The time-resolved fluorescence-based PCA3 test on urinary sediments after digital rectal examination; a Dutch multicenter validation of the diagnostic performance

PURPOSE

To improve the specificity in prostate cancer diagnosis and to prevent unnecessary prostate biopsies, especially in the serum prostate-specific antigen (PSA) "gray zone" between 3 and 15 ng/mL, the implementation of prostate cancer-specific markers is urgently needed. The recently discovered prostate cancer antigen 3 (PCA3) is such a promising prostate cancer marker. In a previous single institution study, the PCA3 urine test clearly proved to be of diagnostic value. Therefore, the diagnostic performance of the PCA3 urine test was validated in a multicenter study.

EXPERIMENTAL DESIGN

The first voided urine after digital rectal examination was collected from a total of 583 men with serum PSA levels between 3 and 15 ng/mL who were to undergo prostate biopsies. We determined the PCA3 score in these samples and correlated the results with the results of the prostate biopsies.

RESULTS

A total of 534 men (92%) had an informative sample. The area under the receiver-operating characteristic curve, a measure of the diagnostic accuracy of a test, was 0.66 for the PCA3 urine test and 0.57 for serum PSA. The sensitivity for the PCA3 urine test was 65%, the specificity was 66% (versus 47% for serum PSA), and the negative predictive value was 80%.

CONCLUSIONS

In this multicenter study, we validated the diagnostic performance of the PCA3 urine test in the largest group studied thus far using a PCA3 gene-based test. This study shows that the PCA3 urine test, when used as a reflex test, can improve the specificity in prostate cancer diagnosis and could prevent many unnecessary prostate biopsies.

Case–control prostate cancer screening studies should not exclude subjects with lower urinary tract symptoms

OBJECTIVE

Prostate-specific antigen (PSA)/digital rectal exam (DRE) screening for prostate cancer has become standard medical practice; however, its effectiveness in terms of reducing prostate cancer mortality remains undetermined. Case-control screening studies may help determine screening efficacy, though the proper disposition of symptomatic subjects is unclear. This paper presents a prostate cancer-specific methodological modification for analyzing symptomatic case-control screening subjects.

METHODS

Prostate cancer detection studies and case-control studies of PSA/DRE screening were reviewed, and the results for symptomatic and asymptomatic subjects were compared.

RESULTS

Most PSA/DRE detection studies have found that the prostate cancer detection rate among symptomatic patients is the same as or lower than that among asymptomatic patients. Lower urinary tract symptoms (LUTS), often referred to as early prostate cancer symptoms, occur more often in benign prostatic hyperplasia (BPH), a more commonly diagnosed, nonmalignant disease. Screened symptomatic subjects are usually removed from the "screened" category in case-control studies even though BPH-related symptoms do not confer increased prostate cancer risk and odds ratios do not change with inclusion of symptomatic subjects in the analysis.

CONCLUSION

Screened subjects with LUTS should remain in the "screened" category in case-control prostate cancer screening studies since these symptoms may not be associated with increased risk of prostate cancer or validity of the odds ratio.

Urinary prostate-specific antigen is a noninvasive indicator of sexual development in male children

Testicular androgen induces the synthesis of prostate specific antigen (PSA) in acinar epithelial cells of the prostate. We examined PSA activity in urine from 136 male children from birth up to 17 years of age. We detected PSA at various intervals in early infant urine over a period of 1-4 months. During this period, urinary secretion of testosterone (T) gradually declined, accompanied by 1 or more surges of T prior to a transient increase in PSA in urine from full- and preterm infants (67%, n = 6). Although mean urinary T concentrations during elevations of PSA in preterm infants were 3.1 and 5.6 times greater than in full-term infants and adults, the overall mean urinary PSA concentration of full and preterm infants was just 45% and 18% that of adults, respectively. PSA was not detected in children aged 0.3 to 9 years, after which a gradual increase in urinary PSA activity was observed after 10 years of age. Urinary PSA activity was markedly persistent after Tanner stage III pubertal development. To our knowledge, this is the first study to demonstrate an induction of PSA during early infancy by bioactive T in normally developing human males. We conclude that urinary PSA is a non-invasive, useful indicator for developmental studies from neonatal and adolescent males, which can be measured with a confirmatory semiquantitative PSA assay.

Urinary prostate specific antigen: is the clinical use likely?

Prostate specific antigen (PSA) blood test represents the standard procedure in prostate cancer (CaP) diagnosis and follow-up. However, determination of PSA in the urine, where PSA is present in much higher concentrations than in the blood, still remains in the field of research.

OBJECTIVES

To determine urinary concentrations of PSA (uPSA) in different groups of patients (pts.), and to estimate is it possible to differentiate benign and malignant prostate diseases and to follow-up the results of treatment.

METHODS

Between January 2001. and November 2003., urinary concentrations of PSA were determined at 142 pts. divided in seven groups: 1. young and healthy volunteers, 2. "BPH-24": pts. with benign prostatic hyperplasia (BPH) who collected the sample of 24-hour voided urine, 3. "BPH-I": pts. with BPH who collected the first portion of first urinary voiding, 4. "TRUS-CaP": pts. with CaP which gave the first portion of urine just prior to transrectal ultrasound-guided prostate biopsy (TRUS- biopsy), 5. "TRUS-non-CaP": pts. who gave first portion of urine prior to TRUS-biopsy, but biopsy did not prove the presence of CaP, 6. "RRP": pts. who underwent radical retropubic prostatectomy (RRP), 7. "AAT": pts. who underwent androgen deprivation therapy.

RESULTS

Average uPSA value in the group of young and healthy volunteers, was 13.8 +/- 19.6 ng/ml, in "BPH-24": 38.0 +/- 44.4 ng/ml, in "BPH-I": 140.8 +/- 140.9 ng/ml, in "TRUS-CaP": 234.8 +/- 277.7 ng/ml, in TRUS-non-CaP: 113.1 +/- 148.5 ng/ml, and in the group "RRP": 4.4 +/- 4.7 ng/ml. There was no statistically significant difference of average uPSA values between "BPH-I" and "TRUS-CaP" groups. The significant difference was found between the group of young volunteers and "BPH-I". In "TRUS-CaP" group, there was strong correlation between tumour size and aggressivenes and uPSA concentration. Finally, PSA and uPSA decline during androgen deprivation therapy, strongly correlated (up to r = 0.95).

CONCLUSIONS

Determination of uPSA cannot differentiate BPH and CaP. However, in the group of pts. with proven localized CaP, uPSA can provide additional information concerning T-staging. Moreover, simultaneous monitoring of PSA and uPSA response on hormonal therapy, can provide an early recognition of androgen-indiferent CaP (AIPCA) and hormone-resistent CaP (HRPCA).

Resin-based micropipette tip for immunochromatographic assays in urine samples

A novel bioanalysis system based on immunochromatography was developed in connection with a nitrocellulose resin modified micropipette tip, such as ZipTip. The sandwich-type immunoassay was applied to our bioanalysis system. The simple handling of the micropipette enabled us to increase the sample volume and detect low concentrations of target antigens in urine samples. In addition, the washing procedure could also be performed easily to reduce the background signal levels. For analytical evaluations, the color intensity was captured by a flatbed scanner, and processed by a software. We have achieved the detection of human chorionic gonadotropin (hCG) and prostate-specific antigen (PSA). The detection limit of hCG was 0.5 ng/ml (0.05 ng/tip), which is comparable to that of other conventional immunochromatographic systems. Moreover, the detection of PSA was greatly improved over the existing systems with the application of different sample volumes, such as 1 ng/ml (0.2 ng/tip) in a 200 microl sample volume, and 1 ng/ml (0.3 ng/tip) in 300 microl sample volume. Our bioanalysis system is a promising candidate for application to point-of-care tests with its simple handling and high sensitivity.

APTIMA PCA3 molecular urine test: development of a method to aid in the diagnosis of prostate cancer

BACKGROUND

Prostate cancer gene 3 (PCA3) encodes a prostate-specific mRNA that has shown promise as a prostate cancer diagnostic tool. This report describes the characterization of a prototype quantitative PCA3-based test for whole urine.

METHODS

Whole-urine specimens were collected after digital rectal examination from 3 groups: men scheduled for prostate biopsy (n = 70), healthy men (<45 years of age with no known prostate cancer risk factors; n = 52), and men who had undergone radical prostatectomy (n = 21). PCA3 and prostate-specific antigen (PSA) mRNAs were isolated, amplified, and quantified by use of Gen-Probe DTS400 Systems. Prostate biopsy results were correlated with the PCA3/PSA mRNA ratio, and PSA mRNA concentrations were used to normalize PCA3 signals and confirm the yield of prostate-specific RNA. Assay precision, specimen stability, and mRNA yield were also evaluated.

RESULTS

The specimen informative rate (fraction of specimens yielding sufficient RNA for analysis) was 98.2%. In this clinical research study, ROC curve analysis of prebiopsy specimens yielded an area under the curve of 0.746; sensitivity was 69% and specificity 79%. Serum PSA assay specificity was 28% for this same group. PCA3 and PSA mRNAs were undetectable in postprostatectomy specimens except for one man with recurrent prostate cancer. Assay interrun CVs were < or =12%. Both mRNAs were stable in processed urine up to 5 days at 4 degrees C and after 5 freeze-thaw cycles.

CONCLUSION

The APTIMA PCA3 assay combines simple specimen processing with precise assays and existing instruments and could add specificity to the current algorithm for prostate cancer diagnosis.

Urinary/serum prostate-specific antigen ratio: comparison with free/total serum prostate-specific antigen ratio in improving prostate cancer detection

OBJECTIVES

To test the previously reported hypothesis, that the urinary/total serum (U/S) prostate-specific antigen (PSA) ratio improves the detection of prostate cancer, by evaluating the clinical usefulness of the U/S PSA ratio and comparing it with the free/total (F/T) serum PSA ratio.

METHODS

A total of 165 patients undergoing transrectal ultrasound-guided prostate biopsy were prospectively included in this multicenter study. In all patients, PSA was measured from preoperative serum and 12-hour urine specimens in a centralized laboratory.

RESULTS

Prostate cancer was identified in 83 of 165 patients. The differences between patients with and without prostate cancer were statistically significant (P <0.001) when considering the total PSA value (median, 10.2 ng/mL and 6.6 ng/mL respectively), F/T serum PSA ratio (0.11 and 0.18), and U/S PSA ratio (1.2 and 4.2). In the group of 79 patients with a PSA level between 4 and 10 ng/mL, receiver operating characteristic curves showed that the U/S PSA ratio was associated with a larger area under the curve (0.63; 95% confidence interval, 0.51 to 0.73) than the total PSA value (0.55; 95% confidence interval, 0.43 to 0.66) or F/T serum PSA ratio (0.60; 95% confidence interval, 0.49 to 0.71). The U/S PSA ratio did not correlate with patient age or prostate volume.

CONCLUSIONS

Our results confirmed that the U/S PSA ratio may be a useful test in prostate cancer detection when the total serum PSA level is between 4 and 10 ng/mL. The F/T serum PSA ratio and U/S PSA ratio did not correlate. This suggests that these two tests could complement each other.

Adherence to a low-fat diet in men with prostate cancer

OBJECTIVES

To evaluate, in a feasibility study, the adherence to a low-fat diet by men with prostate cancer. Evidence is growing that a low-fat diet affects the development and course of prostate cancer. To design preventive and therapeutic interventions, it is important to know whether men will adhere to these nutritional recommendations, particularly when motivated by the diagnosis of prostate cancer.

METHODS

Men with elevated prostate-specific antigen levels, most of whom were recently treated for prostate cancer, were randomized to one of four dietary regimens for which they received nutritional counseling: a low-fat diet (15% fat or less) with supplements (vitamin E and selenium), a low-fat diet (15% fat or less) without the supplements, the supplements alone, and a control group. Adherence was evaluated by the change in weight, fat intake, free fatty acids, cholesterol, high-density and low-density lipoproteins, and triglycerides during a 12-month period.

RESULTS

The mean age of the 48 participants was 66 years. For those counseled about a low-fat diet, the mean change in the percentage of energy (kilocalories) in the diet from fat was greater after 3 months (-8.6% versus +2.1%, P <0.001) and 12 months (-9.8% versus -1.6%, P = 0.001). Three months after starting the intervention, those randomized to low-fat dietary counseling had lost 2 kg, on average, compared with 0.8 kg lost by those who did not receive this counseling (P = 0.09). At 12 months, those receiving low-fat counseling had lost 2.8 kg, on average, compared with 0.5 kg gained among the other groups (P = 0.02).

CONCLUSIONS

With appropriate counseling, men with prostate cancer can adhere to a low-fat dietary intervention for a 12-month period.

Use of thymosin beta15 as a urinary biomarker in human prostate cancer

BACKGROUND

Additional prostate cancer (CaP) biomarkers are needed to increase the accuracy of diagnosis and to identify patients at risk of recurrence. In tissue-based assays, thymosin beta15 (Tbeta15) has been linked to an aggressive CaP phenotype and correlated with future tumor recurrence. We hypothesized that Tbeta15 may have clinical utility in biological fluids.

METHODS

Tbeta15 was measured in urine from CaP patients; untreated (N = 61), prostatectomy (RP, N = 46), androgen deprivation therapy (ADT, N = 14) and control groups; normal (N = 52), genitourinary carcinoma (N = 15), non-malignant prostate disease (N = 81), and other urology (N = 73). We evaluated the utility of urinary Tbeta15 for CaP diagnosis, alone or in combination with prostate-specific antigen (PSA), and the relationship to CaP progression.

RESULTS

A normal threshold of 40 (ng/dl)/(mug_protein/mg_creatinine) was defined using receiver operating characteristic analysis and marked the 19th centile for age-matched controls. The proportion of untreated CaP patients with urinary Tbeta15 above the threshold was significantly higher than normal and genitourinary disease controls (P < 0.001). RP caused urinary Tbeta15 to drop significantly (P = 0.005). Pre-surgery Tbeta15 concentrations greater than the normal threshold may confer greater risk of CaP recurrence. Relative to normal controls, patients receiving ADT for aggressive CaP were 12 times more likely to have elevated urinary Tbeta15 (P = 0.001, 95% CI = 2.8, 51.8). Combining PSA and Tbeta15 (PSA > 4, or PSA > 2.5, Tbeta15 > 40, or PSA = 2.5, Tbeta15 > 90) provided the same sensitivity as a 2.5 ng/ml PSA cutoff, but markedly improved diagnostic specificity.

CONCLUSIONS

We report that Tbeta15 is a urinary biomarker for CaP and suggest that Tbeta15, in combination with PSA, can be used to improve both the sensitivity and specificity of CaP diagnosis.

Glycosylation of urinary prostate-specific antigen in benign hyperplasia and cancer: assessment by lectin-binding patterns

OBJECTIVES

In the present study, we examined the glycosylation of urinary prostate-specific antigen (PSA) from benign prostatic hyperplasia (BPH) and prostate cancer (PCa) subjects, specifically looking at alterations in its oligosaccharide chain as a potential biomarker of these pathophysiological conditions.

DESIGN AND METHODS

First morning urine voids were collected from subjects with PCa and BPH before initiation of any treatment. Urinary PSA was characterized by ion-exchange chromatography, followed by lectin affinity chromatography on the columns using immobilized plant lectins.

RESULTS

Four isoforms of urinary PSA from both BPH and PCa samples were separated by ion-exchange chromatography. The elution profiles from lectin-affinity columns reflected molecular heterogeneity of PSA isoforms and the main differences observed were in the reactivity to Ulex europaeus agglutinin, Aleuria aurantia agglutinin, Phaseolus vulgaris erythroagglutinin and Phaseolus vulgaris leukoagglutinin.

CONCLUSIONS

The observed differences in the lectin reactivities between BPH PSA and PCa PSA may be of clinical importance in the evaluation of prostate health.

Clinical relevance of genetic instability in prostatic cells obtained by prostatic massage in early prostate cancer

We investigated whether genetic lesions such as loss of heterozygosity (LOH) are detected in prostatic cells obtained by prostatic massage during early diagnosis of prostate cancer (CaP) and discussed their clinical relevance. Blood and first urine voided after prostatic massage were collected in 99 patients with total prostate-specific antigen (PSA) between 4 and 10 ng ml⁻¹, prior to prostate biopsies. Presence of prostatic cells was confirmed by quantitative RT–PCR analysis of PSA mRNA. Genomic DNA was analysed for LOH on six chromosomal regions. One or more allelic deletions were found in prostatic fluid from 57 patients analysed, of whom 33 (58%) had CaP. Sensitivity and specificity of LOH detection and PSA free to total ratio <15% for positive biopsy were respectively 86.7 and 44% (P=0.002) for LOH, and 55 and 74% (P=0.006) for PSA ratio <15%. Analysis of LOH obtained from prostatic tumours revealed similar patterns compared to prostatic fluid cells in 86% of cases, confirming its accuracy. The presence of LOH of urinary prostatic cells obtained after prostatic massage is significantly associated with CaP on biopsy and may potentially help to identify a set of patients who are candidates for further prostate biopsies.

DD3(PCA3)-based molecular urine analysis for the diagnosis of prostate cancer

BACKGROUND

DD3(PCA3) is the most prostate cancer-specific gene described to date. To assess the clinical utility of DD3(PCA3) a time-resolved fluorescence-based, quantitative RT-PCR analysis for DD3(PCA3) was developed.

METHODS

The diagnostic potential of DD3(PCA3) was determined by quantitative measurement of DD3(PCA3) transcripts in non-malignant and malignant prostate specimens. Moreover, DD3(PCA3) transcripts were determined quantitatively in urine sediments obtained after prostatic massage. A cohort of 108 men, admitted for prostate biopsies based on a PSA of >3ng/ml, was studied.

RESULTS

Prostate tumors showed a 66-fold up-regulation of DD3(PCA3) (median 158.4.10(5) copies/microg tissue RNA) when compared to benign prostate tissue (median 2.4.10(5) copies/microg tissue RNA). This up-regulation was found in more than 95% of prostate cancer specimens studied. These data revealed that specimens with less than 10% of cancer cells could be accurately discriminated from non-cancer tissues. Hence, detection of a small fraction of prostate cancer cells in a background of normal cells seemed feasible. Therefore, this DD3(PCA3)-based RT-PCR assay was used for the identification of prostate cancer in urine sediments obtained after prostatic massage. From 108 men with a serum PSA value >3ng/ml, 24 men were shown to have prostate cancer upon biopsy. Of these 24 men, 16 were shown to be positive for DD3(PCA3), indicating a sensitivity of the assay of 67%. Furthermore, a negative predictive value of 90% was calculated.

CONCLUSION

The quantitative RT-PCR assay for DD3(PCA3) described, bears great promise as a tool for molecular urine analysis. It has great potential in reducing the number of unnecessary biopsies. A multi-center study using this DD3(PCA3) assay can provide the basis for the utility of molecular diagnostics in clinical urological practice.

[Diagnostic and prognostic value of quantitative monitoring of prostate specific antigen in blood serum and urine from patients with prostate cancer after radical prostatectomy]

AIM

To study values of prostate-specific antigen (PSA) in the blood serum and urine before and after massage of the prostatic bed in patients with prostatic cancer (PC) after radical prostatectomy.

MATERIAL AND METHODS

Changes in serum and urine PSA concentrations were followed up in 17 patients with PC (T2-3N0M0) 14 months (4-24 mon) after radical prostatectomy. Control examinations were made once a month. MRT or CT and osteoscintigraphy were made in suspected recurrence and/or metastases of PC.

RESULTS

There were no changes in PSA consentrations in the serum and urine before and after the massage of prostatic bed in 10 of 17 patients. In 3 patients PSA concentrations in blood and serum increased after the massage, in one of them blood levels of PSA after the massage went up 5 months after PSA increase in the urine. In 4 of 17 patients urine PSA levels increased after the massage, the blood levels remaining the same.

CONCLUSION

Follow-up measurements of blood and urinary levels in PC patients after radical prostatectomy before and following massage of the prostatic bed allow detection of prostatic PSA-positive cells which were not removed at surgery. We suggest that these cells may be the basis of recurrent disease.

Use of the "SMITEST" PSA card to identify the presence of prostate-specific antigen in semen and male urine

To determine whether the prostate-specific antigen (PSA) could be identified in semen using the "SMITEST" PSA immunochromatographic membrane test card, we examined semen and other body fluids, including urine. Although PSA activity was detected in semen with high sensitivity using the "SMITEST" PSA card, it was also detected in adult male urine. However, the lower detectable limit in the urine was 1000-fold lower than that in semen. The concentration of PSA in adult male urine was found to be 800 ng/ml using the card. PSA activity usually can be detected in urine of individuals over 14 years old and it has been detected in urine from children as young as 11 years old. Therefore, the appearance of PSA in urine may occur anytime between the age of 12 and 14 years. To determine the stability of PSA activity in urine, dried samples of urine on filter paper were kept at room temperature for up to 3 years. Although the immunoreactive line showing PSA activity became weak after storage, it was still detectable, but faint, after 3 years. In addition, PSA activity was not detected in male serum or saliva and in the urine from human females, male cats or male dogs using the PSA card. We conclude that the PSA card is useful for identification of PSA in both semen and adult male urine.

Prostate-specific antigen in female urine: a prospective study involving 217 women

OBJECTIVES

Histomorphologic studies have provided evidence of prostate-specific antigen (PSA)-producing tissue in the female urethra. Some urine samples from women in a small series were positive for PSA, but no systematic investigation of this subject has been done to date.

METHODS

In a prospective study, we analyzed whether PSA occurs in the urine of women and what factors induce detectable PSA levels. The urine samples of 217 women were analyzed (Hybritech-Tandem E-PSA) under standardized conditions. The impact of urine pH and volume was investigated, and the results were correlated with clinical data (age, residual urine, urinary tract infection and prior sexual intercourse within 48 hours).

RESULTS

A positive PSA level greater than the detection limit of 0.1 ng/mL was found in 11% of the analyzed samples; their mean value was 0.29 ng/mL. pH correction did not result in a significant difference. The voiding volume had no influence on the PSA level. Among the cases of detectable PSA, women younger than 50 years of age (n = 14) had a mean PSA of 0.34 ng/mL and those older than 50 years (n = 9) a mean of 0.23 ng/mL. One of 9 women with and 22 of 208 women without residual urine volume had a detectable PSA level, as did 0 of 20 with and 23 of 197 women without urinary tract infection, and 3 of 7 with and 20 of 210 women without prior sexual intercourse within the previous 48 hours. None of the differences were significant.

CONCLUSIONS

A urine PSA level was detected in 11% of all women studied, with PSA values apparently age dependent. Any urine portion is suitable for analysis. No influence was determined for residual urine volume or urinary tract infection. Sexual intercourse may cause detectable PSA values, but the data of this study did not provide sufficient evidence for this hypothesis.

Prostate-specific antigen and human glandular kallikrein 2 are markedly elevated in urine of patients with polycystic ovary syndrome

Prostate-specific antigen (PSA) is a well-established tumor marker of prostatic adenocarcinoma. Human glandular kallikrein 2 (hK2), another serine protease closely related to PSA, is also gaining ground as a promising diagnostic tool in prostate cancer. The expression of these 2 proteases is known to be regulated by androgens and progestins in hormonally responsive tissues, such as the male prostate and the female breast. Previously, we have shown that serum PSA levels in normal women are very low but still detectable by ultrasensitive PSA immunoassays. We have also demonstrated that some women with hyperandrogenic syndromes have elevated serum PSA levels. In this study, we have measured urinary PSA and urinary hK2 levels in 35 polycystic ovary syndrome (PCOS) patients and compared them to those of 41 age-matched controls. We found that urinary PSA levels were significantly higher (P < 0.0001) in PCOS patients (mean +/- SE = 820 +/- 344 ng/L) than in the controls (mean +/- SE = 4.3 +/- 1.8 ng/L). Similarly, the difference between urinary hK2 of patients (mean +/- SE = 8.2 +/- 3.1 ng/L) and controls (0.5 +/- 0.3 ng/L) was also significant (P < 0.001). A weak correlation was observed between urinary PSA and serum 3 alpha-androstanediol glucuronide (r(s) = 0.42, P = 0.03) as well as between urinary PSA and serum testosterone (r(s) = 0.40, P = 0.04). The results of this study indicate that urinary PSA, and possibly urinary hK2, are promising markers of hyperandrogenism in females suffering from PCOS.

Prostate-specific antigen

Serum prostate-specific antigen (PSA) measurements are the most useful serum biomarker to aid in early prostate cancer detection, clinical staging and therapeutic monitoring. Although the optimal use of PSA testing remains controversial, population based studies suggest that PSA screening reduces prostate cancer mortality. Customizing screening protocols based on individual risk factors and PSA level may be a useful approach to reduce overall costs incurred by widespread PSA testing. Lowering PSA cut-offs (i.e., from 4.0 ng/ml to 2.5 ng/ml) may reduce advanced stage prostate cancer, and the use of different PSA derivatives and PSA forms may reduce 'unnecessary' biopsies in some men. In addition to prostate cancer, manipulation and benign diseases of the prostate falsely elevate serum PSA levels. In contemporary clinical practice, PSA testing plays an important role in prostate cancer diagnosis and treatment.

Serum-to-urinary prostate-specific antigen ratio in patients with benign prostatic hyperplasia and prostate cancer

BACKGROUND

Prostate-specific antigen (PSA) is the single most important tumor marker in early detection and monitoring of prostate cancer (CaP). However, routine analysis of serum PSA concentrations does not allow differentiation between CaP and prostatic diseases. The aim of the present study was to evaluate the usefulness of the serum-to-urinary PSA ratio in a clinical setting.

MATERIALS AND METHODS

In a retrospective clinical study, we determined serum and urine PSA concentrations in 48 patients with benign prostatic hyperplasia (BPH) and 57 patients with histologically confirmed CaP.

RESULTS

The serum-to-urinary PSA ratio is able to discriminate BPH from CaP.

CONCLUSIONS

Determination of the serum-to-urinary PSA ratio enhances the specificity of PSA in screening for CaP and monitoring of patients with CaP under androgen deprivation therapy.

Serum and urinary prostate-specific antigen and urinary human glandular kallikrein concentrations are significantly increased after testosterone administration in female-to-male transsexuals

BACKGROUND

The genes that encode prostate-specific antigen (PSA) and human glandular kallikrein (hK2) are up-regulated by androgens and progestins in cultured cells, but no published studies have described the effect of androgen administration in women on serum and urinary PSA or hK2.

METHODS

We measured serum and urinary PSA and hK2 before, and 4 and 12 months post testosterone treatment by immunofluorometric methods in 32 female-to-male transsexuals.

RESULTS

Mean serum PSA increased from 1.1 ng/L to 11.1 ng/L and then to 22 ng/L by 4 and 12 months post treatment, respectively; the corresponding mean values in urine were 17, 1420, and 18 130 ng/L, respectively. Serum hK2, another kallikrein closely related to PSA, remained undetectable at the three time points. However, urinary hK2 concentration rose from below the detection limit (<6 ng/L) before treatment to 18 and 179 ng/L by the 4th and the 12th month of treatment, respectively. All changes were statistically significant (P <0.001) at 4 months.

CONCLUSIONS

Testosterone administration increases serum and urinary PSA and urinary hK2 in women. These measurements may be useful as indicators of androgenic stimulation in women.

A dual-monoclonal sandwich assay for prostate-specific membrane antigen: levels in tissues, seminal fluid and urine

BACKGROUND

Prostate-specific membrane antigen (PSMA) is a 750-residue integral membrane glycoprotein and the target of an in-vivo imaging agent for metastatic prostate carcinoma (PCa). PSMA expression in normal and diseased prostatic tissues has previously been demonstrated by immunohistochemical techniques. In order to quantify PSMA levels in tissue homogenates and physiological fluids, we have developed a dual monoclonal antibody (mAb) sandwich assay which detects the antigen at a sensitivity <1 ng/mL and which is linear across the working range 0-50 ng/mL.

METHODS

The assay involves capture of the PSMA by a biotinylated mAb (7E11) immobilized onto a streptavidin-coated microtiter plate; this mAb binds to the N-terminus of the antigen. The captured PSMA is detected by an Eu-labelled mAb (PEQ226) which binds in the region corresponding to Residues 134-437 of the antigen. PSMA was purified from LNCaP cells by immunoaffinity chromatography, and used as a calibrator, based on its concentration by the bicinchoninic acid (BCA) protein assay.

RESULTS

The assay was applied to a panel of normal and tumor tissues. Levels were highest in the prostate tissues (292-4254 ng/mg protein). Low levels (21-51 ng/mL) were observed in membranes from ovary and breast, and neglible levels (1-10 ng/mg) in membranes from skin, liver, intestine, and kidney. Levels in the corresponding cytosol fractions were 20-to 50-fold lower. The average PSMA level in seminal fluid from 21 donors was 9, 012 ng/mL. On average, levels in normal-male urine (3.47 ng/mL) were ten-fold higher than in normal-female urine (0.3 ng/mL).

CONCLUSIONS

This report is the first to describe absolute quantitation of PSMA in tissues and fluids. Congruent with earlier tissue studies based on immunohistochemical staining and Western-blot analysis, prostate tissue membranes expressed the highest levels of PSMA.

Dramatic suppression of plasma and urinary prostate specific antigen and human glandular kallikrein by antiandrogens in male-to-female transsexuals

PURPOSE

Prostate specific antigen (PSA) and human glandular kallikrein (hK2) are mainly produced by the prostate and their genes are regulated by androgens through the androgen receptor. We determine whether PSA and hK2 change significantly in plasma and urine after antiandrogen treatment in male-to-female transsexuals.

MATERIALS AND METHODS

Plasma and urine PSA and hK2 were measured with highly sensitive immunofluorometric procedures capable of detecting within 1 or 6 ng./l. PSA or hK2, respectively. Study groups consisted of 10 men treated with cyproterone acetate only (group 1), 15 transdermal estradiol plus cyproterone acetate (group 2) and 31 ethinyl estradiol plus cyproterone acetate (group 3). Plasma and urine samples were collected before initiation of treatment as well as after 4 months of hormonal therapy. For a subset of group 3 patients blood and urine samples were also obtained after 12 months of treatment.

RESULTS

Cyproterone acetate, a steroidal antiandrogen, alone or with estradiol was able to suppress greater than 90% of plasma and urinary PSA and hK2 concentration after 4 or 12 months of therapy.

CONCLUSIONS

Cyproterone acetate therapy causes dramatic suppression of plasma and urinary PSA and hK2 in men without prostate cancer. Since cyproterone acetate is used for prostate cancer treatment, suppression of PSA after hormonal therapy may not accurately reflect therapy success in reducing tumor burden.