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Background: Stem cells are postulated to mediate prostate cancer progression, and represent a small fraction of the entire tumor. Various proteins (α2-integrin, α6-integrin, CD117, CD133, EZH2, OCT3/4) are associated with a prostate cancer stem cell phenotype in cell lines and xenografts. Our objective was to investigate expression of stem cell markers in clinical prostate cancer in relation to outcome., Methods: We validated immunohistochemical expression of stem cell markers in 481 prostate cancer patients and correlated expression with clinicopathologic parameters., Results: Sporadic expression of α2-integrin was present in a fraction of tumor cells (<5%) in 94.7% of tumors and associated with PSA > 10 ng/ml (P = 0.04). α6-Integrin expression (<5%) occurred in 28.4% patients, while ≥5% α6-integrin expression was associated with PSA≤10 ng/ml (P = 0.01), Gleason score <7 (P < 0.01) and pT2-disease (P = 0.02). α6-integrin was predictive for biochemical recurrence (P < 0.01), local recurrence (P = 0.03) and disease specific death (P = 0.03). EZH2 expression was generally low with 2.6% of tumors showing ≥1% positive cells. EZH2 was associated with Gleason score ≥7 (P = 0.01) and biochemical recurrence (P = 0.01). We did not identify expression of CD117, CD133, and OCT3/4 in prostate cancer samples., Conclusions: Expression of α2-integrin and EZH2 in a small fraction of prostate cancer cells is supportive for their role as stem cell marker. Although α6-integrin was not a unique stem cell marker, it was predictive for prostate cancer biochemical and local recurrence, and disease specific death. The validity of CD117, CD133, and OCT3/4 as prostate cancer stem cell marker is questionable since these proteins were not expressed in clinical prostate cancer., (© 2013 Wiley Periodicals, Inc.)

Background: We developed a korean prostate cancer risk calculator (KPCRC) for predicting the probability of a positive initial prostate biopsy using clinical and laboratory data from a Korean male population (http://pcrc.korea.ac.kr). We compared its performance to prostate-specific antigen (PSA) testing and the Prostate Risk Calculator 3 (PRC 3) based on data from the Dutch part of European Randomized Study of Screening for Prostate Cancer (ERSPC), which predicts biopsy results for previously unscreened men., Methods: Data were collected from 602 Korean men who were previously unscreened and underwent initial ten-core prostate biopsies. Multiple logistic regression analysis was performed to determine the significant predictors. Area under the receiver operating characteristic curve (AUC) and calibration plots of both calculators were evaluated., Results: Prostate cancer (PCa) was detected in 172 (28.6%) men. Independent predictors of a positive biopsy included advanced age, elevated PSA levels, reduced volume of the transition zone, and abnormal digital rectal examination findings. The AUC of the KPCRC was higher than the PRC 3 and PSA alone on internal and external validation. Calibration plots of the KPCRC showed better performance than the other models on internal and external validation. Applying a cut-off of 10% of KPCRC implied that 251 of the 602 men (42%) would not have been biopsied and that 12 of the 172 PCa cases (7%) would not have been diagnosed., Conclusions: The KPCRC improves the performance of the PRC 3 and PSA testing in predicting Korean population's risk of PCa. It implies that Asian populations need their own risk calculators for PCa., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: The prostate may often harbor a prostate cancer (PC) which will not cause morbidity if left untreated. Screening for PC leads to increased detection of these insignificant cancers. Objective of this study is to compare PC detected by PSA screening at subsequent screening rounds and treated by radical prostatectomy (RP) with PC incidentally found in cystoprostatectomy specimens., Methods: Radical prostatectomy specimens of 617 screen-detected PC were compared with 123 PC identified in cystoprostatectomy specimens. Surgical specimens were systematically examined and stage, grade, tumor volume were recorded. Next, we classified PC as clinically significant or insignificant (i.e., tumor volume <0.5 cm(3), absence of Gleason pattern 4/5, organ confined). Pathological features of incidentally detected PC were compared with PC detected in subsequent screening rounds and with screen-detected T1c PC., Results: Screen-detected PC overall were more often multifocal, larger in volume, more advanced in tumor stage and of higher grade, while the frequency of insignificant PC was lower as compared to those in cystoprostatectomy specimens. This effect became more pronounced during subsequent screening rounds. Screen-detected T1c PC were also more often multifocal (73% vs. 37%) in average fivefold larger (0.85 cm(3) vs. 0.16 cm(3)), less often organ confined (81% vs. 94%), and less frequently clinically insignificant (33% vs. 81%)., Conclusions: Screen-detected (T1c) PC treated with RP shows more aggressive features than incidentally found PC. This PSA screening-related selection seems to be mainly driven by tumor volume and-in later screening rounds-by the preferential treatment by prostatectomy of more aggressive PC., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: Ongoing research on the best way to diagnose prostate cancer has yielded and will continue to yield vast amounts of information. Based on, for example, information from prostate cancer screening trials models have been made that enable urologists to predict which man has prostate cancer on the basis of pre-biopsy data. In patients with screen detected prostate cancer, the presence of indolent disease can now be identified with reasonable certainty by a different model. For these men active surveillance may be a better option than aggressive treatment with its possible side effects as impotence, incontinence and bowel damage. Both models mentioned above are logistic regression models. Nomograms enable their use in daily clinical practice., Methods: Nomograms require the memorization and addition of intermediate results. We aimed to design a device that has the same function as a nomogram without this draw back., Results: A new device that resembles a circular slide rule was developed and is currently being tested in prostate cancer diagnosis and in prostate cancer patient counseling., Conclusions: The new device has identical functionality to the nomogram without the drawback of the latter. The application of the device is not limited to the field of prostate cancer research., ((c) 2008 Wiley-Liss, Inc.)

Background: To analyze to what extent the percentage of suspicious digital rectal examination (DRE) findings vary between examiners and to what extent the percentage of prostate cancers (PCs) detected in men with these suspicious findings varies between examiners., Methods: In the first screening round of the European Randomized study of Screening for PC (ERSPC) Rotterdam, 7,280 men underwent a PSA-determination and DRE of whom 2,102 underwent prostate biopsy (biopsy indication PSA > or = 4.0 ng/ml and/or suspicious DRE and/or TRUS). Descriptive statistics of DRE-outcome per PSA-range were used to determine the observer variability of six examiners. Because this analysis did not correct properly for other predictors of a suspicious DRE (PSA-level, biopsy indication, TRUS-outcome, prostate volume and age), a logistic regression analysis controlling for these explanatory variables was performed as well., Results: In 2,102 men biopsied, 443 PCs were detected (PPV = 21%). For all PSA levels the percentage suspicious DRE varied between examiners from 4% to 28% and percentage PC detected in men with a suspicious DRE varied from 18% to 36%. Logistic regression analysis showed that three of six examiners considered DRE significantly more often abnormal than others (ORs 3.48, 2.80, 2.47, P < 0.001). For all examiners the odds to have PC was statistically significantly higher in case of a suspicious DRE (ORs 2.21-5.96, P < 0.05). This increased chance to find PC was not significantly observer-dependent., Conclusions: Three of six examiners considered DRE significantly more often suspicious than the others. However, under equal circumstances a suspicious DRE executed by each examiner increased the chance of the presence of PC similarly.

Background: The use of PSA as a screening test has become increasingly prevalent in the general population and therefore also in the control arm of the European Randomized study of Screening for Prostate Cancer (ERSPC). We present a feasibility study and impact simulation of a secondary analysis, which imitates a situation where all participants in the study are managed according to their random assignment., Methods: The results of the Rotterdam section of the ERSPC were adjusted for contamination and non-compliance according to Cuzick et al. [Stat Med 1997; 16:1017-1029]. Endpoints of this analysis were simulated reductions in prostate cancer mortality., Results: Of the men allocated to the screen arm, 27.1% were non-compliant. In the control arm 30.7% had their PSA-level measured by a general practitioner (GP) (i.e., contamination). For a scenario in which the intention-to-screen analysis was assumed to give a decrease in the mortality in the men randomized to screening of 6.7%, the secondary analysis resulted in a decrease of 16.1% for those actually screened., Conclusion: Although the definition of contamination as "PSA ever tested" gives an indication of the proportion of contamination, it will be important to differentiate the screening use of PSA from its diagnostic use. For the rest, adjustment for non-compliance and contamination was shown to be feasible in this prostate cancer screening trial. It can therefore be used to carry out a secondary analysis on the definitive outcome of the ERSPC and will provide accurate information for those men who are in fact screened.

Objectives: To compare tumor characteristics of screen-detected prostate cancers (PCs) either by digital rectal examination (DRE) or by prostate-specific antigen (PSA) as biopsy indication at low PSA., Methods: Two populations with PSA between 2.0 and 3.9 ng/ml were studied. Group-1 was biopsied if DRE was suspicious (1st screening round, N = 1877). In group-2 all men were offered biopsy, regardless of DRE result (side-study in 2nd screening-round, N = 801). We compared cancer detection rates (CDRs) and tumor characteristics., Results: In group-1 abnormal DRE prompted biopsy in 253 (13.5%) men (236 (93.3%) actually biopsied). Forty-nine PCs were detected, CDR 49/1877 = 2.6%. In group-2 we found 120 cancers in 666 (83.1%) men actually biopsied, CDR = 120/801 = 15.0%. Of all cancers detected, organ confinement (clinical T2) was found in 77.5% (group-1) and 96.6% (group-2; of which 99 T1c). Of all PCs 46.9% in group-1 and 15.0% in group-2 had biopsy Gleason score (GS) > or = 7. In the latter, 15.2% of T1cs were classified GS > or = 7. Considering only PCs with organ confinement or GS > or = 7 for each group, CDRs amounted to 2.0% versus 14.5% and 1.2% versus 2.3% for group-1 and group-2, respectively., Conclusions: PSA-based screening detected a considerable amount (15.2%) of potentially aggressive tumors as T1cs, but in addition large numbers of possibly insignificant cancers (T1c, GS = 6) were diagnosed. DRE seemed to detect more selectively high-grade cancers, but also missed many of these. Considering both populations and the need to detect aggressive but confined cancers, PSA as biopsy indication outperformed DRE at the price of more biopsies (13.5% vs. 100% if all would comply)., ((c) 2006 Wiley-Liss, Inc.)

Background: The European Randomized study of Screening for Prostate Cancer (ERSPC) investigates the feasibility of population-based screening. This report compares the preliminary outcome of cancers detected in the screen and the control arm of its Rotterdam section, by means of biochemical progression rates., Methods: In the screen arm of this study (21,210 men), screening was applied according to well-established protocols, and a 4-year screen interval was chosen. Widely accepted biochemical progression-criteria were used to evaluate the diagnosed cancers over time., Results: Although more cancers were detected in the screen than in the control arm (1,339 vs. 298, P < 0.001), their clinico-pathological features were more favorable. Furthermore, screened men had higher 5-year survival rates for biochemical progression after surgery (84.4% vs. 58.9% in controls), radiotherapy (71.0% vs. 58.0%), and endocrine therapy (40.5% vs. 16.3%)., Conclusions: The higher biochemical progression-free survival can at least in part be explained by lead and length-time. How screening will effect the mortality remains unclear., (Copyright 2005 Wiley-Liss, Inc.)

Background: Omission of DRE/TRUS as biopsy indication results in fewer unnecessary biopsies, but may increase the risk of missing potentially aggressive prostate cancers (PCs). In 1997, the biopsy indication within the ERSPC was changed from a PSA cut-off of 4.0 ng/ml and/or abnormal DRE/TRUS (group-1) to solely a PSA cut-off of 3.0 ng/ml (group-2). We estimated the effect of omitting DRE/TRUS by comparing the results of a re-screening 4 years after initial screening to the original policy., Methods: We compared rate and characteristics of detected PCs in the second round in men initially screened in group-1 (N=5,957) or group-2 (N=8,044). Additionally, we compared the rate of interval cancers (ICs) after screening with and without DRE/TRUS., Results: There was no significant difference in second round cancer-detection-rates (group-1, 3.0%; group-2, 2.7%), positive-predictive-values (group-1, 23.9%; group-2, 26.3%), and number of poorly-differentiated tumors (group-1, 2.6%; group-2, 3.8%). Most PCs were clinically confined to the prostate. Eleven ICs were detected in each group (0.18 and 0.14%)., Conclusions: Omitting DRE/TRUS did not result in an increased IC- or PC-detection. However, considering the natural history of PC, the 4-year follow-up may be too short to draw a definitive conclusion., (Prostate 66:625-631, 2006. (c) 2005 Wiley-Liss, Inc.)

Background: The identification of predictors for prostate biopsy outcome at two screening rounds using a PSA>or=3.0 ng/ml as biopsy indication., Materials and Methods: We compared predictors by means of descriptive statistics and logistic regression analysis in men (55-75 years) biopsied in either the 1st or 2nd screening round of ERSPC Rotterdam (interval 4 years)., Results: Positive predictors for biopsy outcome in both screening rounds were an increased PSA level in the absence of a previous negative biopsy (PrevNB), DRE and TRUS suspicious and a positive family history (PFH). A higher than median prostate volume was a consistent negative predictor. Having had a PrevNB at initial screening strongly reduced the chance of cancer detection at repeat screening and in addition canceled the predictive potential of PSA., Conclusion: If "detecting prostate cancer efficiently" were the aim, this study indicates that a "PSA only based biopsy threshold" may be replaced by another criterion incorporating, e.g., DRE, TRUS and prostate volume in men who were biopsied in the preceding 4 year interval., (Prostate 66:604-612, 2006. (c) 2005 Wiley-Liss, Inc.)

Background: We evaluated the incidence of prostate cancer, high-grade prostatic intraepithelial neoplasia (PIN) and lesions suspicious for prostate cancer (LSPC) in sextant biopsies in two subsequent screening rounds at a 4-year interval and their predictive value for subsequent prostate cancer detection., Methods: In the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer (ERSPC), 4,117 men underwent sextant biopsy in the 1st screening round. The 2nd round was performed at a 4-year interval and biopsies were taken in 1,840 men., Results: The incidences of prostate cancer, LSPC and PIN in the 1st, respectively 2nd round were 24.6, resp. 19.9% (P = 0.001), 2.7, resp. 2.8% and 0.8, resp. 2.5% (P < 0.0001). Prostate cancer incidence after repeat biopsy for LSPC in the 1st, respectively 2nd round was 36.7 and 17.0%, and after repeat biopsy for PIN 13.3% in both rounds, respectively. Men with a benign biopsy in the 1st round had a significantly lower prostate cancer incidence in the 2nd round compared to men who did not undergo biopsy in the 1st round (10.7 vs. 22.7%, P < 0.0001)., Conclusions: The decrease of prostate cancer detection in the 2nd round was associated with an increase in the incidence of PIN. Strikingly, LSPC diagnosed during the 1st round, but not during the 2nd round were predictive for prostate cancer, while isolated PIN was never predictive for prostate cancer. PIN should not be an indication for repeat biopsy in a screening population. Importantly a 1st round benign biopsy outcome proved to be a negative predictor of subsequent prostate cancer detection., (2004 Wiley-Liss, Inc.)

Background: Neuroendocrine (NE) cells are androgen-independent cells and secrete growth-modulating peptide hormones via a regulated secretory pathway (RSP). We studied NE differentiation after long-term androgen withdrawal in the androgen-dependent human prostate cancer xenograft PC-310., Methods: Tumor-bearing nude mice were killed at 0, 2, 5, 7, 14, 21, 47, 84, and 154 days after castration. The half-life of the PC-310 tumor was 10 days, with a stable residual tumor volume of 30--40% after 21 days and longer periods of androgen deprivation., Results: Proliferative activity and prostate-specific antigen serum levels decreased to zero after castration, whereas cell-cycle arrest was manifested by increased p27(kip1) expression. A temporary downregulation of androgen receptor (AR) expression was noted after androgen deprivation. The expression of chromogranin A, secretogranin III, and secretogranin V (7B2) increased 5 days after castration and later. Subsequently, pro-hormone convertase 1 and peptidyl alpha--amidating monooxygenase as well as vascular endothelial growth factor were expressed from 7 days after castration on. Finally, such growth factors as gastrin-releasing peptide and serotonin were expressed in a small part of the NE cells 21 days after castration, but strong expression was induced late during androgen deprivation, that is, 84 and 154 days after castration, respectively., Conclusions: Androgen deprivation of the NE-differentiated PC-310 model induced the formation of NE-differentiated AR(minus sign) and non-NE AR(+) tumor residues. The NE-differentiated cells actively produced growth factors via an RSP that may lead to hormone-refractory disease. The dormant non-NE AR(+) tumor cells were shown to remain androgen sensitive even after long-term androgen deprivation. In the PC-310 xenograft, time-dependent NE differentiation and subsequent maturation were induced after androgen depletion. The androgen-dependent PC-310 xenograft model constitutes an excellent model for studying the role of NE cells in the progression of clinical prostate cancer., (Copyright 2002 Wiley-Liss, Inc.)

Background: The meta-analysis of maximal androgen blockade (MAB) concluded that there is no survival advantage of MAB over castration alone. However, the results from the largest trials yield conflicting results., Methods: The design and results of three trials were examined., Results: Most studies were planned to detect an over-optimistic difference in survival and immature data were published. The survival curves show that statistical assumptions are not fulfilled. Excluding from the meta-analysis all trials where a negative impact of disease flare on survival could not be excluded resulted in no difference in survival between MAB and castration., Conclusions: Trials of MAB should be planned to detect differences of no more than 5-10% in median survival. The analyses should only be carried out on mature data and should take into account the possibility of a negative impact on survival due to disease flare if no anti-androgen has been given initially with an LH-RH agonist., (Copyright 2001 Wiley-Liss, Inc.)

Background: The value of rectal examination as initial screening test for prostate cancer at low PSA values (0.0-3.9 ng/ml) was determined by evaluating the number and tumor characteristics of the cancers detected., Methods: Two study populations were subjected to screening with (n = 10,226) and without (n = 10,753) rectal examination as initial screening test. The number of cancers detected at low PSA values for both screening regimens, the corresponding biopsy and radical prostatectomy tumor characteristics were assessed. Possibly harmless cancers were defined as small (< 0.5 ml) organ-confined tumors without Gleason growth-patterns 4/5., Results: At low PSA, 26.6% (117/440) of screen-detected cancers were detected after the evaluation of a suspicious rectal examination. The number of cancers and tumor aggressiveness features were highly associated with serum-PSA level. The proportion of possibly harmless disease steadily declined from 100% (PSA 0.0-0.9 ng/ml) to 15.4% (PSA 3.0-3.9 ng/ml). Rectal examinations were performed unnecessarily in 94.7-100% of cases, when detection of clinically significant disease was aimed at. Using PSA (and a cut-off of 3.0 ng/ml) as the only screening tool, 24.3% (121/498) of screen-detected cancers were in the PSA range 3.0-3.9 ng/ml, and 60.0% were assessed as clinically significant., Conclusions: Rectal examination as initial screening test for prostate cancer at low PSA values may be replaced by screening using serum-PSA only. At PSA levels below 3.0 ng/ml, 289 rectal examinations are required to find one case of clinically significant disease, and 96 rectal examinations are needed to diagnose prostate cancer of any size, grade, or stage., (Copyright 2001 Wiley-Liss, Inc.)

Background: The purpose of this study was to evaluate baseline health-related quality of life (HRQOL) in patients with localized prostate cancer before primary treatment (radical prostatectomy or radiotherapy)., Methods: Two hundred patients with newly diagnosed localized (screen-detected or clinically diagnosed) prostate cancer completed HRQOL questionnaires (generic and disease-specific measures). Clinical data were collected from patients' medical records in four Rotterdam hospitals., Results: Screen-detected tumors were of more favorable stages and grades than clinically diagnosed ones. The diagnostic groups did not differ significantly in bowel and sexual functioning. Differences were found in urinary functioning, favoring patients with screen-detected tumors of T2-T3 stages. Patients with screen-detected T2 cancer reported better generic HRQOL (physical aspects) than the clinical group, but HRQOL of the latter group was similar to the population norm. Radiotherapy patients were significantly older and had more comorbidity than subjects referred to prostatectomy. Urinary, bowel, and sexual problems were uncommon. Older (> 65 years) radiotherapy patients appeared to be less sexually active. Radiotherapy patients also reported poorer levels of generic HRQOL., Conclusions: Screen-detected prostate cancer patients presented with more favorable cancer stage and grade. HRQOL was related to both the tumor stage and the detection method. Pre-treatment HRQOL differences between prostatectomy and radiotherapy patients were associated neither with tumor characteristics nor with the detection method. Baseline differences in HRQOL should be taken into account when evaluating post-treatment HRQOL., (Copyright 2001 Wiley-Liss, Inc.)

Background: Subdividing cancers according to the natural course of disease, both at the time of diagnosis and after radical prostatectomy, may influence management decisions of patients with prostate cancer. We investigated whether categorization of prostate cancers into different prognostic subgroups is feasible., Methods: In 218 screened participants of a randomized study, conventional post-operative tumor features were assessed for their accuracy in predicting PSA relapse after radical prostatectomy using Cox regression analysis. Independent prognostic tumor features were combined to identify subsets of cancers with similar biological potential. A cancer was defined that may be curable after its detection by screening tests, though is destined to progress to clinically manifest disease and cancer-related mortality in the absence of screening., Results: After a median follow-up of 33.0 months, pathological stage (P = 0.03), tumor volume (P = 0.04), and margin status (P = 0.01) each independently predicted PSA relapse after surgery. The proportion of poorly differentiated cancer proved highly superior to the Gleason score and most strongly predicted PSA relapse (P < 0.0001). Based on combined independent prognostic tumor features, a tumor classification model powerfully predicted PSA relapse., Conclusions: Based on tumor characteristics, possibly harmless, and conversely, possibly non-curable disease, may be distinguished from cancers that are likely to show clinical progression in the absence of screening and treatment. Prediction of these subclasses prior to treatment may eventually lead to proper patient management., (Copyright 2001 Wiley-Liss, Inc.)

Background: An endpoint for clinical trials of prostate cancer which simplifies traditional endpoints (response of measurable lesions, progression rates, and death) is urgently needed. This is especially true for hormone-unresponsive disease, for which many new drugs are presently in a development phase. This paper presents a rationale for the use of prostate-specific antigen (PSA) in clinical trials of progressive prostate cancer under endocrine treatment., Methods: The study is based on 84 patients who progressed after radical prostatectomy or node dissection, of whom 24 showed increasing PSA levels under subsequent endocrine treatment. An average linear relationship between (log-transformed) PSA and time and a subject-specific deviation from this average relationship were assessed. The predictive value of the subject-specific parameters of the linear fit with respect to time to prostate cancer-specific death was determined. The outcomes of the fitting procedure were used to calculate sample sizes for future studies (duration, 6 months) using PSA increase over time in hormone-unresponsive prostate cancer as a marker for treatment efficacy., Results: The average PSA doubling time in this population was 4 months (corresponding time constant = 0.25). The assessed variance of the time constants equalled 0.04; the overall residual variance equalled 0.265. The subject-specific rate of change of the log-transformed PSA value in hormone-unresponsive prostate cancer was a highly significant predictor of prostate cancer-specific death. This suggests the potential usefulness of PSA as an endpoint in trials of hormone-unresponsive prostate cancer. Depending on conditions chosen (e.g, desired power and changes in log PSA slope), 18-70 participants per arm will be necessary in future phase III studies. A suggestion (algorithm) for the use of PSA in drug development is presented., Conclusions: Relatively small PSA-based trials in patients with hormone-unresponsive prostate cancer are possible if a similar patient population is utilized. As long as surrogacy is not established, such studies cannot be considered conclusive with respect to effectiveness of treatment, but are likely to be useful as a screening tool for new drugs. Experimental confirmation in human prostate cancer model systems of synergism between PSA decrease and tumor control by a given test treatment is likely to enhance the level of certainty of PSA-based drug evaluation., (Copyright 2000 Wiley-Liss, Inc.)

Background: Androgen-independent growth leads to progressive prostate cancer after androgen-ablation therapy. This may be caused by altered specificity of the androgen receptor (AR), by ligand-independent stimulation of the AR, or by paracrine growth modulation by neuropeptides secreted by neuroendocrine (NE) cells., Methods: We established and characterized the androgen-independent FGC-DCC from the androgen-dependent LNCaP fast growing colony (FGC) cell line. The androgen-independent DU-145, FGC-DCC, and PC-3, and the androgen-dependent LNCaP and PC-346C cell lines were used to study growth modulation of gastrin-releasing peptide (GRP), calcitonin (CT), serotonin (5-HT), and vasoactive intestinal peptide (VIP) by (3)H-thymidine incorporation. Specificity of the growth-modulating effects was tested with the anti-GRP monoclonal antibody 2A11 and induction of cAMP by neuropeptides., Results: Androgen-independent growth stimulation by neuropeptides was shown in DU-145 and PC-346C. 2A11 inhibited GRP-induced (3)H-thymidine incorporation in DU-145 and PC-346C and inhibited proliferation of the FGC-DCC and PC-3 cell lines. With some exceptions, cAMP induction paralleled growth stimulation. Dideoxyadenosine (DDA) inhibited the GRP-induced growth effect in DU-145 and PC-346C, whereas oxadiazoloquinoxaline-1-one (ODQ) had no effect on (3)H-thymidine incorporation. None of the neuropeptides stimulated growth of LNCaP, FGC-DCC, or PC-3., Conclusions: GRP-induced growth of DU-145 and PC-346C was specific and cAMP-mediated. Androgen-independent growth of FGC-DCC cells was mainly due to an induction of Bcl-2 expression and possibly through the activation of an autocrine and NE-like pathway, as has been shown also for the PC-3 cell line. Growth induction of non-NE cells by neuropeptides could be a possible role for NE cells in clinical prostate cancer., (Copyright 2000 Wiley-Liss, Inc.)

Background: Prostate cancer has displayed an increase in incidence unparalleled by any other tumor in the last two decades, with a steady, more gradual increase in mortality rate. Current curative strategies are focused on the detection and treatment of early-stage (T1-2 N0 M0), clinically significant tumors., Methods: To this aim, refinement of surgical approaches, with appropriate adjuvant therapies, will ensure more complete cancer control, while minimizing associated morbidity. New delivery systems for radiotherapy, as well as other energy sources, are evolving, while a number of promising pharmacological agents, including angiogenesis inhibitors and drugs which alter signal transduction pathways, are currently under investigation. Early detection is also being facilitated by a more widespread implementation of screening programs. Advances in tumor markers, and imaging and biopsy techniques, will allow more accurate preoperative staging. These, coupled with improvements in prognostic markers, aid the physician and patient alike in deciding on the suitability of treatment options with better estimation of outcome. Perhaps the most exciting developments in prostate cancer will come from knowledge of the molecular mechanisms underlying carcinogenesis. The potential for the development of diagnostic and therapeutic tools is immense. The efficacy of treatment can be studied at a molecular level, and strategies for preventing or slowing the development of malignancy can be formulated. RESULTS AND CONCLUSIONS Application of this knowledge in the form of gene and cellular therapy and in the development of novel systemic agents is beginning to enter the realm of clinical practice, and it may be in this field that means for cure and prevention of prostate cancer will eventually be found., (Copyright 1999 Wiley-Liss, Inc.)

Background: If prostate cancer screening proves to be effective, some cases will be prevented from reaching the advanced stage. In order to evaluate screening programs thoroughly, it is important to quantify course, care, and accompanying costs of advanced disease., Methods: We studied 70 files of patients in two hospitals, who had received a diagnosis of distant metastases of prostate cancer and who had died in the years 1994-1998. The total healthcare received by these patients, including symptoms and complaints, was recorded., Results: The most frequently reported symptoms were pain (42%), urogenital symptoms (25%), and malaise (20%). Eighty-nine percent of all patients were hormonally treated (either by orchidectomy and/or chemical castration), and 47% received one or more series of radiation therapy. Sixty-nine percent of all patients were treated with pain medication. The average duration of advanced disease in all patients was 24 months. Average costs of advanced disease were estimated at $11,182 over the total period: $1,547 (14%) was allocated to assessment and outpatient care, and $9,635 (86%) to treatment and costs of hospital stay. Almost half of the total costs were determined by hospital stay., Conclusions: These data give a better understanding of the course, care, and costs of advanced prostate cancer. These estimates, together with the effects of advanced prostate cancer on quality of life, will be used for the evaluation of prostate cancer screening.

Background: In the European Randomized Study of Screening for Prostate Cancer (ERSPC, Rotterdam region), men aged 55-74 years are screened for prostate cancer by prostate-specific antigen (PSA) sampling, digital rectal examination (DRE), and transrectal ultrasound investigation (TRUS). All men with a PSA > or =4 ng/ml and/or a suspicious DRE and/or a suspicious TRUS are biopsied., Methods: Logistic regression analysis was applied to derive a predictive index that equals the chance to find prostate cancer in a biopsy given the outcomes of the screening tests. This model was used to assess the number of cancers that could have been detected if all men had been biopsied (extrapolation). Furthermore, the model was used to study the possibilities for improvement of the current screening protocol., Results: PSA was the dominant predictor for prostate cancer in a biopsy, followed by prostate volume, DRE, and TRUS result. It is assessed that 69% (95% CI, 52-86%) of cancers that could be identified if all men were biopsied are currently detected. Application of the same methods to screening data obtained in Göteborg (the Swedish ERSPC partner) yielded almost identical results. It was found that, in the Rotterdam protocol, a considerable number of men were biopsied according to the screening protocol with an assessed lower chance to have prostate cancer than men who were not biopsied according to the protocol., Conclusions: The chance to detect prostate cancer in a biopsy can be modeled quite accurately as a function of serum PSA, prostate volume, DRE, and TRUS results. Important improvements in the screening protocol can be achieved by the application of the predictive index.

Background: To study the metastatic behavior of human prostate cancer cell lines, orthotopic injection in nude mice was performed., Methods: Local tumor growth, metastasis formation, prostate-specific antigen, and androgen receptor expression were examined., Results: Hormone-independent cell lines (PC-3, PC-3-125-IL, and TSU-Pr1) were highly tumorigenic and had a higher rate of lymph node metastasis after orthotopic than after subcutaneous implantation. PC-3 cell lines also consistently metastasized to the lungs. The androgen-sensitive LNCaP cell line showed local growth in 7 of 10, and lymph node metastasis in 4 animals. Significant serum PSA levels and strong receptor expression in primary and metastatic tumor tissues were observed., Conclusions: These results demonstrates that orthotopic implantation of human prostate cancer cell lines, including LNCaP, reproducibly leads to metastasis formation in nude mice.

In order to assess the accuracy of various volumetric methods for screening and follow-up of prostatic disease, total prostate volume and inner zone volume were measured by transrectal ultrasonography in a screening population of 716 men. Semiplanimetric and caliper formula methods were compared with step section planimetry as the gold standard. Planimetric volumetry of the prostate is regarded as the most reproducible method for individual follow-up of total gland and inner zone volume. The prolate spheroid formula is the most reproducible of caliper formula methods for both volumes. In this study the elliptical volume was, however, more accurate than the prolate spheroid volume of the total gland, as the correlation coefficient between total elliptical volume and planimetry was higher compared to the prolate spheroid volume (0.89 vs. 0.83), and the standard deviation of the mean volumetric difference smaller. The mean total prolate spheroid volume resembled the mean total planimetric volume better than the elliptical volume did, as the mean volumetric difference was smaller. For measurement of the inner zone volume the prolate spheroid volume was more accurate that the elliptical volume. The correlation coefficient between length and planimetric volume was similar to that of width and height, which accounted for more accuracy of the elliptical volume that of the prolate spheroid volume in larger prostates. The elliptical volume might be used for incidental volumetric measurements of the total gland, and for comparison of different individuals, e.g., in preoperative evaluation or screening studies.

The correlation between both prostate specific antigen levels (PSA) and prostate specific antigen density (PSAD) and age, prostate volume parameters, body mass index, and the International Prostate Symptom Score (IPSS) were studied in a community-based population. A sample of 502 men aged 55 through 74 years was evaluated, excluding those with a serum PSA above 10 ng/ml, those with biopsy proven prostate cancer, and those who had previously undergone a prostate operation. PSA and PSAD did not correlate with the body mass index. Weak correlations were found between PSA and age (r = 0.25; P < 0.001), PSAD and age (r = 0.17; P < 0.001) and between PSA and the total prostate volume (r = 0.58; P < 0.001). PSA did not correlate independently with age after adjustment for volume (P = 0.22). The finding that PSAD correlates with age (r = 0.17; P < 0.001) is partly explained by the incomplete volume adjustment of PSAD which is proved by the positive correlation between PSAD and prostate volume (r = 0.26; P < 0.001). In the main target age-range for prostate cancer screening there is a poor basis for the use of age-specific reference values or volume adjustment for PSA levels in order to increase the clinical usefulness of this serum marker. Comparison of the results of the present study and studies conducted in others regions shows that there may be significant differences in PSA values per age stratum. Further studies are needed to clarify the reasons for these differences.

The applicability of MIB-1, a monoclonal antibody directed against the Ki-67 antigen, was studied in the PC-82 and LNCaP prostatic tumor models at various levels of proliferative activity. Statistically significant correlations were found in LNCaP cultures between Ki-67 and MIB-1 scores (r = 0.84, P < 0.001), and in PC-82 tumors between MIB-1 scores and paraffin tissue Ki-67 (pKi-67) (r = 0.90, P < 0.001), frozen tissue (fKi-67) (r = 0.86, P < 0.001), and BrdU uptake (r = 0.70, P < 0.001), respectively. pKi-67 scores were double the fKi-67 scores, which may be due to methodological differences. MIB-1 scores exceeded both the fKi-67 and pKi-67 scores. The affinity of MIB-1 for the antigen is much higher than the affinity of Ki-67, which may explain the differences. MIB-1 is a promising means of evaluating the presence of only minute amounts of the Ki-67 antigen in paraffin-embedded human tumor material, especially in relatively slowly growing tumors.

The study of stromal-epithelial interactions greatly depends on the ability to culture both cell types separately, in order to permit analysis of their interactions under defined conditions in reconstitution experiments. Here we report the establishment of explant cultures of human prostatic stromal cells and their immunocytochemical characterization. As determined by antibodies to keratin and prostate specific acid phosphatase, only small numbers (< 5%) of epithelial cells were present in primary cultures; subsequent passaging further reduced epithelial cell contamination. Antibodies against intermediate filament proteins (keratins, vimentin, and desmin) and smooth muscle actin microfilaments demonstrated that stromal cells from benign prostatic hyperplasia and prostate carcinoma differed in regard to their differentiation markers. Two contrasting phenotypes were identified in cultures derived from these two different lesions: One exhibiting fibroblastic features, was predominant in cultures derived from benign lesions and a second, showing varying degrees of smooth muscle differentiation, was more abundant in carcinoma-derived cultures. These findings are indicative of a remarkable divergence in the stromal-epithelial relationships associated with these pathological conditions and may provide us with a potential tool for studying these processes.

Stromal cells from the prostate were recently shown to inhibit clonal growth of the prostatic carcinoma cell lines PC-3 (hormone-independent) and LNCaP (hormone-sensitive) in coculture. Our study revealed that stromal cell-conditioned medium strongly inhibited proliferation of PC-3 and LNCaP cells when grown in monolayer culture. Antiproliferative activity was found to be reversible, and was produced specifically by prostatic stromal cells and not by stromal cells derived from skin, foreskin, uterus, kidney, and Wilms' tumor. Inhibition was not species-specific, since the cell lines AT-2.1 and MATLyLu, derived from the Dunning rat prostate tumor, were also sensitive. No inhibition, however, occurred on breast and renal carcinoma cell lines, suggesting a prostate-specific action. The putative inhibiting factor(s) could be concentrated and partially purified by ammonium sulfate precipitation. The possible role in stromal control of epithelial cell proliferation is discussed.

Nuclear suspensions of 42 prostate carcinoma specimens obtained at surgery were used to investigate loss and gain chromosomes 1, 18, and Y by fluorescence in situ hybridization (FISH) with centromere-specific probes. The outcome of FISH analysis was correlated with clinical parameters and the relationship between DNA-FCM (ploidy at cellular level) and FISH (ploidy of individual chromosomes) was assessed. Significant loss of chromosomes 1 and 18 was infrequent (respectively, three and five cases), but 53% of the tested specimens showed loss of Y. Loss was not correlated with DNA ploidy. Significant gain occurred in 36% (chromosome 1), 63% (chromosome 18), and 28% (Y) of the specimens. Gain of chromosome 18 was shown in DNA diploid (7/14) and aneuploid tumors (18/26), while gain of chromosomes 1 and Y was nearly restricted to DNA aneuploid specimens. Significant unbalance between these chromosomes occurred in 11 cases. Most cases which had significant gain of chromosome 1 or 18 showed trisomic as well as tetrasomic cells. Simultaneous loss of some and gain of other investigated chromosomes is suggestive of clonal heterogeneity and/or multiclonality. This was observed in eight tumors. Correlation between DNA-FCM and FISH was best for the Y chromosome. DNA-FCM showed more aberrant histograms with increasing stage and grade of tumors. The presence of numerical aberrations of the investigated chromosomes however, seemed independent of clinical grade or stage.

The transplantable human prostate tumor lines PC-82 and PC-EW regress after androgen depletion. The castration-induced decline in tumor volume was faster in the PC-EW tumor (half-life 6 days) than in the PC-82 tumor (half-life 18 days), despite similar castrate androgen levels of less than 3 pmol/g tissue. Androgen ablation of the PC-82 tumor induced a wave of apoptosis, whereas in the PC-EW tumor, necrotic cell death was predominantly observed. The proliferative activity (BrdU index) of PC-82 and PC-EW tumor tissue declined from 3% to less than 1% after castration. After androgen depletion, some proliferative activity remained, the major part of which was localized in the (murine) stromal compartment of the tumors. In contrast to the PC-EW tumors, regrowth of androgen-ablated PC-82 tumors was rapidly induced by androgen resubstitution. The differences in response of these tumor models to androgen depletion and repletion appear to be related to the putative involvement of different cell death pathways. The role of the stroma in these processes is unclear.

Androgen receptor (AR) levels were measured in PC-82 tumor tissue grown in hormonally manipulated nude mice. In the nuclei of tumor tissue from intact male mice a relatively low concentration (mean 25 fmol/mg protein) of androgen receptors (ARn) was found, while no receptors for estrogens or progestins were detected. The total number of androgen receptors in the PC-82 tumor tissue (measured in the nuclei 1 h after injection of a single high dose of testosterone (T) was found to be 100 fmol/mg protein. The antiandrogen cyproterone acetate, administered in combination with the high dose of T, significantly lowered the amount of ARn in the tumor tissue. In the nuclei of tumor tissue from intact tumor-bearing male mice with T-containing Silastic implants, a 4-times higher amount of tightly associated AR was found. In addition, an increased growth rate of the tumor was observed following T implantation. This finding suggests that the increased growth rate of the PC-82 tumor is associated with a continuous occupancy of AR in the nuclei of the tumor tissue. Castration of tumor-bearing male mice, which arrests the growth of this tumor, did not affect the concentration of ARn in the tissue compared to that of tissue in the intact control situation. In addition, the total amount of AR measured after T injection was not affected by castration. Therefore, the availability of a sufficient and steady level of T in the plasma and consequently the duration of the presence of AR in the nucleus of the PC-82 tumor tissue, rather than the total concentration of AR, appear to be the limiting factors in the modulation of hormonal responses in this androgen target tissue.

The transplantable human prostatic tumor model (PC-82) in nude mice was used to evaluate the indirect and possibly direct effects of estrogens on the growth of prostatic tumor tissue. High (pharmalogical) doses of plasma estradiol (E2) were achieved in tumor-bearing mice by using E2-containing Silastic implants of different lengths. In comparison with the situation in men, in mice much higher concentrations of circulating E2 (exceeding 3 nmol/liter) were necessary to attain (near)-castrate levels of plasma testosterone (T). Treatment of tumor-bearing mice with a high dose of E2 resulted in tumor growth arrest and a subsequent decline of the tumor volume, which equals the effects of castration. No evidence was found that either of the two doses of E2 applied had any additive inhibitory effect on tumor growth when compared to castration alone. It was inferred from these findings that in the PC-82 tumor model, estrogens, rather than having a direct effect on the tumor tissue, mainly act indirectly by their suppressive effect on T secretion in the host animal. A different and unexpected result was obtained in castrated tumor-bearing mice treated with a combination of E2 and T. With both doses of E2 this type of treatment led to a smaller increase of the tumor volume compared with mice receiving T only, the result of the high dose being statistically significant. This antagonistic effect of the two steroids on the PC-82 tissue was paradoxically associated with a sharp increase of nuclear androgen receptor levels and a higher concentration of dihydrotestosterone in the tumor tissue. Plasma and tissue concentrations of T appeared to be unaltered. The present study of the PC-82 prostate tumor shows that only by careful monitoring of plasma steroid levels in tumor-bearing mice can conclusions about the effectiveness of hormonal treatment regimens, such as estrogen therapy, be drawn.

The nuclear androgen receptor (ARn) content of cancerous prostatic tissue has been investigated as a prognosticator for time to progression under endocrine therapy. In 1981 a prospective study was started to investigate whether the ARn content in biopsy specimens of patients with prostatic carcinoma predicts the duration of response following hormonal treatment. ARn was estimated by a microassay which involves extraction of nuclear pellets with a heparin-containing buffer, exchange labeling of the nuclear extract with 3H-R1881, and quantitation of the receptor with protamine sulphate precipitation. One hundred and fifteen patients with prostatic cancer entered this study; 47 patients had evidence of metastatic disease as proven by bone scan. Forty-two patients were treated by orchiectomy; 37 of these patients are evaluable with a minimal follow-up of 30 months. A relationship between the nuclear androgen receptor content and the time to progression following orchiectomy in these patients with metastatic disease of the prostate was not found. This could possibly be attributed to the heterogeneous nature of the prostatic tumor tissue with respect to the distribution of the ARn. We conclude that androgen receptor assay in needle biopsies, at least in this study, had no value for the prediction of the time to progression after orchiectomy.

Epithelial cells were isolated from human prostatic hyperplasia (BPH) after mechanical disruption of the tissue. The tissue was cut into small pieces, then mechanical pressure was applied. Stroma and epithelium were separated by a sequence of sedimentation steps. The recovery rate of epithelial cells was around 20 million cells per gram of tissue and more than 95% of the cells did exclude trypan blue. Epithelial cells can be identified by phase contrast microscopy and by the acid phosphatase content of the cells. In more than 95% of the cells the presence of acid phosphatase could be shown cytochemically with phosphorylcholine as a substrate. This finding indicates that the contamination with other cell types is very small. Histological study of the remaining stroma indicates that most of the epithelial cells are removed. Also, the acid phosphatase content of this fraction was found to be very low. The problem of obtaining large quantities of stromal cells in suspension has not yet been resolved. However, the technique described may be more suitable than others for the separate study of stroma and epithelium from BPH.

Androgen receptors (ARn) were assayed in nuclear extracts of prostatic biopsies from 60 patients with benign prostatic hyperplasia (BPH) and 82 patients with prostatic cancer (PC), with an exchange assay using heparin extraction, labelling with 3H-R1881, and protamine sulphate precipitation. The content of ARn of BPH biopsies (38 +/- 34 fmol/mg protein [mean +/- SD]; n = 70) was not different from that of PC biopsies (39 +/- 32 fmol/mg protein; n = 115). Biopsies showing essentially normal prostatic tissue had a lower ARn content (12 +/- 13 fmol/mg protein; n = 6). The content of ARn was independent of the age of the patient and of the histological grade of the carcinomas. A considerable variation in ARn content within tumors of individual patients was found, indicating that ARn are not uniformly distributed over prostatic tissue; ie, cells with high and low receptor content may coexist in different proportions in different regions of the prostate. Therefore, assays on multiple biopsies may be required for a proper estimation of the mean receptor content. The question remains, however, whether the behavior of the tumor is adequately predicted by the mean receptor level or, for instance, by the region with the lowest receptor content.

The rat ventral prostate contains prolactin receptors, and during sexual maturation prolactin stimulates the growth of this gland. The aim of the present investigation was to evaluate whether prolactin is involved in the regulation of the number of its own receptor sites in the rat ventral prostate. To this end, the content of prolactin receptors was estimated in prostate membranes of control and chronically hyperprolactinemic rats both before and after in vitro desaturation with 4 M MgCl2. Hyperprolactinemia resulted in a 40% increase in the number of available prolactin receptors (P less than 0.05). In vitro desaturation of receptors resulted in loss of 84% of protein and 36 +/- 6% and 52 +/- 6% of prolactin receptors from ventral prostate membranes of control and hyperprolactinemic rats respectively (P less than 0.05). We have concluded that the rat ventral prostate membranes are not suited to in vitro desaturation of prolactin receptors with MgCl2. From the increase in the number of available prolactin receptors after hyperprolactinemia we have concluded that prolactin is involved in the regulation of the number of its own receptors in the rat ventral prostate.