Prostate cancer: a comprehensive review

The targeted inhibition of prostate cancer by iron-based nanoparticles based on bioinformatics

Prostate cancer is an epithelial malignant tumor of the prostate, and it is one of the malignant tumors with a high incidence of urogenital system in men. The local treatment of prostate cancer is mainly radical resection and radical radiotherapy, but they are not applicable to advanced prostate cancer. Systemic therapy mainly includes targeted therapy and immunotherapy which could cause many complications, and will affect the prognosis and quality of life of patients. It is urgent to find new treatments for prostate cancer. Bioinformatics offers hope for us to find reliable therapeutic targets. Bioinformatics can use the tumor informations in database and analyze them to screen out the best differentially expressed genes. Using the selected differentially expressed genes as targets, a gene interference plasmid was designed, and the constructed plasmid was used for targeted gene therapy. There are some problems about gene therapy that need to be solved, such as how to transfer genes to target cells is also an important challenge. Due to their large molecular weight and hydrophilic nature, they cannot enter cells through passive diffusion mechanisms. Here we synthesized a DNA carrier used surface modified iron based nanoparticles, and used it to load plasmid including ShRNA which can inhibit the expression of oncogene SLC4A4 selected by bioinformatics’ method. After that we use this iron based nanoparticles/plasmid DNA nanocomposite to treat prostate cancer cells in vitro and in vivo. The target gene SLC4A4 we had selected using bioinformatics had a strong effect on the proliferation of prostate cells; Our nanocomposite could inhibit the expression of SLC4A4 effectively, it had strong inhibitory effects on prostate cancer cells both in vivo and in vitro, and can be used as a potential method for prostate cancer treatment.

Recent advances in bone-targeted therapy

The coordination between bone resorption and bone formation plays an essential role in keeping the mass and microstructure integrity of the bone in a steady state. However, this balance can be disturbed in many pathological conditions of the bone. Nowadays, the classical modalities for treating bone-related disorders are being challenged by severe obstacles owing to low tissue selectivity and considerable safety concerns. Moreover, as a highly mineralized tissue, the bone shows innate rigidity, low permeability, and reduced blood flow, features that further hinder the effective treatment of bone diseases. With the development of bone biology and precision medicine, one novel concept of bone-targeted therapy appears to be promising, with improved therapeutic efficacy and minimized systematic toxicity. Here we focus on the recent advances in bone-targeted treatment based on the unique biology of bone tissues. We summarize commonly used bone-targeting moieties, with an emphasis on bisphosphonates, tetracyclines, and biomimetic bone-targeting moieties. We also introduce potential bone-targeting strategies aimed at the bone matrix and major cell types in the bone. Based on these bone-targeting moieties and strategies, we discuss the potential applications of targeted therapy to treat bone diseases. We expect that this review will put together useful insights to help with the search for therapeutic efficacy in bone-related conditions.

Risk factors for developing osteonecrosis of jaw in advanced cancer patients underwent zoledronic acid treatment

Aim: To investigate the risk factors for developing osteonecrosis of jaw (ONJ) in advanced cancer patients with bone metastases underwent zoledronic acid (ZA) treatment. Materials & methods: Univariate and multivariate logistic regression analyses were performed to investigate factors associated with developing ONJ in advanced cancer patients. Results: A total of 2214 advanced cancer patients were included. Univariate and multivariate logistic regression analyses for risk factors associated with ONJ were older age (≥66 years, hazards ratio [HR]: 3.21; p = 0.007), anemia (HR: 3.29; p = 0.006) and duration of ZA exposure (between 1 and 2 years, HR: 3.91, p = 0.01; ≥2 years, HR: 8.07, p < 0.001), respectively. Conclusion: Patients with older age, anemia and/or more than 1 year of ZA treatment are at high risk of developing ONJ.

In vitro Models of Bone Remodelling and Associated Disorders

Disruption of bone remodelling by diseases such as osteoporosis results in an imbalance between bone formation by osteoblasts and resorption by osteoclasts. Research into these metabolic bone disorders is primarily performed in vivo; however, in the last decade there has been increased interest in generating in vitro models that can reduce or replace our reliance on animal testing. With recent advances in biomaterials and tissue engineering the feasibility of laboratory-based alternatives is growing; however, to date there are no established in vitro models of bone remodelling. In vivo, remodelling is performed by organised packets of osteoblasts and osteoclasts called bone multicellular units (BMUs). The key determinant of whether osteoclasts form and remodelling occurs is the ratio between RANKL, a cytokine which stimulates osteoclastogenesis, and OPG, its inhibitor. This review initially details the different circumstances, conditions, and factors which have been found to modulate the RANKL:OPG ratio, and fundamental factors to be considered if a robust in vitro model is to be developed. Following this, an examination of what has been achieved thus far in replicating remodelling in vitro using three-dimensional co-cultures is performed, before overviewing how such systems are already being utilised in the study of associated diseases, such as metastatic cancer and dental disorders. Finally, a discussion of the most important considerations to be incorporated going forward is presented. This details the need for the use of cells capable of endogenously producing the required cytokines, application of mechanical stimulation, and the presence of appropriate hormones in order to produce a robust model of bone remodelling.

Ductal variant of prostate adenocarcinoma harbor Xenotropic murine leukemia virus related virus (XMRV) infection: a novel finding in subtype of prostate cancer

OBJECTIVE

Xenotropic murine leukemia virus related virus (XMRV), is the first gammaretrovirus identified a decade ago, in human tissue bearing adenocarcinoma of prostate, followed by several researches documenting little or no prevalence of XMRV in prostate cancer samples. However, the status of XMRV within subtype of prostate adenocarcinoma has not been investigated yet. In this study, we investigated the relationship between XMRV and broad spectrum morphological entities of prostate adenocarcinoma, including acinar, ductal and other rare subtypes.

MATERIAL AND METHODS

The prevalence of XMRV DNA in different histological subtypes of prostate adenocarcinoma was examined after characterizing the tumors into groups, using formalin-fixed, paraffin-embedded tissue samples from newly diagnosed prostate adenocarcinomas and archival prostate cancer tissue from our XMRV case control analysis. Broad-spectrum XMRV DNA amplification was performed by end-point polymerase chain reaction, using commercially available primer set.

RESULTS

The study included 100 patients with prostate cancer. XMRV DNA was detected in 4 of 8 (50%) ductal adenocarcinomas, exhibiting papillary and cribriform histological features. XMRV DNA was not detected in any other variant of adenocarcinoma including acinar (0/91) and mucinous carcinomas (0/1). Majority of XMRV positive cases were biologically aggressive and present cancer at an early age upon diagnosis.

CONCLUSION

Ductal adenocarcinomas demonstrate a significant association of XMRV DNA while other histological variants of prostate adenocarcinoma seem unrelated to XMRV infection.

Functional and Structural Consequences of Damaging Single Nucleotide Polymorphisms in Human Prostate Cancer Predisposition Gene RNASEL

A commonly diagnosed cancer, prostate cancer (PrCa), is being regulated by the gene RNASEL previously known as PRCA1 codes for ribonuclease L which is an integral part of interferon regulated system that mediates antiviral and antiproliferative role of the interferons. Both somatic and germline mutations have been implicated to cause prostate cancer. With an array of available Single Nucleotide Polymorphism data on dbSNP this study is designed to sort out functional SNPs in RNASEL by implementing different authentic computational tools such as SIFT, PolyPhen, SNPs&GO, Fathmm, ConSurf, UTRScan, PDBsum, Tm-Align, I-Mutant, and Project HOPE for functional and structural assessment, solvent accessibility, molecular dynamics, and energy minimization study. Among 794 RNASEL SNP entries 124 SNPs were found nonsynonymous from which SIFT predicted 13 nsSNPs as nontolerable whereas PolyPhen-2 predicted 28. SNPs found on the 3' and 5' UTR were also assessed. By analyzing six tools having different perspectives an aggregate result was produced where nine nsSNPs were found to be most likely to exert deleterious effect. 3D models of mutated proteins were generated to determine the functional and structural effect of the mutations on ribonuclease L. The initial findings were reinforced by the results from I-Mutant and Project HOPE as these tools predicted significant structural and functional instability of the mutated proteins. Expasy-ProSit tool defined the mutations to be situated in the functional domains of the protein. Considering previous analysis this study revealed a conclusive result deducing the available SNP data on the database by identifying the most damaging three nsSNP rs151296858 (G59S), rs145415894 (A276V), and rs35896902 (R592H). As such studies involving polymorphisms of RNASEL were none to be found, the results of the current study would certainly be helpful in future prospects concerning prostate cancer in males.

A new protocol for intermittent androgen suppression therapy of prostate cancer with unstable saddle-point dynamics

Intermittent androgen suppression (IAS) therapy is a class of hormonal treatment for prostate cancer, in which a drug-induced androgen deprivation can reduce the population of prostate cancer cells. In IAS therapy, drugs are administrated only in on-treatment periods that are separated intermittently by off-treatment periods. The presence of off-treatment periods may be beneficial for maintaining the sensitivity of the tumor cells to androgen deprivation. Thus, IAS can be superior to continuous androgen suppression (CAS) for delaying or possibly preventing relapse of a tumor. IAS therapy usually monitors the level of serum prostate-specific antigen (PSA), which is related to the population of tumor cells. Each on-treatment period begins when the PSA level is greater than an upper threshold; treatment results in a decrease in the PSA level. The on-treatment period is suspended when the PSA level falls below a lower threshold; the PSA level then rises again until the beginning of the next on-treatment period. To determine the transitions between on- and off-treatment periods, we propose a new IAS protocol that uses a model-based estimate of the state point in the phase space of the tumor dynamics. We show that the proposed protocol is effective if, in each of the on- and off-treatment periods, the tumor dynamics exhibits a saddle-point instability accompanied by a stable manifold. Mathematical analysis reveals that tumor dynamics can be controlled in a more effective and robust manner with the proposed protocol than with conventional IAS. We also discuss the clinical feasibility of the proposed protocol as an alternative to conventional IAS therapy.

Risk of osteonecrosis of the jaw in cancer patients receiving denosumab: a meta-analysis of seven randomized controlled trials

AIMS

The aim of this study is to gain a better understanding of the overall incidence and risk of osteonecrosis of the jaw (ONJ) in cancer patients receiving denosumab.

METHODS

We performed a meta-analysis of relevant randomized controlled trials identified in Pubmed, Embase, and Cochrane databases. Abstracts presented at the conferences were also searched. Overall incidence rates, relative risk (RR), and 95 % confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity of the included trials.

RESULTS

A total of 8963 patients with a variety of solid tumors from 7 randomized controlled trials (RCTs) were included for the meta-analysis. The overall incidence of ONJ in cancer patients receiving denosumab was 1.7 % [95 % CI: 0.9-3.1 %]. Also, the use of denosumab was associated with significantly increased risk of ONJ in comparison with bisphosphonates (BPs)/placebo treatment (RR 1.61, 95 % CI: 1.05-2.48, P = 0.029). Subgroup analysis based on controlled therapies demonstrated an increased risk of ONJ in denosumab therapy, when compared with BPs (RR 1.48, 95 % CI: 0.96-2.29, P = 0.078) or placebo (RR 16.28, 95 % CI: 1.68-158.05, P = 0.017). Similar results were observed in prostate cancer (RR 3.358, 95 % CI: 1.573-7.166, P = 0.002) while there was a non-significantly increased risk of denosumab-related osteonecrosis of the jaw (DONJ) in non-prostate cancers (RR 1.142, 95 % CI: 0.678-1.921, P = 0.618).

CONCLUSIONS

The use of denosumab is associated with an increased risk of developing ONJ when compared with BP treatment or placebo, although the increased risk was not statistically significant between denosumab and BP treatment. Further studies are still needed to establish guidelines for the prevention and effective treatment of ONJ.

Current and emerging treatments in the management of castration-resistant prostate cancer

Historically, patients diagnosed with castration-resistant prostate cancer (CRPC) have had poor survival rates. In recent years there have been significant advances in the treatment of CRPC. In addition to cytotoxic chemotherapy, treating physicians and their patients now have the option of several new agents that target not only androgen- and cytotoxic-mediated pathways, but also the patient's own immune system. In this review, we discuss the existing US FDA-approved therapies, a wide range of experimental treatments that are currently in development, and also palliative options for patients with symptoms secondary to metastatic disease. We also discuss the progression-free survival, overall survival, PSA levels and other end points used in clinical trials in order to evaluate and compare novel therapeutic options for CRPC. Currently, docetaxel and sipuleucel-T are the first line treatment options for patients with CRPC; approved second-line treatments for first line treatment failure are limited to cabazitaxel and abiraterone acetate. Recently, a few experimental agents, MDV3100 and radium-223, have demonstrated efficacy in improving overall survival in patients who had previously failed chemotherapy. These agents, and possibly others introduced in this review, are positioned to change the treatment landscape for CRPC.

Cost effectiveness of zoledronic acid in the management of skeletal metastases in hormone-refractory prostate cancer patients in France, Germany, Portugal, and the Netherlands

OBJECTIVE

Zoledronic acid (ZOL) reduces the risk of skeletal related events (SREs) in hormone-refractory prostate cancer (HRPC) patients with bone metastases. This study assessed the cost effectiveness of ZOL for SRE management in French, German, Portuguese, and Dutch HRPC patients.

METHODS

This analysis was based on the results of a randomized phase III clinical trial wherein HRPC patients received up to 15 months of ZOL (n = 214) or placebo (n = 208). Clinical inputs were obtained from the trial. Costs were estimated using hospital tariffs, published, and internet sources. Quality adjusted life-years (QALYs) gained were estimated from a separate analysis of EQ-5D scores reported in the trial. Uncertainty surrounding outcomes was addressed via univariate sensitivity analyses.

RESULTS

ZOL patients experienced an estimated 0.759 fewer SREs and gained an estimated 0.03566 QALYs versus placebo patients. ZOL was associated with reduced SRE-related costs [net costs] (-€2396 [€1284] in France, -€2606 [€841] in Germany, -€3326 [€309] in Portugal and -€3617 [€87] in the Netherlands). Costs per QALY ranged from €2430 (Netherlands) to €36,007 (France).

CONCLUSIONS

This analysis is subject to the limitations of most cost-effectiveness analyses: it combines data from multiple sources. Nevertheless, the results strongly suggest that ZOL is cost effective versus placebo in French, German, Portuguese, and Dutch HRPC patients.

Structural and functional analysis of human prostatic acid phosphatase

Prostatic acid phosphatase (PAP) is the most abundant phosphatase in human prostate tissue/secretions. It is a clinically important protein for its relevance as a biomarker of prostate carcinoma. Furthermore, it has a potential role in fertilization. We describe here most of the features of PAP including gene regulation, gene/protein structure, functions, its role in tumor progression and evolutionary features. PAP has phosphatase activity and is an extensively studied biomarker of prostate cancer. The major action of PAP is to dephosphorylate macromolecules with the help of catalytic residues (His(12) and Asp(258)) that are located in the cleft between two domains. This article will be of great interest to all those scientists who are working in the area of prostate pathophysiology.

Metabolic syndrome in sub-Saharan Africa: "smaller twin" of a region's prostatic diseases?

Prostate cancer (PC) and benign prostate hyperplasia (BPH) constitute many of the health concerns of males around the world. Prostate cancer is the major cause of death after lung cancer in men. Benign prostate hyperplasia affects most males above 40 years of age. A variety of factors, chiefly age, genetics and lifestyle, have been linked to the development of PC and BPH. The metabolic syndrome describes a chain of chronic disorders that are inter-related in aetiology, and result from unhealthy lifestyles, often due to an affluent economy. The eating of processed foods and a sedentary lifestyle apparently are status symbols among the middle and upper classes in sub-Saharan Africa. These have resulted in a surge in the disease burden of sub-Saharan Africa. This paper looks at the aetiology and prevalence of the metabolic syndrome and prostatic diseases, especially in sub-Saharan Africa. Evidence from the available literature shows that prostate disorders may be related to the metabolic syndrome. There is a likelihood that if sub-Saharan Africans keep copying the lifestyles of the developed world, especially in the direction of the nature of food items consumed, then the rising prevalence of diseases of the metabolic syndrome and the attendant prostate disorders may become very formidable healthcare "twin" problems for the region.

Bone metastases in prostate cancer: a targeted approach

PURPOSE OF REVIEW

New therapies are needed for hormone refractory prostate cancer. Promising new treatments specifically target metastatic disease in the bone, the predominant site of spread in prostate cancer. Recent advances in the understanding of the biology of the tumor-bone microenvironment are leading to the development of new bone-targeted therapies. In this article, we review current and developing clinical strategies designed to control prostate-cancer bone metastases.

RECENT FINDINGS

Newly developed biologic therapies that target prostate-cancer bone metastases have shown promising results in animal models and clinical trials. Additionally, currently established drugs such as bisphosphonates and bone-seeking radiopharmaceuticals are being applied in novel ways in an effort to improve patient care.

SUMMARY

Therapies targeting bone in advanced prostate cancer have demonstrated improvements in morbidity, and more recently, in overall survival. The continuing development and use of these targeted therapies have the potential to alter the course of this currently fatal disease.

Moderate physical activity and prostate cancer risk: A case?control study in china

A case-control study was conducted to investigate the association between physical activity and prostate cancer risk in China. A total of 130 recent histopathologically confirmed cancer cases and 274 controls were interviewed. Information collected included type, intensity and duration of various physical activities. The adjusted odds ratios of prostate cancer risk for physical activity variables were obtained from multivariate logistic regression models. Results showed that moderate physical activity was inversely related to the prostate cancer risk, with adjusted odds ratio being 0.20 (95% confidence interval 0.07-0.62) for the upper vs. the lower quartiles of weekly metabolic equivalent task-hours. The dose-response relationship was also significant (p = 0.015). The findings suggest that moderate physical activity may be protective against prostate cancer for Chinese men.

Managing metastatic bone disease: three case studies

Metastatic bone disease constitutes a major clinical problem. Skeletal complications are common and lead to significant morbidity, and patients live with metastatic bone disease for several years, increasing the prevalence of this problem. Effective management aims to reduce the incidence of skeletal complications and relieve symptoms, such as severe bone pain, which adversely affect patient mobility and quality of life. This article describes and discusses strategies for managing metastatic bone disease, with particularly emphasis on the role of the bisphosphonate ibandronate. Two case histories show the long-term efficacy and tolerability of oral ibandronate in the treatment of metastatic breast cancer. The third case history illustrates the benefits of rapid pain relief from an intensive, high-dose regimen of intravenous ibandronate in metastatic prostate cancer.

Advances in the use of bisphosphonates in the prostate cancer setting

Prostate cancer incidence is rising, and represents a major public health issue. Bone is by far the most common site for metastases in this disease, accounting for considerable morbidity. Until recently, there have been few viable options for the treatment of patients with hormone-refractory metastatic disease. This review examines the pathophysiology underlying the development of bone metastases. It also summarises some of the clinical approaches for the management of this common condition, focusing on recent evidence supporting the use of zoledronic acid, a member of one of the most promising groups of pharmacological agents, the third-generation bisphosphonates.

Androgen receptor in prostate cancer

The normal development and maintenance of the prostate is dependent on androgen acting through the androgen receptor (AR). AR remains important in the development and progression of prostate cancer. AR expression is maintained throughout prostate cancer progression, and the majority of androgen-independent or hormone refractory prostate cancers express AR. Mutation of AR, especially mutations that result in a relaxation of AR ligand specificity, may contribute to the progression of prostate cancer and the failure of endocrine therapy by allowing AR transcriptional activation in response to antiandrogens or other endogenous hormones. Similarly, alterations in the relative expression of AR coregulators have been found to occur with prostate cancer progression and may contribute to differences in AR ligand specificity or transcriptional activity. Prostate cancer progression is also associated with increased growth factor production and an altered response to growth factors by prostate cancer cells. The kinase signal transduction cascades initiated by mitogenic growth factors modulate the transcriptional activity of AR and the interaction between AR and AR coactivators. The inhibition of AR activity through mechanisms in addition to androgen ablation, such as modulation of signal transduction pathways, may delay prostate cancer progression.

Familial risk of prostate cancer in Iceland

OBJECTIVE

To estimate the risk of prostate and other types of cancer among relatives of Icelandic men diagnosed with prostate cancer over a 5-year period.

PATIENTS AND METHODS

The risk ratio (RR) was used to estimate the risk among relatives of 371 patients with prostate cancer, all of whom lived in Iceland and were diagnosed when alive over a 5-year interval (1983-7). Information on cancer incidence was obtained from the population-based Icelandic Cancer Registry, and information on families from a comprehensive genealogical database covering the population of Iceland.

RESULTS

First-degree male relatives were at a 1.7-fold greater age-adjusted risk of prostate cancer (1832 men; 95% confidence interval, CI, 1.28-2.34). The risk was independent of proband's age at diagnosis. First-degree male relatives of patients who died from prostate cancer were at a statistically significantly greater risk of the disease (784 men; RR 2.17; 95% CI 1.34-3.53) and relatives of patients with incidental disease (T1a) were at a greater risk but not statistically significant so (261; RR 1.86; 95% CI 0.75-4.58). Female first-degree relatives were not at greater risk of breast cancer. The risk of kidney cancer was higher in first- and second-degree female relatives, with an RR (n, CI) of 2.50 (1780, 1.10-5.66) and 2.67 (5534, 1.04-6.81), respectively. The risk of kidney cancer was not statistically significantly greater in male relatives.

CONCLUSION

Family history is a risk factor for prostate cancer in Icelandic men. The risk is potentially higher for relatives of patients who die from the disease. Female relatives are not at greater risk of breast cancer but they may be at greater risk of kidney cancer.

Combined Analysis of Two Multicenter, Randomized, Placebo-Controlled Studies of Pamidronate Disodium for the Palliation of Bone Pain in Men With Metastatic Prostate Cancer

Purpose: Bone metastases occur in approximately 80% of patients with advanced prostate cancer. Pain is common in these patients. The purpose of this study was to evaluate the effect of an intravenous bisphosphonate, pamidronate disodium, on pain control in metastatic prostate cancer patients.

Patients and Methods: Two multicenter, double-blind, randomized, placebo-controlled trials were conducted in patients with bone pain due to metastatic prostate cancer, with disease progression after first-line hormonal therapy. Intravenous pamidronate disodium (90 mg) or placebo was administered every 3 weeks for 27 weeks. Efficacy was measured via self-reported pain score (Brief Pain Inventory), analgesic use, the proportion of patients with a skeletal-related event (SRE; defined as pathologic fracture, radiation or surgery to bone, spinal cord compression, or hypercalcemia), and a pilot quantitative measurement of mobility. Laboratory evaluations included serum prostate-specific antigen, interleukin-6, bone alkaline phosphatase, and urinary bone resorption markers.

Results: Results of the two trials were pooled. There were no sustained significant differences between the pamidronate and placebo groups in self-reported pain measurements, analgesic use, proportion of patients with an SRE, or mobility at week 9 or 27. Urinary bone resorption markers were suppressed in the pamidronate group compared with placebo.

Conclusion: Pamidronate disodium failed to demonstrate a significant overall treatment benefit compared with placebo in palliation of bone pain or reduction of SREs. Evaluation of more potent bisphosphonates in patients with prostate cancer is warranted.

A randomized, placebo-controlled trial of zoledronic acid in patients with hormone-refractory metastatic prostate carcinoma

BACKGROUND

Bone metastases are a common cause of morbidity in patients with prostate carcinoma. We studied the effect of a new bisphosphonate, zoledronic acid, which blocks bone destruction, on skeletal complications in prostate cancer patients with bone metastases.

METHODS

Patients with hormone-refractory prostate cancer and a history of bone metastases were randomly assigned to a double-blind treatment regimen of intravenous zoledronic acid at 4 mg (N = 214), zoledronic acid at 8 mg (subsequently reduced to 4 mg; 8/4) (N = 221), or placebo (N = 208) every 3 weeks for 15 months. Proportions of patients with skeletal-related events, time to the first skeletal-related event, skeletal morbidity rate, pain and analgesic scores, disease progression, and safety were assessed. All statistical tests were two-sided.

RESULTS

Approximately 38% of patients who received zoledronic acid at 4 mg, 28% who received zoledronic acid at 8/4 mg, and 31% who received placebo completed the study. A greater proportion of patients who received placebo had skeletal-related events than those who received zoledronic acid at 4 mg (44.2% versus 33.2%; difference = -11.0%, 95% confidence interval [CI] = -20.3% to -1.8%; P =.021) or those who received zoledronic acid at 8/4 mg (38.5%; difference versus placebo = -5.8%, 95% CI = -15.1% to 3.6%; P =.222). Median time to first skeletal-related event was 321 days for patients who received placebo, was not reached for patients who received zoledronic acid at 4 mg (P =.011 versus placebo), and was 363 days for those who received zoledronic acid at 8/4 mg (P =.491 versus placebo). Compared with urinary markers in patients who received placebo, urinary markers of bone resorption were statistically significantly decreased in patients who received zoledronic acid at either dose (P =.001). Pain and analgesic scores increased more in patients who received placebo than in patients who received zoledronic acid, but there were no differences in disease progression, performance status, or quality-of-life scores among the groups. Zoledronic acid at 4 mg given as a 15-minute infusion was well tolerated, but the 8-mg dose was associated with renal function deterioration.

CONCLUSION

Zoledronic acid at 4 mg reduced skeletal-related events in prostate cancer patients with bone metastases.

Germline alterations of the RNASEL gene, a candidate HPC1 gene at 1q25, in patients and families with prostate cancer

The RNASEL gene (2',5'-oligoisoadenylate-synthetase dependent) encodes a ribonuclease that mediates the antiviral and apoptotic activities of interferons. The RNASEL gene maps to the hereditary-prostate-cancer (HPC)-predisposition locus at 1q24-q25 (HPC1) and was recently shown to harbor truncating mutations in two families with linkage to HPC1. Here, we screened for RNASEL germline mutations in 66 Finnish patients with HPC, and we determined the frequency of the changes in the index patients from 116 families with HPC, in 492 patients with unselected prostate cancer (PRCA), in 223 patients with benign prostatic hyperplasia (BPH), and in 566 controls. A truncating mutation, E265X, was found in 5 (4.3%) of the 116 patients from families with HPC. This was significantly higher (odds ratio [OR] =4.56; P=.04) than the frequency of E265X in controls (1.8%). The highest mutation frequency (9.5%) was found in patients from families with four or more affected members. Possible segregation was detected only in a single family. However, the median age at disease onset for E265X carriers was 11 years less than that for noncarriers in the same families. In addition, of the four missense variants found, R462Q showed an association with HPC (OR=1.96; P=.07). None of the variants showed any differences between controls and either patients with BPH or patients with PRCA. We conclude that, although RNASEL mutations do not explain disease segregation in Finnish families with HPC, the variants are enriched in families with HPC that include more than two affected members and may also be associated with the age at disease onset. This suggests a possible modifying role in cancer predisposition. The impact that the RNASEL sequence variants have on PRCA burden at the population level seems small but deserves further study.