Comparative studies of prostate cancer in Japan versus the United States. A review

Tomato consumption and intake of lycopene as predictors of the incidence of prostate cancer: the Adventist Health Study-2

PURPOSE

Studies have controversially suggested that prostate cancer, the most common cancer among Western men, is less common among those with a high intake of tomato products and lycopene. We examine multivariable associations between the intake of tomatoes and lycopene, and risk of prostate cancer.

METHODS

In a prospective study of 27,934 Adventist men without prevalent cancer, Cox proportional hazard regression analyses were used to address the objectives. Dietary measurement error was partially corrected with regression calibration.

RESULTS

1226 incident cases of prostate cancer, 355 of them aggressive, were identified during 7.9 years of follow-up. Consumption of canned and cooked tomatoes more than four times a week was associated with a HR = 0.72 (95% CI 0.55, 0.94, P = 0.02) comparing to risk in those never consuming this food. Treating this as a continuous variable, adjusting for confounders, produces a similar result, HR = 0.86 (95% CI 0.75, 0.99), comparing 64 g/day with zero intakes (questionnaire data). Regression calibration, although less precise, suggests a yet stronger and statistically significant inverse relationship, comparing a 24-h dietary recall intake of 71 g/day canned and cooked tomato product, with zero intake. Uncalibrated multivariable-adjusted competing risk analyses do not find differences in tomato associations between aggressive and non-aggressive prostate cancers although power for aggressive cancers is limited.

CONCLUSION

Consumption of canned and cooked tomatoes may reduce the risk of prostate cancer. These products contain more available lycopene. However, an observational study cannot exclude confounding by some unidentified, prostate cancer preventive factor. Clinical Trial Registry: ClinicalTrials.gov Identifier: NCT03615599.

Research Evidence on High-Fat Diet-Induced Prostate Cancer Development and Progression

Although recent evidence has suggested that a high-fat diet (HFD) plays an important role in prostate carcinogenesis, the underlying mechanisms have largely remained unknown. This review thus summarizes previous preclinical studies that have used prostate cancer cells and animal models to assess the impact of dietary fat on prostate cancer development and progression. Large variations in the previous studies were found during the selection of preclinical models and types of dietary intervention. Subcutaneous human prostate cancer cell xenografts, such as LNCaP, LAPC-4, and PC-3 and genetic engineered mouse models, such as TRAMP and Pten knockout, were frequently used. The dietary interventions had not been standardized, and distinct variations in the phenotype were observed in different studies using distinct HFD components. The use of different dietary components in the research models is reported to influence the effect of diet-induced metabolic disorders. The proposed underlying mechanisms for HFD-induced prostate cancer were divided into (1) growth factor signaling, (2) lipid metabolism, (3) inflammation, (4) hormonal modulation, and others. A number of preclinical studies proposed that dietary fat and/or obesity enhanced prostate cancer development and progression. However, the relationship still remains controversial, and care should be taken when interpreting the results in a human context. Future studies using more sophisticated preclinical models are imperative in order to explore deeper understanding regarding the impact of dietary fat on the development and progression of prostate cancer.

LXRs, SHP, and FXR in Prostate Cancer: Enemies or Ménage à Quatre With AR?

Androgens and androgen receptor (AR, NR3C4) clearly play a crucial role in prostate cancer progression. Besides, the link between metabolic disorders and the risk of developing a prostate cancer has been emerging these last years. Interestingly, “lipid” nuclear receptors such as LXRα/NR1H3 and LXRβ/NR1H2 (as well as FXRα/NR1H4 and SHP/NR0B2) have been described to decrease the lipid metabolism, while AR increases it. Moreover, these former orphan nuclear receptors can regulate androgen levels and modulate AR activity. Thus, it is not surprising to find such receptors involved in the physiology of prostate. This review is focused on the roles of liver X receptors (LXRs), farnesoid X receptor (FXR), and small heterodimeric partner (SHP) in prostate physiology and their capabilities to interfere with the androgen-regulated pathways by modulating the levels of active androgen within the prostate. By the use of prostate cancer cell lines, mice deficient for these nuclear receptors and human tissue libraries, several authors have pointed out the putative possibility to pharmacologically target these receptors. These data open a new field of research for the development of new drugs that could overcome the castration resistance in prostate cancer, a usual phenomenon in patients.

Current status and progress of focal therapy in Asia

PURPOSE OF REVIEW

With the increasing incidence of low-to-intermediate risk of prostate cancer (PCa) by the introduction of prostate-specific antigen (PSA) screening, focal therapy has become one of the promising treatment options in the world. In Asia, same movement are occurring using several technologies including cryoablation, high-intensity focused ultrasound, brachytherapy and irreversible electroporation. However, these are still not common strategies to treat organ-confined PCa. The purpose of this review is to summarize the most updated experience and future direction of focal therapy in Asian countries.

RECENT FINDINGS

The prevalence and diagnosis of PCa are increasing in Asian countries. This increase is related to various factors including the widespread implementation of PSA testing and lifestyle changes to more Westernized diets. With the increasing detection rate of early stage PCa, overdetection and overtreatment are recognized even in Asia. In this setting, accumulating data on multiparametric MRI and MRI-targeted biopsy as well as MRI-transrectal ultrasound (TRUS) fusion biopsy suggest the potential in improving the detection of clinically significant PCa in Asia. Furthermore, targeted focal therapy has emerged as a promising treatment strategy aiming for both providing oncological outcome and maintaining functional preservation in many Asian countries.

SUMMARY

At present, focal therapy is not a current standard choice for the treatment of localized PCa in Asian countries. However, with the increase of localized PCa and patient's preference for less invasive treatment with preservation of organ-function, focal therapy should become a definite treatment option for localized PCa in Asia.

AB0/Rhesus Blood Group Does Not Influence Clinicopathological Tumor Characteristics or Oncological Outcome in Patients Undergoing Radical Prostatectomy

Objectives

AB0 blood group is an inherited characteristic that has been associated with the incidence as well as the prognosis of several malignancies. The aim of the current study was to clarify the role of the blood group in cancer epidemiology and clinical outcome of patients with prostate cancer (PCa).

Methods

Data from 3,574 patients undergoing radical prostatectomy between 2009 and 2010 at a single European institution were retrospectively analyzed. The correlation of AB0 and Rhesus blood group with PCa-related characteristics and oncological outcome were evaluated using univariable and multivariable Cox proportional hazard models.

Results

Median follow-up was 36.9 months. The overall distributions of AB0, as well as Rhesus blood groups among patients with PCa, did not differ from the distribution observed in the normal population. There was no significant association between AB0/Rhesus blood groups and Gleason score, prostate volume, surgical margin, pT-stage, pN-status, or preoperative prostate-specific antigen level. In multivariable Cox regression analysis, no statistically significant correlation between AB0/Rhesus group and biochemical recurrence was observed (all p > 0.05).

Conclusion

Our data suggest no relevant association of AB0/Rhesus blood group with adverse clinicopathological tumor characteristics or oncological outcome after surgery in contrast to several other malignancies.

Prostate cancer in Jordanian-Arab population: ERG status and relationship with clinicopathologic characteristics

TMPRSS2/ERG fusion was found to be the most common genetic event in prostate adenocarcinoma. There is a strong correlation between the fusion and ERG-positive immunostaining. Many studies showed racial variation in ERG expression in prostate cancer patients. There is no data however on the rate of ERG-positive cancer in Jordanian or Arab population. We evaluated the frequency and the significance of ERG fusion in Jordanian-Arab population using immunohistochemistry for ERG. The cohort included 193 prostate cancer specimens: 109 needle core biopsies, 45 radical prostatectomies, 37 transurethral resections of prostate, and 2 enucleation specimens. We found ERG reactivity in 64 (33.2%) of evaluated cases. The observed ERG frequency in the Jordanian-Arab population is lower than the one documented in North America, but it is higher than in Asian patient cohorts. The ERG positivity was significantly associated with lower baseline prostate-specific antigen but was unrelated to patient age, Gleason Score, or the novel Gleason Grade Groups. In the 45 prostatectomy cases, ERG did not correlate with the pathologic stage, margin, nodal status, and the biochemical recurrence, and it did not appear to represent an important prognosticator.

Prostate cancer screening in Europe and Asia

Prostate cancer (PCa) is the second most common cancer among men worldwide and even ranks first in Europe. Although Asia is known as the region with the lowest PCa incidence, it has been rising rapidly over the last 20 years mostly due to the introduction of prostate-specific antigen (PSA) testing. Randomized PCa screening studies in Europe show a mortality reduction in favor of PSA-based screening but coincide with high proportions of unnecessary biopsies, overdiagnosis and subsequent overtreatment. Conclusive data on the value of PSA-based screening and hence the balance between harms and benefits in Asia is still lacking. Because of known racial variations, Asian countries should not directly apply the European screening models. Like in the western world also in Asia, new predictive markers, tools and risk stratification strategies hold great potential to improve the early detection of PCa and to reduce the worldwide existing negative aspects of PSA-based PCa screening.

DNA methylation-based variation between human populations

Several studies have proved that DNA methylation affects regulation of gene expression and development. Epigenome-wide studies have reported variation in methylation patterns between populations, including Caucasians, non-Caucasians (Blacks), Hispanics, Arabs, and numerous populations of the African continent. Not only has DNA methylation differences shown to impact externally visible characteristics, but is also a potential biomarker for underlying racial health disparities between human populations. Ethnicity-related methylation differences set their mark during early embryonic development. Genetic variations, such as single-nucleotide polymorphisms and environmental factors, such as age, dietary folate, socioeconomic status, and smoking, impacts DNA methylation levels, which reciprocally impacts expression of phenotypes. Studies show that it is necessary to address these external influences when attempting to differentiate between populations since the relative impacts of these factors on the human methylome remain uncertain. The present review summarises several reported attempts to establish the contribution of differential DNA methylation to natural human variation, and shows that DNA methylation could represent new opportunities for risk stratification and prevention of several diseases amongst populations world-wide. Variation of methylation patterns between human populations is an exciting prospect which inspires further valuable research to apply the concept in routine medical and forensic casework. However, trans-generational inheritance needs to be quantified to decipher the proportion of variation contributed by DNA methylation. The future holds thorough evaluation of the epigenome to understand quantification, heritability, and the effect of DNA methylation on phenotypes. In addition, methylation profiling of the same ethnic groups across geographical locations will shed light on conserved methylation differences in populations.

Importance of Estrogenic Signaling and Its Mediated Receptors in Prostate Cancer

Prostate cancer (PCa) treatment was first established by Huggins and Hodges in 1941, primarily described as androgen deprivation via interference of testicular androgen production. The disease remains incurable with relapse of hormone-refractory cancer after treatments. Epidemiological and clinical studies disclosed the importance of estrogens in PCa. Discovery of estrogen receptor ERβ prompted direct estrogenic actions, in conjunction with ERα, on PCa cells. Mechanistically, ERs upon ligand binding transactivate target genes at consensus genomic sites via interactions with various transcriptional co-regulators to mold estrogenic signaling. With animal models, Noble revealed estrogen dependencies of PCa, providing insight into potential uses of antiestrogens in the treatment. Subsequently, various clinical trials were conducted and molecular and functional consequences of antiestrogen treatment in PCa were delineated. Besides, estrogens can also trigger rapid non-genomic signaling responses initiated at the plasma membrane, at least partially via an orphan G-protein-coupled receptor GPR30. Activation of GPR30 significantly inhibited in vitro and in vivo PCa cell growth and the underlying mechanism was elucidated. Currently, molecular networks of estrogenic and antiestrogenic signaling via ERα, ERβ and GPR30 in PCa have not been fully deciphered. This crucial information could be beneficial to further developments of effective estrogen- and antiestrogen-based therapy for PCa patients.

PC-SPES: A Brief Overview

PC-SPES is a botanically based dietary supplement that has been used by men following prostate cancer treatment to reduce prostate-specific antigen levels. It is a complex matrix comprising 8 herbs whose known chemistry and biology do not account for the observed clinical activity. Recent disclosures have forced the product to be withdrawn from the market. Aspects of previous scientific research on the product, including clinical information, are reviewed, and some suggestions are offered for the future scientific needs of this product. Some thoughts are also offered on what the recall of PC-SPES means for the future scientific directions of the dietary supplement industry.

Latent prostate cancer in Japanese men who die unnatural deaths: A forensic autopsy study

BACKGROUND

An accurate natural history of prostate cancer (PC) can be obtained from forensic autopsies of individuals who had performed their normal daily activities immediately before death and had not undergone long-term medical interventions. A retrospective analysis of such individuals was performed to understand the features of latent PC in Japan.

METHODS

The findings of forensic autopsies performed at Dokkyo Medical University from August 2002 to July 2005 on men without severely destroyed or severely decomposed tissues were collected. Two cross sections, at the base and apex of the prostate, were examined histopathologically. Data collected included basic history, cause of death, location of PC, and Gleason score.

RESULTS

Of 196 forensically autopsied males aged 0-90 years, 24 (12.7%) had latent PC. When analyzed by age group, PC was most prevalent among individuals in their eighties (33.3%). The prevalence of PC was similar in males who died of disease and of external causes. Most PCs were located at the base of the prostate, but were present on both the anterior and posterior sides. Nine of the 24 autopsied individuals also had other diseases, with three having cancers other than PC.

CONCLUSIONS

This is the first report of the features of latent PC in Asian men who died of unnatural causes. Forensic autopsies can clarify the natural history of PC and may help fill knowledge gaps regarding latent PC.

Survival of patients with prostate cancer in Yazd, Iran

BACKGROUND

Prostate cancer is the second leading cause of cancer death in men worldwide. Several factors such as availability of screening tests, and dietary, other lifestyle, environmental and genetic influences contribute to worldwide disparities in prostate cancer incidence and mortality rates. Our aims were to investigate patient characteristics at the time of diagnosis, common treatment strategies employed and survival in an Iranian male population with prostate cancer.

MATERIALS AND METHODS

Archives of Pathology Departments of five referral centers affiliated with the School of Medicine of Shahid Sadoughi University in Yazd province were reviewed. Paraffin-embedded blocks were reviewed by two independent pathologists to confirm the diagnosis. The latest modification of the Gleason Scoring System was adopted to determine pathological grading. Following pathological evaluation, patients were contacted via telephone to acquire information regarding their current status.

RESULTS

Pathology blocks were available for 113 patients. However, upon phone contacts, we were unable to determine the survival status in 23 patients (response rate=83%). Therefore, 90 patients were enrolled in the final analysis. The median follow-up time was 6.0 years (ranging from 0.3 to 8.8 years). There were 30 death attributed to prostate cancer in the study group. Kaplan-Meier analysis revealed that patient age at the time of diagnosis was a significant predictor of survival. Another significant predictor of poorer survival was higher tumor grade.

CONCLUSIONS

Our observations indicate that age and pathological grade can negatively affect survival of individuals with prostate cancer in Iran.

Prostate cancer risk profiles of Asian-American men: disentangling the effects of immigration status and race/ethnicity

PURPOSE

Asian-American men with prostate cancer have been reported to present with higher grade and later stage disease than white American men. However, Asian-American men comprise a heterogeneous population with distinct health outcomes. We compared prostate cancer risk profiles among the diverse racial and ethnic groups in California.

MATERIALS AND METHODS

We used data from the California Cancer Registry on 90,845 nonHispanic white, nonHispanic black and Asian-American men diagnosed with prostate cancer between 2004 and 2010. Patients were categorized into low, intermediate and high risk groups based on clinical stage, Gleason score and prostate specific antigen at diagnosis. Using polytomous logistic regression we estimated adjusted ORs for the association of race/ethnicity and nativity with risk group.

RESULTS

In addition to the nonHispanic black population, 6 Asian-American groups (United States born Chinese, foreign born Chinese, United States born Japanese, foreign born Japanese, foreign born Filipino and foreign born Vietnamese) were more likely to have an unfavorable risk profile compared to nonHispanic white men. The OR for high vs intermediate risk disease ranged from 1.23 (95% CI 1.02-1.49) for United States born Japanese men to 1.45 (95% CI 1.31-1.60) for foreign born Filipino men. These associations appeared to be driven by higher grade and prostate specific antigen rather than by advanced clinical stage at diagnosis.

CONCLUSIONS

In this large, ethnically diverse, population based cohort Asian-American men were more likely to have an unfavorable risk profile at diagnosis. This association varied by racial/ethnic group and nativity, and was not attributable to later stage at diagnosis. This suggests that Asian men may have biological differences that predispose to more severe disease.

Epithelial cancers in the post-genomic era: should we reconsider our lifestyle?

The age-related epithelial cancers of the breast, colorectum and prostate are the most prevalent and are increasing in our aging populations. Epithelial cells turnover rapidly and mutations naturally accumulate throughout life. Most epithelial cancers arise from this normal mutation rate. All elderly individuals will harbour many cells with the requisite mutations and most will develop occult neoplastic lesions. Although essential for initiation, these mutations are not sufficient for the progression of cancer to a life-threatening disease. This progression appears to be dependent on context: the tissue ecosystem within individuals and lifestyle exposures across populations of individuals. Together, this implies that the seeds may be plentiful but they only germinate in the right soil. The incidence of these cancers is much lower in Eastern countries but is increasing with Westernisation and increases more acutely in migrants to the West. A Western lifestyle is strongly associated with perturbed metabolism, as evidenced by the epidemics of obesity and diabetes: this may also provide the setting enabling the progression of epithelial cancers. Epidemiology has indicated that metabolic biomarkers are prospectively associated with cancer incidence and prognosis. Furthermore, within cancer research, there has been a rediscovery that a switch in cell metabolism is critical for cancer progression but this is set within the metabolic status of the host. The seed may only germinate if the soil is fertile. This perspective brings together the different avenues of investigation implicating the role that metabolism may play within the context of post-genomic concepts of cancer.

Selective liver X receptor modulators (SLiMs): what use in human health?

Liver X receptors (LXR) are members of the nuclear receptor family. As activated transcription factors, their putative association with human diseases makes them promising pharmacological targets because of the large potential to develop ligands. LXR are mainly considered as intracellular cholesterol "sensors" whose activation leads to decreased plasma cholesterol. They also modulate numerous physiological functions: fatty acid synthesis and metabolism, glucose homeostasis, steroidogenesis, immunity, and neurological homeostasis. LXR-deficiency in mouse results in several phenotypes mimicking pathological conditions in humans. This review will be focused on the various natural and synthetic LXR agonists and antagonists. Putative clinical targets including atherosclerosis, diabetes, Alzheimer's disease, skin disorders, and cancer will be covered.

Number of screens for overdetection as an indicator of absolute risk of overdiagnosis in prostate cancer screening

As with wide-spread use of prostate cancer (Pca) screening with prostate-specific antigen testing, overdetection has increasingly gained attention. The authors aimed to estimate absolute risk of overdetection (RO) in Pca screening with various interscreening intervals and ages at start of screening. We estimated age-specific preclinical incidence rates (per 100,000 person-years) for progressive cancer (from 128 for age group 55-58 years to 774 for age group 67-71 years) and nonprogressive cancer (from 40 for age group 55-58 years to 66 for age group 67-71 years), the mean sojourn time (7.72 years) and the sensitivity (42.8% at first screen and 59.8% at the second screen) by using a multistep epidemiological model with data from the Finnish randomized controlled trial. The overall number of screens for overdetection (NSO) was 29 (95% confidence interval (CI): 18, 48) for screenees aged 55-67 years, equivalent to 3.4 (95% CI: 2.1, 5.7) overdetected Pcas per 100 screenees. The NSO decreased from 63 (95% CI: 37, 109) at the first screen to 29 (95% CI: 18, 48) at the third screen and from 43 (95% CI: 36, 52) for age 55 years to 25 (95% CI: 8, 75) at age 67 years at the first screen. In conclusion, around 3.4 cases for every 100 screened men would be overdetected during three screen rounds (~ 13 years of follow-up) in the Finnish randomized controlled trial. Elucidating the absolute RO under various scenarios makes contribution for evaluating the benefit and harm of Pca screening.

Predictive value in the analysis of RNASEL genotypes in relation to prostate cancer

BACKGROUND

We would like to compare the different RNASEL genotypes with the stage of the cancer using parameters such as PSA levels, Gleason score and T-stage, and to develop a clinical protocol for the monitoring of the disease for trying a better evolution of the patient.

METHODS

A total of 231 patients with sporadic prostate cancer and 100 of controls were genotyped in RNASEL gene by sequencing the exons 1 and 3. A survey of clinical information was collected by a specialist following the Helsinki protocol. All patients and controls were interviewed by a researcher and signed their informed consent to participation in the study, which was approved by Ethics Committee of the hospital. The genetic information was processed and collected with an ABI PRISM Genetic Analyser 3130 using SeqScape software v.2.6. All the patients were analysed by comparing the genetic and clinical data. χ(2)-tests, Monte Carlo, Fisher tests and contigency tables were performed using SPSS v.15.0 and ARLEQUIN v.3.5 software on patient population.

RESULTS

Significant differences were found only between patients and controls in D541E, R461Q and I97L genotypes, the remainder of the variants did not seem relevant to our population in contrast to other populations, such as north-Caucasians, Afro Americans and Ashkenazi Jews. The genotypes associated with the worst prognoses are G/G in D541E, A/A in R462Q and A/G in I97L. The controls were included in our study to determine an approximation of the genotype in our population compared with the patients, but they did not account for the statistical process.

CONCLUSIONS

The genetic profile of patients with this cancer combined with other parameters could be used as a prognosis factor in deciding to give more radical and frequent treatments, depending on personal genotype.

The dietary isoflavone biochanin-A sensitizes prostate cancer cells to TRAIL-induced apoptosis

Biochanin-A, a major dietary isoflavone in soy and red clover, possesses anticancer and chemopreventive properties. Induction of apoptosis by naturally occurring dietary agents is an important event for cancer chemoprevention. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis selectively in cancer cells but not in normal cells. Soluble or expressed in immune cells, molecules TRAIL plays a significant role in surveillance and defense mechanisms against tumours. Prostate cancer is an ideal disease for nutritional prevention. The TRAIL-mediated apoptosis pathway in prostate cancer cells is an attractive target for chemopreventive activities of dietary agents. LNCaP and DU145 prostate cancer cells are resistant to TRAIL-induced apoptosis. We showed that biochanin-A markedly augmented TRAIL-induced cytotoxicity and apoptosis in both prostate cancer cell lines. Then, we investigated the mechanisms by which biochanin-A enhanced TRAIL-mediated apoptosis using the LNCaP cell line. The isoflavone sensitized the TRAIL-resistant LNCaP cells through the inhibition of transcription factor NF-κB(p65) activity, increased the expression of the death receptor TRAIL-R2 (DR5), and disrupted mitochondrial membrane potential (ΔΨm). Our study confirmed that biochanin-A overcame TRAIL-resistance by engaging both intrinsic and extrinsic apoptotic pathways and by regulating the NF-κB activity. The results suggested a potential role of biochanin-A in prostate cancer chemoprevention through the enhancement of TRAIL-mediated apoptosis.

Does physical activity reduce the risk of prostate cancer? A systematic review and meta-analysis

CONTEXT

Numerous observational epidemiologic studies have evaluated the association between physical activity and prostate cancer (PCa); however, the existing results are inconsistent.

OBJECTIVE

To determine the association between physical activity and risk of PCa.

EVIDENCE ACQUISITION

A systematic search was performed using the Medline, Embase, and Web of Science databases through 15 May 2011 to identify all English-language articles that examined the effect of physical activity on the risk of PCa. This meta-analysis was conducted according to the guidelines for the meta-analysis of observational studies in epidemiology.

EVIDENCE SYNTHESIS

This meta-analysis consisted of 88,294 cases from 19 eligible cohort studies and 24 eligible case-control studies. When data from both types of studies were combined, total physical activity (TPA) was significantly associated with a decreased risk of PCa (pooled relative risk [RR]: 0.90; 95% confidence interval [CI], 0.84-0.95). The pooled RR for occupational physical activity (OPA) and recreational physical activity (RPA) were 0.81 (95% CI, 0.73-0.91) and 0.95 (95% CI, 0.89-1.00), respectively. Notably, for TPA, we observed a significant PCa risk reduction for individuals between 20 and 45 yr of age (RR: 0.93; 95% CI, 0.89-0.97) and between 45 and 65 yr of age (RR: 0.91; 95% CI, 0.86-0.97) who performed activities but not for individuals <20 yr of age or >65 yr of age.

CONCLUSIONS

There appears to be an inverse association between physical activity and PCa risk, albeit a small one. Given that increasing physical activity has numerous other health benefits, men should be encouraged to increase their physical activity in both occupational and recreational time to improve their overall health and potentially decrease their risk of PCa.

Liver X receptors, lipids and their reproductive secrets in the male

Liver X receptor (LXR) α and LXRβ belong to the nuclear receptor superfamily. For many years, they have been called orphan receptors, as no natural ligand was identified. In the last decade, the LXR natural ligands have been shown to be oxysterols, molecules derived from cholesterol. While these nuclear receptors have been abundantly studied for their roles in the regulation of lipid metabolism, it appears that they also present crucial activities in reproductive organs such as testis and epididymis, as well as prostate. Phenotypic analyses of mice lacking LXRs (lxr-/-) pointed out their physiological activities in the various cells and organs regulating reproductive functions. This review summarizes the impact of LXR-deficiency in male reproduction, highlighting the novel information coming from the phenotypic analyses of lxrα-/-, lxrβ-/- and lxrα;β-/- mice. This article is part of a Special Issue entitled: Translating nuclear receptor from health to disease.

A novel androgen-dependent prostate cancer xenograft model derived from skin metastasis of a Japanese patient

BACKGROUND

The incidence of, and mortality from, prostate cancer (PCa) has increased in Asian countries over the past decades, partly due to a change in dietary habits. Recent reports have revealed differences in the molecular basis of PCa among people of differing racial or ethnic backgrounds. PCa xenograft models established from Asian patients would be useful for understanding the basis of PCa in Asian populations; we therefore established and characterized a novel PCa xenograft model, JDCaP, from a metastatic skin lesion of a Japanese hormone-refractory prostate cancer (HRPC) patient.

METHODS

Skin metastatic tissue derived from poorly differentiated prostatic adenocarcinoma in a 61-year-old Japanese male was transplanted to nude mice and JDCaP was established by serial passage. Expression of androgen receptor (AR) and prostate-specific antigen (PSA) was evaluated by immunohistochemistry and the AR sequence was analyzed. Hormone sensitivity of JDCaP was investigated in vivo by orchiectomy followed by administration of steroid hormones, including testosterone, estradiol, progesterone, and hydrocortisone. Therapeutic effects of leuprorelin acetate, bicalutamide, flutamide, diethylstilbestrol (DES), and estradiol were investigated.

RESULTS

JDCaP expressed wild-type AR and PSA and showed androgen dependence. Only testosterone administration maintained tumor proliferation after orchiectomy. Administration of leuprorelin acetate, bicalutamide, and flutamide inhibited tumor growth. DES and estradiol also demonstrated significant antitumor effects.

CONCLUSIONS

JDCaP expresses wild-type ARs and exhibits androgen dependence despite its origin from a HRPC patient. The model may be useful to elucidate the molecular basis of PCa in Asian populations and to develop prevention and therapeutic strategies.

Soy, isoflavones, and prostate cancer

Prostate cancer has marked geographic variations between countries. Genetic, epigenetic, and environmental factors co-contribute to the development of the cancer. The association between dietary factors and prostate cancer has been investigated and one explanation for the low incidence of the cancer in Asia might be high consumption of fresh vegetables including soybean and its products. Soybean is a species of legume contain high amount of isoflavones including genistein, daidzein, glycitein, and equol, which have a prophylactic effect on prostate cancer. In this article, epidemiological and laboratory studies on the relationship between soybeans, isoflavones and prostate cancer are reviewed and large scale multiethnic epidemiological studies are recommended.

Simultaneously detection of genomic and expression alterations in prostate cancer using cDNA microarray

BACKGROUND

Prostate cancer is a common disease among men but the knowledge of the prostate carcinogenesis is still limited.

METHODS

cDNA microarray-based comparative genomic hybridization (CGH) and expression profiling were performed to screen the genomic and the expression changes in prostate cancer respectively. The two data were integrated to study the influence of genomic aberrations on gene expression and seek for the genes with their expression affected by the genomic aberrations. Real-time PCR was performed to evaluate the array data.

RESULTS

Array-based CGH detected gains at 2q, 3p/q, 5q, 6q, 8q, 9p, 10p/q, 11q, 12p, 14q, and 19p/q and losses at 1p, 2p, 4q, 6p/q, 7p, 11p/q, 12q, 17p/q, 19p/q, and Xp/q in more than 20% prostate tumors and narrowed these aberrations. For example, the gain of 8q was mapped to five minimal regions. Novel aberrations were also identified, such as loss at Xq21.33-q22.2. Expression profiling discovered the significant biological processes involved in the prostate carcinogenesis, such as exogenous antigen presentation via MHC class II and protein ubiquitination. Integration analysis revealed a weak positive correlation between genomic copy number and gene expression level. Fifty-three genes showed their expression directly affected by the genomic aberrations possibly, including more than one member of Ras superfamily and major histocompatibility complex (MHC). These genes are involved in multiple biological processes.

CONCLUSIONS

Integration of the CGH and expression data provided more information than separate analysis. Although the direct influence of genomic aberrations on gene expression seems weak, the influence can be extended by indirect regulation through a few directly affected genes. Because the influence can be persistent, the genes directly affected by the genomic aberrations may play key roles in the prostate carcinogenesis and are worth further analysis.

Cancer as an endocrine problem

Many of the most common cancers that blight our societies are very rare in other large populations in the world; studies of migrants exclude a simple genetic explanation for these wide geographical variations and imply that environmental exposures are key determinants of the development of these cancers. The most heavily implicated factor is nutrition. There are many other clinical indicators that nutrition, energy balance and metabolic status are perturbed in large numbers of individuals in 'Westernized' societies. Many of the tissue morbidities associated with metabolic disturbance are mediated by the consequent hormonal perturbations, and it is likely that these endocrine controls also mediate the effects of nutrition and metabolic status on the development of many clinical cancers. The recent characterization of the genomic landscape of breast and colorectal cancers have established that a few cell signalling pathways are critical for the clinical course of these cancers, in particular cell signalling pathways that are also central to the regulation of cell metabolism. These signalling pathways are normally under hormonal control, and again this evidence suggests that these hormonal controls may determine the context that is permissive for the progression of clinical cancers. This new understanding indicates that many cancers are potentially preventable, and that nutrition, metabolic and endocrine interventions are the most promising strategies for disease prevention.

Candidate genes involved in enhanced growth of human prostate cancer under high fat feeding identified by microarray analysis

BACKGROUND

Several studies have suggested that a high fat diet (HFD) may be a risk factor of prostate cancer (PCa). As a first step to delineate the molecular mechanisms underlying the enhanced progression of PCa under HFD, we investigated the differential gene expressions of a human PCa xenograft under HFD and a low fat diet (LFD).

METHODS

LNCaP cells were subcutaneously injected in 20 nude mice, which were equally divided into two groups, the HFD group and LFD group. Oligonucleotide microarray analyses were performed using mice xenografts from HFD and LFD, and the results of candidate genes with a significant differential expression were validated by quantitative RT-PCR experiments. As for insulin-like growth factor I receptor (IGF-IR), protein expression levels were further examined by immunohistochemistry in xenograft tissues and in 78 radical prostatectomy specimens.

RESULTS

Tumor volume and serum PSA levels were significantly higher in the HFD group than in the LFD group (P<0.001 and P=0.006, respectively). We found 64 up-regulated genes (0.19%) and 14 down-regulated genes (0.04%) with more than twofold differences in the HFD xenograft. IGF-IR, TNFRSF, and LPL showed striking differences in the quantitative RT-PCR experiment. Immunostaining further revealed marked enhanced IGF-IR expression in the HFD xenograft. In human PCa, the lowest IGF-IR immunoreactivity group tended to have the lowest body mass index in both normal and PCa epithelium.

CONCLUSION

HFD induced remarkable up- and down-regulation of mRNA of a substantial number of genes. Furthermore, the IGF-I system may be involved in the HFD-associated enhanced progression of PCa.

Outcomes of locally advanced prostate cancer: a single institution study of 209 patients in Japan

AIM

To investigate the outcomes for Asian populations with locally advanced/clinical stage III prostate cancer (PCa) treated with currently prevailing modalities.

METHODS

We reviewed the record of 209 patients with clinical stage III PCa, who were treated at Niigata Cancer Center Hospital between 1992 and 2003. Treatment options included hormone therapy-combined radical prostatectomy (RP+HT), hormone therapy-combined external beam irradiation (EBRT+HT) and primary hormone therapy (PHT).

RESULTS

The 5- and 10-year overall survival rates were 80.3% and 46.1% in all cohorts, respectively. The survival rates were 87.3% and 66.5% in the RP+HT group, 94.9% and 70.0% in the EBRT+HT group and 66.1% and 17.2% in the PHT group, respectively. A significant survival advantage was found in the EBRT+HT group compared with that in the PHT group (P < 0.0001). Also, the RP+HT group had better survival than the PHT group (P = 0.0107). The 5- and 10-year disease-specific survival rates for all cases were 92.5% and 80.0%, respectively. They were 93.8% and 71.4% in the RP+HT group, 96.6% and 93.6% in the EBRT+HT group and 88.6% and 62.3% in the PHT group, respectively. A survival advantage was found in the EBRT+HT group compared with the PHT group (P = 0.029). No significant difference was found in disease-specific survival between the EBRT+HT and RP+HT groups or between the RP+HT and PHT groups.

CONCLUSION

Although our findings indicate that radiotherapy plus HT has a survival advantage in this stage of PCa, we recommend therapies that take into account the patients'social and medical conditions for Asian men with clinical stage III PCa.

Alterations in nuclear structure and expression of proPSA predict differences between native Japanese and Japanese-American prostate cancer

OBJECTIVES

To differentiate the benign and/or malignant epithelial cells in prostate cancer (PCa) glands of native Japanese (NJ) and Japanese-American (JA) men using biomarkers.

METHODS

Tissue microarrays from radical prostatectomy specimens of cancerous and adjacent benign areas from 25 NJ and 25 JA prostate glands were studied. Image analysis was used to quantify total prostate-specific antigen (PSA) and proPSA immunohistochemical staining, as well as the variance of several morphometric features from Feulgen-stained epithelial cell nuclei. Logistic regression analysis was applied to determine whether quantitative nuclear grade (QNG) calculations and PSA immunohistochemical staining could differentiate the two test groups.

RESULTS

The QNG model differentiated changes in the benign epithelium of the two Japanese groups with an area under the receiver operating characteristic curve of 84% and accuracy of 82% (P = 0.0001). A second QNG model differentiated changes in the malignant epithelium of the two groups with an area under the receiver operating characteristic curve of 84% and accuracy of 76% (P = 0.0023). Logistic regression models combining proPSA immunohistochemical data and QNG from either benign or malignant tissue components yielded areas under the receiver operating characteristic curve of 96% and 91% (P <0.0001) for differentiation of the JA and NJ groups, respectively.

CONCLUSIONS

Unique nuclear morphometric alterations demonstrated by QNG combined with proPSA immunohistologic localization independently predicted for significant differences between NJ and JA men with PCa. These preliminary observations indicate a basis for biologic and molecular alterations in the benign adjacent and malignant epithelium between these two groups.

Recent changes in the spatial pattern of prostate cancer in the U.S

INTRODUCTION

Spatial-temporal trends in prostate cancer mortality are of interest because of the introduction and increasing use of the prostate-specific antigen (PSA) screening test after 1986. This article describes spatial-temporal changes in U.S. prostate cancer mortality from 1968 to 1998.

METHODS

Prostate cancer mortality data were obtained from Compressed Mortality Files available from the National Center for Health Statistics. To minimize potential problems such as small numbers or missing data, the analysis was limited to white males aged 25 and over, and located in 2970 counties with complete data. Statistical analyses included the global distance between observed and expected multinomial probabilities, Hoover's Index of Concentration, and a retrospective test for change in spatial patterns.

RESULTS

Fairly steady declines were observed in prostate cancer mortality from 1968 until 1993, with an increasing tendency toward spatial uniformity. Spatial concentration increased from 1994 to 1998, and by 1998 the level of spatial concentration had returned to levels that prevailed during the early to mid-1980s. Comparing 1991-1998 to 1968-1990, the observed number of prostate deaths increased the most rapidly with respect to the expected number in western Appalachia and the south central U.S. Recent relative declines in mortality were observed in southern California and parts of Florida.

CONCLUSIONS

The observed results are generally consistent with prior evaluations of prostate cancer spatial-temporal patterns. However, the current study identified a heretofore unnoticed recent pattern of change in western Appalachia and the south central U.S. Recent declines in Florida and southern California may have contributed to recent increases in spatial concentration of prostate cancer mortality, and may possibly be associated with realized benefits from screening programs.

Molecular pathology of prostate cancer

The incidence of prostate cancer has increased in Japan recently and is developing into a life-threatening disease for many Japanese men. This is a result of several convergent factors including the adoption of a Western lifestyle, the widespread use of prostate-specific antigen (PSA) testing, and an increased population of advanced years in Japanese men. Although there is much information to date relating to molecular events underlying the etiology of prostate cancer, it is still unclear as to how and when these genetic alterations occur in each step of tumorigenesis. One fruitful area of investigation has been in the analysis of chromosomal abnormalities commonly observed in prostate cancer. However, no single candidate gene has been definitely identified in cancer initiation and/or progression; in addition, less research has been devoted to understanding the molecular events that underlie tumor histogenesis in terms of likely precursor lesions, such as prostatic intraepithelial neoplasia (PIN). This article reviews the current knowledge of the molecular pathology of prostate cancer, including its histogenesis, genetic and epigenetic alterations, and hereditary factors.

Ethnic group-related differences in CpG hypermethylation of the GSTP1 gene promoter among African-American, Caucasian and Asian patients with prostate cancer

The incidence and mortality of prostate cancer (PC) is approximately 2-fold higher among African-Americans as compared to Caucasians and very low in Asian. We hypothesize that inactivation of GSTP1 genes through CpG methylation plays a role in the pathogenesis of PC, and its ability to serve as a diagnostic marker that differs among ethnic groups. GSTP1 promoter hypermethylation and its correlation with clinico-pathological findings were evaluated in 291 PC (Asian = 170; African-American = 44; Caucasian = 77) and 172 benign prostate hypertrophy samples (BPH) (Asian = 96; African-American = 38; Caucasian = 38) using methylation-specific PCR. In PC cells, 5-aza-dC treatment increased expression of GSTP1 mRNA transcripts. The methylation of all CpG sites was found in 191 of 291 PC (65.6%), but only in 34 of 139 BPH (24.5%). The GSTP1 hypermethylation was significantly higher in PC as compared to BPH in each ethnic group (p < 0.0001). Logistic regression analysis (PC vs. BPH) showed that African-Americans had a higher hazard ratio (HR) (13.361) compared to Caucasians (3.829) and Asian (8.603). Chi-square analysis showed correlation of GSTP1 hypermethylation with pathological findings (pT categories and higher Gleason sum) in Asian PC (p < 0.0001) but not in African-Americans and Caucasian PC. Our results suggest that GSTP1 hypermethylation is a sensitive biomarker in African-Americans as compared to that in Caucasians or Asian, and that it strongly influences tumor progression in Asian PC. Ours is the first study investigating GSTP1 methylation differences in PC among African-American, Caucasian and Asian.

Functional Loss of the gamma-catenin gene through epigenetic and genetic pathways in human prostate cancer

Gamma-catenin is a cell adhesion molecule and a candidate mediator of Wnt signal transduction. We hypothesized that impaired regulation of gamma-catenin through genetic and epigenetic pathways is associated with the pathogenesis of prostate cancer. To test this hypothesis, cytosine-phosphate-guanine methylation, loss of heterozygosity (LOH), and mutation status of the gamma-catenin gene were analyzed in cultured prostate cancer cell lines, 180 localized prostate cancers, 69 benign prostatic hyperplasias, and 11 hormone refractory prostate cancers (HRPC). In prostate cancer cell lines (DuPro, LNCaP, ND-1, and PC3), gamma-catenin mRNA transcripts were increased after 5-aza-2'-deoxycytidine treatment. In localized prostate cancer, gamma-catenin expression was lower but prevalence of gamma-catenin methylation was higher compared with benign prostatic hyperplasia. However, gamma-catenin methylation did not correlate with Gleason sum, pT category, or capsular penetration. Among localized prostate cancers with positive gamma-catenin methylation, the presence of LOH at chromosome 17q21 was closely related to down-regulation of gamma-catenin mRNA expression. The gamma-catenin mutations were not found in localized prostate cancers, whereas six mutations were found in five HRPCs within or close to the GSK-3beta consensus motif phosphorylation site, among which four HRPCs showed strong nuclear gamma-catenin accumulation. In these four HRPCs, Bcl-2 expression was increased, whereas the target of the Wnt signal, c-myc, was only expressed in one HRPC. Therefore, although epigenetic gamma-catenin methylation is an early event in the development of prostate cancer, simultaneous events of epigenetic cytosine-phosphate-guanine methylation and genetic LOH may be responsible for functional loss of gamma-catenin. The gamma-catenin mutation related to Bcl-2 overexpression has a significant effect on the pathogenesis of HRPC. This is the first report to characterize the epigenetic and genetic regulation of gamma-catenin in human prostate cancer.

Do dietary lycopene and other carotenoids protect against prostate cancer?

To determine whether dietary intake of lycopene and other carotenoids has an etiological association with prostate cancer, a case-control study was conducted in Hangzhou, southeast China during 2001-2002. The cases were 130 incident patients with histologically confirmed adenocarcinoma of the prostate. The controls were 274 hospital inpatients without prostate cancer or any other malignant diseases. Information on usual food consumption, including vegetables and fruits, was collected by face-to-face interviews using a structured food frequency questionnaire. The risks of prostate cancer for the intake of carotenoids and selected vegetables and fruits rich in carotenoids were assessed using multivariate logistic regression, adjusting for age, locality, education, income, body mass index, marital status, number of children, family history of prostate cancer, tea drinking, total fat and caloric intake. The prostate cancer risk declined with increasing consumption of lycopene, alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein and zeaxanthin. Intake of tomatoes, pumpkin, spinach, watermelon and citrus fruits were also inversely associated with the prostate cancer risk. The adjusted odds ratios for the highest versus the lowest quartiles of intake were 0.18 (95% CI: 0.08-0.41) for lycopene, 0.43 (95% CI: 0.21-0.85) for alpha-carotene, 0.34 (95% CI: 0.17-0.69) for beta-carotene, 0.15 (95% CI: 0.06-0.34) for beta-cryptoxanthin and 0.02 (95% CI: 0.01-0.10) for lutein and zeaxanthin. The corresponding dose-response relationships were also significant, suggesting that vegetables and fruits rich in lycopene and other carotenoids may be protective against prostate cancer.

A retrospective study of the treatment of locally advanced prostate cancer by six institutions in eastern and north-eastern Japan

OBJECTIVE

To investigate patients with locally advanced prostate cancer treated at six academic institutions in eastern and north-eastern Japan from 1988 to 2000, to facilitate the establishment of Japanese guidelines for the diagnosis and treatment of locally advanced prostate cancer.

PATIENTS AND METHODS

The study included 391 eligible patients with locally advanced prostate cancer who were treated by radical prostatectomy (RP), radiotherapy and/or primary hormone therapy. Disease-specific survival rates for these patients were assessed in relation to their clinicopathological characteristics and the types of treatment they received. The Mann-Whitney U-test, Kruskal-Wallis, chi-square and log-rank test were used for statistical analysis, as appropriate.

RESULTS

In all, 128 patient with lower prostate-specific antigen levels (P = 0.023) and/or better performance status (P = 0.001) had RP. Neoadjuvant hormone therapy before RP was the treatment in 68 (53%) of these 128 patients; 66 (52%) received immediate adjuvant hormone therapy. Of 87 patients treated with radiotherapy, 75 (86%) had external beam radiotherapy (EBRT) as the primary treatment with no brachytherapy, and 12 (14%) had brachytherapy as the primary method. Neoadjuvant hormone therapy was given to 56 of the 87 patients (64%); 48 (55%) received immediate adjuvant hormone therapy. Of the 176 patients treated with primary hormone therapy alone, combined androgen blockade and surgical or medical castration was the treatment in 76 (43%) and 85 (48%), respectively. Disease-specific survival rates at 5 years for patients treated with RP, EBRT and primary hormone therapy were 90%, 98%, and 89%, respectively.

CONCLUSION

The treatments provided by the participating institutions did not differ significantly from those set out in European and American guidelines, and short-term disease-specific survival rates for each treatment did not differ significantly from those of historical controls. Further investigation may facilitate the establishment of Japanese guidelines for the diagnosis and treatment of locally advanced prostate cancer.

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.

Prostate cancer in native Japanese and Japanese-American men: Effects of dietary differences on prostatic tissue

OBJECTIVES

To investigate the relationship between diet and prostate cancer (CaP) among native Japanese (NJ) and second-generation or third-generation Japanese-American (J-A) men--focusing on the effects of animal fat and soy on prostatic tissues.

METHODS

The subjects were 50 Japanese men undergoing radical prostatectomy, 25 NJ living in Nagoya, Japan and 25 U.S.-born J-A men, living in Los Angeles, California. A priori, the NJ men were believed to be a low-fat, high-soy group and the J-A men, a high-fat, low-soy group. The studies included postoperative measurements of diet (Block questionnaire), body fat (bioimpedance), blood, urine, and prostatic biomarkers in malignant and adjacent normal tissue, using a tissue microarray made from the original paraffin blocks.

RESULTS

The NJ and J-A men were similar in age (65 to 70 years old; P <0.05), prostate-specific antigen level (7.1 to 8.6 ng/mL), prostate volume (35 to 38 cm3), and Gleason score (5.6 to 6.6), but their body composition differed. J-A men had more body fat (24% versus 19%), higher serum triglyceride levels (245 versus 106 mg/dL), lower estradiol levels (27 versus 31 ng/mL), and much lower urinary soy-metabolite levels (1:3) than NJ men (P <0.02). In both NJ and J-A groups, expression of numerous tissue biomarkers separated normal from CaP tissue, including markers for apoptosis (Bcl-2, caspase-3), growth factor receptors (epidermal growth factor receptor), racemase, 5-lipoxygenase, kinase inhibition (p27), and cell proliferation (Ki-67; all P <0.02). Furthermore, within both normal and CaP tissues, caspase-3 and 5-lipoxygenase were expressed more in NJ than in J-A men (P <0.01). Nuclear morphometry showed that the chromatin in each of the four groups (normal versus CaP, NJ versus J-A) was different (area under the curve 85% to 94%, P <0.01), despite fundamental genetic homogeneity.

CONCLUSIONS

NJ and J-A men, products of similar genetics but differing environments, were shown to have differences in body composition that could influence CaP evolution. The CaP specimens from the NJ and J-A men were histologically similar, but tissue biomarker expression, especially of lipoxygenase and the caspase family, suggested differing mechanisms of carcinogenesis. Differences in nuclear morphometry suggested the additional possibility of gene-nutrient interactions.

MISCAN: estimating lead-time and over-detection by simulation

OBJECTIVE

To estimate the mean lead-time and rate of over-detection associated with screening for prostate cancer with prostate-specific antigen.

METHODS

Simulation models, fitted to the results of the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer, were used to predict the mean lead-time and over-detection rate in population-based screening programmes.

RESULTS

The mean lead-time is estimated to be 11-12 years and over-detection to occur in half the cases found by population screening. The estimates are compared with published estimates.

CONCLUSIONS

The effect of lead-time and over-detection on the balance of positive and negative consequences of screening cannot be neglected.

Lack of Evidence for the Association of E-Cadherin Gene Polymorphism with Increased Risk or Progression of Prostate Cancer

BACKGROUND

E-cadherin is an epithelial cell adhesion molecule, and decreased E-cadherin expression in human prostate cancer is associated with tumor grade and advanced clinical stage. A -160 C-->A polymorphism in the promoter region of E-cadherin has been shown to decrease gene transcription. This allelic variation may be a potential genetic marker that can help identify those individuals at higher risk for invasive/metastatic disease.

MATERIALS AND METHODS

We studied the effect of E-cadherin gene polymorphism on prostate cancer susceptibility in a case control study of 219 prostate cancer patients and 219 male controls, to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is.

RESULTS

The genotype frequencies in the prostate cancer group were C/C: 0.607, C/A: 0.352, A/A: 0.041, and in the control group C/C: 0.671, C/A: 0.301, A/A: 0.027. A significant difference between the two groups was not found (p = 0.34), and the adjusted OR for A/A genotype was not statistically significant (OR = 1.66, 95% CI 0.58-4.78). Subdividing prostate cancer according to tumor differentiation and stage, we found no association between E-cadherin polymorphism and poor differentiation and invasiveness of prostate cancer.

CONCLUSIONS

These data do not support an association between the E-cadherin genotype and the occurrence or progression of prostate cancer in Japanese populations.

The Janus-faced nature of prostasomes: their pluripotency favours the normal reproductive process and malignant prostate growth

Prostasomes are submicron secretory granules synthesized, stored and secreted by the epithelial cells of the human prostate gland. They are membrane-surrounded also in their extracellular appearance and the membrane architecture is composite. They are believed to be life-giving and act as protectors of the spermatozoa in the lower and upper female genital tract on their way to the ovum. Hence, the prostasomes are immunosuppressive and inhibitory of complement activation. Further, they promote sperm's forward motility and have antioxidant and antibacterial capacities. The prostasomes with their many composite abilities seem to turn against the host cell after the age of 50 y being conducive to the transition of the normal prostate epithelial cell into a neoplastic cell and therewith lay the foundations of the very high prevalence of prostate cancer of men of more than 50 y of age.

Altered methylation of multiple genes in carcinogenesis of the prostate

The methylation status of 7 genes was examined in four cell lines, 36 samples of benign prostatic hyperplasia (BPH), 20 samples of prostatic intraepithelial neoplasia (PIN) and 109 samples of prostate cancer (PCa), using methylation-specific PCR (MSP): the pi-class glutathione S-transferase (GSTP1), retinoic acid receptor beta 2(RARbeta2), androgen receptor (AR), death-associated protein kinase (DAPK), tissue inhibitor of metalloproteinase-3 (TIMP-3), O(6)-methylguanine DNA methyltransferase (MGMT), and hypermethylated in cancer-1 (HIC-1). The frequencies of methylation in PCa were 88% for GSTP1, 78% for RARbeta2, 36% for DAPK, 15% for AR, 6% for TIMP-3, and 2% for MGMT, whereas the values were 11% for AR and DAPK, 6% for TIMP-3, 3% for GSTP1, and 0 for RARbeta2 and MGMT in BPH. Aberrant methylation of the GSTP1 and RARbeta2 genes was detected in 30% and 20% of PIN, respectively. Most samples of BPH and PCa were positive for HIC-1 methylation. Regarding accumulation of methylated cancer-related genes, there were significant correlations between PCa and BPH as well as PIN and BPH. In the present study, a high frequency of aberrant promoter methylation of the GSTP1 and RARbeta2 genes was noted in PCa. Our findings suggest that methylation of cancer-related genes may be involved in carcinogenesis of the prostate.

Lead times and overdetection due to prostate-specific antigen screening: estimates from the European Randomized Study of Screening for Prostate Cancer

BACKGROUND

Screening for prostate cancer advances the time of diagnosis (lead time) and detects cancers that would not have been diagnosed in the absence of screening (overdetection). Both consequences have considerable impact on the net benefits of screening.

METHODS

We developed simulation models based on results of the Rotterdam section of the European Randomized Study of Screening for Prostate Cancer (ERSPC), which enrolled 42,376 men and in which 1498 cases of prostate cancer were identified, and on baseline prostate cancer incidence and stage distribution data. The models were used to predict mean lead times, overdetection rates, and ranges (corresponding to approximate 95% confidence intervals) associated with different screening programs.

RESULTS

Mean lead times and rates of overdetection depended on a man's age at screening. For a single screening test at age 55, the estimated mean lead time was 12.3 years (range = 11.6-14.1 years) and the overdetection rate was 27% (range = 24%-37%); at age 75, the estimates were 6.0 years (range = 5.8-6.3 years) and 56% (range = 53%-61%), respectively. For a screening program with a 4-year screening interval from age 55 to 67, the estimated mean lead time was 11.2 years (range = 10.8-12.1 years), and the overdetection rate was 48% (range = 44%-55%). This screening program raised the lifetime risk of a prostate cancer diagnosis from 6.4% to 10.6%, a relative increase of 65% (range = 56%-87%). In annual screening from age 55 to 67, the estimated overdetection rate was 50% (range = 46%-57%) and the lifetime prostate cancer risk was increased by 80% (range = 69%-116%). Extending annual or quadrennial screening to the age of 75 would result in at least two cases of overdetection for every clinically relevant cancer detected.

CONCLUSIONS

These model-based lead-time estimates support a prostate cancer screening interval of more than 1 year.

High-grade prostatic intraepithelial neoplasia and prostate cancer risk reduction

High-grade prostatic intraepithelial neoplasia (PIN) is the earliest accepted stage in carcinogenesis, possessing most of the phenotypic and biochemical changes in cancer without invasion of the basal membrane of the acini. The support for high-grade PIN as the main premalignant lesion of prostate cancer is based on several lines of evidence derived from prostate cancer animal models, epidemiological, morphological, genetic, and molecular studies. The incidence of high-grade PIN averages 9% (range 4-16%) in prostate biopsies, representing 115,000 new cases of high-grade PIN diagnosed each year in the United States. Performing saturation prostate biopsies to rule out any coexistent prostate cancer followed by every 3-6 month serial repeated prostate biopsies is currently the only way in which to manage patients found to have high-grade PIN. Medical therapy for high-grade PIN may easily become the mainstay treatment for high-grade PIN. Treatment of high-grade PIN appears to be of clinical benefit notwithstanding the potential for prostate cancer risk reduction. These clinical benefits would reduce morbidity, enhance quality of life, delay surgery or radiation, and increase the interval for surveillance requiring invasive procedures.

Prevalence of prostate cancer and prostatic intraepithelial neoplasia in Caucasian Mediterranean males: an autopsy study

BACKGROUND

The prevalence of carcinoma of the prostate gland (CaP) and high-grade prostatic intraepithelial neoplasia (HGPIN) was assessed in a Spanish population, representative of the Caucasian Mediterranean (CM) ethnic group. Data were compared with those described in populations from other geographical regions and in other ethnic groups.

METHODS

CaP and HGPIN were evaluated in a consecutive series of prostatic glands collected at the post-mortem examination of 162 male patients born and living in Spain, aged 20-80 years, and dying from trauma. The glands were sliced every 2-3 mm. All slices were paraffin embedded and sectioned to obtain 5 microm whole-mount sections. To compare the prevalence rate in our series and in other Caucasian populations with that from other geographical areas and other ethnic groups, we used data from the autopsy study performed at the Wayne State University.

RESULTS

Prevalence of CaP is 3.58, 8.82, 14.28, 23.80, 31.7, and 33.33% in the 3rd, 4th, 5th, 6th, 7th, and 8th decades, respectively. The rates of HGPIN were 7.14, 11.75, 35.71, 38.06, 45.40, and 48.15% at the 3rd, 4th, 5th, and 8th decades of life. Both CaP and HGPIN are located preferentially at the peripheral zone of the gland and in 21/27 cases (77.7%), an association between CaP and HGPIN was found. The prevalence of both lesions in CM males is significantly lower than in Caucasian American (CA) and Afro-American (AA) males in all the age groups evaluated.

CONCLUSIONS

Microscopic foci of CaP and HGPIN can be documented in CM males from the 3rd decade of life onwards. The lesions become more frequent and extensive as age increases. The prevalence of both lesions seems to be significantly lower in the CM population than in CA and AA males in all the age groups evaluated.