Current status of linkage studies in hereditary prostate cancer

Carriage of mutations R462Q (rs 486907) and D541E (rs 627928) of the RNASEL gene and risk factors in patients with prostate cancer in Burkina Faso

Background

Prostate cancer (Pca) is a public health problem that affects men, usually of middle age or older. It is the second most common cancer diagnosed in men and the fifth leading cause of death. The RNASEL gene located in 1q25 and identified as a susceptibility gene to hereditary prostate cancer, has never been studied in relation to prostate cancer in Burkina Faso. The aim of this study was to analyze the carriage of RNASEL R462Q and D541E mutations and risks factors in patients with prostate cancer in the Burkina Faso.

Methods

This case–control study included of 38 histologically diagnosed prostate cancer cases and 53 controls (cases without prostate abnormalities). Real-time PCR genotyping of R462Q and D541E variants using the TaqMan® allelic discrimination technique was used. Correlations between different genotypes and combined genotypes were investigated.

Results

The R462Q variant was present in 5.3% of cases and 7.5% of controls. The D541E variant was present in 50.0% of cases and 35% of controls. There is no association between R462Q variants (OR = 0.60; 95%IC, 0.10–3.51; p = 0.686) and D541E variants (OR = 2.46; 95%IC, 0.78–7.80; p = 0.121) and genotypes combined with prostate cancer. However, there is a statistically significant difference in the distribution of cases according to the PSA rate at diagnosis (p ˂ 0.001). For the Gleason score distribution, only 13.2% of cases have a Gleason score greater than 7. There is a statistically significant difference in the Gleason score distribution of cases (p ˂ 0.001).

Conclusions

These variants, considered in isolation or in combination, are not associated with the risk of prostate cancer.

Prostate Cancer Germline Variations and Implications for Screening and Treatment

Prostate cancer (PCa) is a highly heritable disease, and rapid evolution of sequencing technologies has enabled marked progression of our understanding of its genetic inheritance. A complex polygenic model that involves common low-penetrance susceptibility alleles causing individually small but cumulatively significant risk and rarer genetic variants causing greater risk represent the current most accepted model. Through genome-wide association studies, more than 100 single-nucleotide polymorphisms (SNPs) associated with PCa risk have been identified. Consistent reports have identified germline mutations in the genes BRCA1, BRCA2, MMR, HOXB13, CHEK2, and NBS1 as conferring moderate risks, with some leading to a more aggressive disease behavior. Considering this knowledge, several research strategies have been developed to determine whether targeted prostate screening using genetic information can overcome the limitations of population-based prostate-specific antigen (PSA) screening. Germline DNA-repair mutations are more frequent in men with metastatic disease than previously thought, and these patients have a more favorable response to therapy with poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitors. Genomic information is a practical tool that has the potential to enable the concept of precision medicine to become a reality in all steps of PCa patient care.

Translating genetic risk factors for prostate cancer to the clinic: 2013 and beyond

Prostate cancer (PrCa) is the most commonly diagnosed cancer in the male UK population, with over 40,000 new cases per year. PrCa has a complex, polygenic predisposition, due to rare variants such as BRCA and common variants such as single nucleotide polymorphisms (SNPs). With the introduction of genome-wide association studies, 78 susceptibility loci (SNPs) associated with PrCa risk have been identified. Genetic profiling could risk-stratify a population, leading to the discovery of a higher proportion of clinically significant disease and a reduction in the morbidity related to age-based prostate-specific antigen screening. Based on the combined risk of the 78 SNPs identified so far, the top 1% of the risk distribution has a 4.7-times higher risk of developing PrCa compared with the average of the general population.

Prostate cancer and physical activity: adaptive response to oxidative stress

Prostate cancer is the most common form of cancer affecting men in the Western world. Its relative incidence increases exponentially with age and a steady increase is observed with extended life span. A sedentary lifestyle represents an important risk factor and a decrease in prostate cancer prevalence is associated with exercise. However, the molecular mechanisms involved in this process remain unknown. We hypothesize that reactive oxygen species generated by physical exercise are a key regulatory factor in prostate cancer prevention. Aging is correlated with increased oxidative stress (OS), which in turn provides a favorable environment for tumorigenesis. Running training is known to enhance the antioxidant defense system, reducing oxidative stress. In this context, the decrease in OS induced by exercise may delay the development of prostate cancer. This review focuses on oxidative stress-based mechanisms leading to prostate cancer sensitization to exercise, which could have some impact on the development of novel cancer therapeutic strategies.

Genetic and epigenetic changes in human prostate cancer

Acquired or inherited genetic alterations either alone or in combination with epigenetic alterations are associated with prostate carcinogenesis and its progression toward advance metastatic or castration-resistant disease. A major objective of translational cancer research in post-genome era is to discover the repertoire of genetic and epigenetic variations associated with prostate cancer. Genome-wide association studies have been at least partially successful in identifying potential germline polymorphisms and allelic imbalances such as microsatellite instability and loss of heterozygosity associated with prostate cancer susceptibility. Epigenetic mechanisms such as DNA hyper- or hypomethylation and histone modifications are reversible genetic alterations which allow stable inheritance of cellular phenotypes without any changes in the DNA sequence or quantity. Epigenetic modifications can potentially be used for the molecular classification, detection, and risk assessment in prostate cancer. Chemical inhibitors of DNA methyltransferases and histone deacetylases have been used in different clinical trials and hold promise as novel chemotherapeutics to be effective alone or in combination with other therapeutic interventions in prostate cancer.

Knowledge of hereditary prostate cancer among high-risk African American men

PURPOSE/OBJECTIVES

To measure knowledge of hereditary prostate cancer in a group of high-risk African American men.

DESIGN

Cross-sectional, correlational pilot study.

SETTING

Four geographic sites: Detroit, MI; Houston, TX; Chicago, IL; and Columbia, SC.

SAMPLE

79 men enrolled in the African American Hereditary Prostate Cancer Study.

METHODS

Telephone interviews.

MAIN RESEARCH VARIABLES

Knowledge of hereditary prostate cancer.

FINDINGS

Knowledge of hereditary prostate cancer was low.

CONCLUSIONS

The high percentage of incorrect responses on questions that measure genetic testing, prevention, and risk based on a positive family history highlights educational needs.

IMPLICATIONS FOR NURSING

A critical need exists for nurses to educate high-risk African American men about hereditary prostate cancer.

Infrared spectroscopy with multivariate analysis potentially facilitates the segregation of different types of prostate cell

The prostate gland is conventionally divided into zones or regions. This morphology is of clinical significance as prostate cancer (CaP) occurs mainly in the peripheral zone (PZ). We obtained tissue sets consisting of paraffin-embedded blocks of cancer-free transition zone (TZ) and PZ and adjacent CaP from patients (n = 6) who had undergone radical retropubic prostatectomy; a seventh tissue set of snap-frozen PZ and TZ was obtained from a CaP-free gland removed after radical cystoprostatectomy. Paraffin-embedded tissue slices were sectioned (10-mum thick) and mounted on suitable windows to facilitate infrared (IR) spectra acquisition before being dewaxed and air dried; cryosections were dessicated on BaF(2) windows. Spectra were collected employing synchrotron Fourier-transform infrared (FTIR) microspectroscopy in transmission mode or attenuated total reflection-FTIR (ATR) spectroscopy. Epithelial cell and stromal IR spectra were subjected to principal component analysis to determine whether wavenumber-absorbance relationships expressed as single points in "hyperspace" might on the basis of multivariate distance reveal biophysical differences between cells in situ in different tissue regions. After spectroscopic analysis, plotted clusters and their loadings curves highlighted marked variation in the spectral region containing DNA/RNA bands ( approximately 1490-1000 cm(-1)). By interrogating the intrinsic dimensionality of IR spectra in this small cohort sample, we found that TZ epithelial cells appeared to align more closely with those of CaP while exhibiting marked structural differences compared to PZ epithelium. IR spectra of PZ stroma also suggested that these cells are structurally more different to CaP than those located in the TZ. Because the PZ exhibits a higher occurrence of CaP, other factors (e.g., hormone exposure) may modulate the growth kinetics of initiated epithelial cells in this region. The results of this pilot study surprisingly indicate that TZ epithelial cells are more likely to exhibit what may be a susceptibility-to-adenocarcinoma spectral signature. Thus, IR spectroscopy on its own may not be sufficient to identify premalignant prostate epithelial cells most likely to progress to CaP.

Cancer de la prostate. Épidémiologie. Facteurs de risques. Anatomopathologie

Prostate cancer (prostate adenocarcinoma) has become an important concern in terms of public health these past fifteen years; recent French epidemiological data revealed 10,104 deaths due to this disease in 2000. The two main factors involved are the serum prostatic specific antigen (PSA), routinely used since late 1980's and which allows early diagnosis (before symptom onset), and the lengthened duration of life. Such cancer is rare before the age of 50, but its frequency increases with age, making it the most frequent type of cancer in French men. Although the aetiology of this disease is unknown, the ethnic origin, and a familial history of prostate or breast cancer are known risk factors. Predisposing genes to such hereditary types remain to be identified. Other genetic factors (polymorphisms), combined with environmental factors such as nutrition, have been incriminated, which is likely to explain the geographical variations of this affection. At the molecular level, the mechanisms involved in the tumoral initiation and progression remain unclear. Various genetic alterations have been identified among the genome of cancerous cells, at various stages of the affection: intraepithelial neoplasia, localized, locally advanced, metastatic or hormone refractory stage -, hormonal escape). However, the precise sequence and nature of the complex molecular events remain to be determined prior to their routine utilisation in the determination of subjects at risk, or as prognostic factors, and even as therapeutic targets. The anatomopathology is a key for the diagnosis. Intraepithelial neoplasia is the pre-cancerous lesion observed in most adenocarcinomas; these are localized in the peripheral part of the prostate gland in 70% of the cases. Gleason's classification is the current gold standard for the determination of tumoral aggressiveness and categorisation of the adenocarcinomas which are basically heterogeneous (coexistence of tumors cells with different degrees of differenciation in the same tumor). This anatomopathological classification allows distinguishing the tumours in terms of potential progressiveness and prognosis, and hence, to orientate the therapeutic strategy in case of localised or locally advanced prostate cancer.

Facteurs de risque génétiques pour le cancer de la prostate

Prostate cancer is the most frequent malignant tumor among men over 50 years old. Its incidence varies according to countries and ethnic group. Known risk factors are race and positive family history of the disease. Familial aggregation (at least 2 cases in the family) is observed in about 20% of cases and an hereditary form of prostate cancer in 5%. This proportion increases with younger age at diagnosis. Six putative loci are already identified but undoubtedly, others will be found in forthcoming studies. The genetic heterogeneity observed in hereditary prostate cancer reflects variety of origins of the studied families. In some families, aggregation of prostate cancer and other cancers suggests the involvement of common predisposing genes. In other familial and in sporadic cases, the genetic component should be polygenic: prostate cancer wouldn't result to segregation of a major gene mutations transmitted according to a monogenic inheritance, but rather to sharing of alleles at many loci, each contributing to a small increase in cancer risk. Indeed, several genetic polymorphism were associated with an increased risk of developing prostate cancer and could explain the variations of prostate cancer incidence observed between populations.

Germline Mutation Analysis of the Androgen Receptor Gene in Finnish Patients With Prostate Cancer

PURPOSE

Steroid hormones, particularly androgens, are suspected to have a major role in prostate carcinogenesis. Since androgen receptor mediates androgenic effects on cells and recent studies suggest that the androgen receptor gene is a putative prostate cancer susceptibility locus, we screened the coding region of the androgen receptor gene for germline mutations using the genomic DNA of patients with prostate cancer.

MATERIALS AND METHODS

DNA samples from 38 patients with early onset prostate cancer and 36 from Finnish prostate cancer families showing no male-to-male transmission of prostate cancer were analyzed for mutations in the androgen receptor gene using single strand conformation polymorphism analysis and subsequent sequencing.

RESULTS

R726L substitution in the hormone binding region of androgen receptor was found in 1 prostate cancer family but no previously uncharacterized germline mutations were detected.

CONCLUSIONS

Our results indicate that constitutional androgen receptor mutations explain only a small fraction of familial and early onset prostate cancer cases in Finland.

Oligogenic segregation analysis of hereditary prostate cancer pedigrees: evidence for multiple loci affecting age at onset

Previous studies have suggested strong evidence for a hereditary component to prostate cancer (PC) susceptibility. Here, we analyze 3,796 individuals in 263 PC families recruited as part of the ongoing Prostate Cancer Genetic Research Study (PROGRESS). We use Markov chain Monte Carlo (MCMC) oligogenic segregation analysis to estimate the number of quantitative trait loci (QTLs) and their contribution to the variance in age at onset of hereditary PC (HPC). We estimate 2 covariate effects: diagnosis of PC before and after prostate-specific antigen (PSA) test availability, and presence/absence of at least 1 blood relative with primary neuroepithelial brain cancer (BC). We find evidence that 2 to 3 QTLs contribute to the variance in age at onset of HPC. The 2 QTLs with the largest contribution to the total variance are both effectively dominant loci. We find that the covariate for diagnosis before and after PSA test availability is important. Our findings for the number of QTLs contributing to HPC and the variance contribution of these QTLs will be instructive in mapping and identifying these genes.

Molecular markers and determinants of prostate cancer metastasis

Although intensely studied, the molecular and biochemical determinants of prostate cancer development and progression remain ill-defined. Moreover, current markers and methodologies cannot distinguish between a tumor that will remain indolent and not impinge on patient survival, versus a tumor with aggressive traits culminating in metastatic spread and death. Once prostate cancer is confirmed the most significant threat to a patient's survival and quality of life involves tumor metastasis. Radical surgery notwithstanding, prostate cancer accounts for 10% of all cancer-related deaths primarily arising through development of metastasis. Metastasis markers demonstrating an acceptable level of reliability are an obvious necessity if disproportionate and costly treatment is to be avoided and a reasonably accurate determination of clinical prognosis and measure of successful response to treatment is to be made. Therapeutic strategies that specifically inhibit metastatic spread are not presently possible and may not become available in the immediate future. This is because, while localized tumorigenesis has been relatively amenable to detection, analysis and treatment, metastasis remains a relatively undefined, complex and underexplored area of prostate cancer research. New findings in the field such subclasses of genes called metastasis suppressors and cancer progression suppressors, have opened up exciting avenues of investigation. We review current methodological approaches, model experimental systems and genes presently known or having potential involvement in human prostate cancer metastasis.