The rate of the founder Jewish mutations in BRCA1 and BRCA2 in prostate cancer patients in Israel

Mutational spectrum of DNA damage and mismatch repair genes in prostate cancer

Over the past few years, a number of studies have revealed that a significant number of men with prostate cancer had genetic defects in the DNA damage repair gene response and mismatch repair genes. Certain of these modifications, notably gene alterations known as homologous recombination (HRR) genes; PALB2, CHEK2 BRCA1, BRCA2, ATM, and genes for DNA mismatch repair (MMR); MLH1, MSH2, MSH6, and PMS2 are connected to a higher risk of prostate cancer and more severe types of the disease. The DNA damage repair (DDR) is essential for constructing and diversifying the antigen receptor genes required for T and B cell development. But this DDR imbalance results in stress on DNA replication and transcription, accumulation of mutations, and even cell death, which compromises tissue homeostasis. Due to these impacts of DDR anomalies, tumor immunity may be impacted, which may encourage the growth of tumors, the release of inflammatory cytokines, and aberrant immune reactions. In a similar vein, people who have altered MMR gene may benefit greatly from immunotherapy. Therefore, for these treatments, mutational genetic testing is indicated. Mismatch repair gene (MMR) defects are also more prevalent than previously thought, especially in patients with metastatic disease, high Gleason scores, and diverse histologies. This review summarizes the current information on the mutation spectrum and clinical significance of DDR mechanisms, such as HRR and MMR abnormalities in prostate cancer, and explains how patient management is evolving as a result of this understanding.

Prevalence of Germline BRCA1/2 Variants in Ashkenazi and Non-Ashkenazi Prostate Cancer Populations: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

International guidelines recommend testing BRCA2 in men with prostate cancer, due to the presence of a strong association with this gene. Some ethnicities present disparities in genetic distribution for the relation with specific founder variants. Ashkenazi Jewish people are, importantly, at high risk of breast cancer for their inherited cluster with germline BRCA1/2 variants. However, in Ashkenazi men with prostate cancer, the prevalence of BRCA1 and/or BRCA2 is not well defined. We assessed the frequency of these variants in Ashkenazi vs. non-Ashkenazi men with prostate cancer. Materials and Methods: In accord with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement, we revised all germline BRCA variants reported in MEDLINE from 1996 to 2021 in Ashkenazi and non-Ashkenazi men with prostate cancer. Results: Thirty-five original studies were selected for the analysis. Among populations from Israel and North America, Ashkenazi Jewish men presented higher prevalence of BRCA1 variants [0.9% (0.4-1.5) vs. 0.5% (0.2-1.1), p = 0.09] and a lower prevalence of BRCA2 variants [1.5% (1.1-2.0) vs. 3.5% (1.7-5.9), p = 0.08] in comparison to the non-Ashkenazi population. Conclusions: Since germline BRCA1 variants are more prevalent and BRCA2 variants are less prevalent in PCa patients of Ashkenazi Jewish ethnicity in comparison to non-Ashkenazi patients, prostate cancer genetic screening in Ashkenazi men should not be restricted to the BRCA2 gene.

Prognostic Role of DNA Damage Response Genes Mutations and their Association With the Sensitivity of Olaparib in Prostate Cancer Patients

Objective

Evidence shows that gene mutation is a significant proportion of genetic factors associated with prostate cancer. The DNA damage response (DDR) is a signal cascade network that aims to maintain genomic integrity in cells. This comprehensive study was performed to determine the link between different DNA damage response gene mutations and prostate cancer.

Materials and methods

A systematic literature search was performed using PubMed, Web of Science, and Embase. Papers published up to February 1, 2022 were retrieved. The DDR gene mutations associated with prostate cancer were identified by referring to relevant research and review articles. Data of prostate cancer patients from multiple PCa cohorts were obtained from cBioPortal. The OR or HR and 95% CIs were calculated using both fixed-effects models (FEMs) and random-effects models (REMs).

Results

Seventy-four studies were included in this research, and the frequency of 13 DDR genes was examined. Through the analysis of 33 articles that focused on the risk estimates of DDR genes between normal people and PCa patients, DDR genes were found to be more common in prostate cancer patients (OR = 3.6293 95% CI [2.4992; 5.2705]). Also, patients in the mutated group had a worse OS and DFS outcome than those in the unmutated group (P < .05). Of the 13 DDR genes, the frequency of 9 DDR genes in prostate cancer was less than 1%, and despite differences in race, BRCA2 was the potential gene with the highest frequency (REM Frequency = .0400, 95% CI .0324 - .0541). The findings suggest that mutations in genes such as ATR, BLM, and MLH1 in PCa patients may increase the sensitivity of Olaparib, a PARP inhibitor.

Conclusion

These results demonstrate that mutation in any DDR pathway results in a poor prognosis for PCa patients. Furthermore, mutations in ATR, BLM, and MLH1 or the expression of POLR2L, PMS1, FANCE, and other genes significantly influence Olaparib sensitivity, which may be underlying therapeutic targets in the future.

BRCA1 and BRCA2 pathogenic variants and prostate cancer risk: systematic review and meta-analysis

BACKGROUND

BRCA1 and BRCA2 pathogenic variants (PVs) are associated with prostate cancer (PCa) risk, but a wide range of relative risks (RRs) has been reported.

METHODS

We systematically searched PubMed, Embase, MEDLINE and Cochrane Library in June 2021 for studies that estimated PCa RRs for male BRCA1/2 carriers, with no time or language restrictions. The literature search identified 27 studies (BRCA1: n = 20, BRCA2: n = 21).

RESULTS

The heterogeneity between the published estimates was high (BRCA1: I2 = 30%, BRCA2: I2 = 83%); this could partly be explained by selection for age, family history or aggressive disease, and study-level differences in ethnicity composition, use of historical controls, and location of PVs within BRCA2. The pooled RRs were 2.08 (95% CI 1.38-3.12) for Ashkenazi Jewish BRCA2 carriers, 4.35 (95% CI 3.50-5.41) for non-Ashkenazi European ancestry BRCA2 carriers, and 1.18 (95% CI 0.95-1.47) for BRCA1 carriers. At ages <65 years, the RRs were 7.14 (95% CI 5.33-9.56) for non-Ashkenazi European ancestry BRCA2 and 1.78 (95% CI 1.09-2.91) for BRCA1 carriers.

CONCLUSIONS

These PCa risk estimates will assist in guiding clinical management. The study-level subgroup analyses indicate that risks may be modified by age and ethnicity, and for BRCA2 carriers by PV location within the gene, which may guide future risk-estimation studies.

Next-generation sequencing of BRCA1 and BRCA2 genes in Moroccan prostate cancer patients with positive family history

Prostate cancer is the most common male cancer in Morocco. Although sporadic forms account for a large proportion of patients, familial forms of prostate cancer are observed in 20% of cases and about 5% are due to hereditary transmission. Indeed, germline mutations in BRCA1/2 genes have been associated with prostate cancer risk. However, the spectrum of these mutations was not investigated in Moroccan Prostate cancer patients. Thereby, the aim of this study was to characterize and to estimate the prevalence of germline BRCA1/2 mutations and large rearrangements in Moroccan patients with familial prostate cancer. The entire coding regions and intron/exon boundaries of BRCA1 and BRCA2 genes have been analyzed by next generation sequencing (NGS) in a total of 30 familial prostate cancer patients. Three pathogenic mutations were detected in four unrelated patients (13.3%). One BRCA1 mutation (c.1953_1956delGAAA) and two BRCA2 mutations (c.7234_7235insG and BRCA2ΔE12). In addition, sixty-three distinct polymorphisms and unclassified variants have been found. Early identification of germline BRCA1/2 mutations may be relevant for the management of Moroccan prostate cancer patients.

A systematic review of the prevalence of DNA damage response gene mutations in prostate cancer

Several ongoing international prostate cancer (PC) clinical trials are exploring therapies that target the DNA damage response (DDR) pathway. This systematic review summarizes the prevalence of DDR mutation carriers in the unselected (general) PC and familial PC populations. A total of 11 electronic databases, 10 conference proceedings, and grey literature sources were searched from their inception to December 2017. Studies reporting the prevalence of somatic and/or germline DDR mutations were summarized. Metastatic PC (mPC), castration‑resistant PC (CRPC) and metastatic CRPC (mCRPC) subgroups were included. A total of 11,648 records were retrieved, and 80 studies (103 records) across all PC populations were included; 59 records were of unselected PC and 13 records of familial PC. Most data were available for DDR panels (n=12 studies), ataxia telangiectasia mutated (ATM; n=13), breast cancer susceptibility gene (BRCA)1 (n=14) and BRCA2 (n=20). ATM, BRCA2 and partner and localizer of BRCA2 (PALB2) had the highest mutation rates (≥4%). Median prevalence rates for DDR germline mutations were 18.6% in PC (range, 17.2‑19%; three studies, n=1,712), 11.6% in mPC (range, 11.4‑11.8%; two studies, n=1,261) and 8.3% in mCRPC (range, 7.5‑9.1%; two studies, n=738). Median prevalence rates for DDR somatic mutations were 10.7% in PC (range, 4.9‑22%; three studies, n=680), 13.2% in mPC (range, 10‑16.4%; two studies, n=105) and not reported (NR) in mCRPC. The prevalence of DDR germline and/or somatic mutations was 27% in PC (one study, n=221), 22.67% in mCRPC (one study, n=150) and NR in mPC. In familial PC, median mutation prevalence was 12.1% (range, 7.3‑16.9%) for germline DDR (two studies, n=315) and 3.7% (range, 1.3‑7.9%) for BRCA2 (six studies, n=945). In total, 88% of studies were at a high risk of bias. The prevalence of DDR gene mutations in PC varied widely within somatic subgroups depending on study size, genetic screening techniques, DDR mutation definition and PC diagnosis; somatic and/or germline DDR mutation prevalence was in the range of 23‑27% in PC. These findings support DDR mutation testing for all patients with PC (including those with mCRPC). With the advent of the latest clinical practice PC guidelines highlighting the importance of DDR mutation screening, and ongoing mCRPC clinical trials evaluating DDR mutation‑targeted drugs, future larger epidemiological studies are warranted to further quantify the international burden of DDR mutations in PC.

The association of BRCA1 and BRCA2 mutations with prostate cancer risk, frequency, and mortality: A meta-analysis

BACKGROUND

A prior meta-analysis found no association between BRCA1 mutation and prostate cancer (PCa). Subsequent BRCA2 mutation studies have shown an association with PCa risk and mortality. We conducted a meta-analysis of overall BRCA mutation carriers and in subgroups to (1) estimate PCa risk in BRCA mutation carriers, (2) evaluate the frequency of BRCA mutation carriers in patients with PCa, and (3) compare cancer-specific survival (CSS) and overall survival (OS) among BRCA mutation carriers and noncarriers.

METHODS

We searched the PubMed/MEDLINE, Embase, and Cochrane databases. Unadjusted odds ratio (OR), percentage (%), and hazard ratio (HR) were used to calculate pooled estimates for PCa risk, frequency, and survival, respectively. Subgroup analyses by mutation type ( BRCA1 or BRCA2) were conducted for the three objectives. Further subgroup analyses by study design (age-sex-adjusted or crude), ascertainment method (ascertained or inferred genotyping), population (Ashkenazi Jewish or general population), and survival outcomes (CSS or OS) were conducted. The associations were evaluated using random-effects models, in two-sided statistical tests.

RESULTS

A total of 8 cohort, 7 case-control, 4 case-series, 28 frequency, and 11 survival studies were included. Being a BRCA mutation carrier ( BRCA1 and/or BRCA2) was associated with a significant increase in PCa risk (OR = 1.90, 95% CI = 1.58-2.29), with BRCA2 mutation being associated with a greater risk of PCa (OR = 2.64, 95% CI = 2.03-3.47) than BRCA1 (OR = 1.35, 95% CI = 1.03-1.76). The frequency of BRCA1 and BRCA2 carriers in patients with PCa was 0.9% and 2.2%, respectively. OS (HR = 2.21, 95% CI = 1.64-2.30) and CSS (HR = 2.63, 95% CI = 2.00-3.45) were significantly worse among BRCA2 carriers compared to noncarriers, whereas OS (HR = 0.47, 95% CI = 0.11-1.99) and CSS (HR = 1.07, 95% CI = 0.38-2.96) were statistically not significant when comparing BRCA1 carriers and noncarriers.

CONCLUSIONS

There is a 1.90-fold greater risk of PCa in overall BRCA mutation carriers. This elevated PCa risk is attributable mainly to a 2.64-fold greater risk of PCa in BRCA2 carriers compared to a moderate 1.35-fold greater risk in BRCA1 carriers. The frequency of BRCA2 mutations was higher than BRCA1 mutations among patients with PCa. BRCA2 but not BRCA1 mutations were associated with higher PCa mortality. The BRCA mutation may be a clinical factor to stratify high-risk patients and guide clinical strategies for more effective treatments for patients with PCa.

Germline BRCA mutation in male carriers-ripe for precision oncology?

BACKGROUND

Prostate cancer (PC) is one of the known heritable cancers with individual variations attributed to genetic factors. BRCA1 and BRCA2 are tumour suppressor genes with crucial roles in repairing DNA and thereby maintaining genomic integrity. Germline BRCA mutations predispose to multiple familial tumour types including PC.

METHODS

We performed a Pubmed database search along with review of reference lists from prominent articles to capture papers exploring the association between BRCA mtuations and prostate cancer risk and prognosis. Articles were retrieved until May 2017 and filtered for relevance, and publication type.

RESULTS

We explored familial PC genetics; discussed the discovery and magnitude of the association between BRCA mutations and PC risk and outcome; examined implications of factoring BRCA mutations into PC screening; and discussed the rationale for chemoprevention in this high-risk population. We confirmed that BRCA1/2 mutations confer an up to 4.5-fold and 8.3-fold increased risk of PC, respectively. BRCA2 mutations are associated with an increased risk of high-grade disease, progression to metastatic castration-resistant disease, and 5-year cancer-specific survival rates of 50 to 60%.

CONCLUSION

Despite the growing body of research on DNA repair genes, deeper analysis is needed to understand the aetiological role of germline BRCA mutations in the natural history of PC. There is a need for awareness to screen for this marker of PC risk. There is similarly an opportunity for structured PC screening programs for BRCA mutation carriers. Finally, further research is required to identify potential chemopreventive strategies for this high-risk subgroup.

Androgen receptor-related diseases: what do we know?

The androgen receptor (AR) and the androgen-AR signaling pathway play a significant role in male sexual differentiation and the development and function of male reproductive and non-reproductive organs. Because of AR's widely varied and important roles, its abnormalities have been identified in various diseases such as androgen insensitivity syndrome, spinal bulbar muscular atrophy, benign prostatic hyperplasia, and prostate cancer. This review provides an overview of the function of androgens and androgen-AR mediated diseases. In addition, the diseases delineated above are discussed with respect to their association with mutations and other post-transcriptional modifications in the AR. Finally, we present an introduction to the potential therapeutic application of most recent pharmaceuticals including miRNAs in prostate cancer that specifically target the transactivation function of the AR at post-transcriptional stages.

The role of BRCA1 and BRCA2 in prostate cancer

One of the strongest risk factors for prostate cancer is a family history of the disease. Germline mutations in the breast cancer predisposition gene 2 (BRCA2) are the genetic events known to date that confer the highest risk of prostate cancer (8.6-fold in men ≤65 years). Although the role of BRCA2 and BRCA1 in prostate tumorigenesis remains unrevealed, deleterious mutations in both genes have been associated with more aggressive disease and poor clinical outcomes. The increasing incidence of prostate cancer worldwide supports the need for new methods to predict outcome and identify patients with potentially lethal forms of the disease. As we present here, BRCA germline mutations, mainly in the BRCA2 gene, are one of those predictive factors. We will also discuss the implications of these mutations in the management of prostate cancer and hypothesize on the potential for the development of strategies for sporadic cases with similar characteristics.

BRCA1 mutations do not increase prostate cancer risk: results from a meta-analysis including new data

BACKGROUND

Although in recent years deleterious BRCA1 mutations have been extensively studied as a prostate cancer risk factor, results are inconclusive. To assess the contribution of the BRCA1 Galician founder mutation c.211A>G in prostate cancer morbidity we conducted a case-control study. Moreover, to better elucidate whether deleterious BRCA1 mutations are involved in the development of prostate cancer, we performed a systematic review and a meta-analysis of BRCA1 studies on prostate cancer.

METHODS

A total of 905 unselected men diagnosed with adenocarcinoma of the prostate and a control group of 936 unrelated men without history of prostate cancer were evaluated for c.211A>G. Adjusted by age Odds ratios (OR) and 95% confidence intervals (CIs) were estimated using logistic regression. To construct the meta-analysis, genotype-based epidemiological studies reporting BRCA1 founder mutations on prostate cancer were identified by comprehensive and systematic bibliographic search. After extraction of relevant data, main and subgroup analysis by mutation were performed to assess the effect of BRCA1 on prostate cancer risk.

RESULTS

Four c.211A>G heterozygous individuals, one patient and three controls, were detected (OR = 0.27; 95% CI: 0.01-2.36; P = 0.28). Meta-analysis results from the integration of our data and other seven studies with BRCA1 genotyping data (5,705 prostate cancer cases and 13,218 controls) did not detect an association with prostate cancer risk (OR = 1.36; 95% CI: 0.87-2.14; P = 0.18).

CONCLUSIONS

Our conclusive trial demonstrates the lack of association between Galician splicing mutation c.211A>G in the BRCA1 gene and prostate cancer risk. Moreover, the result of the meta-analysis also discards the involvement of BRCA1 mutations in the development of prostate cancer.

BRCA1 and BRCA2 families and the risk of skin cancer

BRCA1 and BRCA2 mutation carriers have elevated risks of breast and ovarian cancers. The risks for cancers at other sites remain unclear. Melanoma has been associated with BRCA2 mutations in some studies, however, few surveys have included non-melanoma skin cancer. We followed 2729 women with a BRCA1 or BRCA2 mutation for an average of 5.0 years. These women were asked to report new cases of cancer diagnosed in themselves or in their family. The risks of skin cancer were compared for probands with BRCA1 and BRCA2 mutations. Of 1779 women with a BRCA1 mutation, 29 developed skin cancer in the follow-up period (1.6%). Of the 950 women with a BRCA2 mutation, 28 developed skin cancer (3.0%) (OR = 1.83 for BRCA2 versus BRCA1; 95% CI 1.08-3.10; P = 0.02). The odds ratio for basal cell carcinoma was higher (OR = 3.8; 95% CI 1.5-9.4; P = 0.002). BRCA2 mutation carriers are at increased risk for skin cancer, compared with BRCA1 carriers, in particular for basal cell carcinoma.

Targeted prostate cancer screening in men with mutations in BRCA1 and BRCA2 detects aggressive prostate cancer: preliminary analysis of the results of the IMPACT study

OBJECTIVE

To evaluate the role of targeted prostate cancer screening in men with BRCA1 or BRCA2 mutations, an international study, IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls), was established. This is the first multicentre screening study targeted at men with a known genetic predisposition to prostate cancer. A preliminary analysis of the data is reported.

PATIENTS AND METHODS

Men aged 40-69 years from families with BRCA1 or BRCA2 mutations were offered annual prostate specific antigen (PSA) testing, and those with PSA > 3 ng/mL, were offered a prostate biopsy. Controls were men age-matched (± 5 years) who were negative for the familial mutation.

RESULTS

In total, 300 men were recruited (205 mutation carriers; 89 BRCA1, 116 BRCA2 and 95 controls) over 33 months. At the baseline screen (year 1), 7.0% (21/300) underwent a prostate biopsy. Prostate cancer was diagnosed in ten individuals, a prevalence of 3.3%. The positive predictive value of PSA screening in this cohort was 47·6% (10/21). One prostate cancer was diagnosed at year 2. Of the 11 prostate cancers diagnosed, nine were in mutation carriers, two in controls, and eight were clinically significant.

CONCLUSIONS

The present study shows that the positive predictive value of PSA screening in BRCA mutation carriers is high and that screening detects clinically significant prostate cancer. These results support the rationale for continued screening in such men.

Germline BRCA mutations denote a clinicopathologic subset of prostate cancer

PURPOSE

Increased prostate cancer risk has been reported for BRCA mutation carriers, but BRCA-associated clinicopathologic features have not been clearly defined.

EXPERIMENTAL DESIGN

We determined BRCA mutation prevalence in 832 Ashkenazi Jewish men diagnosed with localized prostate cancer between 1988 and 2007 and 454 Ashkenazi Jewish controls and compared clinical outcome measures among 26 BRCA mutation carriers and 806 noncarriers. Kruskal-Wallis tests were used to compare age of diagnosis and Gleason score, and logistic regression models were used to determine associations between carrier status, prostate cancer risk, and Gleason score. Hazard ratios (HR) for clinical end points were estimated using Cox proportional hazards models.

RESULTS

BRCA2 mutations were associated with a 3-fold risk of prostate cancer [odds ratio, 3.18; 95% confidence interval (95% CI), 1.52-6.66; P = 0.002] and presented with more poorly differentiated (Gleason score > or =7) tumors (85% versus 57%; P = 0.0002) compared with non-BRCA-associated prostate cancer. BRCA1 mutations conferred no increased risk. After 7,254 person-years of follow-up, and adjusting for clinical stage, prostate-specific antigen, Gleason score, and treatment, BRCA2 and BRCA1 mutation carriers had a higher risk of recurrence [HR (95% CI), 2.41 (1.23-4.75) and 4.32 (1.31-13.62), respectively] and prostate cancer-specific death [HR (95% CI), 5.48 (2.03-14.79) and 5.16 (1.09-24.53), respectively] than noncarriers.

CONCLUSIONS

BRCA2 mutation carriers had an increased risk of prostate cancer and a higher histologic grade, and BRCA1 or BRCA2 mutations were associated with a more aggressive clinical course. These results may have implications for tailoring clinical management of this subset of hereditary prostate cancer.

Tumor suppressor BRCA1 is expressed in prostate cancer and controls insulin-like growth factor I receptor (IGF-IR) gene transcription in an androgen receptor-dependent manner

PURPOSE

The insulin-like growth factor (IGF) system plays an important role in prostate cancer. The BRCA1 gene encodes a transcription factor with tumor suppressor activity. The involvement of BRCA1 in prostate cancer, however, has not yet been elucidated. The purpose of the present study was to examine the functional correlations between BRCA1 and the IGF system in prostate cancer.

EXPERIMENTAL DESIGN

An immunohistochemical analysis of BRCA1 was done on tissue microarrays comprising 203 primary prostate cancer specimens. In addition, BRCA1 levels were measured in prostate cancer xenografts and in cell lines representing early stages (P69 cells) and advanced stages (M12 cells) of the disease. The ability of BRCA1 to regulate IGF-I receptor (IGF-IR) expression was studied by coexpression experiments using a BRCA1 expression vector along with an IGF-IR promoter-luciferase reporter.

RESULTS

We found significantly elevated BRCA1 levels in prostate cancer in comparison with histologically normal prostate tissue (P<0.001). In addition, an inverse correlation between BRCA1 and IGF-IR levels was observed in the androgen receptor (AR)-negative prostate cancer-derived P69 and M12 cell lines. Coexpression experiments in M12 cells revealed that BRCA1 was able to suppress IGF-IR promoter activity and endogenous IGF-IR levels. On the other hand, BRCA1 enhanced IGF-IR levels in LNCaP C4-2 cells expressing an endogenous AR.

CONCLUSIONS

We provide evidence that BRCA1 differentially regulates IGF-IR expression in AR-positive and AR-negative prostate cancer cells. The mechanism of action of BRCA1 involves modulation of IGF-IR gene transcription. In addition, immunohistochemical data are consistent with a potential survival role of BRCA1 in prostate cancer.

The role of the BRCA2 gene in susceptibility to prostate cancer revisited

Prostate cancer is a genetically complex disease with multiple predisposing factors affecting presentation, progression, and outcome. Epidemiologic studies have long shown an aggregation of breast and prostate cancer in some families. More recently, studies have reported an apparent excess of prostate cancer cases among BRCA2 mutation-carrying families. Additionally, population-based screens of early-onset prostate cancer patients have suggested that the prevalence of deleterious BRCA2 mutations in this group is 1% to 2%, imparting a significantly increased risk of the disease compared with noncarrier cases. However, studies of high-risk prostate cancer families suggest that BRCA2 plays at most a minimal role in these individuals, highlighting the potential genetic heterogeneity of the disease. In this commentary, we review the current literature and hypotheses surrounding the relationship between BRCA2 mutations and susceptibility to prostate cancer and speculate on the potential for involvement of additional genes.

Counseling for male BRCA mutation carriers: a review

BRCA mutations in women confer a high risk for breast and ovarian cancers. The risks to male carriers are poorly understood and risk management strategies undescribed. This review summarizes current evidence and gives recommendations for counseling male BRCA mutation carriers. Reported risks for breast, prostate, pancreatic, gastric and hematologic cancers are higher in male BRCA mutation carriers vs non-carriers. Especially in male BRCA2 mutation carriers under age 65 prostate and pancreatic cancer risks are increased. The risk increase for primary cancers of organs like the liver, bone and brain is difficult to assess as these organs are common sites for metastases. Reports on colorectal cancer and melanoma risks are inconclusive. On the current limited evidence available, male BRCA mutation carriers should be regarded as at high risk for breast, prostate, gastric, pancreatic and colorectal cancers; surveillance by appropriate investigations should start at age 40 years.

Prostate cancer in male BRCA1 and BRCA2 mutation carriers has a more aggressive phenotype

There is a high and rising prevalence of prostate cancer (PRCA) within the male population of the United Kingdom. Although the relative risk of PRCA is higher in male BRCA2 and BRCA1 mutation carriers, the histological characteristics of this malignancy in these groups have not been clearly defined. We present the histopathological findings in the first UK series of BRCA1 and BRCA2 mutation carriers with PRCA. The archived histopathological tissue sections of 20 BRCA1/2 mutation carriers with PRCA were collected from histopathology laboratories in England, Ireland and Scotland. The cases were matched to a control group by age, stage and serum PSA level of PRCA cases diagnosed in the general population. Following histopathological evaluation and re-grading according to current conventional criteria, Gleason scores of PRCA developed by BRCA1/2 mutation carriers were identified to be significantly higher (Gleason scores 8, 9 or 10, P=0.012) than those in the control group. Since BRCA1/2 mutation carrier status is associated with more aggressive disease, it is a prognostic factor for PRCA outcome. Targeting screening to this population may detect disease at an earlier clinical stage which may therefore be beneficial.

Prostate cancer in fathers with fewer male offspring: the Jerusalem Perinatal Study cohort

Recent studies have suggested the involvement of loci on the Y chromosome in prostate cancer. We studied the relative risk (RR) of prostate cancer in relation to sex ratio of offspring in a cohort of 38,934 Israeli men who were followed from the birth of their offspring (in 1964 through 1976) until 2005. Cox models were used to adjust for changes in incidence over time, age, the man's year of birth, and social and ethnic variables. A total of 712 men were diagnosed with prostate cancer. Compared with men who had at least one son, men with only daughters had an increased risk of prostate cancer (adjusted RR = 1.40, 95% confidence interval [CI] = 1.20 to 1.64, P<.0001). In men with one, two, or three or more offspring, the relative risks associated with absence of sons were 1.25 (95% CI = 1.00 to 1.56), 1.41 (95% CI = 1.04 to 1.91), and 1.60 (95% CI = 1.05 to 2.43), respectively. Men with no daughters showed no statistically significantly altered risk, compared with men who had offspring of both sexes. The relative risk of prostate cancer decreased as the number of sons increased (P(trend)<.0001) but did not change with the number of daughters. These findings suggest that a Y chromosome locus may be involved in prostate cancer risk in this population.

Ashkenazi Jews and breast cancer: the consequences of linking ethnic identity to genetic disease

We explored the advantages and disadvantages of using ethnic categories in genetic research. With the discovery that certain breast cancer gene mutations appeared to be more prevalent in Ashkenazi Jews, breast cancer researchers moved their focus from high-risk families to ethnicity. The concept of Ashkenazi Jews as genetically unique, a legacy of Tay-Sachs disease research and a particular reading of history, shaped this new approach even as methodological imprecision and new genetic and historical research challenged it. Our findings cast doubt on the accuracy and desirability of linking ethnic groups to genetic disease. Such linkages exaggerate genetic differences among ethnic groups and lead to unequal access to testing and therapy.

BRCA1 and BRCA2: the genetic testing and the current management options for mutation carriers

Approximately 5-10% of breast carcinomas and 10% of ovarian carcinomas are ascribable to a genetic susceptibility. Of these, about 40% are related to genetic mutations in the genes BRCA1 and BRCA2. Despite the increasing demand for genetic testing arising from the patients and their relatives, the genetic testing can be offered yet only to individuals belonging to high-risk families in which the probability that there is a germline mutation in a BRCA gene is high and thus cancer occurrence is likely the expression of a highly penetrant genetic predisposition. In this article, we review how the current knowledge on the biological mechanisms underlying BRCA1 and BRCA2 dysfunction may contribute to the understanding of breast and ovarian cancer predisposition. The most currently employed methods for genetic testing are critically overviewed, together with some indications for the interpretation of the test outcome and the clinical management of mutation carriers.

Spectrum and prevalence of BRCA1 and BRCA2 germline mutations in Sardinian patients with breast carcinoma through hospital-based screening

BACKGROUND

Factors that are predictive of carrying BRCA1 and BRCA2 germline mutations in patients with breast carcinoma are awaited widely. The genetically homogeneous Sardinian population may be useful for defining the role of such genetic alterations further through a clinical evaluation program.

METHODS

One hundred two of 659 patients with breast carcinoma (15.5%) who were collected consecutively had a family history of breast carcinoma and were screened for BRCA1/2 mutations by denaturing high-performance liquid chromatography and DNA sequencing.

RESULTS

Three deleterious germline BRCA1/2 mutations were detected in 15 of 102 families (14.7%), including 13 families (86.7%) with BRCA2 mutations and 2 families (13.3%) with BRCA1 mutations. A single variant, BRCA2-8765delAG, was the most recurrent mutation in the series and was found in 12 of 102 families (11.8%) and in 18 of 657 patients (2.7%). The average age at diagnosis was significantly younger in families with BRCA1/2 mutations (48.6 yrs) compared with the age of patients who had no detectable mutation (52.9 yrs; P = 0.039). Moreover, BRCA1/2 mutations were found at a significantly higher rate in families who had at least 1 member with ovarian carcinoma or male breast carcinoma (5 of 12 families; 41.7%) than in families without such an association (10 of 90 families; 11.1%; P = 0.003).

CONCLUSIONS

BRCA2 mutations were approximately 6 times more prevalent than BRCA1 mutations. A diagnosis of breast carcinoma before age 50 years, ovarian carcinoma, male breast carcinoma, and 3 affected generations all were associated significantly with BRCA1/2 mutations. Although the current findings provided further support for the hypothesis that additional breast carcinoma susceptibility genes remain to be identified, such indicators of the presence of BRCA1/2 mutations may be useful in counseling patients about undergoing genetic testing.

BRCA1 and BRCA2 germ-line mutations and oral contraceptives: to use or not to use

Approximately 10% of the cases of breast cancer and invasive ovarian cancer are hereditary, occurring predominantly in women with germ-line mutations in the BRCA1 or BRCA2 gene. In deciding whether women with germ-line mutations in the BRCA1 gene should use oral contraceptives a possible increase in the risk of breast cancer needs to be weighed against the convenience of this means of birth control and its potential to reduce the risk of ovarian cancer. In women with BRCA2 mutations, oral contraceptive use has not been associated with an increased risk of breast cancer and does have the potential to reduce the risk of ovarian cancer. Prophylactic surgical options and intensified surveillance should, of course, be discussed with these patients.

BRCA1 and BRCA2 pathways and the risk of cancers other than breast or ovarian

OBJECTIVE

Germline mutations in the tumor suppressor genes BRCA1 and BRCA2 predispose women to breast and ovarian cancer. Female carriers of BRCA1 or BRCA2 gene mutations have very high lifetime risks for breast and ovarian cancers. Genetic abnormalities occur in all cancers, so BRCA-related pathways are critical because they serve to safeguard genetic content. Although protecting genetic information is a general function, BRCA-related pathways seem largely specific to preventing breast and ovarian cancer. The objective of this study was to resolve this difference between the theoretical functions of BRCA genes and their specific clinical effects.

DATA SOURCES, DATA EXTRACTION, DATA SYNTHESIS

The author collected data published in > 30 epidemiologic studies on the incidence of cancers other than breast or ovarian in mutation carriers and in large populations eligible for mutation testing. Data were extracted and used directly as published whenever possible with a minimum of statistical manipulation.

CONCLUSIONS

Although mutations target breast and ovary, a broader spectrum of cancers also occur with statistically significant elevated frequencies. Risks for "all cancers except breast or ovary" are elevated, with some population subgroups differing with regard to how frequently elevated risks were found at individual sites. Additional sites at risk included stomach, pancreas, prostate, and colon. The increased risk ranged from about 20% to 60%, with the greatest increases in risk in stomach and pancreas. The collected data show BRCA-pathway functions are probably required at multiple sites, not just in breast or ovary. Known interactions and relationships among BRCA-related pathways strongly support the idea that their inactivation provides growth or survival advantages for a variety of cancers. The data suggest applying an increased level of clinical alertness to those with defects in BRCA-related pathways. Identifying molecules that confer growth or survival advantages to BRCA-related cancers may provide broadly useful targets for chemotherapy or chemoprevention.

BRCA mutations and risk of prostate cancer in Ashkenazi Jews

PURPOSE

The Breast Cancer Linkage Consortium and other family-based ascertainments have suggested that male carriers of BRCA mutations are at increased risk of prostate cancer. Several series looking at the frequency of BRCA mutations in unselected patients with prostate cancer have not confirmed this finding. To clarify this issue, we conducted a large case-control study.

EXPERIMENTAL DESIGN

Blood specimens from 251 unselected Ashkenazi men with prostate cancer were screened for the presence of one of the three common Ashkenazi founder mutations in BRCA1 and BRCA2. The incidence of founder mutations was compared with the incidence of founder mutations in 1472 male Ashkenazi volunteers without prostate cancer using logistic regression analysis after adjusting for age.

RESULTS

Thirteen (5.2%) cases had a deleterious mutation in BRCA1 or BRCA2 compared with 28 (1.9%) controls. After adjusting for age, the presence of a BRCA1 or BRCA2 mutation was associated with the development of prostate cancer (odds ratio, 3.41; 95% confidence interval, 1.64-7.06; P = 0.001). When results were stratified by gene, BRCA2 mutation carriers demonstrated an increased risk of prostate cancer (odds ratio, 4.78; 95% confidence interval, 1.87-12.25; P = 0.001), whereas the risk in BRCA1 mutation carriers was not significantly increased.

CONCLUSIONS

BRCA2 mutations are more likely to be found in unselected individuals with prostate cancer than age-matched controls. These results support the hypothesis that deleterious mutations in BRCA2 are associated with an increased risk of prostate cancer.

The genetic epidemiology of breast cancer genes

Genetic susceptibility to breast cancer in women is conferred by a large number of genes, of which six have so far been identified. In the context of multiple-case families, BRCA1 and BRCA2 are the most important. Mutations in these genes confer high lifetime risks of breast cancer and ovarian cancer, and more moderate risks of prostate cancer and some other cancer types. Mutations in the CHEK2 and ATM genes, by contrast, cause much more modest (2-4 fold) risks of breast cancer. Genes so far identified explain approximately 20% of the familial aggregation of breast cancer. The remaining susceptibility genes have, so far, proved illusive, suggesting that they are numerous and confer moderate risks. A variety of techniques including genome-wide association studies, use of quantitative intermediate endpoints, and resequencing of genes may be required to identify them. The identification of such genes can provide a basis for targeted prevention of breast cancer.

Androgen receptor in prostate cancer

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

Cancer risks for male carriers of germline mutations in BRCA1 or BRCA2: a review of the literature

Major risks conferred by BRCA1 and BRCA2 in women are for cancers of the breast, ovary, fallopian tube, and peritoneum. Male carriers of mutations in BRCA1 or BRCA2 are also susceptible to cancer; however, their risks remain poorly understood and their optimal clinical management has not yet been defined. This article reviews studies that estimate risk associated with mutations in BRCA1 or BRCA2, with a focus on the cancer sites most relevant to men. Male BRCA1 mutation carriers are at increased risk of cancers of the prostate and breast. Evidence supporting increased susceptibility to colon cancer is limited. In contrast to women, who have a greater lifetime risk of cancer with mutations of the BRCA1 gene, BRCA2 is the more important gene for men. The spectrum of cancers is wide for BRCA2 and some studies report that the overall cancer risk for male BRCA2 carriers exceeds the risk for female carriers. In particular, the relative risk to male BRCA2 mutation carriers is high before age 65 years, largely attributable to breast, prostate, and pancreatic cancers. BRCA2 mutation carriers are also at risk of stomach cancer and melanoma (of the skin and eye). Additional research into risks to male BRCA1 or BRCA2 mutation carriers is necessary, specifically to determine the magnitude of excess cancer risk among BRCA2 carriers and to increase our understanding of the basis for the observed site-specificity in cancer development.

Evaluation of familial clustering of breast and prostate cancer in the Minnesota Breast Cancer Family Study

Few studies examining familial clustering of breast and prostate cancer (PC) have focused on a clearly defined high-risk population with epidemiologic risk factors. We conducted a cohort study of prostate cancer among a subset of 426 families ascertained through female breast cancer probands. Three groups of males were included: 804 relatives in 60 families with four or more breast or ovarian cancers, 536 marry-ins in these high-risk families, and 484 relatives in 81 families where only the proband had breast cancer. A total of 118 prostate cancers were reported. The rate of prostate cancer among blood relatives in high-risk families was significantly lower than among marry-ins (RR = 0.6, 95% C.I.: 0.4-0.9). The rate of prostate cancer among blood relatives in low-risk families was not significantly different from the rate among marry-ins (RR = 0.8, 95% C.I.: 0.5-1.2). These results provide little evidence that male relatives in high-risk breast cancer families are at increased risk of prostate cancer.

Founder mutations in BRCA1/2 are not frequent in Canadian Ashkenazi Jewish men with prostate cancer

BACKGROUND

Relatives of BRCA1 and BRCA2 mutation carriers have long been proposed by epidemiological studies to have an increased risk of developing prostate cancer. In the Ashkenazi Jewish (AJ) population, the existence of 3 frequent founder mutations, 185delAG and 5382insC in BRCA1 and 6174delT in BRCA2 greatly facilitates screening for carriers.

METHODS

We tested 146 AJ men with confirmed diagnoses of invasive prostate cancer. Thirteen had at least one first degree relative with prostate cancer. The median age at diagnosis of participants was 67.9 years (range 48.6-84.2 years). Subjects were screened for the BRCA1:185delAG, BRCA1:5382insC and BRCA2:6174delT mutations simultaneously using a multiplex sizing assay detecting band shifts in the presence of the variant sequence.

RESULTS

Two out of 146 individuals were found to carry the germline BRCA2 mutation 6174delT (1.4%); the previously reported population frequency for this mutation is ~1% in AJ. We found no BRCA1 mutations. One carrier had 2 uncles affected with prostate cancer, while the other had an uncle and daughter with breast cancer. We combined our results with previously published data examining these 3 founder AJ mutations in men with prostate cancer and in population controls. Including our results, studies to date reported 5/463 (1.1%), 2/293 (0.68%) and 7/461 (1.3%) carriers for the BRCA1:185delAG, BRCA1:5382insC and BRCA2:6174delT mutations in prostate cancer cases, respectively. This compares with combined reported frequencies of 85/9371 (0.91%), 24/8867 (0.27%) and 119/9514 (1.3%) for the same mutations in control individuals. There was no statistically significant excess of mutations in cases compared to controls in either gene.

CONCLUSIONS

Our observations remain preliminary. By combining all studies published to date, we have an 80% power to detect ORs of 2.7, 6.6 and 2.5 (185delAG, 5382insC and 6174 delT, respectively) while the values we observed range between 1.0 and 2.5. However, the contribution of rare mutations with such low odds ratios to the population prostate cancer burden is unlikely to be large enough to be clinically useful. Thus, contrary to suggestions from some previous epidemiological data, our observations do not support an important role for AJ founder BRCA1/2 mutations in prostate cancer risk.

Two percent of men with early-onset prostate cancer harbor germline mutations in the BRCA2 gene

Studies of families with breast cancer have indicated that male carriers of BRCA2 mutations are at increased risk of prostate cancer, particularly at an early age. To evaluate the contribution of BRCA2 mutations to early-onset prostate cancer, we screened the complete coding sequence of BRCA2 for germline mutations, in 263 men with diagnoses of prostate cancer who were Collapse

Key Words Collapse

MESH Headings

• Adult
• Age of Onset
• Aged
• Base Sequence
• Breast Neoplasms/genetics
• DNA Mutational Analysis
• Female
• Genes, BRCA2
• Genetic Predisposition to Disease/genetics
• Genetic Testing
• Germ-Line Mutation/genetics
• Heterozygote
• Humans
• Male
• Middle Aged
• Ovarian Neoplasms/genetics
• Pedigree
• Polymorphism, Genetic/genetics
• Prostatic Neoplasms/genetics

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Grants Collapse

Affiliation(s)

Stephen M Edwards Translational Cancer Genetics Team, Institute of Cancer Research, Sutton, Surrey, United Kingdom
Zsofia Kote-Jarai
Julia Meitz
Rifat Hamoudi
Questa Hope
Peter Osin
Rachel Jackson
Christine Southgate
Rashmi Singh
Alison Falconer
David P Dearnaley
Audrey Ardern-Jones
Annette Murkin
Anna Dowe
Jo Kelly
Sue Williams
Richard Oram
Margaret Stevens
Dawn M Teare
Bruce A J Ponder
Simon A Gayther
Doug F Easton
Rosalind A Eeles

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Familial prostate and breast cancer in men treated with prostatectomy for prostate cancer: a population based case-control study

PURPOSE

We assessed familial prostate and breast cancer in Quebec.

MATERIALS AND METHODS

Using a self-administered mail survey we assessed the prevalence of prostate and breast cancer in first degree relatives of 1,633 men treated with prostatectomy for prostate cancer in the province of Quebec and in first degree relatives of 1,386 spouse controls.

RESULTS

The OR of familial breast cancer was 1.1 (95% CI 0.9 to 1.4). The OR of 3.0 (95% CI 2.5 to 3.6) recorded for prostate cancer was modified by francophone versus anglophone linguistic preference (OR 3.2, 95% CI 2.6, 3.9 versus 1.5, 95% CI 0.8 to 2.7, p = 0.02). Male sibship size was a statistically significant parameter modifying this association (p = 0.02), namely no brothers (OR 1.7, 95% CI 1.0 to 2.8), 1 or 2 (OR 3.1, 95% CI 2.2 to 4.3) and 3 or more (OR 3.9, 95% CI 2.9 to 5.2). Geographic regions of the province including and neighboring greater Montreal showed a lower OR than more peripheral regions (2.5, 95% CI 2.0 to 3.2 versus 4.1, 95% CI 2.9 to 5.7, p = 0.02).

CONCLUSIONS

Francophone men with large male sibships residing in remote areas may be at higher risk for familial prostate cancer and represent the ideal target for further efforts to determine the genetic component of prostate cancer in Quebec.

Prevalence of the BRCA2 6174 del T mutation in Israeli uveal melanoma patients

Substantial differences exist in the incidence rates of uveal melanoma (UM) among Israeli Jewish subpopulations: high in immigrants from North America and Europe (Ashkenazic) and low in immigrants from Africa and Asia (Sepharadic). This trend persists in Israeli-born individuals when stratified by their ancestral place of birth. There have been several anecdotal reports of uveal melanoma occurring in breast cancer families with mutations in the BRCA2 gene as well as one systematic study reporting BRCA2 mutations in UM. A single BRCA2 mutation, 6174 del T, occurs in about 1% of the Ashkenazic population and rarely in non-Ashkenazic. To assess the contribution of this germline mutation to uveal melanoma in Jewish Israeli patients, we tested this relationship through analysis of blood samples from a series of UM patients. A total of 153 cases (84 female, 69 male) were available for study, which represents 30% of all cases of UM diagnosed in Israel during the period 1984-1999 (82% for the period 1992-1999). Of the 143 UM patients for which a result could be obtained (4 due to refusals, 6 due to damage to the blood sample), 4 (2.8%, 95% confidence interval [CI] 0-5.6) carried the 6174 del T mutation. Assuming a population frequency of the mutation of 1% as estimated among Ashkenazic Jews in the United States, the probability of observing 4 or more carriers with the 6174 del T mutation, assuming no relationship between uveal melanoma and BRCA2, is 0.057. Although our study confirms the relationship between uveal melanoma and BRCA2, it is clear that the 6174 del T mutation accounts for only a small fraction of all Israeli UM cases. Therefore, BRCA2 mutations are likely to account for an even smaller proportion in populations with low frequencies of BRCA2 alterations.

Epithelial ovarian carcinoma and fertility of parents

We studied the fertility of the parents of 163 women with epithelial ovarian carcinoma in two hospitals in New York City, compared with the parents of 159 controls from similar neighborhoods. We used unconditional logistic regression to control for covariates, including parity, oral contraceptive use, age at menarche, and Jewish ancestry. Compared with women with zero or one sibling, those with two, three or four or more siblings had adjusted odds ratios (95% confidence intervals) of 0.91 (0.47-1.77), 0.61 (0.28-1.37), and 0.50 (0.26-0.98). On average, each additional sibling was associated with a risk reduction to 0.80 (0.66-0.98). These findings support the hypothesis that heritable conditions associated with reduced fertility of the subjects' parents may contribute to risk and may explain some of the effects of parity on the risk of this carcinoma. Alternatively, they may reflect some unidentified aspect of the environment experienced by girls growing up in small families. If confirmed in other data sets, these findings imply that sibship size might have confounded previous estimates of risk associated with a family history of cancer or with Jewish ethnicity.

Evaluation of the needs of male carriers of mutations in BRCA1 or BRCA2 who have undergone genetic counseling

To date, the concerns of men at risk of inheriting a BRCA1 mutation or a BRCA2 mutation have received little attention. It had been anticipated that few men would be interested in predictive testing when a BRCA mutation was identified in their family. However, these men are often affected emotionally by diagnoses of breast cancer in their relatives and may themselves harbor fears that cancer will develop. Male carriers of BRCA1/2 mutations are at increased risk of development of cancers of several types, including those of the breast and prostate. We conducted an evaluation of the needs and experiences of 59 male carriers of BRCA1/2 mutations followed at either the University of Toronto or Creighton University. We assessed their motivations for seeking genetic counseling and testing, involvement in family discussions of breast and ovarian cancer, risk perception, changes in cancer-screening practices, and overall satisfaction with the genetic-counseling process. The principal motivation for seeking genetic counseling was concern for their daughters. The majority (88%) of men participated in family conversations about breast and ovarian cancer, and 47% participated in conversations about prophylactic surgery. Most men believed that they were at increased risk of development of cancer (prostate, breast, colorectal, and skin cancers). However, fewer than one-half (43%) of the men with no previous diagnosis of cancer stated that their prostate cancer-surveillance practices had changed after they had received genetic test results. More than one-half (55%) had intrusive thoughts about their cancer risk. Although levels of satisfaction were high, practitioners should be aware of (a) potential pressures influencing men to request predictive testing, (b) the difficulties that men encounter in establishing surveillance regimens for breast and prostate cancer, and (c) the general lack of information about men's particular experiences in the medical community.