A comparison of the performance of microsatellite and methylation urine analysis for predicting the recurrence of urothelial cell carcinoma, and definition of a set of markers by Bayesian network analysis

OBJECTIVE

To compare the potential of two diagnostic methods for detecting recurrence of urothelial cell carcinoma (UCC) of the bladder, by (i) detecting alterations in microsatellite DNA markers and loss of heterozygosity (LOH), and (ii) detecting aberrant gene hypermethylation, as UCC has a high recurrence rate in the urinary tract and the disease can invade muscle if new tumours are overlooked.

PATIENTS AND METHODS

Over 1 year, urine samples were retrieved from 40 patients already diagnosed with bladder UCC (30 pTa, two pTis, eight pT1). Samples were collected 6 months after bladder tumour resection, during the follow-up schedule. We used samples to analyse nine microsatellite markers and the methylation status of 11 gene promoters. Receiver operating characteristic curves were generated and Bayesian statistics used to create an interaction network between recurrence and the biomarkers.

RESULTS

During the study, 15 of the 40 patients (38%) had a tumour recurrence and 14 were identified by cystoscopy (reference method). Overall, microsatellite markers (area under curve, AUC 0.819, 95% confidence interval, CI, 0.677-0.961) had better performance characteristics than promoter hypermethylation (AUC 0.448, 0.259-0.637) for detecting recurrence. A marker panel of IFNA, MBP, ACTBP2, D9S162 and of RASSF1A, and WIF1 generated a higher diagnostic accuracy of 86% (AUC 0.92, 0.772-0.981).

CONCLUSION

Microsatellite markers have better performance characteristics than promoter hypermethylation for detecting UCC recurrence. These data support the further development of a combination of only six markers from both methods in urinary DNA. Once validated, it could be used routinely during the follow-up for the early detection and surveillance of UCC from the lower and upper urinary tract.

The Polycomb Group protein EZH2 regulates actin polymerization in human prostate cancer cells

BACKGROUND

The Polycomb Group protein EZH2 is implicated in prostate cancer progression. EZH2 promotes prostate cancer cell proliferation and invasiveness. We describe a link between EZH2 function and actin polymerization in prostate cancer cells.

METHODS

Nuclear and cytoplasmic EZH2 expression in benign and malignant prostate tissue samples was assessed. An association between EZH2 function and actin polymerization in prostate cancer cells was investigated using siRNA-mediated knock-down of EZH2. Effects of EZH2 knock-down on actin polymerization dynamics were analyzed biochemically using immunoblot analysis of cell lysate fractions, and morphologically using immunocytochemistry.

RESULTS

Cytoplasmic EZH2 is expressed at low levels in benign prostate epithelial cells and over-expressed in prostate cancer cells. Cytoplasmic EZH2 expression levels correlate with nuclear EZH2 expression in prostate cancer samples. Knock-down of EZH2 in PC3 prostate cancer cells increases the amount of F-actin polymerization, cell size, and formation of actin-rich filaments.

CONCLUSIONS

Cytoplasmic EZH2 is over-expressed in prostate cancer cells. EZH2 function promotes a reduction in the pool of insoluble F-actin in invasive prostate cancer cells. EZH2 may regulate actin polymerization dynamics and thereby promote prostate cancer cell motility and invasiveness.

iTRAQ-facilitated proteomic analysis of human prostate cancer cells identifies proteins associated with progression

The unpredictable behavior of prostate cancer presents a major clinical challenge during patient management. In order to gain an insight into the molecular mechanisms associated with prostate cancer progression, we employed the shot-gun proteomic approach of isobaric tags for relative and absolute quantitation (iTRAQ), followed by 2D-LC-MS/MS, using the poorly metastatic LNCaP cell line and its highly metastatic variant LNCaP-LN3 cell line as a model. A total number of 280 unique proteins were identified (> or =95% confidence), and relative expression data was obtained for 176 of these. Ten proteins were found to be significantly up-regulated (> or =1.50 fold), while 4 proteins were significantly down-regulated (> or = -1.50 fold), in LNCaP-LN3 cells. Differential expression of brain creatine kinase (CKBB), soluble catechol-O-methyltransferase (S-COMT), tumor rejection antigen (gp96), and glucose regulated protein, 78 kDa (grp78), was confirmed by Western blotting or independent 2D-PAGE analysis. Additionally, iTRAQ analysis identified absence of the lactate dehydrogenase-B (LDH-B) subunit in LNCaP-LN3 cells, confirming our published data. The clinical relevance of gp96 was assessed by immunohistochemistry using prostate tissues from benign ( n = 95), malignant ( n = 66), and metastatic cases ( n = 3). Benign epithelium showed absent/weak gp96 expression in the basal cells, in contrast to the moderate/strong expression seen in malignant epithelium. Furthermore, there was a statistically significant difference in the intensity of gp96 expression between benign and malignant cases ( p < 0.0005, Mann-Whitney U). Our study is the first to report the application of iTRAQ technology and its potential for the global proteomic profiling of prostate cancer cells, including the identification of absent protein expression.

Promoter hypermethylation in circulating blood cells identifies prostate cancer progression

Promoter hypermethylation of circulating cell DNA has been advocated as a diagnostic marker for prostate cancer, but its prognostic use is currently unclear. To assess this role, we compared hypermethylation of circulating cell DNA from prostate cancer patients with (Group 1, n = 20) and without (Group 2, n = 22) disease progression and age-matched controls (benign prostatic hyperplasia, Group 3, n = 22). We measured hypermethylation of 10 gene promoters in 2 sequential venous samples, obtained at diagnosis and during disease progression (median time, 15 months later). Matched time samples were obtained in the nonprogressing patients. We found that more hypermethylation was detected in the diagnostic sample from the patients with cancer than in controls for GSTP1, RASSF1 alpha, APC and RAR beta (p < 0.0001). Patients undergoing disease progression had a significant increase in methylation levels of these 4 genes when compared to the other patients (p < 0.001). Patients at risk of disease progression have higher detectable concentrations of circulating cell hypermethylation, than those without progression. The extent of this hypermethylation increases during disease progression and can be used to identify the extent and duration of treatment response in prostate cancer.

Low risk research using routinely collected identifiable health information without informed consent: encounters with the Patient Information Advisory Group

Current UK legislation is impacting upon the feasibility and cost-effectiveness of medical record-based research aimed at benefiting the NHS and the public heath. Whereas previous commentators have focused on the Data Protection Act 1998, the Health and Social Care Act 2001 is the key legislation for public health researchers wishing to access medical records without written consent. The Act requires researchers to apply to the Patient Information Advisory Group (PIAG) for permission to access medical records without written permission. We present a case study of the work required to obtain the necessary permissions from PIAG in order to conduct a large scale public health research project. In our experience it took eight months to receive permission to access basic identifying information on individuals registered at general practices, and a decision on whether we could access clinical information in medical records without consent took 18 months. Such delays pose near insurmountable difficulties to grant funded research, and in our case 560,000pound of public and charitable money was spent on research staff while a large part of their work was prohibited until the third year of a three year grant. We conclude by arguing that many of the current problems could be avoided by returning PIAG's responsibilities to research ethics committees, and by allowing "opt-out" consent for many public health research projects.

Detection of prostate cancer in unselected young men: prospective cohort nested within a randomised controlled trial

OBJECTIVE

To investigate the feasibility of testing for prostate cancer and the prevalence and characteristics of the disease in unselected young men.

DESIGN

Prospective cohort nested within a randomised controlled trial, with two years of follow-up.

SETTING

Eight general practices in a UK city.

PARTICIPANTS

1299 unselected men aged 45-49.

INTERVENTION

Prostate biopsies for participants with a prostate specific antigen level of 1.5 ng/ml or more and the possibility of randomisation to three treatments for those with localised prostate cancer.

MAIN OUTCOME MEASURES

Uptake of testing for prostate specific antigen; positive predictive value of prostate specific antigen; and prevalence of prostate cancer, TNM disease stage, and histological grade (Gleason score).

RESULTS

442 of 1299 men agreed to be tested for prostate specific antigen (34%) and 54 (12%) had a raised level. The positive predictive value for prostate specific antigen was 21.3%. Ten cases of prostate cancer were detected (2.3%) with eight having at least two positive results in biopsy cores and three showing perineural invasion. One tumour was of high volume (cT2c), Gleason score 7, with a positive result on digital rectal examination; nine tumours were cT1c, Gleason score 6, and eight had a negative result on digital rectal examination. Five of the nine eligible participants (55%) agreed to be randomised. No biochemical disease progression in the form of a rising prostate specific antigen level occurred in two years of follow-up.

CONCLUSIONS

Men younger than 50 will accept testing for prostate cancer but at a much lower rate than older men. Using an age based threshold of 1.5 ng/ml, the prevalence of prostate cancer was similar to that in older men (3.0 ng/ml threshold) and some cancers of potential clinical significance were found.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN20141297.

Human prostate cancer cells express neuroendocrine cell markers PGP 9.5 and chromogranin A

BACKGROUND

A proportion of men with prostate cancer will progress to develop metastatic disease involving the lymph-nodes and bone. To identify novel candidates associated with metastatic progression, we compared the proteomic profiles of LNCaP (lymph-node metastatic, androgen-dependant) and PC-3 (bone metastatic, androgen-independent), human prostate cancer cells.

METHODS

Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), followed by electrospray ionisation tandem mass spectrometry (ESI-MS/MS), was used to identify differentially expressed proteins. Western blotting was used to validate the identity of any candidates. Immunohistochemistry was used to assess tissue expression.

RESULTS

2D-PAGE followed by ESI-MS/MS analyses identified the expression of glutathione S-transferase-pi (GST-pi) and protein gene product 9.5 (PGP 9.5) in PC-3 cells, but absent expression in LNCaP cells. PGP 9.5 expression in PC-3 cells was confirmed by Western blotting, in addition to expression in DU145 cells. Analysis of cell conditioned media showed that PGP 9.5 was secreted. Sequencing of the PGP 9.5 gene promoter region in bisulfite modified DNA, suggested that the regulation of expression involves promoter hypermethylation. RT-PCR analysis for Chromogranin A (ChA) mRNA (a marker of neuroendocrine cells), showed expression in PC-3 and DU145 cells but was undetectable in LNCaP cells. Immunohistochemistry localised PGP 9.5 expression exclusively within neuroendocrine cells and nerve fibres.

CONCLUSIONS

Our unexpected finding that the neuroendocrine cell markers PGP 9.5 and ChA are expressed by PC-3 and DU145 cells, suggests that these cells may have been derived from metastatic adenocarcinomas which had undergone neuroendocrine differentiation or alternatively the expression occurred ectopically as a result of cell culture.

The antibody MAB8051 directed against osteoprotegerin detects carbonic anhydrase II: implications for association studies with human cancers

A commonly used monoclonal antibody targeting osteoprotegerin (OPG), MAB8051, detects a truncated protein species in breast and prostate cancer cell lysates. OPG expression has been reported to contribute to cell survival of both of these cancers. We hypothesised that the truncated protein represented a unique tumour-associated OPG isoform. However, here we show that the truncated protein identified by MAB8051 in cancer cell lines is carbonic anhydrase II (CA II), also implicated in tumour biology. We clearly demonstrate cross-reactivity of this OPG antibody in western blots. OPG and CA II RNA-interference studies confirmed the identity of the bands. We show almost identical staining patterns between MAB8051 and CA II immunohistochemistry of different human tissue types and human tumour types using serial sections. We conclude that care should be exercised using this antibody for immunohistochemistry studies, without additional in situ hybridisation, or parallel use of other OPG-specific antibodies.

The impact of reducing the prostate-specific antigen threshold and including isoform reflex tests on the performance characteristics of a prostate-cancer detection programme

OBJECTIVE

To assess the effects on the performance characteristics, in a prostate-cancer detection programme using prostate-specific antigen (PSA) levels, of a lower PSA threshold and the incorporation of reflex (free or complexed PSA) tests.

METHODS

We reviewed publications and extracted data on PSA distributions and performance characteristics of the PSA test and isoform tests from population-based surveys. We estimated the rate of biopsy, cancers detected, and cancers missed that would result from lowering PSA thresholds and including reflex testing.

RESULTS

Lowering the PSA threshold for biopsy referral to 2 ng/mL would increase the number of referrals from 110 to 230 per 1000 men tested, with most of the extra biopsies being among men with no cancer, i.e. an increase from 74 to 172 per 1000 men tested. However, this increased testing would result in an increase in the cancer-detection rate from 3.6% to 5.8%. Including a reflex test for men with moderately elevated PSA levels has little effect on programme performance, with only a modest (10-15%) reduction in unnecessary biopsies and a small increase in the numbers of missed cancers.

CONCLUSIONS

Lowering PSA thresholds, with or without the concurrent introduction of reflex tests, would increase both the numbers of cancers detected and the number of patients referred for biopsy procedures, of which most would be unnecessary. As the extra cancers detected are likely to be clinically localized, and with no evidence that their treatment improves the outcome of the disease, such changes place a possibly unjustified additional burden on the healthcare provider.

Gene expression assays

The study of the profile of gene expression in a cell or tissue at a particular moment gives an insight into the plans of the cell for protein synthesis. Recent technological advances make it possible to analyze the expression of the entire genome in a single experiment. These "gene expression assays" complement or replace previous assays which measured the gene expression of only one gene, or a select group of genes. Within this chapter we outline the development of the gene expression assay and provide examples of the wide range of disciplines in which it is used. An overview of the current technologies is given, and includes an introduction to laser capture microdissection and linear amplification of RNA, both of which have extended the application of gene expression assays. Illustrative examples in the field of cancer and neuroscience highlight the scientific achievements. This technology has made in understanding the pathogenesis of diseases, including breast cancer, Huntington's disease, and schizophrenia. With recent advances including exon arrays to investigate alternative splicing, tiling arrays to investigate novel transcription start sites, and on-chip chromatin immunoprecipitation to investigate DNA-protein interactions, the future of gene expression assays is set to further our understanding of the complexities of gene expression.

Screening for prostate cancer: an update

OBJECTIVES

To review evidence regarding the potential introduction of prostate cancer screening programmes and highlight issues pertinent to the management of screen-detected prostate cancer.

METHODS

Screening for prostate cancer is a controversial health care issue in general and urological practice. A PubMed database search was performed, followed by a systematic review of the literature, to examine the evidence base underlying prostate cancer screening.

RESULTS

A prostate cancer screening programme should satisfy several key postulates prior to its introduction. To date, several of these postulates have not been satisfied, and the evidence available for prostate cancer screening is currently insufficient to warrant its introduction as a public health policy. The natural history of screen-detected prostate cancer remains poorly understood, and recent evidence suggests that a screening programme may detect a large number of men with indolent disease who may be subsequently overtreated. Several randomised clinical trials are currently in progress and it is hoped that they will provide robust evidence to inform future practice.

CONCLUSIONS

National systematic prostate cancer screening programmes outside randomised clinical trial settings have not been implemented to date owing to lack of robust evidence that such programmes would improve survival and/or quality of life in men with screen-detected disease. Forthcoming results of clinical trials and the application of appropriate risk stratification to prevent overtreatment of indolent prostate cancer are likely to change practice in coming years.

Combination of Polymorphisms From Genes Related to Estrogen Metabolism and Risk of Prostate Cancers: The Hidden Face of Estrogens

Purpose

The association between common functional polymorphisms from the CYP17, CYP19, CYP1B1, and COMT genes involved in the estrogen metabolism and the risk of prostate carcinoma was evaluated.

Patients and Methods

The study investigated 1,983 white French men (1,101 patients with prostate cancer and 882 healthy controls) aged between 40 and 98 years. The different alleles and genotypes were analyzed according to case-control status, aggressiveness pattern of the tumors, age at onset, and family history of cancers.

Results

The VV (high activity) genotype of the V432L polymorphism from CYP1B1 (odds ratio [OR] = 1.36; 95% CI, 1.03 to 1.79; P = .031), and the long allele (> 175 bp) of the TTTA repeat from CYP19 (OR, 1.26; 95% CI, 1.08 to 1.47; P = .003) were significantly associated with the risk of prostate cancer. An additive effect was observed when we combined the two at-risk alleles (OR = 1.63; 95% CI, 1.24 to 2.13; P < .001). The association was stronger for the CYP1B1 VV genotype (OR = 1.55; 95% CI, 1.13 to 2.13; P = .007) among the group of patients with highly aggressive disease. Stratification by age at onset showed that the associations of CYP1B1 and CYP19 variants were largely confined to the younger prostate cancer patients.

Conclusion

This association between polymorphisms from genes related to estrogen metabolism and prostate cancer risk suggest new clinical considerations in the management of prostate cancer: the development of new prevention trials based on genetic profiling and the evaluation of specific inhibitors involving the estrogen pathways.

Application of artificial intelligence to the management of urological cancer

PURPOSE

Artificial intelligence techniques, such as artificial neural networks, Bayesian belief networks and neuro-fuzzy modeling systems, are complex mathematical models based on the human neuronal structure and thinking. Such tools are capable of generating data driven models of biological systems without making assumptions based on statistical distributions. A large amount of study has been reported of the use of artificial intelligence in urology. We reviewed the basic concepts behind artificial intelligence techniques and explored the applications of this new dynamic technology in various aspects of urological cancer management.

MATERIALS AND METHODS

A detailed and systematic review of the literature was performed using the MEDLINE and Inspec databases to discover reports using artificial intelligence in urological cancer.

RESULTS

The characteristics of machine learning and their implementation were described and reports of artificial intelligence use in urological cancer were reviewed. While most researchers in this field were found to focus on artificial neural networks to improve the diagnosis, staging and prognostic prediction of urological cancers, some groups are exploring other techniques, such as expert systems and neuro-fuzzy modeling systems.

CONCLUSIONS

Compared to traditional regression statistics artificial intelligence methods appear to be accurate and more explorative for analyzing large data cohorts. Furthermore, they allow individualized prediction of disease behavior. Each artificial intelligence method has characteristics that make it suitable for different tasks. The lack of transparency of artificial neural networks hinders global scientific community acceptance of this method but this can be overcome by neuro-fuzzy modeling systems.

Promoter hypermethylation identifies progression risk in bladder cancer

PURPOSE

New methods to accurately predict an individual tumor behavior are urgently required to improve the treatment of cancer. We previously found that promoter hypermethylation can be an accurate predictor of bladder cancer progression, but it is not cancer specific. Here, we investigate a panel of methylated loci in a prospectively collected cohort of bladder tumors to determine whether hypermethylation has a useful role in the management of patients with bladder cancer.

EXPERIMENTAL DESIGN

Quantitative methylation-specific PCR was done at 17 gene promoters, suspected to be associated with tumor progression, in 96 malignant and 30 normal urothelial samples. Statistical analysis and artificial intelligence techniques were used to interrogate the results.

RESULTS

Using log-rank analysis, five loci were associated with progression to more advanced disease (RASSF1a, E-cadherin, TNFSR25, EDNRB, and APC; P < 0.05). Multivariate analysis revealed that the overall degree of methylation was more significantly associated with subsequent progression and death (Cox, P = 0.002) than tumor stage (Cox, P = 0.008). Neuro-fuzzy modeling confirmed that these five loci were those most associated with tumor progression. Epigenetic predictive models developed using artificial intelligence techniques identified the presence and timing of tumor progression with 97% specificity and 75% sensitivity.

CONCLUSION

Promoter hypermethylation seems a reliable predictor of tumor progression in bladder cancer. It is associated with aggressive tumors and could be used to identify patients with either superficial disease requiring radical treatment or a low progression risk suitable for less intensive surveillance. Multicenter studies are warranted to validate this marker.

The spectrum of prostate cancer care: From curative intent to palliation

Prostate cancer is one of the most prevalent malignancies affecting men in the developed world. A spectrum of disease states exists and management is tailored to individual patients. Increasing public awareness and prostate-specific antigen testing have led to earlier detection and the possibility of cure but have increased the risk of overtreatment of indolent disease. Advances in curative modalities have reduced side effects and offer patients a choice of treatments. Nonetheless, many need no intervention and may be safely treated with active monitoring. Choice and timing of therapy for locally advanced and recurrent disease are variable, with potential benefits of early intervention counterbalanced by side effects of treatment. Progress has been made in the management of advanced disease; skeletal-related events have been reduced and survival has been increased. This review examines the evidence and rationale behind the treatment options from curative intent to management of locally advanced disease and palliation of metastatic disease.

Behavior of urothelial carcinoma with respect to anatomical location

PURPOSE

Urothelial carcinoma is a disease of the entire urothelium. Recent molecular insights suggest that the biology of some upper urinary tract and bladder urothelial carcinoma differ. These differences may affect tumor phenotype. Observational studies conflict as to the significance of anatomical location on the behavior of urothelial carcinoma. We compared the biological outcome in a large series of urothelial carcinoma with respect to anatomical location.

MATERIALS AND METHODS

We analyzed urothelial carcinoma in 425 patients treated at 4 centers according to stage and anatomical location, including the bladder in 275, the ureter in 67 and the renal pelvis in 79. Relapse surveillance was performed for a median of 46 months (range 2 to 216). A separate invasive bladder urothelial carcinoma population was also included to pathologically balance upper and lower tract urothelial carcinoma cases to allow behavioral comparisons.

RESULTS

As a whole, upper urinary tract urothelial carcinoma is more invasive and worse differentiated than bladder cancer (chi-square test p<0.0001 and 0.015, respectively). In pathologically matched cohorts recurrence to less aggressive disease, progression to more advanced disease and death occurred in 37%, 40% and 44% of patients with bladder urothelial carcinoma, and in 41%, 44% and 43% of those with upper urinary tract urothelial carcinoma, respectively. Multivariate analysis revealed that tumor stage and grade (Cox p=0.0001 and 0.012, respectively) but not location were associated with behavior.

CONCLUSIONS

Urothelial carcinoma behaves identically in the upper and lower urinary tracts when stage and grade are considered. The majority of tumors relapse within 5 years of excision. The current move to minimally invasive/nephron sparing techniques for urothelial carcinoma of the upper urinary tract appears safe. Care could be analogous to that for bladder urothelial carcinoma.

EZH2 promotes proliferation and invasiveness of prostate cancer cells

BACKGROUND

The transcriptional repressor EZH2 is implicated in control of cell proliferation in embryonic, immortalized and transformed cells. EZH2 expression in prostate cancer correlates with progression to hormone-refractory and metastatic disease, but it is unknown whether EZH2 plays a specific role in the acquisition of an advanced prostate cancer phenotype.

METHODS

Using siRNA knockdown, we investigated the role of EZH2 in maintenance of prostate cancer cell proliferation and invasiveness. Using LNCaP cells with inducible EZH2 overexpression, we investigated whether EZH2 upregulation promotes an aggressive phenotype.

RESULTS

Knockdown of endogenous EZH2 reduced proliferation of androgen-responsive and androgen-independent prostate cancer cells. EZH2 knockdown also inhibited prostate cancer cell invasion. However, overexpression of EZH2 in androgen-responsive cancer cells did not appreciably affect either proliferation or invasiveness.

CONCLUSIONS

EZH2 promotes proliferation and invasion of prostate cancer cells, which can account for the correlation between EZH2 expression levels and an adverse prostate cancer prognosis.

Molecular Detection of Localized Prostate Cancer Using Quantitative Methylation-Specific PCR on Urinary Cells Obtained Following Prostate Massage

PURPOSE

The diagnosis of localized prostate cancer is difficult due to a lack of cancer-specific biomarkers. Many patients require repeat prostate biopsies to diagnose the disease. We investigated whether aberrant promoter hypermethylation in prostatic fluid could reliably detect prostate cancer.

EXPERIMENTAL DESIGN

Urine samples were collected after prostate massage from 95 patients with localized prostate cancer undergoing radical prostatectomy (63 pT(1), 31 pT(2), and 1 pT(3)) and from 38 control patients. Ten genes (GSTP1, RASSF1a, ECDH1, APC, DAPK, MGMT, p14, p16, RARbeta2, and TIMP3) were investigated using quantitative real-time methylation-specific PCR. Receiver operator curves were generated.

RESULTS

The frequency of gene methylation ranged from 6.3% (p14) to 83.2% (GSTP1) in prostate cancer patients. At least one gene was hypermethylated in 93% of cancer patients. The specificity of methylation was 0.74. Methylation was significantly more frequent (P < 0.05) in cancer than control patients for all genes except p14 and p16. According to receiver operator curve analysis, the four-gene combination of GSTP1 (0.86), RASSF1a (0.85), RARbeta2 (0.80), and APC (0.74) best discriminated malignant from nonmalignant cases. The sensitivity and accuracy of this four-gene set were 86% and 89%, respectively.

CONCLUSIONS

The presence of aberrant methylation in urinary cells obtained after prostate massage is significantly associated with prostate cancer. A panel of four genes could stratify patients into low and high risk of having prostate cancer and optimize the need for repeat prostatic biopsies.

DNA methylation and immunohistochemical analysis of the S100A4 calcium binding protein in human prostate cancer

BACKGROUND

The role of DNA methylation in the transcriptional regulation of S100A4 is unknown in human prostate cancer.

METHODS

Critical CpG sites within intron 1 of S100A4 were sequenced in DNA obtained from prostatic adenocarcinoma, non-malignant epithelium, and prostate cancer cell lines. S100A4 protein expression was assessed by immunohistochemistry and Western blotting.

RESULTS

Methylation was seen in all cases of cancer, non-malignant epithelium, and in prostate cancer cell lines, but was absent in all cases of blood DNA. S100A4 immunoexpression was absent in all cases of malignant and non-malignant epithelium, while strong-moderate expression was seen in the stroma and lymphocytes. Western blotting showed absent S100A4 expression in LNCaP and Du145 cells and low levels in PC-3 cells.

CONCLUSIONS

S100A4 protein is not expressed in benign or malignant prostatic epithelium nor in LNCaP and Du145 cells. The mechanism underlying absent S100A4 expression in prostatic epithelium and cell lines may involve methylation.

Lack of noggin expression by cancer cells is a determinant of the osteoblast response in bone metastases

Prostate and mammary cancer bone metastases can be osteoblastic or osteolytic, but the mechanisms determining these features are unclear. Bone morphogenetic and Wnt proteins are osteoinductive molecules. Their activity is modulated by antagonists such as noggin and dickkopf-1. Differential expression analysis of bone morphogenetic and Wnt protein antagonists in human prostate and mammary cancer cell lines showed that osteolytic cell lines constitutively express in vitro noggin and dickkopf-1 and at least one of the osteolytic cytokines parathyroid hormone-related protein, colony-stimulating factor-1, and interleukin-8. In contrast, osteoinductive cell lines express neither noggin nor dickkopf-1 nor osteolytic cytokines in vitro. The noggin differential expression profile observed in vitro was confirmed in vivo in prostate cancer cell lines xenografted into bone and in clinical samples of bone metastasis. Forced noggin expression in an osteoinductive prostate cancer cell line abolished the osteoblast response induced in vivo by its intraosseous xenografts. Basal bone resorption and tumor growth kinetics were marginally affected. Lack of noggin and possibly dickkopf-1 expression by cancer cells may be a relevant mechanism contributing to the osteoblast response in bone metastases. Concomitant lack of osteolytic cytokines may be permissive of this effect. Noggin is a candidate drug for the adjuvant therapy of bone metastasis.

Clinically localised prostate cancer is microsatellite stable

OBJECTIVES

To determine the frequency of microsatellite instability (MSI) change with mono-, di- and tetranucleotide markers in clinically localized prostate cancer, and to correlate those markers with clinical and pathological variables.

MATERIALS AND METHODS

Two forms of MSI have been described in human cancer: MSI typical of hereditary nonpolyposis colon cancer, defined with mono- and dinucleotide repeat MS; and a second variety of MSI is best seen at selective tetranucleotide repeats, i.e. elevated microsatellite alterations at select tetranucleotides (EMAST). Prostate specimens were taken from 50 patients. The MS analysis used the Bethesda consensus panel (BCP) and four tetranucleotide loci shown to detect the presence of EMAST.

RESULTS

All but four tumours were stable for the 14 loci investigated. There were two (4%) cases with adenomatous polyposis coli (APC) instability among the BCP markers and the same instability rate (4%) amongst the EMAST markers. These four tumours were all unstable at one locus of the 10 markers of the BCP that classified them as MS stable.

CONCLUSIONS

The MSI related to a mismatch repair deficiency or to the EMAST does not seem to be important in prostate cancer in the early stages of the disease.

Artificial intelligence and bladder cancer arrays

Non-muscle invasive bladder cancer is a heterogenous disease whose management is dependent upon the risk of progression to muscle invasion. Although the recurrence rate is high, the majority of tumors are indolent and can be managed by endoscopic means alone. The prognosis of muscle invasion is poor and radical treatment is required if cure is to be obtained. Progression risk in non-invasive tumors is hard to determine at tumor diagnosis using current clinicopathological means. To improve the accuracy of progression prediction various biomarkers have been evaluated. To discover novel biomarkers several authors have used gene expression microarrays. Various statistical methods have been described to interpret array data, but to date no biomarkers have entered clinical practice. Here, we describe a new method of microarray analysis using neurofuzzy modeling (NFM), a form of artificial intelligence, and integrate it with artificial neural networks (ANN) to investigate non-muscle invasive bladder cancer array data (n=66 tumors). We develop a predictive panel of 11 genes, from 2800 expressed genes, that can significantly identify tumor progression (average Logrank p = 0.0288) in the analyzed cancers. In comparison, this panel appears superior to those genes chosen using traditional analyses (average Logrank p = 0.3455) and tumor grade (Logrank, p = 0.2475) in this non-muscle invasive cohort. We then analyze panel members in a new non-muscle invasive bladder cancer cohort (n=199) using immunohistochemistry with six commercially available antibodies. The combination of 6 genes (LIG3, TNFRSF6, KRT18, ICAM1, DSG2 and BRCA2) significantly stratifies tumor progression (Logrank p = 0.0096) in the new cohort. We discuss the benefits of the transparent NFM approach with respect to other reported methods.

Measuring the psychosocial impact of population-based prostate-specific antigen testing for prostate cancer in the UK

OBJECTIVE

To evaluate the psychosocial impact of participation in a population-based prostate-specific antigen (PSA) testing programme, akin to screening, and to explore the relationship between urinary symptoms reported before PSA testing and the response to the subsequent PSA result.

PATIENTS AND METHODS

This prospective questionnaire study was nested within the case-finding component of the ProtecT (prostate testing for cancer and treatment) feasibility study (ISRCTN20141297). Men aged 50-69 years from 18 general practices in three cities in the UK completed the Hospital Anxiety and Depression Scale (HADS), the Short Form-12 (SF-12) Health Survey, and the International Continence Society 'male' (ICSmale) questionnaires before giving consent for a PSA test in a community clinic (baseline). Men with an 'abnormal' PSA result returned for further investigation (including biopsy) and repeated these questionnaires before biopsy.

RESULTS

At baseline, study participants had similar levels of anxiety and depression to the general male population. There was no increase in the HADS scores, or reduction in the SF-12 mental health component summary score, on attendance at the biopsy clinic after receiving an 'abnormal' PSA result. Urinary symptoms were associated with levels of anxiety and depression before receiving a PSA result (baseline), but were not associated with anxiety and depression at biopsy independently of baseline scores. Therefore changes in anxiety or depression at biopsy did not appear to differ between those with and without urinary symptoms.

CONCLUSIONS

This study confirms the findings of other studies that the deleterious effects of receiving an abnormal PSA result during population screening are not identified by generic health-status questionnaires. Comparisons with outcomes of studies measuring cancer-specific distress and using qualitative research methods raise the question of whether a prostate cancer screening-specific instrument is required. However, a standardized measure of anxiety identified differences at baseline between those who did and did not report urinary symptoms. These findings suggest that it might be advisable to better inform men undergoing PSA testing about the uncertain relationship between urinary symptoms and prostate cancer, to minimize baseline levels of psychological distress.

Multifocal urothelial cancers with the mutator phenotype are of monoclonal origin and require panurothelial treatment for tumor clearance

PURPOSE

UC is a disease of the entire urothelium, characterized by multiplicity and multifocality. The clonal relationship among multiple UCs has implications regarding adjuvant chemotherapy. It has been investigated in studies of chromosomal alteration and single gene mutation. However, these genetic changes can occur in unrelated tumors under similar carcinogenic selection pressures. Tumors with high MSI have numerous DNA mutations, of which many provide no selection benefit. While these tumors represent an ideal model for studying UC clonality, their low frequency has prevented their previous investigation.

MATERIALS AND METHODS

We investigated 32 upper and lower urinary tract UCs with high MSI and 4 nonUC primary cancers in 9 patients. We used the high frequency and specificity of individual DNA mutations in these tumors (MSI at 17 loci) and the early timing of epigenetic events (methylation of 7 gene promoters) to investigate tumor clonality.

RESULTS

Molecular alterations varied among tumors from different primary organs but they appeared related in the UCs of all 9 patients. While 7 patients had a high degree of concordance among UCs, in 2 the UCs shared only a few similar alterations. Genetic and epigenetic abnormalities were frequently found in normal urothelial samples.

CONCLUSIONS

Multiple UCs in each patient appeared to arise from a single clone. The molecular order of tumor development varied from the timing of clinical presentation and suggested that residual malignant cells persist in the urinary tract despite apparent curative surgery. These cells lead to subsequent tumor relapse and new methods are required to detect and eradicate them.

Lactate dehydrogenase-B is silenced by promoter hypermethylation in human prostate cancer

In order to identify novel candidates associated with prostate cancer metastasis, we compared the proteomic profile of the poorly metastatic human prostate cancer cell line LNCaP, with its highly metastatic variant LNCaP-LN3, by two-dimensional gel electrophoresis. A major protein spot (pI of 5.9 and molecular weight of 37 kDa) was seen in LNCaP cells, but not in LNCaP-LN3 cells and was identified as lactate dehydrogenase-B (LDHB), by tandem mass spectrometry. Furthermore, enzyme kinetic assays and zymography showed a higher LDH enzyme activity in LNCaP cells compared with LNCaP-LN3. Bisulphite-modified DNA sequencing showed promoter hypermethylation in LNCaP-LN3 cells but not in LNCaP, Du145, PC3, CWR22 or BPH45 cells. Treatment of LNCaP-LN3 cells with 5'-azacytidine caused re-expression of LDHB transcripts. In tissues, LDHB promoter hypermethylation occurred at a higher frequency in prostate cancer, 14/ 31 (45%), compared to adjacent nonmalignant or benign tissue, 2/19 (11%) (P < 0.025). Immunohistochemistry showed a higher frequency of LDHB expression in benign or non-malignant tissues, 59/ 73 (81%), compared to cancer cases, 3/53 (6%) (P < 0.001). Absent LDHB expression was also seen in 7/7 (100%) cases of metastatic cancer in bone. Our data are the first to show loss of LDHB expression in prostate cancer, the mechanism of which appears to involve promoter hypermethylation.

Methylational urinalysis: a prospective study of bladder cancer patients and age stratified benign controls

Tumour suppressor gene (TSG) methylation has been proposed as a diagnostic marker for urothelial cancer (UC). Here, we compare the frequency of urinary TSG methylation in young and elderly patients, with and without UC. Urine samples were obtained prospectively from 35 UC patients, 35 benign controls over the age of 70 years and 34 healthy volunteers under the age of 40 years. Methylation analysis was performed for eight gene promoters using quantitative methylation-specific PCR. Methylation was detected in urine DNA from all three patient groups. The highest frequencies were seen in UC patients. Significantly less methylation was present in control samples than UC cases for RASSF1a and APC (P < 0.034). The 'methylation index' and level of methylation was highest in the UC group and lowest in the young control group. A marker panel of RASSF1a, E-cad and APC generated a sensitivity of 69%, a specificity of 60% and a diagnostic accuracy of 86%. TSG methylation is detectable in urine DNA from patients with and without bladder cancer. The frequency and extent of methylation appears to increase with age and malignancy. The lack of tumour specificity suggests that further investigation is required before this test is introduced into clinical practice.

A comparison of socio-demographic and psychological factors between patients consenting to randomisation and those selecting treatment (the ProtecT study)

BACKGROUND

Patient preferences for treatment can pose problems for the conduct of randomised controlled trials: patients with a preference may refuse participation and thereby potentially compromise external validity. Moreover, randomising patients with a preference may affect treatment efficacy and threaten internal validity.

AIMS

This study compared baseline characteristics and short-term psychological outcomes of patients who selected their treatment and those who agreed to random allocation.

METHODS

Men participating in the prostate testing for cancer and treatment (ProtecT) study and who were randomised to active monitoring (n=138) were compared with those who had refused randomisation and selected this management (n=180). Socio-demographic data were collected at baseline, and anxiety and depression data were collected at baseline and six month follow-up. Socio-demographic characteristics were compared across these two groups in univariable analyses, and then linear regression was used to compare levels of anxiety and depression at follow-up with adjustments for confounders.

RESULTS

Participants who selected active monitoring were more affluent (based on occupation details) and had less anxiety at baseline than those who were randomised. There were no differences with respect to age and marital status. Levels of anxiety and depression at six months follow-up were similar across the two groups of men.

CONCLUSIONS

This study found some differences at baseline between the socio-demographic and psychological status of those randomised and self-selecting treatment, but no psychological differences at short-term follow-up. Further empirical evidence is required to assess whether preferences impact upon the process and outcome of randomised controlled trials.

Gene therapy for prostate cancer: current strategies and new cell-based approaches

Prostate cancer is the most commonly diagnosed cancer in adult males in the Western world. It accounts for one in ten cancer cases and is the second leading cause of cancer death in men, after lung cancer. A number of curative treatments are available for patients with localized prostate cancer such as radical prostatectomy, radiotherapy, or brachytherapy. However, a proportion of these men will develop progressive disease, and some will present de novo with advanced and metastatic prostate cancer, which is amenable to palliation only with androgen-withdrawal therapy. Most of these patients will eventually develop hormone refractory disease which is incurable, and for whom gene therapy, if feasible may develop as an alternative treatment option. In this review we discuss the gene therapy vectors and strategies that are currently in use, new cell-based approaches, discuss their advantages and disadvantages, and review the potential or proven pre-clinical and clinical efficacy in prostate cancer models/patients.

Comparative study of intelligent models for the prediction of bladder cancer progression

New techniques for the prediction of tumour behaviour are needed since statistical analysis has low accuracy and is not applicable to the individual. Artificial intelligence (AI) may provide suitable methods. We have compared the predictive accuracies of neuro-fuzzy modelling (NFM), artificial neural networks (ANN) and traditional statistical methods for the prediction of bladder cancer. Experimental molecular biomarkers, including p53 expression and gene methylation, and conventional clinicopathological data were studied in a cohort of 117 patients with bladder cancer. For all 3 methods, models were produced to predict the presence and timing of tumour progression. Both methods of AI predicted progression with an accuracy ranging from 88-100%, which was superior to logistic regression, and NFM appeared to be better than ANN at predicting the timing of progression.

Neuro-Fuzzy Modeling: An Accurate and Interpretable Method for Predicting Bladder Cancer Progression

PURPOSE

New methods are required to improve the prediction of cancer progression as traditional statistical tests have limited accuracy. Accurate predictions would allow physicians to offer specific treatment according to individual patient risk. While predictive improvements are obtained using ANN, the hidden nature of these networks prevents insight and has hindered their widespread implementation. NFM is an alternate form of artificial intelligence using fuzzy logic (which is a multivalued logic which provides reasoning under uncertainty). By defuzzification the NFM rule base becomes transparent to overcome the black box nature of ANN.

MATERIALS AND METHODS

Combinations of clinicopathological (tumor stage and grade, patient age, gender, and smoking status) and molecular (immunohistochemical expression of p53 and methylation status of 11 loci) data from 117 patients were used to develop and compare predictive models of tumor progression using NFM, ANN and LR.

RESULTS

NFM (88% to 100% sensitivity, 97% to 100% specificity and 94% to 100% accuracy) predicted the presence and timing of cancer progression more accurately than ANN (81% to 87%, 95% to 100% and 89% to 90%, p = 0.002) and LR 3%, 61% to 72% and 47% to 53%, p = 0.00005). NFM was able to interrogate the clinicopathological and molecular data, and select the most important parameters (age, grade, stage, smoking, methylation) for progression prediction.

CONCLUSIONS

Intelligent systems and molecular biomarkers improved the accuracy of cancer progression predictions. NFM appeared superior to ANN in terms of accuracy, sensitivity, specificity and transparency. The use of NFM in routine clinical practice warrants further validation.

[Mutation of the FGFR3 oncogene is an independent and favorable prognostic factor for tumor-specific survival in patients with urothelial carcinoma of the upper urinary tract]

AIMS

Urothelial tumors of the upper urinary tract (UUTT) frequently display microsatellite Instability (MSI) and a distinct pathway of tumorigenesis resembling MMR-deficient colorectal cancers has been recognized for MSI-UUTT. For MSS-UUTT however oncogenic mechanisms as in bladder cancer (BC) are debated. Mutation of the oncogene FGFR3 has been linked to lower stage, lower grade and favourable clinical outcome in BC. The aim of this study was to evaluate FGFR3 mutation in MSI and MSS-UUTT.

METHODS

172 unselected UUTT were screened for MSI using the National Cancer Institute Consensus Panel and additional markers; FGFR3 status was studied using mutation analysis. Histopathological and clinical data were reviewed.

RESULTS

Microsatellite status had no impact on histopathological or clinical outcome. 52/99 MSS, 10/22 MSI-low and 25/51 MSI-high UUTT displayed mut. FGFR3 respectively. Overall FGFR3 mutation was associated with favourable stage and grade (p <0.0001 and p <0.002), as 62.1% of mut. vs. 23.5 % of wt. FGFR3 UUTT were stage Ta and T1 and graded G3 in 25.3 % vs. 47.1% respectively. That effect depended on MS-status however, as FGFR3 mutation was related to lower stage (pTa and pT1) in MSS/MSI-L (mut 62.9 % vs. wt 18.7%; p <0.01) only as opposed to MSI-H (mut 60% vs. wt. 50%; p = 0,1) UUTTs and as FGFR3 mut UUTTs tended to display lower grade (G1 and G2) provided stable (mut 74,2 % vs. wt. 44.1%; p <0,01) as opposed to instable microsatellite status (mut 76 % vs. wt. 73 %; p = 0.7). There was no marked relation of MS-status or FGFR3 mutation to sex, age or tobacco-exposure; localization in the renal pelvis (p < 0.01) however was more prevalent in the FGFR3 mut group. As opposed to MSI-status FGFR3 mutation had a favourable impact on survival, as 24.1% vs. 54.2 % cancer related deaths occured in the mutated group (p <0.001); this effect was indendent on stage or MSI-status. Neither MSI- nor FGFR3-status had any influence on subsequent bladder tumors.

CONCLUSIONS

FGFR3 mutation is frequent in UUTT and appears to be independent of MS-status; however it is related to significantly favourable histopathological parameters and clinical outcome in MSS cases. Thus our findings might back the notion, that MSS and MSI-UUTTs stem from different oncogenic pathways and that their differing molecular character might have some relevance. Further research is warranted to study the clinical behavior of these tumors and to evaluate a potential role for MS-status and FGFR3 as prognostic tools.

Evidence for the early onset of aberrant promoter methylation in urothelial carcinoma

There is evidence that carcinoma in situ (CIS) is the precursor of invasive urothelial carcinoma, a tumour characterized by frequent gene promoter methylation. The timing of altered DNA methylation is unknown in this pathway. Here we investigate gene methylation in 196 consecutive samples of normal urothelium, CIS, and tumours from 104 patients with both CIS and invasive urothelial carcinoma using quantitative methyl-sensitive polymerase chain reaction for six genes (p16, p14, E-cadherin, RARbeta2, RASSF1a, and GSTP1). Control normal urothelial samples from 15 patients with no history of urothelial carcinoma were also analysed. Immunohistochemistry established the expression of well-characterized CIS markers p53 and cytokeratin 20. Promoter methylation occurred frequently in both normal urothelium and CIS samples from patients with urothelial carcinoma, and increased with progression from normal to invasive urothelial carcinoma, at both specific loci (chi2 test: E-cadherin, p=0.0001; RASSF1a, p=0.003, RARbeta2, p=0.007, p16, p=0.024) and in general (methylation indices [t-test, p<0.0001]). Methylation was associated with cytokeratin 20 expression (t-test, p=0.004) and poor prognosis, and with increased progression to tumour death in patients whose CIS samples showed methylation, in comparison with those without methylation (log rank p<0.03). Promoter methylation occurs early in the urothelial carcinogenic pathway and appears to be a good biomarker of the invasive urothelial carcinoma phenotype.

Use of prostate-specific antigen (PSA) isoforms for the detection of prostate cancer in men with a PSA level of 2-10 ng/ml: systematic review and meta-analysis

OBJECTIVE

Measurement of serum prostate-specific antigen (PSA) for the detection of prostate cancer has poor specificity in men with PSA levels between 2 and 10 ng/ml. It has been suggested that measurement of the ratio of free to total PSA (f/tPSA) or complexed PSA (cPSA) might offer an improvement. We performed a systematic review and meta-analysis to evaluate the diagnostic performance of these tests among men with PSA levels between 2 and 10 ng/ml.

METHODS

Data on sensitivity and specificity were extracted from 66 eligible studies. Likelihood ratios and summary receiver operating characteristic curves were estimated and possible sources of heterogeneity between studies examined.

RESULTS

Use of the f/tPSA or the cPSA test improved diagnostic performance among men with a total PSA (tPSA) of 2-4 or 4-10 ng/ml compared to tPSA alone. The diagnostic performance of the f/tPSA test was significantly higher in the tPSA range of 4-10 ng/ml compared to a tPSA range of 2-4 ng/ml (p < 0.01); at a sensitivity of 95%, the specificity was 18% in the 4-10 ng/ml tPSA range and 6% in the 2-4 ng/ml tPSA range. Among studies that measured both isoforms, the diagnostic performance of the f/tPSA test and the cPSA was equivalent in both PSA ranges.

CONCLUSIONS

The use of the f/tPSA or cPSA test among men with PSA levels between 2 and 10 ng/ml can reduce the number of unnecessary biopsies whilst maintaining a high cancer detection rate.

Prognostic value of serum markers for prostate cancer

The incidence of prostate cancer has increased dramatically during the last 10-15 years and it is now the commonest cancer in males in developed countries. The increase is mainly caused by the increasing use of opportunistic screening or case-finding based on the use of prostate-specific antigen (PSA) testing in serum. With this approach, prostate cancer is detected 5-10 years before giving rise to symptoms and on average 17 years before causing the death of the patient. While this has led to detection of prostate cancer at a potentially curable stage, it has also led to substantial overdiagnosis, i.e. detection of cancers that would not surface clinically in the absence of screening. A major challenge is thus to identify the cases that need to be treated while avoiding diagnosing patients who will not benefit from being diagnosed and who will only suffer from the stigma of being a cancer patient. It would be useful to have prognostic markers that could predict which patients need to be diagnosed and which do not. Ideally, it should be possible to measure these markers using non-invasive techniques, i.e. by means of serum or urine tests. As it is very useful for both early diagnosis and monitoring of prostate cancer, PSA is considered the most valuable marker available for any tumor. Although the prognostic value of PSA is limited, measurement of the proportion of free PSA has improved the identification of patients with aggressive disease. Furthermore, the rate of increase in serum PSA reflects tumor growth rate and prognosis but, due to substantial physiological variation in serum PSA, reliable estimation of the rate of PSA increase requires follow-up for at least 2 years. Algorithms based on the combined use of free and total PSA and prostate volume in logistic regression and neural networks can improve the diagnostic accuracy for prostate cancer, and assays for minor subfractions of PSA and other new markers may provide additional prognostic information. Markers of neuroendocrine differentiation are useful for the monitoring of androgen-independent disease and various bone markers are useful in patients with metastatic disease.

Promoter hyper-methylation of calcium binding proteins S100A6 and S100A2 in human prostate cancer

BACKGROUND

S100A6 and S100A2 are members of the S100 family of calcium binding proteins, which are down regulated in prostate cancer, however the molecular mechanism(s) underlying their loss of expression is unknown.

METHODS

The promoter and exon 1 region of the S100A6 and S100A2 genes was sequenced in bisulfite modified DNA from non-malignant, benign prostatic hyperplasia (BPH), malignant and metastatic prostate tissues and in cell lines. Immunohistochemistry was performed to correlate S100A2 expression with methylation status.

RESULTS

S100A6 methylation was absent or occurred at isolated sites in 14/14 cases of non-malignant epithelium and 5/5 cases of BPH tissues, whereas methylation was seen in 14/27 (52%) cases of prostatic cancer (P<0.0001), 2/2 cases of metastatic cancer and in the CWR22 prostatic cancer xenograft. Critical CpG sites within the S100A2 promoter were methylated in LNCaP, LNCaP-LN3, and CWR22 cells but not in Du145, PC3 or BPH45 cells. In tissues, S100A2 methylation was seen in 32/34 (94%) cases of adenocarcinoma and 5/5 cases of metastatic cancer. However, S100A2 methylation was also seen in 9/12 (75%) cases of non-malignant tissues and in 5/5 cases of BPH. Immunostaining, showed absent S100A2 expression all 41 cases of prostatic cancer, whereas staining was seen in the basal cells of non-malignant epithelium.

CONCLUSIONS

Loss of S100A6 and S100A2 proteins is frequent in human prostatic cancer. A major mechanism underlying the loss of S100A6 expression appears to involve promoter hyper-methylation. However, mechanisms other than methylation of the known promoter are involved in silencing S100A2 in the prostate.

Prostate cancer: screening approaches

Introducing screening for prostate cancer requires evidence that this would do more good than harm. Current evidence about the impact and natural history of prostate cancer, screening and diagnostic tests, and the effectiveness of treatments is reviewed below.

Proteomic analysis of voided urine after prostatic massage from patients with prostate cancer: a pilot study

OBJECTIVES

Serum prostate-specific antigen measurements are widely used for the early detection of prostate cancer but lack specificity, thus warranting the search for additional biomarkers.

METHODS

Two-dimensional gel electrophoresis followed by matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) analysis was used to investigate the protein profiles of voided urine after prostatic massage from 6 patients with histologically confirmed prostate cancer and 6 age-matched patients with benign prostatic hyperplasia.

RESULTS

The median number of protein spots per gel was lower in the urine from the patients with cancer (median 143 spots, range 118 to 163) than in the urine from those with benign prostatic hyperplasia (median 154 spots, range 142 to 209), although the difference was not statistically significant. MALDI-TOF-MS analysis identified six commonly expressed proteins: alpha-enolase, isocitrate dehydrogenase, beta-2-microglobulin, alpha-1-microglobulin, complex-forming glycoprotein HC, and PRO2044. Of the five protein spots seen in a subset of patients with cancer, one was identified as calgranulin B/MRP-14. Immunohistochemical staining of prostatic tissue showed greater expression of calgranulin B/MRP-14 in 2 of 7 well-differentiated, 1 of 12 moderately differentiated, and 0 of 8 poorly differentiated tumors relative to adjacent benign tissue; expression of calgranulin A/MRP-8, a heterodermic binding partner of calgranulin B/MRP-14, was absent.

CONCLUSIONS

The role of urinary calgranulin B/MRP-14 as a potential novel marker for prostate cancer needs additional investigation.