Evaluation of prostate-specific antigen and prostatic acid phosphatase as prostate cancer markers

Enzymes as indispensable markers in disease diagnosis

Enzymes have been used for disease diagnosis for many decades; however, advancements in technology like ELISA and flow cytometry-based detection have significantly increased their use and have increased the sensitivity of detection. Technological advancements in recombinant enzyme production have increased enzymatic stability, and the use of colorimetric-based and florescence-based assays has led to their increased use as biomarkers for disease detection. Enzymes like acid phosphatase, cathepsin, lactate dehydrogenase, thymidine kinase and creatine kinase are indispensable markers for diagnosing cancer, cardiovascular diseases and others. This minireview summarizes various enzymes used in disease diagnosis, their metabolic role, market value and potential as disease markers across various metabolic and other disorders.

Physical and in silico immunopeptidomic profiling of a cancer antigen prostatic acid phosphatase reveals targets enabling TCR isolation

Tissue-specific antigens can serve as targets for adoptive T cell transfer-based cancer immunotherapy. Recognition of tumor by T cells is mediated by interaction between peptide-major histocompatibility complexes (pMHCs) and T cell receptors (TCRs). Revealing the identity of peptides bound to MHC is critical in discovering cognate TCRs and predicting potential toxicity. We performed multimodal immunopeptidomic analyses for human prostatic acid phosphatase (PAP), a well-recognized tissue antigen. Three physical methods, including mild acid elution, coimmunoprecipitation, and secreted MHC precipitation, were used to capture a thorough signature of PAP on HLA-A*02:01. Eleven PAP peptides that are potentially A*02:01-restricted were identified, including five predicted strong binders by NetMHCpan 4.0. Peripheral blood mononuclear cells (PBMCs) from more than 20 healthy donors were screened with the PAP peptides. Seven cognate TCRs were isolated which can recognize three distinct epitopes when expressed in PBMCs. One TCR shows reactivity toward cell lines expressing both full-length PAP and HLA-A*02:01. Our results show that a combined multimodal immunopeptidomic approach is productive in revealing target peptides and defining the cloned TCR sequences reactive with prostatic acid phosphatase epitopes.

Use of MS-GUIDE for identification of protein biomarkers for risk stratification of patients with prostate cancer

Background

Non-invasive liquid biopsies could complement current pathological nomograms for risk stratification of prostate cancer patients. Development and testing of potential liquid biopsy markers is time, resource, and cost-intensive. For most protein targets, no antibodies or ELISAs for efficient clinical cohort pre-evaluation are currently available. We reasoned that mass spectrometry-based prescreening would enable the cost-effective and rational preselection of candidates for subsequent clinical-grade ELISA development.

Methods

Using Mass Spectrometry-GUided Immunoassay DEvelopment (MS-GUIDE), we screened 48 literature-derived biomarker candidates for their potential utility in risk stratification scoring of prostate cancer patients. Parallel reaction monitoring was used to evaluate these 48 potential protein markers in a highly multiplexed fashion in a medium-sized patient cohort of 78 patients with ground-truth prostatectomy and clinical follow-up information. Clinical-grade ELISAs were then developed for two of these candidate proteins and used for significance testing in a larger, independent patient cohort of 263 patients.

Results

Machine learning-based analysis of the parallel reaction monitoring data of the liquid biopsies prequalified fibronectin and vitronectin as candidate biomarkers. We evaluated their predictive value for prostate cancer biochemical recurrence scoring in an independent validation cohort of 263 prostate cancer patients using clinical-grade ELISAs. The results of our prostate cancer risk stratification test were statistically significantly 10% better than results of the current gold standards PSA alone, PSA plus prostatectomy biopsy Gleason score, or the National Comprehensive Cancer Network score in prediction of recurrence.

Conclusion

Using MS-GUIDE we identified fibronectin and vitronectin as candidate biomarkers for prostate cancer risk stratification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12014-022-09349-x.

Should We Call It a Prostate? A Review of the Female Periurethral Glandular Tissue Morphology, Histochemistry, Nomenclature, and Role in Iatrogenic Sexual Dysfunction

INTRODUCTION

There is evidence of glandular tissue within the region of the anterior vaginal wall-female periurethral tissue (AVW-FPT) having similar morphology and immunohistochemistry to the prostate in men and having physiological roles in the female sexual response (FSR). Whether this tissue should be called a prostate in women has been debated. Iatrogenic injury to structures of the AVW-FPT, including these glands and the associated neurovasculature, could be a cause of female sexual dysfunction (FSD).

OBJECTIVES

To consolidate the current knowledge concerning the glandular tissue surrounding the urethra in women, evidence was reviewed to address whether: (i) these glands comprise the prostate in women, (ii) they have specific functions in the FSR, and (iii) injury to the AVW-FPT and prostate has sexual dysfunction as a likely outcome.

METHODS

A literature review was conducted using keywords including female prostate, Skene's/paraurethral glands, periurethral tissue, Gräfenberg (G)-spot, female ejaculation, mid-urethral sling (MUS), and sexual dysfunction.

RESULTS

Histological and immunohistochemical studies of the glandular tissue surrounding the urethra support the existence of prostate in women. Evidence suggests this tissue may have physiologically and clinically relevant autonomic and sensory innervation, and during sexual arousal may contribute to secretions involved in ejaculation and orgasm. Gaps in knowledge relating to the functional anatomy, physiological roles, and embryological origins of this tissue have impeded the acceptance of a prostate in women. Injury to the innervation, vasculature, and/or glandular tissue within the surgical field of MUS implantation suggests iatrogenic sexual dysfunction is plausible.

CONCLUSIONS

Continuing to advance our understanding of the morphology, histochemistry, and physiologic capacity of this glandular tissue will clarify the characterization of this tissue as the "prostate" involved in the FSR, and its role in FSD following surgical injury. Tomalty D, Giovannetti O, Hannan J, et al. Should We Call It a Prostate? A Review of the Female Periurethral Glandular Tissue Morphology, Histochemistry, Nomenclature, and Role in Iatrogenic Sexual Dysfunction. Sex Med Rev 2021;XX:XXX-XXX.

Utility of cardiac biomarkers in sports medicine: Focusing on troponin, natriuretic peptides, and hypoxanthine

Evidence-based consensus suggests that physical activity and regular exercise training can reduce modifiable risk factors as well as rate of mortality and morbidity in patients with chronic diseases, such as cardiovascular disease (CVD), diabetes, obesity and cancer. Conversely, long-term exercise training and drastic increase in vigorous physical activity may also cause acute cardiovascular events (e.g. acute myocardial infarction) and deleterious cardiac remodeling, particularly when exercise is performed by unfit or susceptible individuals. There is a reversed J-shaped hormesis-like curve between the duration and intensity of exercise and level of CVD risks. Therefore, it is important for an early detection of cardiac injuries in professional and amateur athletes. Under this context, this article focuses on the use of biomarker testing, an indispensable component in the current clinical practices especially in Cardiology and Oncology. We attempt to justify the importance of using circulating biomarkers in routine practices of Sports Medicine for an objective assessment of CVD events following exercise. Special attentions are dedicated to three established or emerging cardiac biomarkers (i.e. cardiac troponins, natriuretic peptides, hypoxanthine) for myocardial tissue hypoxia/ischemia events, muscle stress, and the consequent cellular necrotic injury. Based on these focused analyses, we propose use of circulating biomarker testing in both laboratory and point-of-care settings with an increasingly broader involvement or participation of team physicians, trainers, coaches, primary care doctors, as well as educated athlete community. This diagnostic approach may improve the quality of medical surveillance and preventive measures on exercise-related CVD risks/outcomes.

Effects of the Training About Prostate Cancer and Screening Methods on Knowledge Level

This quasi-experimental study aims to identify the effects of the training about prostate cancer and screening methods given to men aged 40 and over on their knowledge level. It was found that there were no differences between the experimental and control groups in terms of the perceived susceptibility, perceived seriousness, health motivation, perceived barriers, and perceived benefits subscale mean scores, but the posttest data revealed that the perceived susceptibility, health motivation, and perceived benefits subscale mean scores of the experimental group were higher and their perceived barriers mean score was lower; the differences between the mean scores were statistically significant (p < .05, p < .01, p < .001). An analysis of the Health Belief Model after the training about prostate cancer and screening methods showed that the training was effective. Actually, the authors recommended that especially male nurses can play an effective role in training about prostate cancer and screening methods for men in Turkey.

Instructed-Assembly of Small Peptides Inhibits Drug-Resistant Prostate Cancer Cells

Despite multiple new-drug approvals in recent years, prostate cancer remains a global health challenge because of the prostate cancers are resistant to androgen deprivation therapy. Here we show that a small D-phosphopeptide undergoes prostatic acid phosphatase (PAP)-instructed self-assembly for inhibiting castration-resistant prostate cancer (CRPC) cells. Specifically, the installation of phosphate at the C-terminal of a D-tripeptide results in the D-phosphopeptide. Dephosphorylating the D-phosphopeptide by PAP forms uniform nanofibers that inhibit VCaP, a castration-resistant prostate cancer cell. A non-hydrolyzable phosphate analogue of the D-phosphopeptide, which shares similar self-assembling properties with the D-phosphopeptide, confirms that PAP-instructed assembly is critical for the inhibition of VCaP. This work, for the first time, demonstrates PAP-instructed self-assembly of peptides for selective inhibiting castration-resistant prostate cancer (CRPC) cells.

Pre- and early postoperative GFAP serum levels in glioma and brain metastases

SUBJECT

To date there is no established tumor marker for the clinical follow-up of glioblastoma, WHO grade IV, (GBM) which constitutes the most frequent and malignant primary brain tumor. However, since there is promising data that the serum glial fibrillary acidic protein (sGFAP) may serve as a biomarker for glial brain tumors, this prospective study aimed at evaluating the diagnostic relevance of perioperative changes in sGFAP levels for the assessment of residual glial tumor tissue in patients undergoing surgery of intracerebral tumors.

METHODS

Serum GFAP was measured using an electrochemiluminometric immunoassay (ElecsysR GFAP prototype test, Roche Diagnostics, Penzberg/Germany) in 32 prospectively recruited patients between September 2009 and August 2010. Twenty-five were diagnosed with glioma and seven with brain metastases (BM). We assessed sGFAP levels prior to and at different time points during the early postoperative phase until patient discharge.

RESULTS

There were only significant differences in the pre-operative sGFAP levels of patients with gliomas compared to BM (0.18 vs. 0.08 µg/l; p = 0.0198, Welch's t-Test). Even though there was an increase of sGFAP after surgery, there were no significant differences between glioma and BM patients at any other time point. Peak sGFAP levels where reached on postoperative day 1 followed by a slight decrease, but not reaching pre-operative levels until postop day 7. There was no significant correlation between postoperative glioma tumor volume and sGFAP levels in univariate analyses.

CONCLUSION

According to our data sGFAP does not appear to be suitable to detect residual glioma tissue in the acute postoperative phase.

Incidence and mortality of prostate cancer and their relationship with the Human Development Index worldwide

Background

The aim of this study was to evaluate the incidence and mortality of prostate cancer and their relationship with the Human Development Index (HDI) and its components in Asia in 2012.

Methods

This study was an ecological study conducted based on the GLOBOCAN project of the World Health Organization. The correlation between standardized incidence rate (SIR) and standardized mortality rate (SMR) of prostate cancer with HDI and its components was assessed using SPSS Inc Version 18.0 (Chicago).

Results

There were 1,094,916 incident cases of prostate cancer and 307,481 deaths recorded in 2012 worldwide. SIR and SMR due to HDI were 72 and 9.7 in very high human development regions, 37.5 and 12.9 in high human development regions, 7 and 3.7 in medium human development regions, and 14.9 and 12.1 in low human development regions per 100,000 people, respectively. A positive correlation of 0.475 was seen between SIR of prostate cancer and HDI (P ≤ 0.001). Also, a negative correlation of 0.160 was seen between SMR of prostate cancer and HDI (P = 0.032).

Conclusion

The incidence of prostate cancer is high in countries with higher development. A positive correlation was observed between the SIR of prostate cancer and the HDI and its components, such as life expectancy at birth, mean years of schooling, and the gross national income per capita. In addition, there was a negative correlation between SMR and HDI.

The clinic-pathological characteristics of prostate cancer in an Irish subpopulation with a serum PSA less than 4.0ng/ml

Background:

Prostate specific antigen (PSA) has been used as a biomarker for prostate cancer for the last 20 years. Traditionally, a serum PSA <4 ng/ml has been used as a general cut-off between normal and abnormal readings. There is evidence to demonstrate that men with a normal serum PSA can develop prostate cancer. The aim of this study was to investigate the clinico-pathological features of prostate cancer in a non-screened Irish cohort with serum PSA <4 ng/ml.

Methods:

A retrospective analysis was performed of all patients who underwent radical retropubic prostatectomy (RRP) in a tertiary referral unit over a 10-year period (2000–2010). Clinico-pathological characteristics were collated including those from trans-rectal ultrasound-guided (TRUS) prostate biopsies and radical prostatectomy specimens.

Results:

Between 2000 and 2010, 651 men underwent an RRP, with 43 (6.6%) having a serum PSA <4 ng/ml. The median PSA was 3.2 ng/ml (range 0.8–4.0). Nineteen (44.2%) had palpable disease on direct rectal examination (DRE). Following prostatectomy, 28 (65.12%) had Gleason 6 disease, 14 (32.56%) had Gleason 7 disease and one (2.32%) had Gleason 8 disease. Five (11.63%) patients were upgraded from TRUS biopsy to final histopathology. Six (13.95%) patients had pathological evidence of extracapsular extension on final pathology. Three (6.98%) patients experienced biochemical recurrence and received salvage radiation therapy after a median time of 24 months. The median follow-up was 106 months (range 36–158). Twenty (46.51%) patients had a first-degree family history of prostate cancer.

Conclusions:

A PSA cut-off of 4 ng/ml has commonly been used in the detection of prostate cancer. Our study emphasizes that this cut-off is inappropriate and that no specific level of PSA can be used. Management decisions need to be individualized based on index of suspicion with concomitant counselling and rectal examination.

Emerging PSA-based tests to improve screening

This article updates advances in prostate cancer screening based on prostate-specific antigen, its derivatives, and human kallikrein markers. Many men are diagnosed with indolent disease not requiring treatment. Although there is evidence of a survival benefit from screening, the numbers needed to screen and treat remain high. There is risk of exposing men to the side effects of treatment for nonthreatening disease. A screening test is needed with sufficiently good performance characteristics to detect disease at an early stage so treatment may be offered with curative intent, while reducing the number of negative or unnecessary biopsies.

Tumour immunogenicity, antigen presentation and immunological barriers in cancer immunotherapy

Since the beginning of the 20^th century, scientists have tried to stimulate the anti-tumour activities of the immune system to fight against cancer. However, the scientific effort devoted on the development of cancer immunotherapy has not been translated into the expected clinical success. On the contrary, classical anti-neoplastic treatments such as surgery, radiotherapy and chemotherapy are the first line of treatment. Nevertheless, there is compelling evidence on the immunogenicity of cancer cells, and the capacity of the immune system to expand cancer-specific effector cytotoxic T cells. However, the effective activation of anti-cancer T cell responses strongly depends on efficient tumour antigen presentation from professional antigen presenting cells such as dendritic cells (DCs). Several strategies have been used to boost DC antigen presenting functions, but at the end cancer immunotherapy is not as effective as would be expected according to preclinical models. In this review we comment on these discrepancies, focusing our attention on the contribution of regulatory T cells and myeloid-derived suppressor cells to the lack of therapeutic success of DC-based cancer immunotherapy.

NY-ESO-1 antibody as a novel tumour marker of gastric cancer

BACKGROUND

NY-ESO-1 antibodies are specifically observed in patients with NY-ESO-1-expressing tumours. We analysed whether the NY-ESO-1 humoral immune response is a useful tumour marker of gastric cancer.

METHODS

Sera from 363 gastric cancer patients were screened by enzyme-linked immunosorbent assay (ELISA) to detect NY-ESO-1 antibodies. Serial serum samples were obtained from 25 NY-ESO-1 antibody-positive patients, including 16 patients with curative resection and 9 patients who received chemotherapy alone.

RESULTS

NY-ESO-1 antibodies were detected in 3.4% of stage I, 4.4% of stage II, 25.3% of stage III, and 20.0% of stage IV patients. The frequency of antibody positivity increased with disease progression. When the NY-ESO-1 antibody was used in combination with carcinoembryonic antigen and CA19-9 to detect gastric cancer, information gains of 11.2% in stages III and IV, and 5.8% in all patients were observed. The NY-ESO-1 immune response levels of the patients without recurrence fell below the cutoff level after surgery. Two of the patients with recurrence displayed incomplete decreases. The nine patients who received chemotherapy alone continued to display NY-ESO-1 immune responses.

CONCLUSION

When combined with conventional tumour markers, the NY-ESO-1 humoral immune response could be a useful tumour marker for detecting advanced gastric cancer and inferring the post-treatment tumour load in seropositive patients.

Performance characteristics of prostate-specific antigen in patients undergoing radical prostatectomy

OBJECTIVE

To assess the performance characteristics of prostate-specific antigen (PSA) for predicting the volume of total or high-grade cancer in men undergoing radical prostatectomy. It is known that the performance characteristics of PSA are improved for predicting the presence of high-grade prostate cancer.

METHODS

We identified 1459 patients from the Stanford Radical Prostatectomy Database with clinical Stage T1c (n = 783) and T2 (n = 676) disease who underwent surgery from 1988 to 2003 with detailed morphometric mapping. We generated receiver operating characteristic curves for PSA levels according to the total and high-grade (Gleason score 4 or 5) cancer volume and compared the areas under the curve (AUC) for the various total and high-grade cancer volumes.

RESULTS

For patients with Stage T1c disease, the AUC for the PSA ROC curve increased in a stepwise fashion as both the total cancer volume and the high-grade cancer volume increased. Significant differences between the AUCs for low and high volumes of total and high-grade disease were observed. For T2 disease, the AUCs for predicting high-grade cancer volume were generally greater than the corresponding AUCs for T1c disease, although no incremental increase was observed.

CONCLUSION

In patients with Stage T1c disease, in whom the PSA level was the driving force for biopsy, the PSA performance improved in a stepwise fashion with greater total and high-grade cancer volumes as evidenced by improved ROC. Previous studies have shown that PSA performs better for detecting the presence of high-grade disease. We have shown that PSA performs better in predicting greater volumes of high-grade disease in radical prostatectomy specimens.

High-throughput quantitative analysis of total N-glycans by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Accurate and reproducible quantification of glycans from protein drugs has become an important issue for quality control of therapeutic proteins in biopharmaceutical and biotechnology industries. Mass spectrometry is a promising tool for both qualitative and quantitative analysis of glycans owing to mass accuracy, efficiency, and reproducibility, but it has been of limited success in quantitative analysis for sialylated glycans in a high-throughput manner. Here, we present a solid-phase permethylation-based total N-glycan quantitative method that includes N-glycan releasing, purification, and derivatization on a 96-well plate platform. The solid-phase neutralization enabled us to perform reliable absolute quantification of the acidic N-glycans as well as neutral N-glycans from model glycoproteins (i.e., chicken ovalbumin and porcine thyroglobulin) by only using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Furthermore, low-abundance sialylated N-glycans from human serum prostate specific antigen (PSA), an extremely valuable prostate cancer marker, were initially quantified, and their chemical compositions were proposed. Taken together, these results demonstrate that our all-inclusive glycan preparation method based on a 96-well plate platform may contribute to the precise and reliable qualitative and quantitative analysis of glycans.

Etude randomisée multicentrique comparant la castration médicale par triptoréline à la castration chirurgicale dans le traitement du cancer de la prostate localement avancé ou métastatique

OBJECTIVE

To report the results of a trial comparing the efficacy of triptorelin and surgical castration in the treatment of locally advanced or metastatic prostate cancer.

MATERIALS AND METHODS

80 patients with previously untreated locally advanced or metastatic prostate cancer prostate cancer were included in a one-year multicentre, randomized, prospective, open-label therapeutic trial. Patients either received a monthly injection of triptorelin (group 1; n = 40), or were treated by pulpectomy (group 2; n = 40). Patients were reviewed every 3 months, then every 6 months.

RESULTS

The mean age of the patients was 71.22 +/- 8.25 years. At 1 month, 38 patients were castrated (plasma testosterone < 0.5 mg/ml) in the pulpectomy group versus 35 in the triptorelin group. The mean follow-up was 38.8 +/- 26 months in the triptorelin group and 36.3 +/- 25 months in the pulpectomy group. On multivariate analysis, age, impaired performance status and PAP level (> 3.2 ng/ml) were predictive factors of a poor outcome. The median survival was 37.5 +/- 9 months in the triptorelin group and 33 +/- 3 months in the pulpectomy group. At 3 years, no significant difference in specific survival was observed between the 2 groups. At 8 years of follow-up, 63 patients had died.

CONCLUSION

This study demonstrates an equivalent specific survival between patients treated by triptorelin or surgical castration. Castration is rapidly obtained with triptorelin (< 2 months) and is maintained over time throughout the duration of treatment.

?-Vitamin E derivative, RRR-?-tocopheryloxybutyric acid inhibits the proliferation of prostate cancer cells

AIM

To investigate the activity of RRR-alpha-tocopheryloxybutyric acid (TOB), an ether analog of RRR-alpha-tocopheryl succinate (VES), in prostate cancer cells.

METHODS

VES and TOB were used to treat prostate cancer LNCaP, PC3, and 22Rv1 cells and primary-cultured prostate fibroblasts. The proliferation rates were determined by MTT assay, the cell viabilities were determined by trypan blue exclusion assay, and the cell deaths were evaluated by using Cell Death Detection ELISA kit. The protein expression levels were determined by Western blot analysis.

RESULTS

The MTT growth assay demonstrated that TOB could effectively suppress the proliferation of prostate cancer cells, but not normal prostate fibroblasts. Mechanism dissections revealed that TOB reduced cell viability and induced apoptosis in prostate cancer cells similar to VES. In addition, both TOB and VES suppressed prostate-specific antigen (PSA) at the transcriptional level leading to reduced PSA protein expression. Furthermore, vitamin D receptor (VDR) expression increased after the addition of TOB.

CONCLUSION

Our data suggests that the VES derivative, TOB, is effective in inhibiting prostate cancer cell proliferation, suggesting that TOB could be used for both chemopreventive and chemotherapeutic purposes in the future.

Relationship between Serum Prostate Specific Antigen and the Pattern of Inflammation in Both Benign and Malignant Prostatic Disease in Middle Eastern Men

To determine the effect of prostatitis on serum prostate specific antigen in the diagnosis of prostate cancer in Middle Eastern men, H&E-stained sections of all consecutive prostate specimens were reviewed for diagnosis (malignant or benign) and pattern of inflammation. Inflammation was categorized into acute, active chronic and chronic inactive and graded semi-quantitatively according to previously published criteria. Results were correlated with serum PSA obtained from patients' records. Of 513 prostate specimens reviewed; 435 (84.8%) were benign and 78 (15.2%) were malignant. Chronic inactive prostatitis was present in 259 (204 benign, 55 malignant) and active chronic prostatitis in 221 (204 benign, 17 malignant). Acute prostatitis alone was not observed and prostatitis was absent in 33 (27 benign, 6 malignant). There was no significant difference in the prevalence of inactive chronic prostatitis between benign and malignant specimens (p < 0.071), but active chronic prostatitis was more prevalent in benign specimens (p < 0.001). Increasing serum PSA was observed for increasing grades of both inactive and active chronic prostatitis in both benign and malignant disease. Prostate cancer showed higher serum PSA levels than benign, at different cut-off points (4 ng/ml = p < 0.0001; 8 ng/ml = p < 0.0001; 12 ng/ml = p < 0.0001). However, significant numbers of patients with benign prostate biopsies presented with PSA above 12 ng/ml (82/260 = 32%). We conclude that active chronic prostatitis is common in Middle Eastern men with benign prostatic disease and a significant number of these present with very high PSA levels, some over 300 ng/ml.

An alternative approach to modelling relapse in cancer with an application to adenocarcinoma of the prostate

This paper proposes an alternative approach to modelling relapse in cancer. In particular, the dynamic model for the tumor or biomarker will be subjected to a lower elastic boundary at which the process either will be absorbed or reflected. The likelihood of reflection then can be interpreted as the probability of relapse. This framework will be exemplified for prostatic cancer by extending the recently proposed stochastic model of Dayananda et al. [P.W.A. Dayananda, J.T. Kemper, M.M. Shvartsman, A stochastic model for prostate-specific antigen levels, Math. Biosci. 190 (2004) 113] that focussed on the dynamics of the prostate-specific antigen (PSA) biomarker. Analytical results for the conditional density function, given a non-negative lower boundary, are obtained for the extreme cases of certain cure and of certain relapse. Simulations illustrate the relevance of the relapse probability and of the normal value of the biomarker for the design of treatment strategies. The paper thus points to two additional (patient-specific) characteristics that might enter treatment design and monitoring of progress in therapy.

Biomarkers for the detection and prognosis of prostate cancer

Recent studies have cast doubt on the reliability of serum total prostate-specific antigen as a biomarker for the detection and prognosis of prostate cancer. Biomarkers that can identify those men at risk for clinically significant prostate cancer are desperately needed. The search for biomarkers that may improve the detection of biologically consequential prostate cancer is one of the most active areas under current investigation. In this review, we highlight some of these ongoing efforts. Proper validation of newly discovered biomarkers is of paramount importance.

Prevalence of prostate cancer among men with a prostate-specific antigen level < or =4.0 ng per milliliter

BACKGROUND

The optimal upper limit of the normal range for prostate-specific antigen (PSA) is unknown. We investigated the prevalence of prostate cancer among men in the Prostate Cancer Prevention Trial who had a PSA level of 4.0 ng per milliliter or less.

METHODS

Of 18,882 men enrolled in the prevention trial, 9459 were randomly assigned to receive placebo and had an annual measurement of PSA and a digital rectal examination. Among these 9459 men, 2950 men never had a PSA level of more than 4.0 ng per milliliter or an abnormal digital rectal examination, had a final PSA determination, and underwent a prostate biopsy after being in the study for seven years.

RESULTS

Among the 2950 men (age range, 62 to 91 years), prostate cancer was diagnosed in 449 (15.2 percent); 67 of these 449 cancers (14.9 percent) had a Gleason score of 7 or higher. The prevalence of prostate cancer was 6.6 percent among men with a PSA level of up to 0.5 ng per milliliter, 10.1 percent among those with values of 0.6 to 1.0 ng per milliliter, 17.0 percent among those with values of 1.1 to 2.0 ng per milliliter, 23.9 percent among those with values of 2.1 to 3.0 ng per milliliter, and 26.9 percent among those with values of 3.1 to 4.0 ng per milliliter. The prevalence of high-grade cancers increased from 12.5 percent of cancers associated with a PSA level of 0.5 ng per milliliter or less to 25.0 percent of cancers associated with a PSA level of 3.1 to 4.0 ng per milliliter.

CONCLUSIONS

Biopsy-detected prostate cancer, including high-grade cancers, is not rare among men with PSA levels of 4.0 ng per milliliter or less--levels generally thought to be in the normal range.

"PSA-itis": knowledge of serum prostate specific antigen and other causes of anxiety in men with metaststic prostate cancer

PURPOSE

High or increasing prostatic specific antigen (PSA) levels may be a source of anxiety in patients with metastatic prostate cancer.

MATERIALS AND METHODS

Patients with metastatic prostate cancer completed questionnaires, including the Prostate Cancer Specific Quality of Life Instrument, Hospital Anxiety and Depression Scale, and a questionnaire to assess the impact of the knowledge of PSA levels on anxiety. These were completed at home more than 3 days before or after a clinic appointment and returned by mail. Patient medical history was obtained from the record.

RESULTS

Of the 65 patients who consented to the study 52 returned the completed questionnaires. Median age was 70 years (range 55 to 86) and median time since diagnosis was 53 months. Of the patients 81% had hormone resistant disease. Most reported good overall quality of life with a median Prostate Cancer Specific Quality of Life Instrument score of 93 (maximum 100). Of the patients 77% indicated that PSA levels were one of the ways and 44% indicated they were the only way that they knew whether disease was progressing. When asked to rate preferences for treatment outcome, 25% of the men rated decreasing PSA and worse physical symptoms above increasing PSA and better physical symptoms. If measurement of PSA levels ceased, 52% of patients would believe that their doctor was giving up on them and only 1 would be relieved. Before receiving PSA results 76% reported some level of anxiety and 15% reported extreme anxiety.

CONCLUSIONS

PSA related anxiety represents a substantial problem in patients with metastatic prostate cancer.

Expression of prostate-specific antigen is transcriptionally regulated by genistein in prostate cancer cells

Prostate cancer is the second-leading cause of cancer-related deaths in men in the United States. Unfortunately, there is no effective therapy when prostate cancer becomes metastatic and refractory to conventional treatments. For this reason, the identification and exploration of new agents that reduce prostate cancer cell growth are of paramount importance. High consumption of plant-derived phytoestrogens is inversely associated with the incidence and mortality rate of prostate cancer. Previous studies, including our own, have shown that the phytoestrogen genistein inhibits prostate cancer cell growth in vitro and in vivo and decreases secreted and intracellular levels of the androgen-regulated protein prostate-specific antigen (PSA), but the role of genistein as an agonist/antagonist for hormone receptors remains unclear. To elucidate the mechanism by which genistein modulates PSA protein expression in prostate cancer cells, we investigated the effects of genistein on androgen-mediated and estrogen-mediated transcriptional regulation of PSA, androgen receptor (AR) mRNA and protein expression, and the ability of nuclear proteins to bind to androgen-response elements (AREs) in LNCaP cells. We showed that genistein decreased the transcriptional activation of PSA by both androgen-dependent and androgen-independent methods in LNCaP cells. The reduction of androgen-mediated transcriptional activation of PSA was correlated with decreased AR protein and mRNA levels and decreased binding to AREs. In contrast, genistein had differential effects on 17beta-estradiol-mediated PSA expressions. Low concentrations of genistein enhanced 17beta-estradiol-mediated PSA expressions, whereas high concentrations of genistein inhibited estrogen-mediated PSA expression in LNCaP cells. Genistein did not inhibit AR protein expression in the presence of 17beta-estradiol. These results suggest that ligand-dependent differences in the ability to activate PSA expression may contribute to the agonistic/antagonistic responses observed with genistein in prostate cancer cells.

Prostate cancer screening trends of New York State men at least 50 years of age, 1994 to 1997

BACKGROUND

Despite the lack of consensus on prostate cancer screening recommendations, men are being screened at high rates in some states. Our objective was to examine the trends in prostate cancer screening awareness and practices from 1994 through 1997 and the relationship among screening practices and demographic characteristics, perceived risk, and family history of prostate cancer.

METHODS

Data from the New York State Behavioral Risk Factor Surveillance System surveys and questionnaire modules on prostate cancer screening were used for this study, which excluded men younger than 50 years of age and men with a history of prostate cancer. The questionnaires were administered by random-digit-dialed monthly telephone surveys of the civilian, noninstitutionalized adult population in New York State.

RESULTS

A total of 295, 336, 273, and 448 men, the vast majority of whom were white, met the study criteria for 1994, 1995, 1996, and 1997, respectively. Each year the percentage of men who reported having heard of the prostate specific antigen (PSA) test increased (test for trend, P < 0.001). Among those who had heard of the PSA test, the percentage who reported having had a PSA test increased steadily from 1994 to 1997. About 30% of the men in each year's study did not have an impression of their risk of getting prostate cancer.

CONCLUSIONS

Given the increasing rate at which men are reporting being screened for prostate cancer and given their reported perceived risk levels, perhaps more needs to be done to educate men about screening implications and personal risk for prostate cancer.

New developments in the standardization of total prostate-specific antigen

OBJECTIVE

Analytical evaluation of the calibration of three recently launched assays for the measurement of total prostate-specific antigen, i.e., IMx Total PSA (Abbott), Elecsys PSA (Roche), and IMMULITE 3rd Generation PSA (DPC).

DESIGN AND METHODS

For accuracy assessment two reference materials were applied namely, Stanford 90:10 PSA Calibrator and Certified Reference Material 613 Prostate-Specific Antigen. Dilutions of these preparations were analyzed with all assays. In addition, clinical specimens from known prostate cancer or benign prostate hyperplasia patients and samples taken from an ongoing prostate cancer screening study were used for comparison.

RESULTS

Application of the Stanford Calibrator revealed results well within 10% of the calculated values for all assays. Regarding the CRM Calibrator only the IMx Total PSA proved to approach the line of identity. The IMMULITE results differed about 40% and the Elecsys about 18% from the calculated values. The comparison with clinical specimens showed statistically different results for the combination IMMULITE-IMx and for IMMULITE-Elecsys. The regression lines for both collections were: y(IMx) = 0.86x(IMMULITE) +0.12 (n = 104, r = 0.970, Sy/x = 0.883 microg/L) and y(Elecsys) = 0.98x(IMMULITE) +0.38 (n = 97, r = 0.976, Sy/x = 0.733 microg/L). In the lower measuring range (PSA <5.0 microg/L) as measured with the screening samples (n = 43), these differences were less pronounced.

CONCLUSION

In analytical sense a difference was found for both reference preparations in the assays studied. Clinically, despite improvements in methodology, results for total prostate-specific antigen are still not interchangeable. The possible consequences need to be elaborated.

Immunohistochemical analysis of estramustine binding protein with particular reference to proliferative activity in human prostatic carcinoma

BACKGROUND

The estramustine binding protein (EMBP) specifically binds to estramustine and was first discovered in the rat ventral prostate. However, the physiological property of EMBP in the human prostate still remains to be elucidated. To elucidate whether EMBP is interrelated with cellular proliferation in human prostatic carcinoma (PC), the change in EMBP immunostaining during luteinizing hormone-releasing hormone (LH-RH) analog administration or during Cis-platinum-based chemotherapy, and the difference in EMBP immunostaining between hormone refractory (hr-PC) and untreated PC were analyzed.

METHODS

Forty-six patients with histologically proven untreated PCs (34 were treated with LH-RH analog and 12 were treated with chemotherapy as an initial therapy) and 14 with hr-PC were used in this study. PC tissues were obtained before and 3 months after the initial therapy. The changes in immunostainings for EMBP, proliferating cell nuclear antigen (PCNA), and nm23 protein were compared with the change in serum prostate-specific antigen (PSA) level and the histological response during the treatment.

RESULTS

The increased EMBP expression was observed in tumors with high histological grade and high clinical stage as well as in hr-PC. In untreated PC, EMBP expression weakly correlated with PCNA or nm23 protein immunoreactivity. In PC receiving LH-RH analog, EMBP expression was significantly reduced after treatment, however, no significant changes were observed in PCNA or nm23 protein immunoreactivity. In addition, EMBP expression before the treatment significantly correlated with the serum PSA change, while PCNA expression and nm23 protein immunoreactivity did not. On the other hand, no significant relationship was observed between histological changes induced by the LH-RH analog and immunostainings for EMBP, PCNA, and nm23 protein before treatment. In PC patients receiving chemotherapy, immunostainings for EMBP, PCNA, and nm23 protein were not significantly changed during the treatment. EMBP immunoreactivity was significantly higher in hr-PC than in untreated PC with paralleled change of PCNA expression and nm23 protein immunoreactivity.

CONCLUSIONS

These observations indicate that EMBP is androgen regulated in some PCs. However, EMBP expression is demonstrated even in hr-PC and is interrelated with cellular proliferation especially in hr-PC.

Effect of transurethral indwelling catheter on serum prostate-specific antigen level in benign prostatic hyperplasia

OBJECTIVES

The purpose of this prospective study was to determine the influence of indwelling transurethral catheters on the serum prostate-specific antigen (PSA) levels in patients with benign prostatic hyperplasia (BPH). We compared the PSA values of preoperatively catheterized and noncatheterized patients.

METHODS

Ninety patients undergoing a prostatectomy for benign disease were included. The indwelling catheter (IC) group and noncatheterized (NC) group each consisted of 45 patients. A total of 83 patients who did not have prostate carcinoma were analyzed by means of PSA, PSA density (PSAD), and pathologic presentations. Prostate pathologies that might elevate PSA values were excluded to demonstrate the correlation of PSA levels and standard urethral catheterization.

RESULTS

A statistically significant relationship was determined between an indwelling urethral catheter and an elevated serum PSA value. The average PSA level of the IC group was 2.6 times that of the NC group.

CONCLUSIONS

PSA, PSAD, and age-adjusted PSA levels were elevated above normal ranges in patients with BPH who had an indwelling urethral catheter.

Ejaculation increases the serum prostate-specific antigen concentration

OBJECTIVES

To determine the effect of ejaculation on the serum prostate-specific antigen (PSA) concentration in men at risk for developing prostate cancer.

METHODS

A prospective, community-based study was conducted in which 64 men, aged 49 to 79 years, underwent a serum PSA determination immediately before ejaculation (baseline) and at 1 hour, 6 hours, and 24 hours following ejaculation. The serum PSA also was measured 48 hours and 1 week after ejaculation if the concentration had not returned to the baseline value by the previous time interval. All subjects abstained from ejaculation for a minimum of 7 days prior to the study and until the PSA concentration returned to the baseline level. Absolute and relative change in serum PSA concentration, as well as the time to return to baseline PSA concentration following ejaculation, were assessed.

RESULTS

The serum PSA concentration increased following ejaculation in 87% of the subjects. The mean baseline PSA was 1.8 ng/mL (median, 0.7 ng/mL). The mean absolute PSA change +/- standard deviation 1 hour, 6 hours, 24 hours, and 48 hours after ejaculation was 0.8 +/- 1.32 ng/mL, 0.3 +/- 0.66 ng/mL, 0.2 +/- 0.33 ng/mL, and 0.4 +/- 0.40 ng/mL, respectively. The mean relative PSA change +/- standard error 1 hour, 6 hours, 24 hours, and 48 hours after ejaculation was 41 +/- 4%, 9 +/- 1.5%, 8 +/- 1.3%, and 10 +/- 2.3%, respectively. The absolute and relative changes in PSA concentration noted 1 hour, 6 hours, and 24 hours after ejaculation were statistically significant (P = 0.0001). A strong correlation was observed between absolute change in PSA and baseline serum PSA, at each time interval (1 hour: r = 0.68, 6 hours: r = 0.77, 24 hours: r = 0.70; P < 0.0001) after ejaculation. Similarly, a significant correlation was noted between absolute change in PSA and patient age at each time interval (1 hour: r = 0.37, 6 hours: r = 0.38; P = 0.002, 24 hours: r = 0.55; P < 0.0001). Ninety-two percent of subjects returned to baseline by 24 hours (95% confidence interval (Cl) = 83% to 97%), whereas 97% of subjects returned to baseline by 48 hours (95% Cl = 89% to 99%).

CONCLUSIONS

Ejaculation causes a significant increase in the serum PSA concentration in men between 49 and 79 years of age that may persist for up to 48 hours. This change appears to correlate with age and baseline PSA. It is recommended that men abstain from ejaculation for 48 hours prior to having a serum PSA determination.

The clinical usefulness of prostate specific antigen: update 1994

In conclusion, PSA is the first prostate specific serum marker of clinical usefulness in urology. It represents a valuable clinical tool that has improved our ability to detect early prostate cancer and to monitor response to therapy. While large PSA screening studies have demonstrated an appreciable increase in the detection of organ confined, potentially curable prostate cancers, no study to date has yet demonstrated that the increased detection rate will decrease the prostate cancer-specific mortality rate. Yet more importantly, no study to date has demonstrated that early diagnosis using PSA will not decrease the prostate cancer specific mortality rate and until such data exist, PSA should be used to aid in early diagnosis and treatment planning for men with prostate cancer. PSA, when combined with other variables such as Gleason score and clinical stage, improves the prediction of pathological stage for prostate cancer. The introduction of PSA velocity and age specific reference ranges should further enhance the clinical usefulness of PSA. New advances in PSA research hold great promise for further improvements in PSA, and truly make it the most important and useful tumor marker for adenocarcinoma of the prostate.

Relationship between serum prostate specific antigen and histological prostatitis in patients with benign prostatic hyperplasia

The relationship between the serum values of prostate specific antigen (PSA) and the extent of histological prostatitis was investigated in 42 patients undergoing transurethral resection of the prostate for benign hyperplasia (BPH) without clinical evidence of prostatitis. Histological prostatitis was divided into three groups: acute, chronic-active, and chronic-inactive inflammation. The extent of histological prostatitis was expressed as the number of prostatic acinar and ductal glands with inflammatory infiltrate per total number of glands (%). The serum PSA values significantly correlated with the extent of acute and chronic-active prostatitis (correlation coefficient r = 0.765 and 0.656, P < 0.01). A relationship between PSA values and the extent of chronic-inactive prostatitis was not found. In the immunohistochemical study, prostatic epithelial cells with acute and chronic-active inflammation showed negative staining for PSA antigen. These results indicate that histological acute and chronic-active prostatitis is considered an important factor for inducing the high increase in serum PSA values via the leak phenomenon.

Simple method for comparing reliability of two serum tumour markers in breast carcinoma

AIMS

To compare the two breast tumour markers, CA15-3 and mucinous-like carcinoma associated antigen (MCA), using Receiver Operating Characteristic (ROC) curve analysis.

METHODS

One hundred and ninety six patients "presenting" with breast carcinoma had serum CA15-3 and MCA concentrations measured.

RESULTS

Using these markers as indicators of stage IV disease at the recommended laboratory level, true positive rates (TPR) and false positive rates (FPR) were obtained as follows: CA15-3 TPR = 75%, FPR = 7.4%, MCA TPR = 80%, FPR = 59.1%. By increasing the CA15-3 cutoff level to 45 U/ml, a TPR and FPR of 75% and 0.6%, respectively were obtained. By increasing the MCA cutoff level to 23 U/ml, a TPR and FPR of 65% and 2.3%, respectively, were obtained.

CONCLUSIONS

Using ROC curve analysis shows that CA15-3 is a superior indicator of metastatic breast disease than MCA at recommended laboratory levels, and by altering the cutoff points, the specificity and sensitivity for both these markers can be improved.

The impact of ejaculation on serum prostate specific antigen

In a pilot study including 18 patients between 20 and 39 years old serum prostate specific antigen (PSA) was evaluated before as well as 1 and 7 days after ejaculation. In 13 patients who had more than 0 ng./ml. PSA before ejaculation (mean 1.44 ng./ml.) there were statistically significant decreases in serum PSA down to 0.17 ng./ml. and 0.29 ng./ml., respectively (p = 0.0001). These results suggest a physiological relationship between ejaculation and decreased serum PSA levels. Due to the clinical significance of PSA in the diagnosis and monitoring of prostate cancer, further studies are needed including men of risk age and untreated prostate cancer patients.

Effect of digital rectal examination (and ejaculation) on serum prostate-specific antigen after twenty-four hours. A randomized, prospective study

The purpose of this randomized, controlled, clinical trial was to determine the effect of the digital rectal examination (DRE) on the prostate-specific antigen (PSA) serum levels in view of conflicting literature reports and screening methods and misconceptions by physicians. We showed that the DRE had no clinically important effect on PSA values twenty-four hours later. The mean PSA rose from 1.57 to 1.62 ng/mL, similar to the controls. Ejaculation had no meaningful effect on the serum PSA values.

DNA and RNA amplification in urology: the polymerase chain reaction

Polymerase chain reaction (PCR) technology is a promising molecular approach for diagnosis of genitourinary tract infections, inherited disorders, tumor-associated genetic alterations and tumor markers. Because it is based on exponential amplification, the technology is capable of ultimate theoretical sensitivity. Although not entirely free of technical limitations, PCR holds advantages over other diagnostic tests, including exquisite sensitivity, specificity, interchangeability and speed.

Serum prostate specific antigen as pre-screening test for prostate cancer

Prostate cancer has become the most common cancer and the second cause of death due to cancer in men in North America. Since curative therapies are limited to early stages of the disease, the availability of an efficient, easy to perform, widely acceptable and cost-effective method of early detection of prostate cancer is particularly important. Thus, digital rectal examination, transrectal ultrasonography of the prostate as well as measurements of serum prostate specific antigen (PSA) were performed independently in a series of 1,002 men between 45 and 80 years old randomly selected from the electoral rolls of Quebec City and its vicinity as part of a screening program for prostate cancer. Using this population of randomly chosen men, various cutoff serum PSA values were selected in an attempt to find the optimal decision threshold that would indicate a much greater risk of having prostatic cancer. At a threshold value of 3.0 micrograms./l. the sensitivity and specificity of the test are 80.7 and 89.6%, respectively, while the area under the receiver operating characteristic curve reflecting the accuracy of the test is 87.8 +/- 3.3% (plus or minus standard deviation). Moreover, the negative predictive value was estimated at 98.6%, thus leaving only a 1.4% chance of missing cancer when the serum PSA value was 3.0 micrograms./l. or less. Most importantly, such a threshold level of serum PSA retains only 19% of the whole cohort as candidates for transrectal ultrasonography and expensive diagnostic procedures, thus leading to the finding of 1 prostate cancer of 4 such examinations. The present data indicate that simple measurement of serum PSA can be used efficiently as a pre-screening test for prostate cancer in the general population to identify, at a low cost, the subpopulation of men at a much greater risk of having prostate cancer, and who should then be submitted to the more elaborate and expensive diagnostic procedures.