Age specific and attributable risks of familial prostate carcinoma from the family-cancer database

Identification of key genes participating in copper-diethyldithiocarbamate-related cell death process and predicting the development of prostate cancer

Copper (Cu) is used as a cofactor in all organisms, and yet it can be toxic at high intracellular concentrations, causing cell death. Diethyldithiocarbamate (DDC) is a Cu ionophore that can transport Cu effectively into the cell. Copper-diethyldithiocarbamate (Cu-DDC) can treat prostate cancer (PCa) and may correlate with the cell death process. However, the specific Cu-DDC-related cell death genes in PCa are still unknown. Information about the Cu-DDC-related cell death genes was obtained from a previous study. Concurrently, the RNA expression profiles and clinical data were downloaded from public databases such as GEO, TCGA, and CPGEA. Using data from TCGA database, the logistic and lasso regression models were generated using R software. The influence of these genes in affecting PCa progression and prognosis was analyzed. Finally, the expression of these genes was verified in clinical samples. We found five Cu-DDC-related cell death genes associated with the occurrence of PCa from GSE35988, a gene dataset, namely, CDKN2A, PRC1, CDK1, SOX2, and ZNF365. CDKN2A, PRC1, and CDK1 are known to influence PCa patients' disease-free survival (DFS) status and were overexpressed, whereas SOX2 and ZNF365 were under-expressed in PCa in the different databases. Some of these genes can affect PCa progression. Consistent with the database results, the mRNA and protein expression of CDKN2A, PRC1, and CDK1 was also higher in clinical samples. In conclusion, we identified five hub genes which are important for Cu-DDC-related cell death process that can predict the development of PCa.

Genetics of prostate cancer and its utility in treatment and screening

Prostate cancer heritability is attributed to a combination of rare, moderate to highly penetrant genetic variants as well as commonly occurring variants conferring modest risks [single nucleotide polymorphisms (SNPs)]. Some of the former type of variants (e.g., BRCA2 mutations) predispose particularly to aggressive prostate cancer and confer poorer prognoses compared to men who do not carry mutations. Molecularly targeted treatments such as PARP inhibitors have improved outcomes in men carrying somatic and/or germline DNA repair gene mutations. Ongoing clinical trials are exploring other molecular targeted approaches based on prostate cancer somatic alterations. Genome wide association studies have identified >250 loci that associate with prostate cancer risk. Multi-ancestry analyses have identified shared as well as population specific risk SNPs. Prostate cancer risk SNPs can be used to estimate a polygenic risk score (PRS) to determine an individual's genetic risk of prostate cancer. The odds ratio of prostate cancer development in men whose PRS lies in the top 1% of the risk profile ranges from 9 to 11. Ongoing studies are investigating the utility of a prostate cancer PRS to target population screening to those at highest risk. With the advent of personalized medicine and development of DNA sequencing technologies, access to clinical genetic testing is increasing, and oncology guidelines from bodies such as NCCN and ESMO have been updated to provide criteria for germline testing of "at risk" healthy men as well as those with prostate cancer. Both germline and somatic prostate cancer research have significantly evolved in the past decade and will lead to further development of precision medicine approaches to prostate cancer treatment as well as potentially developing precision population screening models.

Recent Insights on Genetic Testing in Primary Prostate Cancer

Prostate cancer (PCa) is one of the most common cancers in developed countries. The results of large trials indicate that the proportion of PCa attributable to hereditary factors is as high as 15%, highlighting the importance of genetic testing. Despite improved understanding of the prevalence of pathogenic variants among men with PCa, it remains unclear which men will most benefit from genetic testing. In this review, we summarize recent evidence on genetic testing in primary PCa and its impact on routine clinical practice. We outline current guideline recommendations on genetic testing, most importantly, for mutations in BRCA1/2, MMR, CHEK2, PALB2, and HOXB13 genes, as well as various single nucleotide polymorphisms associated with an increased risk of developing PCa. The implementation of genetic testing in clinical practice, especially in young patients with aggressive tumors or those with positive family history, represents a new challenge for the coming years and will identify men with pathogenic variants who may benefit from early screening/intervention and specific therapeutic options.

Risk of prostate cancer in relatives of prostate cancer patients in Sweden: A nationwide cohort study

BACKGROUND

Evidence-based guidance for starting ages of screening for first-degree relatives (FDRs) of patients with prostate cancer (PCa) to prevent stage III/IV or fatal PCa is lacking in current PCa screening guidelines. We aimed to provide evidence for risk-adapted starting age of screening for relatives of patients with PCa.

METHODS AND FINDINGS

In this register-based nationwide cohort study, all men (aged 0 to 96 years at baseline) residing in Sweden who were born after 1931 along with their fathers were included. During the follow-up (1958 to 2015) of 6,343,727 men, 88,999 were diagnosed with stage III/IV PCa or died of PCa. The outcomes were defined as the diagnosis of stage III/IV PCa or death due to PCa, stratified by age at diagnosis. Using 10-year cumulative risk curves, we calculated risk-adapted starting ages of screening for men with different constellations of family history of PCa. The 10-year cumulative risk of stage III/IV or fatal PCa in men at age 50 in the general population (a common recommended starting age of screening) was 0.2%. Men with ≥2 FDRs diagnosed with PCa reached this screening level at age 41 (95% confidence interval (CI): 39 to 44), i.e., 9 years earlier, when the youngest one was diagnosed before age 60; at age 43 (41 to 47), i.e., 7 years earlier, when ≥2 FDRs were diagnosed after age 59, which was similar to that of men with 1 FDR diagnosed before age 60 (41 to 45); and at age 45 (44 to 46), when 1 FDR was diagnosed at age 60 to 69 and 47 (46 to 47), when 1 FDR was diagnosed after age 69. We also calculated risk-adapted starting ages for other benchmark screening ages, such as 45, 55, and 60 years, and compared our findings with those in the guidelines. Study limitations include the lack of genetic data, information on lifestyle, and external validation.

CONCLUSIONS

Our study provides practical information for risk-tailored starting ages of PCa screening based on nationwide cancer data with valid genealogical information. Our clinically relevant findings could be used for evidence-based personalized PCa screening guidance and supplement current PCa screening guidelines for relatives of patients with PCa.

Epidemiology and genomics of prostate cancer in Asian men

Prostate cancer is a global health problem, but incidence varies considerably across different continents. Asia is traditionally considered a low-incidence area, but the incidence and mortality of prostate cancer have rapidly increased across the continent. Substantial differences in epidemiological features have been observed among different Asian regions, and incidence, as well as mortality-to-incidence ratio, is associated with the human development index. Prostate cancer mortality decreased in Japan and Israel from 2007 to 2016, but mortality has increased in Thailand, Kyrgyzstan and Uzbekistan over the same period. Genomic analyses have shown a low prevalence of ERG oncoprotein in the East Asian population, alongside a low rate of PTEN loss, high CHD1 enrichments and high FOXA1 alterations. Contributions from single-nucleotide polymorphisms to prostate cancer risk vary with ethnicity, but germline mutation rates of DNA damage repair genes in metastatic prostate cancer are comparable in Chinese and white patients from the USA and UK. Pharmacogenomic features of testosterone metabolism might contribute to disparities seen in the response to androgen deprivation between East Asian men and white American and European men. Overall, considerable diversity in epidemiology and genomics of prostate cancer across Asia defines disease characteristics in these populations, but studies in this area are under-represented in the literature. Taking into account this intracontinental and intercontinental heterogeneity, translational studies are required in order to develop ethnicity-specific treatment strategies.

The association between family history of prostate cancer and development of prostate cancer among Korean population: A prospective cohort study using KoGES data

This study aimed to assess the impact of family history (FH) on prostate cancer (PCa) development among a general Korean population. We conducted a prospective cohort study based on the registry records of 211,789 participants in the database of the Korean Genome and Epidemiology Study from 2001 to 2013. A total of 69,693 men with appropriate records were evaluated by being categorizing into 2 groups; a PCa group (100) and control group (69,593). FH of PCa was also categorized as FH of total, father, or brother. Odds ratios (ORs) of PCa development were calculated by using stratified logistic regression models. The adjusted OR of PCa history of father was 27.7 (95% confidence interval [CI] = 9.7-79.2, P < .001) in PCa patients compared to control, and that of PCa history of brother was 15.8 (95% CI = 3.6-69.6, P < .001). Among the adjusted variables, age (OR, 1.17; 95% CI, 1.14-1.21; P < .001), and hyperlipidemia (OR, 2.25; CI, 1.32-3.84; P = .003) were also identified as significant predictors of PCa development. There was no difference in the impact of FH on PCa development between different age groups at PCa diagnosis (<60 vs ≥60 years). To our knowledge, this study represents the first prospective cohort study based on the registry data of a Korean population showing the significance of FH on PCa development. Additionally, the effect of FH on the early onset of PCa has not been confirmed in our analysis.

Risk of invasive prostate cancer and prostate cancer death in relatives of patients with prostatic borderline or in situ neoplasia: A nationwide cohort study

BACKGROUND

The question of whether having a family history of prostatic borderline or in situ neoplasia (PBISN) is associated with an increased risk of invasive prostate cancer (PCa) or death from PCa remains unanswered. The objective of the current study was to provide an evidence-based risk estimation for the relatives of patients with PBISN.

METHODS

Nationwide Swedish family cancer data sets were used for the current study, including data regarding all residents of Sweden who were born after 1931 and their parents. Standardized incidence ratios (SIRs), standardized mortality ratios (SMRs), and lifetime cumulative risks of PCa were calculated for men with different constellations of family history. Family history was defined as a dynamic (time-dependent) variable considering changes during follow-up (1958-2015).

RESULTS

Of the 6,343,727 men in the current study, a total of 238,961 developed invasive PCa and 5756 were diagnosed with PBISN during the follow-up. Men with 1 first-degree relative who was diagnosed with PBISN had a 70% increased risk of invasive PCa (SIR, 1.7; 95% confidence interval, 1.5-1.9) and PCa death (SMR, 1.7; 95% confidence interval, 1.3-2.2) compared with men with no family history of PBISN or invasive PCa. These were rather close to estimates in men with 1 first-degree relative diagnosed with invasive PCa (SIR, 2.1 and SMR, 1.8). A higher risk of PCa in family members was found among patients with a family history of PBISN and/or PCa diagnosed before age 60 years. The results in terms of cumulative risk resembled this trend.

CONCLUSIONS

A family history of PBISN appears to be as important as a family history of invasive PCa with regard to an increased risk of invasive PCa or PCa mortality. Such a history should not be overlooked in PCa screening recommendations or in future research regarding familial PCa.

Hereditary prostate cancer - Primetime for genetic testing?

Prostate cancer (PCa) remains the most common cancer in men. The proportion of all PCa attributable to high-risk hereditary factors has been estimated to 5-15%. Recent landmark discoveries in PCa genetics led to the identification of germline mutations/alterations (eg. BRCA1, BRCA2, ATM or HOXB13), single nucleotide polymorphisms or copy number variations associated with PCa incidence and progression. However, offering germline testing to men with an assumed hereditary component is currently controversial. In the present review article, we provide an overview about the epidemiology and the genetic basis of PCa predisposition and critically discuss the significance and consequence in the clinical routine. In addition, we give an overview about genetic tests and report latest findings from ongoing clinical studies. Lastly, we discuss the impact of genetic testing in personalized therapy in advanced stages of the disease.

Family history is significantly associated with prostate cancer and its early onset in Chinese population

BACKGROUND

Family history (FH) of prostate cancer (PCa) in Chinese population is poorly understood. The objective of this study is to evaluate the association between FH and PCa in a Chinese biopsy cohort.

METHODS

Consecutive patients who received 10 to 12 core systematic prostate biopsies from April 2013 to October 2018 in three medical centers were enrolled in this study. Demographic information and clinical information were obtained through prebiopsy questionnaire, including cancer FH, age, and total prostate-specific antigen (tPSA).

RESULTS

Of 2321 patients, 83 (3.6%) were reported a FH of PCa. The positive biopsy rate in these patients was 54.2%, significantly higher than the patients without the family history of PCa (42.6%; relative risk [RR] = 1.27; P =  .024). In patients with positive FH of breast cancer gene (BRCA)-related cancers (breast, ovarian, and prostate cancer, n = 154), 74 (48.1%) were diagnosed as PCa, higher than those without FH (42.7%; RR = 1.13; P =  .112). Multivariate logistic regression analysis (after adjusting for age and tPSA values) showed that there was 2.1-fold increased risk of PCa in patients with positive FH of PCa (P =  .005), and 1.6-fold increased risk in patients with positive FH of BRCA-related cancers (P =  .019). However, there was no significant association between FH of PCa or BRCA-related cancer and high-grade PCa after adjusting age and tPSA level (P =  .404 for PCa, P =  0.991 for BRCA-related cancers).

CONCLUSIONS

Patients with positive FH of PCa had 2.1-fold higher risk of PCa, and patients with positive FH of BRCA-related cancers had 1.6-fold higher risk in this biopsy cohort of Chinese population. Patients with positive FH of PCa or BRCA-related cancers would have earlier age at onset of PCa.

Men with a susceptibility to prostate cancer and the role of genetic based screening

Prostate cancer is the second most common malignancy affecting men worldwide, and the commonest affecting men of African descent. Significant diagnostic and therapeutic advances have been made in the past decade. Improvements in the accuracy of prostate cancer diagnosis include the uptake of multi-parametric MRI and a shift towards targeted biopsy. We also now have more life-prolonging systemic and hormonal therapies for men with advanced disease at our disposal than ever before. However, the development of robust screening tools and targeted screening programs has not followed at the same pace. Evidence to support population-based screening remains unclear, with the use of PSA as a screening test limiting our ability to discriminate between clinically significant and insignificant disease. Prostate cancer has a large heritable component. Given that most men without risk factors have a low lifetime risk of developing lethal prostate cancer, much work is being done to further our knowledge of how we can best screen men in higher risk categories, such as those with a family history (FH) of the disease or those of African ancestry. These men have been reported to carry upwards of a two-fold increased risk of developing the disease at an earlier age, with evidence suggesting poorer survival outcomes. In men with a FH of prostate cancer, this is felt to be due to rare, high-penetrance mutations and the presence of multiple, common low penetrance alleles, with men carrying specific germline mutations in the BRCA and other DNA repair genes at particularly high risk. To date, large scale genome-wide association studies (GWAS) have led to the discovery of approximately 170 single nucleotide polymorphisms (SNPs) associated with prostate cancer risk, allowing over 30% of prostate cancer risk to be explained. Genomic tests, utilising somatic (prostate biopsy) tissue can also predict the risk of unfavourable pathology, biochemical recurrence and the likelihood of metastatic disease using gene expression. Targeted screening studies are currently under way in men with DNA repair mutations, men with a FH and those of Afro-Caribbean ethnicity which will greater inform our understanding of disease incidence and behaviour in these men, treatment outcomes and developing the most appropriate screening regime for such men. Incorporating a patient's genetic mutation status into risk algorithms allows us an opportunity to develop targeted screening programs for men in whom early cancer detection and treatment will positively influence survival, and in the process offer male family members of affected men the chance to be counselled and screened accordingly.

Men under the age of 55 years with screen detected prostate cancer do not have less significant disease compared to older men in a population of patients in Australia

Background

The American Urological Association (AUA) changed their Prostate-Specific Antigen (PSA) screening guidelines in 2013 to not recommend testing in men under 55 years of age without significant risk factors (such as a family history of prostate cancer or African ethnicity). The AUA argues that the rates of 'insignificant' prostate cancer (PC) in men under 55 are so high that the potential harms of PSA-testing in this population (over diagnosis and overtreatment) outweigh the benefits (early detection and treatment). Our study aims to identify and compare the rates of insignificant and high-risk PC in men diagnosed with PC ≤55 years and >55 years in two centres in Sydney, Australia.

Methods

Men with an abnormal screening PSA or DRE and diagnosed with PC by prostate biopsy were included in this study. A consecutive series of men were accrued from two major urology centres between the years 2006 and 2014. The analysis was divided into two parts, the first compared PC biopsy characteristics between men aged ≤55 years and those >55 years. The second analysis compared the prostatectomy pathological characteristics between the two groups. Differences were analysed by Chi squared and significance set at p < 0.05.

Results

A total of 598 prostate biopsies and 723 prostatectomy matched subjects were included. On prostate biopsies, 14.0 % of men ≤55 years and 11.9 % of men >55 years had insignificant PC (X² = 0.32, df = 1, p = 0.57), whilst 24.7 % of men ≤55 years and 25.1 % of men >55 years had high-risk PC (X² = 0.007, df = 1, p = 0.93). On prostatectomy specimens, 9.1 % of men ≤55 years and 6.5 % of men >55 years had insignificant PC (X² = 1.25, df = 1, p = 0.26), whilst 20.0 % of men ≤55 years and 24.0 % of men >55 years had high-risk PC (X² = 0.83, df = 1, p = 0.36).

Conclusion

We found no significant difference in the rates of insignificant and high-risk PC between men ≤55 years and >55 years, in either the prostate biopsies or prostatectomy specimens. Further trials need to be performed with comparable sample sizes and controlling of risk factors to assess the utility of PSA screening in younger men.

Prevalence of the HOXB13 G84E germline mutation in British men and correlation with prostate cancer risk, tumour characteristics and clinical outcomes

BACKGROUND

A rare recurrent missense variant in HOXB13 (rs138213197/G84E) was recently reported to be associated with hereditary prostate cancer. Population-based studies have established that, since the frequency of this single-nucleotide polymorphism (SNP) varies between geographic regions, the associated proportion of prostate cancer (PrCa) risk contribution is also highly variable by country.

PATIENTS AND METHODS

This is the largest comprehensive case-control study assessing the prevalence of the HOXB13 G84E variant to date and is the first in the UK population. We genotyped 8652 men diagnosed with PrCa within the UK Genetic Prostate Cancer Study (UKGPCS) and 5252 healthy men from the UK ProtecT study.

RESULTS

HOXB13 G84E was identified in 0.5% of the healthy controls and 1.5% of the PrCa cases, and it was associated with a 2.93-fold increased risk of PrCa [95% confidence interval (CI) 1.94-4.59; P = 6.27 × 10(-8)]. The risk was even higher among men with family history of PrCa [odds ratio (OR) = 4.53, 95% CI 2.86-7.34; P = 3.1 × 10(-8)] and in young-onset PrCa (diagnosed up to the age of 55 years; OR = 3.11, 95% CI 1.98-5.00; P = 6.1 × 10(-7)). There was no significant association between Gleason Score, presenting prostate specific antigen, tumour-node-metastasis (TNM) stage or NCCN risk group and carrier status. HOXB13 G84E was not associated with overall or cancer-specific survival. We found that the polygenic PrCa risk score (PR score), calculated using the 71 known single-nucleotide polymorphisms (SNPs) associated with PrCa and the HOXB13 G84E variant act multiplicatively on PrCa risk. Based on the estimated prevalence and risk, this rare variant explains ∼1% of the familial risk of PrCa in the UK population.

CONCLUSIONS

The clinical importance of HOXB13 G84E in PrCa management has not been established. This variant was found to have no effect on prognostic implications but could be used for stratifying screening, by identifying men at high risk.

CLINICAL TRIALS NUMBERS

Prostate Testing for Cancer and Treatment (ProtecT): NCT02044172.

UK GENETIC PROSTATE CANCER STUDY

Epidemiology and Molecular Genetics Studies (UKGPCS): NCT01737242.

Fine-mapping the HOXB region detects common variants tagging a rare coding allele: evidence for synthetic association in prostate cancer

The HOXB13 gene has been implicated in prostate cancer (PrCa) susceptibility. We performed a high resolution fine-mapping analysis to comprehensively evaluate the association between common genetic variation across the HOXB genetic locus at 17q21 and PrCa risk. This involved genotyping 700 SNPs using a custom Illumina iSelect array (iCOGS) followed by imputation of 3195 SNPs in 20,440 PrCa cases and 21,469 controls in The PRACTICAL consortium. We identified a cluster of highly correlated common variants situated within or closely upstream of HOXB13 that were significantly associated with PrCa risk, described by rs117576373 (OR 1.30, P = 2.62×10(-14)). Additional genotyping, conditional regression and haplotype analyses indicated that the newly identified common variants tag a rare, partially correlated coding variant in the HOXB13 gene (G84E, rs138213197), which has been identified recently as a moderate penetrance PrCa susceptibility allele. The potential for GWAS associations detected through common SNPs to be driven by rare causal variants with higher relative risks has long been proposed; however, to our knowledge this is the first experimental evidence for this phenomenon of synthetic association contributing to cancer susceptibility.

Family history of prostate cancer in a black population

Although family history of prostate cancer (PC) is an established risk factor for the disease, few studies have investigated this relationship among men with an African heritage. The Prostate Cancer in a Black Population (PCBP) study is a large, nationwide case-control study conducted in Barbados, West Indies from 2002 to 2011. In the PCBP study, a family history of PC in fathers or brothers was associated with a threefold increased risk of disease (OR = 3.04, 95 % CI (2.18, 4.22)) and a strong positive relationship was noted for the number of affected first degree relatives. Tumor grade did not generally influence the relationship between family history and PC. The magnitude of risks associated with having a father affected with the disease was slightly higher in the PCBP study compared to other populations. It remains unclear whether this finding is the result of an increased genetic susceptibility in African-Barbadian men.

Association between family history of prostate cancer and positive biopsies in a Brazilian screening program

PURPOSE

To test the association between family history of prostate cancer (FH) and prostate cancer (PCa) risk in a large screening program in Brazil, as no conclusive study has yet investigated this.

METHODS

Between 2004 and 2007, 17,569 men were screened in 231 small municipalities using mobile screening units. Positive FH was defined as any relative having PCa among screened men. Men were biopsied if they had digital rectal examination suggestive of PCa or PSA >4.0 ng/mL or PSA of 2.5-4 ng/mL with percent free PSA ≤ 15 %. We analyzed the association between FH and PCa using multivariable logistic regression in the first screening round of the program.

RESULTS

Positive FH was present in 735 men (4.2 % of total), and they were younger, better educated and more likely to have had previous PCa screening (41.5 vs. 28.5 %; P < 0.001) compared to men with negative FH. FH status did not affect compliance rates in men recommended to undergo biopsy (P = 0.94). In first round, PCa was detected in 3.1 % of screened men (n = 552). In multivariable analysis, positive FH was associated with increased PCa risk (OR = 1.79; 95 % CI, 1.21-2.65; P = 0.003). However, Gleason scores (P = 0.78) or percent of positive cores (P = 0.32) among men with positive biopsies were similar, regardless of FH status.

CONCLUSIONS

In Brazil, men with positive FH were at increased PCa risk, which could not be explained by differential biopsy rates. This finding suggests that FH is also a true PCa risk factor in Brazil, a country with highly diverse population in terms of race, ethnicity, culture and socioeconomic status.

Prostate cancer risk in men with prostate and breast cancer family history: results from the REDUCE study (R1)

BACKGROUND

To what degree the associations between PCa risk and family history of prostate cancer (PCa) and/or breast cancer (BCa) are attributable to screening biases is unclear. We examined these questions within the REDUCE study, where biopsies were largely independent of prostate specific antigen (PSA) minimizing screening biases.

METHODS

Data were from REDUCE, which tested dutasteride 0.5 mg daily for PCa risk reduction in men with PSA 2.5-10.0 ng mL(-1) and a negative prestudy biopsy. Among men undergoing at least one on-study biopsy with complete data (n = 6415; 78.1%), the association between family history and PCa risk was tested using multivariate logistic regression adjusting for clinicodemographic characteristics.

RESULTS

A family history of PCa alone was associated with increased PCa diagnosis (OR: 1.47, 95%CI: 1.22-1.77). In North America, PCa family history was not related to PCa diagnosis (OR: 1.02, 95%CI: 0.73-1.44), whereas outside North America, PCa family history was significantly related to diagnosis (OR: 1.72, 95%CI: 1.38-2.15) (P-interaction = 0.01). A family history of both PCa and BCa (OR: 2.54, 95%CI: 1.72-3.75) but not BCa alone (OR: 1.04, 95%CI: 0.84-1.29) was associated with increased PCa risk versus no family history and irrespective of geographical region.

CONCLUSIONS

In REDUCE, PCa family history was significantly related to PCa diagnosis, although only for men outside North America. The presence of both PCa and BCa family history significantly increased risk versus PCa family history alone, irrespective of geographical region. Ultimately, our observations may support the need for changes in how we address family history in terms of both risk of PCa diagnosis and general risk stratification.

The genetics of cancer risk

One hundred years ago, decades before the discovery of the structure of DNA, debate raged regarding how human traits were passed from one generation to the next. Phenotypes, including risk of disease, had long been recognized as having a familial component. Yet it was difficult to reconcile genetic segregation as described by Mendel with observations exhaustively documented by Karl Pearson and others regarding the normal distribution of human characteristics. In 1918, R. A. Fisher published his landmark article, "The Correlation Between Relatives on the Supposition of Mendelian Inheritance," bridging this divide and demonstrating that multiple alleles, all individually obeying Mendel's laws, account for the phenotypic variation observed in nature.Since that time, geneticists have sought to identify the link between genotype and phenotype. Trait-associated alleles vary in their frequency and degree of penetrance. Some minor alleles may approach a frequency of 50% in the human population, whereas others are present within only a few individuals. The spectrum for penetrance is similarly wide. These characteristics jointly determine the segregation pattern of a given trait, which, in turn, determine the method used to map the trait. Until recently, identification of rare, highly penetrant alleles was most practical. Revolutionary studies in genomics reported over the past decade have made interrogation of most of the spectrum of genetic variation feasible.The following article reviews recent discoveries in the genetic basis of inherited cancer risk and how these discoveries inform cancer biology and patient management. Although this article focuses on prostate cancer, the principles are generic for any cancer and, indeed, for any trait.

Genetics of prostate cancer risk

For decades, physicians and researchers have recognized that family history is a significant risk factor for prostate cancer. The identification of the genes responsible for inherited risk, however, proved difficult. With the sequencing of the human genome and the completion of the initial phases of the International HapMap Project, the tools are available to scan the entire genome and find genetic markers for disease. Since 2006, more than 30 inherited variants strongly associated with prostate cancer have been reported. As the inherited component of the disease is revealed, efforts are ongoing to translate genetic findings into the clinic.

Individual cancer risk as a function of current age and risk profile

Behavioural changes are an important partner in the fight against cancer (primary prevention or the choice to participate in secondary prevention). To make such behavioural changes, people need to have a correct assessment of their own risk, which is often underestimated or overestimated. These risk estimates depend, among others, on the calculation method that is used. Currently, the method that is used most often is 'indirect cumulative risk' (ICR). We discuss several drawbacks of using ICR in individual counselling and therefore use an alternative method. In this alternative (life table method) we calculated 10-year risks for a whole range of cancers as a function of the current age and risk profile, while taking into account other causes of death. These estimates can easily be used to give an individualized assessment of the risk of cancer. Regardless of the risk estimation method used, the risk needs to be broken down for 'risk factors'. If only the risk for an average person of the population is given, this means a small overestimation for the non-risk group, but a significant underestimation for the at-risk group. When we compare the life table risk as a function of risk factors to the more commonly used ICR, large differences are found, especially in prostate, breast and lung carcinomas. The life table method, although it has certain limitations, has advantages over the ICR method for individual counselling. To our knowledge this is the first overview in which 10-year risks as a function of the current risk profile are given for multiple cancers. The calculated risks are primarily intended to better inform people who are considering preventive measures. For example, for a 40-year-old woman without familial risk who is considering the pros and cons of breast cancer mammographic screening, it is more interesting to know that she has a 0.7% chance of getting breast cancer in the next 5 years, rather than being told that 11% of women get breast cancer during their lives (ICR 0-74). Current smokers can now be given absolute risk reduction estimates of smoking cessation. To keep the life table risk estimates up to date, they must be repeated every couple of years, using up-to-date incidence and mortality data.

The evolving role of familial history for prostate cancer

BACKGROUND

family history of prostate cancer is a risk factor for prostate cancer occurrence. Differently from other neoplasms no major predisposing gene has been identified.

MATERIAL AND METHODS

this review article presents the controversial results of studies about the prognostic and predictive role of family history in prostate cancer, reports the discovered predisposing genes, and biologic and pathologic findings.

RESULTS

mortality from PC remains a significant health care problem, but no trial investigated if it changed in presence of positive family history. The largest family study yet published concluded that men with family history are diagnosed and die at earlier ages than men without it. However, it failed to stress the prognostic value of family history. Genome-wide association studies of prostate cancer have identified a number of genetic variants at different loci in different populations. Prostate neoplasms of patients with positive family history exhibit a different pattern of expression of genes related with estrogen and androgen metabolism within the tumor. High-penetrance and low-penetrance genes in diagnosis and prognosis of prostate cancer, difficulties to define a classification and to quantify relative risks of single genes, documented gene-environment interactions are discussed.

CONCLUSION

family history stands for both shared genetic and environmental factors and their interaction. The availability of prostate-specific antigen test could explain partly the high familial risk, among brothers or shortly after the diagnosis of prostate cancer. Polymorphisms in genes associated with prostate cancer probably represent the most part of familial prostate cancer burden. An increasing knowledge of disregulated cellular pathways of lethal prostate cancer could define which of all genetic alterations have a role in defining new preventive and therapeutic strategies.

Prostate cancer segregation analyses using 4390 families from UK and Australian population-based studies

Familial aggregation of prostate cancer is likely to be due to multiple susceptibility loci, perhaps acting in conjunction with shared lifestyle risk factors. Models that assume a single mode of inheritance may be unrealistic. We analyzed genetic models of susceptibility to prostate cancer using segregation analysis of occurrence in families ascertained through population-based series totaling 4390 incident cases. We investigated major gene models (dominant, recessive, general, X-linked), polygenic models, and mixed models of susceptibility using the pedigree analysis software MENDEL. The hypergeometric model was used to approximate polygenic inheritance. The best-fitting model for the familial aggregation of prostate cancer was the mixed recessive model. The frequency of the susceptibility allele in the population was estimated to be 0.15 (95% confidence interval (CI) 0.11-0.20), with a relative risk for homozygote carriers of 94 (95% CI 46-192), and a polygenic standard deviation of 2.01 (95% CI 1.72-2.34). These analyses suggest that one or more genes having a strong recessively inherited effect on risk, as well as a number of genes with variants having small multiplicative effects on risk, may account for the genetic susceptibility to prostate cancer. The recessive component would predict the observed higher familial risk for siblings of cases than for fathers, but this could also be due to other factors such as shared lifestyle by siblings, targeted screening effects, and/or non-additive effects of one or more genes.

Age-specific risk of incident prostate cancer and risk of death from prostate cancer defined by the number of affected family members

BACKGROUND

The thorough assessment of familial prostate cancer (PCa) risk is as important as ever to provide a basis for clinical counselling and screening recommendations.

OBJECTIVE

Our aim was to determine the age-specific risks of PCa and the risk of death from PCa according to the number and the age of affected first-degree relatives.

DESIGN, SETTING, AND PARTICIPANTS

The nationwide Swedish Family-Cancer Database includes a record of >11.8 million individuals and their cancers from 1958 to 2006. All men from the database with identified parents (>3.9 million individuals) were followed between 1961 and 2006. The study included 26 651 PCa patients, of whom 5623 were familial.

MEASUREMENTS

The age-specific hazard ratios (HRs) of PCa and the HRs of death from PCa were calculated according to the number and age of affected fathers and brothers.

RESULTS AND LIMITATIONS

The HRs of PCa diagnosis increased with the number of affected relatives and decreased with increasing age. The highest HRs were observed for men <65 yr of age with three affected brothers (HR: approximately 23) and the lowest for men between 65 and 74 yr of age with an affected father (HR: approximately 1.8). The HRs increased with decreasing paternal or fraternal diagnostic age. The pattern of the risk of death from familial PCa was similar to the incidence data.

CONCLUSIONS

The present results should guide clinical counselling and demonstrate the vast increases in risk when multiple first-degree relatives are affected.

Mutation analysis of the MSMB gene in familial prostate cancer

Background:

MSMB, a gene coding for β-microseminoprotein, has been identified as a candidate susceptibility gene for prostate cancer (PrCa) in two genome-wide association studies (GWAS). SNP rs10993994 is 2 bp upstream of the transcription initiation site of MSMB and was identified as an associated PrCa risk variant. The MSMB protein is underexpressed in PrCa and it was previously proposed to be an independent marker for the recurrence of cancer after radical prostatectomy.

Methods:

In this study, the coding region of this gene and 1500 bp upstream of the 5′UTR has been sequenced in germline DNA in 192 PrCa patients with family history. To evaluate the possible effects of these variants we used in silico analysis.

Results:

No deleterious mutations were identified, however, nine new sequence variants were found, most of these in the promoter and 5′UTR region. In silico analysis suggests that four of these SNPs are likely to have some effect on gene expression either by affecting ubiquitous or prostate-specific transcription factor (TF)-binding sites or modifying splicing efficiency.

Interpretation

We conclude that MSMB is unlikely to be a familial PrCa gene and propose that the high-risk alleles of the SNPs in the 5′UTR effect PrCa risk by modifying MSMB gene expression in response to hormones in a tissue-specific manner.

Age at diagnosis and age at death in familial prostate cancer

OBJECTIVES

A family history of prostate cancer is associated with a higher risk for prostate cancer to first-degree relatives. If greater surveillance of men at familial risk is considered to be useful, population-based estimates of the differences in the age at diagnosis between familial and sporadic prostate cancer cases are needed.

METHODS

The men in the nationwide Swedish Family-Cancer Database were classified according to the number and type of affected first-degree relatives (father or brother) and according to the relative's age at diagnosis. The cumulative incidence of prostate cancer and cumulative prostate cancer-specific mortality were estimated using a stratified Cox model.

RESULTS

The cumulative incidence was highest for men with multiple affected first-degree relatives, and it was higher for brothers than for sons of prostate cancer patients. The age to reach the same cumulative incidence as the general population at age 55 years decreased with decreasing age at diagnosis of the relative, ranging from 48.7 years (father diagnosed before 60 years of age) to 53.7 years (father diagnosed after 82 years of age). Prostate cancer-specific mortality was also related to the number and type of affected relatives but there was no clear evidence for a dependency on the age at diagnosis of the relative.

CONCLUSIONS

Men with a father or a brother affected by prostate cancer are diagnosed and die at earlier ages than men without a family history of prostate cancer. This study should encourage further analysis in order to assess the risks and benefits of screening for prostate cancer in men at higher risk.

Risk factors for prostate cancer in men aged less than 60 years: a case-control study from Italy

OBJECTIVES

To analyze the relationship between selected risk factors and prostate cancer risk in men younger than 60 years, using data from a large, multicenter, case-control study conducted in Italy.

METHODS

Cases were 219 patients, aged 45 to 59 years, with histologically confirmed prostate cancer, and controls were 431 men of the same age group, admitted in hospital for acute, non-neoplastic diseases.

RESULTS

A family history of prostate cancer (odds ratio [OR] = 5.5), brain cancer (OR = 3.7), and leukemia (OR = 6.2) were associated with prostate cancer risk. A significantly increased risk was found for high education level (OR = 3.3 for 12 or more years versus less than 7 years) and a decreased risk for physical activity (OR = 0.5 for active versus inactive). Coffee consumption was directly associated with risk of prostate cancer (OR = 1.9 for the third versus the first tertile). Bread consumption was directly related (OR = 1.6) and consumption of raw and total vegetables inversely related (OR = 0.6) to prostate cancer risk, although these associations were of borderline significance. No association emerged with marital status, body mass index, history of diabetes, alcohol drinking, and other considered foods.

CONCLUSIONS

This study confirms that some recognized risk factors, including family history of prostate cancer, high level of education, and low physical activity, are associated with prostate cancer risk in middle-aged men.

Increased cancer risk for individuals with a family history of prostate cancer, colorectal cancer, and melanoma and their associated screening recommendations and practices

Prostate cancer, colorectal cancer, and melanoma are three malignancies that appear to have strong genetic components that can confer additional risk to family members. Screening tools, albeit controversial, are widely available to potentially aide in early diagnosis. Family members are now more attuned to the risks and benefits of cancer screening, thus, it is imperative that physicians understand the screening tools and how to interpret the information they provide. We reviewed the current literature regarding the cancer risks for individuals with a family history of prostate cancer, colon cancer, and melanoma, the current screening recommendations for family members, and actual screening practices of individuals with a family history of these malignancies. This review should serve as a guide for physicians and cancer control planners when advising their patients and the public regarding screening decisions.

Genetic variation of antigen processing machinery components and association with cervical carcinoma

The antigen processing machinery (APM) plays an important role in immune recognition of virally infected and transformed cells. Defective expression of several APM components is associated with progression and clinical outcome in cervical carcinoma. Genetic variation in the genes encoding APM components is known to be associated with risk of occurrence of several malignancies. However, only limited evidence exists supporting the role of single nucleotide polymorphisms (SNPs) in APM components in cervical carcinoma. We have therefore investigated the occurrence of APM component SNP genotypes and haplotypes in cervical carcinoma. Thirteen coding SNPs in the LMP2, LMP7, TAP1, TAP2, and ERAP1 genes were genotyped in 127 cervical carcinoma patients and 124 controls. Individual genotype and allele distributions were assessed by single-marker analysis. Effects of various SNP combinations were estimated by haplotype construction and subsequent haplotype interaction analysis. Significant haplotypes were modeled on disease risk. Allele distributions at the LMP7-145, TAP2-651, ERAP1-127, and ERAP1-730 loci differed significantly between cases and controls with the major allele at the LMP7 and TAP2 loci and the minor allele at both ERAP1 loci associated with increased cervical carcinoma risk. A combination of the two haplotypes spanning these loci was associated with a three-fold increased risk (OR = 3.024; P << 0.001); approximately 12% of all cervical carcinoma occurrences were attributable to this combination. Our data indicate that combined genetic variation in the TAP2, LMP7, and ERAP1 genes is associated with increased cervical carcinoma risk.

Highly elevated PSA and dietary PhIP intake in a prospective clinic-based study among African Americans

African-American men die from prostate cancer (PC) nearly twice as often as white US men and consume about twice as much of the predominant US dietary heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a genotoxic rat-prostate carcinogen found primarily in well-cooked chicken and beef. To investigate the hypothesis that PhIP exposure increases PC risk, an ongoing prospective clinic-based study compared PC screening outcomes with survey-based estimates of dietary PhIP intake among 40-70-year-old African-American men with no prior PC in Oakland, CA. They completed food-frequency and meat-cooking/consumption questionnaires and had a prostate-specific antigen (PSA) test and digital-rectal exam. Results for 392 men indicated a 17 (+/-17) ng/kg day mean (+/-1 s.d.) daily intake of PhIP, about twice that of white US men of similar age. PhIP intake was attributable mostly to chicken (61%) and positively associated (R(2)=0.32, P<0.0001) with saturated fat intake. An odds ratio (95% confidence interval) of 31 (3.1-690) for highly elevated PSA > or =20 ng/ml was observed in the highest 15% vs lowest 50% of estimated daily PhIP intake (> or =30 vs < or =10 ng/kg day) among men 50+ years old (P=0.0002 for trend) and remained significant after adjustment for self-reported family history of (brother or father) PC, saturated fat intake and total energy intake. PSA measures were higher in African-American men with positive family history (P=0.007 all men, P<0.0001 highest PSA quartile). These preliminary results are consistent with a positive association between PhIP intake and highly elevated PSA, supporting the hypothesis that dietary intervention may help reduce PC risk.

Familial and Hereditary Prostate Cancer by Definition in an Italian Surgical Series: Clinical Features and Outcome

OBJECTIVE

To evaluate the clinical impact of different definitions of hereditary prostate cancer (PCa), the relative risk (RR) of relatives of PCa cases and differences in clinical-pathological features and outcome as function of a family history in a surgical series exposed to Mediterranean diet.

METHODS

We classified as Sporadic (SPC), Familial (FPC) or Hereditary (HPC) 606 consecutive PCa cases, 65 years old or less at diagnosis, underwent radical retropubic prostatectomy between January 1, 1987 and December 31, 2002 (mean follow-up: 6.4 years). The disease-free, overall and PCa-specific survival were also compared between SPC and non-SPC (NSPC) cases.

RESULTS

Overall 12.5% of cases had a positive family history. We found 14 (2.3%) HPC cases versus 16 (2.6%) taking account of X-linked transmission. Relatives of early-onset PCa cases had a higher RR to PCa (4.3) compared to late-onset PCa cases. NSPC cases had a lower frequency of positive margins status (p=0.011), perineural infiltration (p=0.028) and positive lymph nodes (p=0.005) than SPC cases, but no differences were found in major prognostic factors (preoperative PSA, Gleason sum, pathological stage) and outcome endpoints as function of a family history.

CONCLUSIONS

A positive family history is an important risk factor to PCa. HPC frequency is probably underestimated because of exclusion of X-linked transmission. We support the similarity between SPC and NSPC with respect to biological aggressiveness.

Clinical genetic counselling for familial cancers requires reliable data on familial cancer risks and general action plans

Familial cancer clustering, without obvious heritability, poses a major challenge for current cancer risk assessment and management. Reliable determination of familial risks for cancer is important for clinical genetic counselling, but medically verified data on familial risks for many malignancies have been limited. However, the nationwide Swedish Family-Cancer Database allows a reliable characterisation of familial risk for all major neoplasms. Even though alert genetic counsellors and certainly clinical cancer geneticists will consider familial cancer clustering in their purview, the standard medical referral systems, which have already been shown to be poor in capturing and referring families at high risk for heritable cancers, are unlikely to ascertain familial aggregations of other cancers that are not known to belong to an inherited cancer syndrome. The data will be helpful in implementing evidence based guidelines for helping the general medical system to ascertain and refer even familial cancer clusters to cancer genetics professionals.

Prostate cancer screening, changing age-specific incidence trends and implications on familial risk

The incidence of prostate cancer has increased markedly during the past half century. We used the data from the Swedish Cancer Registry to follow the incidence trends and age-specific incidence up to 2002. Two different patterns in the age-incidence relationships were noted. The first one, prevailing until about 1995, was characterized by a preferential increase in incidence in men older than 70 years. In the second pattern, the increase extended preferentially to younger age groups, and it coincided with an introduction of opportunistic prostate specific antigen (PSA) screening, which was the probable cause of the large upward shift in the incidence between 1998 and 2000. The possible effects of diagnostic methods on familial risk estimates were tested by comparing age and calendar time differences among brothers who were diagnosed with prostate cancer, retrieved from the Swedish Family-Cancer Database. The 2 distributions were very different according to the Wilcoxon rank test (p < 0.0001). The data suggest that a diagnosis of prostate cancer in 1 brother leads to an early diagnosis in a second brother. The data are probably explained by the healthy brother seeking medical advice upon diagnosis in another brother. This effect is likely to bias familial risk estimates.

Socioeconomic factors in cancer in Sweden

It is well known that certain cancers have shown clustering in socioeconomic groups, but limited data are available on recent results and time trends in such clustering. We determined standardized incidence ratios (SIR) for cancer, adjusted for age, period, region, parity and age at first childbirth among men and women in 6 socioeconomic groups based on the Swedish Family-Cancer Database. Persons had to be identified with the same socioeconomic status in the census of years 1960 and 1970, or of years 1960, 1970 and 1980; the comparison group was all people according to the same censuses. Cancers were followed from years 1970 to 1998 or from 1980 to 1998. Both increased and decreased SIRs were found, and a consistent pattern emerged, although the overall SIRs for cancer did not differ much, the lowest being for farmers (0.85) and the highest for professional men (1.07) and women (1.11). At individual sites, manual workers were at risk of tobacco-, alcohol- and occupation- and human papilloma virus-related cancers and at a decreased risk at most other cancers. Manual workers and farmers showed an excess of stomach cancer; professionals had an excess of melanoma and squamous cell skin cancer. Male and female SIRs correlated highly for manual and blue-collar workers and for professionals. The overall population-attributable fraction for selected sites was 16.7% for men and 10.9% for women and it was highest, over 50%, for lung cancer in both genders.

A systematic review and meta-analysis of familial prostate cancer risk

OBJECTIVE

To identify published studies quantifying familial prostate cancer risks in relatives of prostate cancer cases and, by meta-analysis, obtain more precise estimates of familial risk according to the family history.

METHODS

Thirteen case-control and cohort studies were identified which have reported risks of prostate cancer in relatives of prostate cancer cases. Pooled estimates of risk for various categories of family history were obtained by calculating the weighted average of the log relative risk (RR) estimates from studies.

RESULTS

The pooled RR (95% confidence interval) in first-degree relatives was 2.5 (2.2-2.8). There was evidence that this was highest in relatives of cases diagnosed before age 60 years and that RRs declined with age. The risk for the few men with two affected relatives was increased 3.5-fold (2.6-4.8). RRs to sons of cases appeared to be lower than in brothers; a complete explanation of this observation is uncertain.

CONCLUSION

Men with a family history of prostate cancer have a significantly greater risk of developing prostate cancer than those with no such history. Risks are greatest for relatives of cases diagnosed when young and those with more than one relative affected.