrane antigen positron emission tomography were included in the study. Biopsy cores were collected from 26 PCa foci. Residual γH2AX foci were counted 24 h after ex-vivo irradiation (with 0 and 4 Gy) of biopsy specimen and served as a surrogate for radio resistance. Clinical, genomic (next generation sequencing) and imaging features were collected and their association with the radio resistance was studied.ResultsIn total 18 PCa lesions from 16 patients were included in the final analysis. The median γH2AX foci value per PCa lesion was 3.12. According to this, the patients were divided into two groups (radio sensitive vs. radio resistant) with significant differences in foci number (p < 0.0001). The patients in the radio sensitive group had significantly higher prostate specific antigen serum concentration (p = 0.015), tumor areas in the radio sensitive group had higher SUV (standardized uptake values in PSMA PET)-max and -mean values (p = 0.0037, p = 0.028) and lower ADC (apparent diffusion coefficient-mean values, p = 0.049). All later parameters had significant (p < 0.05) correlations in Pearson’s test. One patient in the radio sensitive group displayed a previously not reported loss of function frameshift mutation in the NBN gene (c.654_658delAAAAC) that introduces a premature termination codon and results in a truncated protein.ConclusionIn this pilot study, significant differences in intertumoral radio resistance were observed and clinical as well as imaging parameters may be applied for their prediction. After further prospective validation in larger patient cohorts these finding may lead to individual RT dose prescription for PCa patients in the future.

Electrochemical immunosensor based on hybrid MoS2/Pt@Au-nanoprism/PDA for simultaneous detection of free and total prostate specific antigen in serum

As important biomarkers for prostate cancer, total prostate specific antigen (tPSA) and free prostate specific antigen (fPSA) levels in serum play essential roles in early diagnosis. In this study, hybrid molybdenum disulfide (MoS2)/Pt@Au-nanoprism/polydopamine (PDA)-modified screen-printed electrodes were utilized to detect both fPSA and tPSA in serum simultaneously. MoS2 generated by the hydrothermal method assembled on the electrode to provide binding sites for further modification. Au nanoprisms were obtained by reducing chloroauric acid with sodium thiosulfate to achieve uniformity. Pt nanoparticles covered on Au nanoprisms by the displacement method, and the generated Pt@Au-nanoprism structure was then deposited onto the electrode to enhance the electrochemical signals. An electropolymerization-synthesized PDA film further modified the electrode to increase antibody binding sites. The results demonstrated that the proposed electrochemical immunosensor for fPSA and tPSA analysis in serum using differential pulse voltammetry (DPV) had a wide linear range from 0.0001 ng/mL to 100 ng/mL, with limits of detection (3 SD/slope) at 0.1 pg/mL and 1.1 fg/mL, respectively. For clinical patient samples, the proposed biosensor demonstrated good accuracy according to the clinical electrochemiluminescence immunoassay and improved the diagnostic specificity of tPSA concentrations in the “gray zone", suggesting promising prospects for clinical applications of our multiplex biosensors.

Hyaluronic acid spacer in focal prostate reirradiation: A single centre experience

PurposeThe optimal management of locally recurrent prostate cancer after curative radiotherapy is still unknown. In this study, we evaluated the preliminary results of reirradiation using stereotactic body radiotherapy for locally recurrent prostate cancer after initial definitive local radiotherapy. Materials and methodsBetween April 2016 and February 2019, 11 patients with recurrent disease at the previously irradiated prostate were treated. Local recurrence was detected by radiological with or without functional imaging modalities including prostate multiparametric/pelvic MRI or positron-emission tomography–computerised tomography with (68Ga)-labelled prostate-specific membrane antigen performed after rising prostate specific antigen serum level during follow-up. All patients received stereotactic body radiotherapy to the recurrent nodule to a total dose of 30Gy in five fractions. Hyaluronic acid spacer was injected between prostate and rectum in seven patients to decrease the rectal dose. Acute toxicity was evaluated by using Common Terminology Criteria for Adverse Events version 4.0, and late toxicity was evaluated by using Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer late radiation morbidity scoring schema. ResultsAt the diagnosis, the median age was 64 years, and the mean prostate specific antigen serum concentration was 17.7ng/mL. The median interval time between local recurrence and initial definitive radiotherapy was 63 months. Mean prostate specific antigen concentration nadir value during follow-up was 0.43ng/mL. With a median follow up of 19 months, three patients developed either local or distant relapse. One patient had grade 3 acute rectal toxicity, and one patient had grade 2 late urinary toxicity. We did not observe any acute or late toxicity due to hyaluronic acid spacer injection. ConclusionReirradiation after local recurrence following initial definitive radiotherapy together with hyaluronic acid spacer use seems to be effective and safe.

Indications et perspectives de l’hormonoradiothérapie des cancers de prostate à haut risque

Prostate cancer is a sensitive adenocarcinoma, in more than 80% of cases, to chemical castration, due to its hormone dependence. Locally advanced and/or high-risk cancer is defined based on clinical stage, initial prostate specific antigen serum concentration value or high Gleason score. Hormone therapy associated with radiation therapy is the standard of management and improves local control, reduces the risk of distant metastasis and improves specific and overall survival. Duration of hormone therapy, dose level of radiation therapy alone or associated with brachytherapy are controversial data in the literature. The therapeutic choice, multidisciplinary, depends on the age and comorbidity of the patient, the prognostic criteria of the pathology and the urinary function of the patient. Current research focuses on optimizing local and distant control of these aggressive forms and incorporates neoadjuvant or adjuvant chemotherapy and also new hormone therapies.

Electrochemiluminescence immunoassay for the prostate-specific antigen by using a CdS/chitosan/g-C3N4 nanocomposite.

An electrochemiluminescence (ECL) biosensor was fabricated for the evaluation of prostate specific antigen (PSA). The sensor was developed by successively modifying glassy carbon electrode (GCE) electrodes with CdS/Chito/g-C3N4 nanocomposites and DNA1 was labeled at the 5' end with thiol. The aptamer DNA was labeled at the 3' end with a quencher ferrocene (Fc) was ligated to DNA1 by the principle of complementary base pairing. In the absence of PSA, the ECL intensity signal is effectively quenches through the energy transfer and photoexcitation electron transfer between CdS/Chito/g-C3N4 emitter and quencher Fc. After incubation with target PSA, the aptamer DNA interacts with PSA and then moved away from the electrode surface together, which will recover the ECL intensity. Under the optimal conditions, the ECL intensity increases linearly with the logarithm of PSA concentration in the range of 1pg·mL-1 to 100ng·mL-1, and the detection limit is 0.14pg·mL-1 (S/N = 3). The biosensor has been successfully applied to the determination of PSA in serum sample. Graphical abstractSchematic representation of the electrochemiluminescence sensor based on a CdS/chitosan/g-C3N4 nanocomposite, which can be applied to the determination of prostate specific antigen in serum.

Prostate Specific Antigen Serum Levels in Patients with Different Levels of Hepatic or Renal Impairment and in Those with Systemic Inflammation in a University Hospital. A Retrospective Analysis of 10 Years of Laboratory Data

Prostate Specific Antigen Serum Levels in Patients with Different Levels of Hepatic or Renal Impairment and in Those with Systemic Inflammation in a University Hospital. A Retrospective Analysis of 10 Years of Laboratory Data

Precise detection of prostate specific antigen in serum: A surface molecular imprinted sensor based on novel cooperated signal amplification strategy

Prostate specific antigen (PSA) is of great significance for clinical detection. Herein, a surface molecular imprinted sensor based on a novel cooperated signal amplification strategy was constructed for the precise detection of PSA. MoS2 and gold nanoparticles were modified on the electrode surface as the sensing substrate, PSA template and 4-mercaptophenylboronic acid were employed to form the surface imprinted cavities, and the gold polymerized methylene blue composites labeled 4-mercaptophenylboronic acid was constructed as the tracing tag. Cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry measurements were performed to investigate the formation process of the sensor. Transmission electron microscopy, scanning electron microscopy and energy dispersive spectrometer analysis were utilized for the characterization of the sensing substrate and tracing tag. Once the target PSA was anchored on the sensor, an amplified signal was obtained by the cooperated electrochemical catalytic interaction of the nanomaterials on the tracing tag and substrate. The constructed sensor showed a wide linear range from 1.0 × 10−4 to 1.0 × 104 ng·mL-1, and the detection limit was 0.03 pg·mL-1. Besides, such a sensor exhibited favorable selectivity, reproducibility and stability in the assays, indicating an expected application prospect in the determination of tumor markers.

Increased free prostate specific antigen serum levels in Alzheimer's disease, correlation with Cognitive Decline

Background/aimsProstate specific antigen (PSA) is regulated by steroid hormones, such as testosterone, the serum levels of which are altered in patients with Alzheimer's disease (AD).This pilot study compared serum levels of the free (f) PSA between AD, mild cognitive impairment (MCI), and control subjects, and evaluated the relationship between fPSA serum levels and cognitive assessment tests and neuroimaging data. In addition, in a subgroup of AD patients, we correlated fPSA serum levels with the existing data on serum levels of amyloid-beta (Aβ), and iron-related proteins, including hepcidin and ferritin. MethodsFrozen serum samples from the Oregon Tissue Bank were used to measure serum levels of fPSA using enzyme-linked immunosorbent assay. ResultsfPSA serum levels calculated as median ± SD were higher in AD males (663.6 ± 821.0 pg/ml) compared to control males (152.0 ± 207.0 pg/ml), p = 0.003. A similar Pattern emerged when comparing MCI males (310.7 ± 367.0 pg/ml) to control males (P = 0.02). Correlation studies showed a significant association between fPSA and CDR (r = 0.56, P = 0.006) and CDR-SOB (r = 0.54, P = 0.009) in AD males. ConclusionAdditional studies in a larger cohort are required for determining whether fPSA can be used as biomarker of AD disease progression and whether it has the potential to identify male subjects at risk of AD dementia.

Benign prostatc hyperplasia – medicamentous treatment

Benign prostatic hyperplasia (BPH) is characterized with proliferaton of glandular and stromal components of the prostate. BPH can produce prostate enlargement and caused lower urinary tract symptoms (LUTS). The growth of the prostate depends on patent’s age and influence of sexual hormones, specially dihydrotestosterone. Symptoms can be divided as irritatve, obstructve and postmicturation symptoms. The basic evaluation included medical history, symptom score questionnaire, bladder diary, physical examinaton, urinalysis, creatinine and prostate specific antigen serum concentraton, uroflowmetry and postvoid residual urine. The modality of treatment depends about patents symptoms and results of diagnostic evaluaton. The inital step in the treatment are behavioural and dietary modificatons. In the patients with mild symptoms watchful waiting is first line treatment. In the other patients medicamentous treatment is recommended. Pharmacological management included: alpha adrenoreceptor antagonists, 5-alpha-reductase inhibitors, muscarin receptors antagonists, vasopressin analogue – desmopressin, beta-3 agonists, phosphodiesterase 5 inhibitors, phytotherapy and combinaton therapy. If the medicamentous therapy failed or the complicatons of BPH are present surgical treatment is recommended.

Quantitative Lateral Flow Immunoassay for Total Prostate Specific Antigen in Serum

ABSTRACTA simple method for the rapid determination of prostate-specific antigen (PSA) in serum is reported using a lateral flow immunoassay with gold nanoparticles as the label. The method uses the intensity of colored test lines to determine PSA from 0.3 to 30 ng/mL. The limit of detection was 0.3 ng/mL and the coefficient of variation was less than 10%. The analysis time was approximately 20 min. The novel method showed good correlation with enzyme linked immunosorbent assay (ELISA) measurements of prostate-specific antigen concentration in human serum with a linear regression coefficient of 0.985. The developed system was stable for at least 12 months when stored from +4 to 30°C and has potential application for clinical practice.

Bioconjugated persistent luminescence nanoparticles for Föster resonance energy transfer immunoassay of prostate specific antigen in serum and cell extracts without in situ excitation.

A novel Föster resonance energy transfer (FRET) immunoassay based on persistent luminescence nanoparticles (PLNP) was established for prostate specific antigen (PSA) detection in serum and cell extracts without in situ excitation. The specific FRET behavior allows highly selective and sensitive ratiometric photoluminescent detection of PSA in biological samples.

Detection of prostate specific antigen in serum at the femto-gram per milliliter level using the intrinsic amplification of a field-effect enzymatic immuno-sensing system

Ultrasensitive detection of prostate specific antigen (PSA) has been achieved by applying the field-effect enzymatic detection (FEED) technique to the sandwich immuno-sensing technique. The voltage-controlled intrinsic amplification provided by FEED enabled the detection of PSA contained in serum on the femto-gram/mL level. Two electrochemical approaches used to obtain the amperometric detection signal resulted in similar detection limits and sensitivities. The lowest PSA detection limit achieved was 27fgmL−1. The high selectivity of the detection system was reflected in the fact that PSA detection was successful on the fgmL−1 level, where biological substances other than PSA had a 1-million-fold higher concentration. Electron transfer through the immunological sandwich nanostructure has been observed in the detection of biomarkers. However, our results showed that electron transfer through the nanostructure could be controlled using an external voltage, leading to an ultralow detection limit for PSA.

Editorial Comment

No AccessJournal of UrologyAdult Urology1 Oct 2012Editorial Comment Ayman S. Moussa Ayman S. MoussaAyman S. Moussa More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.06.137AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "Editorial Comment." The Journal of Urology, 188(4), p. 1150 References 1 : Prostate cancer detection in a clinical urological practice by ultrasonography, digital rectal examination and prostate specific antigen. J Urol2002; 167: 966. Link, Google Scholar 2 : Measurement of prostate specific antigen in serum as a screening test for prostate cancer. N Engl J Med1991; 324: 1156. Google Scholar Urology Department, Cairo-Beni-Suif University, Cairo, Egypt© 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 188Issue 4October 2012Page: 1150 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ayman S. Moussa More articles by this author Expand All Advertisement PDF DownloadLoading ...

Tissue Polypeptide Specific Antigen as a Marker Used to Determine the Liver Diseases

Tissue polypeptide specific antigen and its specific M3 epitope are increased in malignant as well as in some benign diseases. The level of tissue polypeptide specific antigen in serum is related mostly to proliferation capacity rather than tumor mass and cell necrosis. The aim of this study was to evaluate the levels of tissue polypeptide specific antigen and other tumor markers in patients with liver cirrhosis, chronic active hepatitis and hepatoma to determine if tissue polypeptide specific antigen is important to other tumor markers in hepatoma patients. Ninety-seven patients and 30 controls were included in the study. The patients were divided into three subgroups as cirrhosis, hepatoma and chronic active hepatitis. The levels of tissue polypeptide specific antigen, carcinoembryonic antigen, CA19.9, alpha-fetoprotein and transaminases were determined in all patients. Tissue polypeptide specific antigen levels were significantly higher in all patients than in the control group (p less than 0.005) According to Kruskal-Wallis test with regard to subgroups, the differences in mean values of tissue polypeptide specific antigen and alpha-fetoprotein were significant (p less than 0.0001 for both). There was a low correlation between tissue polypeptide specific antigen and alpha-fetoprotein in the cirrhotic and hepatoma groups, but these were significantly correlated in the chronic active hepatitis group. The correlation coefficient between tissue polypeptide specific antigen and transaminases in all patients was low. Tissue polypeptide specific antigen is efficient for determining primary hepatoma patients and also that this marker is specific for proliferation of cells.

A simple double-bead sandwich assay for protein detection in serum using UV–vis spectroscopy

In this study a double-bead sandwich assay, employing magnetic nanoparticles and gold nanoparticles is proposed. The magnetic nanoparticles allow specific capturing of the analyte in biological samples, while the optical properties of the gold nanoparticles provide the signal transduction. We demonstrated that a major improvement in the assay sensitivity was obtained by selecting an optimal gold nanoparticle size (60nm). A detection limit of 5–8ng/mL, a sensitivity of 0.6–0.8(pg/mL)−1 and a dynamic range of 3 orders of magnitude were achieved without any further amplification using the detection of prostate specific antigen in serum as a model system. The proposed assay has the ability to be easily implemented within a microfluidic device for point-of-care applications whereby the readout can be executed by a fast and cheap optical measurement.

Stability of total and free prostate specific antigen in serum submitted to intermittent cold storage conditions

The goal of this study was to determine the stability of Total Prostrate Specific antigen (PSA-T) and Free Prostrate Specific Antigen (PSA-F) in archival serum stored at 4°C and -20°C and subjected to temperature shift due to interruption in power supply. Our study showed that PSA-T was stable up to 285 days and PSA-F was stable for 158 days under these conditions. Since power supply interruption is an unavoidable problem in developing nations, our study has implication on the validity of measurement of PSA-T and PSA-F in serum that was not properly stored due to emergency situations and for certain types of retrospective studies.

Effectiveness of Antibiotics Given to Asymptomatic Men for an Increased Prostate Specific Antigen

Although there is controversy surrounding this subject, some urologists in daily practice often prescribe antibiotics before biopsy to men with a newly increased prostate specific antigen. We evaluated the effects of antibiotics on serum total prostate specific antigen, free prostate specific antigen, percent free prostate specific antigen and prostate specific antigen density in men with prostate specific antigen between 4 and 10 ng/ml and normal digital rectal examination. We also investigated the incidence of prostate cancer after antibiotic treatment by performing prostate biopsies in all patients regardless of posttreatment prostate specific antigen. Between May 2006 and April 2008 a total of 100 men with total prostate specific antigen between 4 and 10 ng/ml were enrolled in this study. In addition to total prostate specific antigen, free prostate specific antigen, percent free prostate specific antigen and prostate specific antigen density values were evaluated for all of the patients. Patients with pathological digital rectal examination and urinalysis were excluded from the study. All patients received 400 mg ofloxcacin daily for 20 days. After treatment the patients were reevaluated. Regardless of the total prostate specific antigen value after therapy transrectal ultrasound guided prostate biopsy was performed. Overall 23 men (23%) had histologically proven prostate cancer on biopsy. Mean total prostate specific antigen, free prostate specific antigen and prostate specific antigen density decreased after treatment in patients with and without prostate cancer. However, these reductions within these parameters were not significantly different between patients with and without prostate cancer. Only percent free prostate specific antigen change after treatment was found to be significantly different between patients with and without prostate cancer (p = 0.015). In 17 of the 100 men total prostate specific antigen after treatment was less than 4 ng/ml and of these 5 (29.4%) had prostate cancer on biopsy. Although antibiotic therapy will decrease serum total prostate specific antigen, it will not decrease the risk of prostate cancer even if the prostate specific antigen decreases to less than 4 ng/ml. Therefore, prescribing antibiotics for asymptomatic men with a newly increased prostate specific antigen may not be an appropriate method of management.

High-grade Prostatic Intraepithelial Neoplasialike Ductal Adenocarcinoma of the Prostate: A Clinicopathologic Study of 28 Cases

Most of the prostatic ductal adenocarcinomas of the prostate are characterized by cribriform and/or papillary architecture lined by columnar pseudostratified malignant epithelium. We report 28 cases of ductal adenocarcinomas on needle biopsy and transurethral resection of prostate closely resembling high-grade prostatic intraepithelial neoplasia (HGPIN) composed of simple glands with flat, tufting, or micropapillary architecture. The mean age of the patients was 68 years (range, 50 to 91 y). Prostate specific antigen serum level at diagnosis ranged from 1.2 to 12.1 ng/mL. Treatment included radical prostatectomy (n=9), hormone therapy (n=7), radiotherapy (n=5), and cryotherapy (n=1). Three patients had recent biopsies without information on treatment and 3 patients were lost to follow-up after diagnosis. The number of cores involved by tumor in each case ranged from 1 to 18, with more than 1 core involved in 13 cases. Flat was the most common pattern (42%), followed by tufted (41%), and micropapillary (17%) (some with more than 1 pattern). Fourteen cases revealed segments of dilated gland on the edge of the biopsies, suggesting a large gland component. In radical prostatectomies, tumor was primarily composed of small (25%), medium (17%), or cystically dilated (58%) cancer glands, with all cases demonstrating a mixture of different gland sizes. Cytologically, tumors were characterized by tall columnar atypical cells, basally located nuclei, and amphophilic cytoplasm. The tumors lacked marked pleomorphism, necrosis, solid areas, cribriform formation, or true papillary fronds. Immunohistochemically, alpha-methyl acyl coenzyme-A racemase staining was seen in 93% of cases, with the majority showing strong and diffuse staining. No basal cells were present on p63 and/or high molecular weight cytokeratin staining. In the radical prostatectomy specimens, tumor volumes ranged from a small focus (less than 0.01 cm3) to 1.2 cm3. Concurrent conventional acinar Gleason score 6 adenocarcinomas were seen in 6 of the 9 radical prostatectomy cases, in all cases as separate nodules from the PIN-like ductal adenocarcinomas. Only one of the PIN-like ductal adenocarcinomas at radical prostatectomy had extraprostatic extension, which was focal. PIN-like ductal adenocarcinoma differs from HGPIN by the presence of cystically dilated glands, a greater predominance of flat architecture, and less frequently prominent nucleoli. Verification often requires the immunohistochemical documentation of the absence of basal cells in numerous atypical glands. Although usual ductal adenocarcinoma is considered comparable to Gleason score 8, PIN-like ductal adenocarcinoma was accompanied by Gleason score 6 acinar carcinoma and behaved similar to Gleason score 6 acinar cancer. Recognition of this entity is critical to differentiate it from both HGPIN and conventional ductal adenocarcinoma.

-2]Proenzyme Prostate Specific Antigen for Prostate Cancer Detection: A National Cancer Institute Early Detection Research Network Validation Study

This study evaluated the [-2]proenzyme prostate specific antigen serum marker using a blinded reference specimen set from 3 National Cancer Institute Early Detection Research Network centers from men with an indication for prostate biopsy. Serum was collected before biopsy from 123 men with no prior biopsy or prostate cancer history. Specimens (cancer cases 51%, noncancer controls 49%) were selected equally from the 3 sites, and analyzed for prostate specific antigen, free prostate specific antigen, [-2]proenzyme prostate specific antigen, benign prostate specific antigen and testosterone (Beckman Coulter ACCESS(R) analyzer). There was no difference in total prostate specific antigen concentrations (noncancer 6.80 +/- 5.20 ng/ml, cancer 6.94 +/- 5.12 ng/ml) among the groups. Overall %[-2]proenzyme prostate specific antigen had the greatest area under the curve (AUC 0.69) followed by percent free prostate specific antigen (AUC 0.61). For %[-2]proenzyme prostate specific antigen maximal sensitivity was 60% and specificity was 70%. A logistic regression model combining prostate specific antigen, benign prostate specific antigen, percent free prostate specific antigen, %[-2]proenzyme prostate specific antigen, [-2]proenzyme prostate specific antigen/benign prostate specific antigen and testosterone had an AUC of 0.73. In the 2 to 10 ng/ml prostate specific antigen range %[-2]proenzyme prostate specific antigen and the model had the largest AUC (0.73). The AUC for percent free prostate specific antigen was 0.53. Specificities for %[-2]proenzyme prostate specific antigen, the logistic regression model and percent free prostate specific antigen at 90% sensitivity were 41%, 32% and 18%, and at 95% sensitivity were 31%, 26% and 16%, respectively. %[-2]proenzyme prostate specific antigen was the best predictor of prostate cancer detection compared to percent free prostate specific antigen, particularly in the 2 to 10 ng/ml total prostate specific antigen range. These findings provide a rationale for broader validation studies to determine whether %[-2]proenzyme prostate specific antigen alone can replace other molecular prostate specific antigen assays (such as percent free prostate specific antigen) for improving the accuracy of prostate cancer early detection. These findings also support the usefulness of well characterized, carefully collected reference sets to evaluate new biomarkers.