Risk of prostate, ovarian, and endometrial cancer among relatives of women with breast cancer

Detection of Cancer-Associated Gene Mutations in Urinary Cell-Free DNA among Prostate Cancer Patients in South Africa

Prostate cancer (PCa) is the most common cause of cancer death among African men. The presence of tumor-specific variations in cell-free DNA (cfDNA), such as mutations, microsatellite instability, and DNA methylation, has been explored as a source of biomarkers for cancer diagnosis. In this study, we investigated the diagnostic role of cfDNA among South African PCa patients. We performed whole exome sequencing (WES) of urinary cfDNA. We identified a novel panel of 31 significantly deregulated somatic mutated genes between PCa and benign prostatic hyperplasia (BPH). Additionally, we performed whole-genome sequencing (WGS) on matching PCa and normal prostate tissue in an independent PCa cohort from South Africa. Our results suggest that the mutations are of germline origin as they were also found in the normal prostate tissue. In conclusion, our study contributes to the knowledge of cfDNA as a biomarker for diagnosing PCa in the South African population.

BRCA Mutations in Prostate Cancer: Assessment, Implications and Treatment Considerations

Prostate cancer ranks fifth in cancer-related mortality in men worldwide. DNA damage is implicated in cancer and DNA damage response (DDR) pathways are in place against this to maintain genomic stability. Impaired DDR pathways play a role in prostate carcinogenesis and germline or somatic mutations in DDR genes have been found in both primary and metastatic prostate cancer. Among these, BRCA mutations have been found to be especially clinically relevant with a role for germline or somatic testing. Prostate cancer with DDR defects may be sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors which target proteins in a process called PARylation. Initially they were used to target BRCA-mutated tumor cells in a process of synthetic lethality. However, recent studies have found potential for PARP inhibitors in a variety of other genetic settings. In this review, we explore the mechanisms of DNA repair, potential for genomic analysis of prostate cancer and therapeutics of PARP inhibitors along with their safety profile.

First-degree family history of breast cancer is associated with prostate cancer risk: a systematic review and meta-analysis

Background

The relationship between first-degree family history of female breast cancer and prostate cancer risk in the general population remains unclear. We performed a meta-analysis to determine the association between first-degree family history of female breast cancer and prostate cancer risk.

Methods

Databases, including MEDLINE, Embase, and Web of Science, were searched for all associated studies that evaluated associations between first-degree family history of female breast cancer and prostate cancer risk up to December 31, 2018. Information on study characteristics and outcomes were extracted based on the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. The quality of evidence was assessed using the GRADE approach.

Results

Eighteen studies involving 17,004,892 individuals were included in the meta-analysis. Compared with no family history of female breast cancer, history of female breast cancer in first-degree relatives was associated with an increased risk of prostate cancer [relative risk (RR) 1.18, 95% confidence interval (CI) 1.12–1.25] with moderate-quality evidence. A history of breast cancer in mothers only (RR 1.19, 95% CI 1.10–1.28) and sisters only (RR 1.71, 95% CI 1.43–2.04) was associated with increased prostate cancer risk with moderate-quality evidence. However, a family history of breast cancer in daughters only was not associated with prostate cancer incidence (RR 1.74, 95% CI 0.74–4.12) with moderate-quality evidence. A family history of female breast cancer in first-degree relatives was associated with an 18% increased risk of lethal prostate cancer (95% CI 1.04–1.34) with low-quality evidence.

Conclusions

This review demonstrates that men with a family history of female breast cancer in first-degree relatives had an increased risk of prostate cancer, including risk of lethal prostate cancer. These findings may guide screening, earlier detection, and treatment of men with a family history of female breast cancer in first-degree relatives.

The significance of gene mutations across eight major cancer types

Mutations occur spontaneously, which can be induced by either chemicals (e.g. benzene) or biological factors (e.g. virus). Not all mutations cause noticeable changes in cellular functions. However, mutation in key cellular genes leads to developmental disorders. It is one of the main ways in which proto-oncogenes can be changed into their oncogenic state. The progressive accumulation of multiple mutations throughout life leads to cancer. In the past few decades, extensive research on cancer biology has discovered many genes and pathways having role in cancer development. In this review, we tried to summarize the current knowledge of mutational effect on different cancer types and its consequences in brief for future reference and guidance of researchers in cancer biology.

Family history of breast cancer increases the risk of prostate cancer: results from the EPICAP study

Introduction

Familial aggregation is now well established with an increased risk of prostate cancer in patients with a family history of prostate cancer in first degree relatives. The aim of this paper was to investigate the role of family history of cancer in first degree relatives in prostate cancer risk.

Results

As expected, a family history of prostate cancer in first-degree relatives was more frequent in cases than in controls (OR 3.10, 95% CI 2.32-4.15). A family history of early BCa (before age 50) in first-degree relatives was more frequent in cases than in controls (OR 1.79, 95% CI 1.09-2.94) with higher risk of aggressive PCa. The association was more pronounced for BCa in daughters (OR 15.26 95% CI 1.95-120).

Conclusions

In summary, a family history of BCa in first degree relatives before age 50 may increases the risk of PCa with higher Gleason score. This finding could suggest a specific prostate surveillance and/or genetic counselling for men who present such familial history.

Methods

EPIdemiological study of Prostate CAncer (EPICAP) is a population-based case-control study specifically designed to investigate the role of environmental and genetic factors in prostate cancer. Detailed information on family history of cancer in first degree relatives (parents, brothers and sisters, children) was collected as well as the age of occurrence and the localization of each cancer. Overall, 819 cases and 879 controls have been included.

The role of BRCA1 and BRCA2 mutations in prostate, pancreatic and stomach cancers

The association of germline mutations in the breast cancer susceptibility gene 1 (BRCA1) and the breast cancer susceptibility gene 2 (BRCA2) with the development of breast and ovarian cancers have been widely researched and recognised. It is known that these genes function at multiple sites in the body. Research has subsequently evolved into the connection of BRCA1/2 with cancers at other sites within the body. This review examines the association of BRCA1/2 germline gene mutations with prostate, pancreatic and stomach cancers. An extensive literature search revealed conflicting findings regarding the association of BRCA1/2 gene mutations with these cancers. Most studies suggest that there is an association between BRCA1/2 mutations and carcinoma of the prostate, pancreas and stomach, but some reports propose that such a correlation may be due to factors other than possessing a mutated BRCA1/2 gene, and other associations may be revealed as further epidemiological information becomes available. The review concludes that as more knowledge arises about the mechanisms of BRCA1/2 gene mutations, it should pave the way for future screening programmes to be applied effectively.

Risk of breast cancer and family history of other cancers in first-degree relatives in Chinese women: a case control study

Background

Few studies have systematically reported the relationship between the risk of breast cancer and family history of other cancers. This study was designed to systematically determine the relationship between breast cancer risk and family history of other cancers in first-degree relatives.

Methods

Between January 2006 and June 2011, 823 women diagnosed with breast cancer were included, and age-matched women diagnosed with benign breast disease were selected as controls. Family history of other cancers in first-degree relatives was recorded by trained reviewers. Multivariate logistic regression was applied to analyze the relationships.

Results

A family history of esophagus cancer (OR: 2.70, 95% CI: 1.11 – 6.57), lung cancer (OR: 2.49 95% CI: 1.10 – 5.65), digestive system cancer (OR: 1.79, 95% CI: 1.14 – 2.79) and any cancer (OR: 2.13, 95% CI: 1.49 – 3.04) in first-degree relatives was directly associated with increased breast cancer risk. In subgroup analysis, the risk of hormone receptor positive breast cancer was increased in subjects with a family history of lung cancer (OR: 3.37, 95% CI: 1.45 – 7.82), while the risk of hormone receptor negative breast cancer was increased in subjects with a family history of esophagus cancer (OR: 6.19, 95% CI: 2.30 – 16.71), uterus cancer (OR: 6.92, 95% CI: 1.12 – 42.89), digestive tract cancer (OR: 2.05, 95% CI: 1.03 – 4.10) and gynecology cancer (OR: 6.79, 95% CI: 1.46 – 31.65). Additionally, a significant increase in breast cancer was observed with a family history of digestive system cancer for subjects 50 y and younger (OR: 1.88, 95% CI: 1.03 – 3.43), not for subjects 50 y older (OR: 1.67, 95% CI: 0.86 – 3.25).

Conclusions

Breast cancer aggregates in families with several types of cancer especially for digestive system cancer. The influence of a family history of other cancers seems more likely to be limited to hormone receptor negative breast cancer.

Implications of differences in expression of sarcosine metabolism-related proteins according to the molecular subtype of breast cancer

Background

The goal of this study was to investigate the expression of sarcosine metabolism-related proteins, namely glycine N-methyltransferase (GNMT), sarcosine dehydrogenase (SARDH), and l-pipecolic acid oxidase (PIPOX), in the different breast cancer subtypes and to assess the implications of differences in expression pattern according to subtype.

Methods

We analyzed the expression of GNMT, SARDH, and PIPOX in a tissue microarray of 721 breast cancer cases using immunohistochemistry (IHC). We classified breast cancer cases into subtype luminal A, luminal B, HER-2, and triple negative breast cancer (TNBC) according to the status for the estrogen receptor (ER), progesterone receptor (PR), HER-2, and Ki-67. Sarcosine metabolism phenotype was stratified according to IHC results for GNMT, SARDH, and PIPOX: GNMT(+), SARDH and PIPOX(-) was classified as high sarcosine type; GNMT(-), SARDH or PIPOX(-) as low sarcosine type; GNMT(+), SARDH or PIPOX(+) as intermediate sarcosine type, and GNMT(-), SARDH and PIPOX(-) as null type.

Results

Expression of sarcosine metabolism-related proteins differed significantly according to breast cancer subtype (GNMT, p = 0.005; SARDH, p = 0.012; tumoral PIPOX, p = 0.008; stromal PIPOX, p < 0.001). These proteins were the most frequently expressed in HER-2 type tumors and the least in TNBC. Sarcosine metabolism phenotype also varied according to breast cancer subtype, with high sarcosine type the most common in HER-2, and null type the most common in TNBC (p = 0.003). Univariate analysis revealed that GNMT expression (p = 0.042), tumoral PIPOX negativity (p = 0.039), and high sarcosine type (p = 0.021) were associated with shorter disease-free survival (DFS). Multivariate analysis also revealed GNMT expression was an independent factor for shorter DFS (hazard ratio: 2.408, 95% CI: 1.154-5.024, p = 0.019).

Conclusion

Expressions of sarcosine metabolism-related proteins varied according to subtype of breast cancer, with HER-2 type tumors showing elevated expression of these proteins, and TNBC subtype showing decreased expression of these proteins. Expression of sarcosine metabolism-related proteins was also associated with breast cancer prognosis.

Reported family history of cancer in 1,271 prostate cancer cases and 1,909 controls

Prostate cancer risk has been associated with a family history of the disease. A two- to three-fold increase in risk has been observed in several studies. Details concerning modification of this risk by age, type of familial history of prostate cancer, and possible involvement of history of cancer at other sites have been less well documented. This case-control study of 1,271 prostate cancer patients and 1,909 control subjects admitted to Roswell Park Cancer Institute in Buffalo, NY, found age-adjusted increased risk associated with reporting a history of prostate cancer in a father (RR = 2.3, 95% Cl 1.4-3.3) or brother (RR = 2.5, 95% Cl 1.6-3.9). Subjects with both a father and brother affected had a 6.5-fold (95% Cl 1.4-30.5) increased risk of prostate cancer. Greater risk were observed at younger ages of diagnosis. Risks associated with reporting a father or a brother affected were not significantly elevated for patients over age 70 at diagnosis. No significant differences in patients reporting histories of cancer other than prostate cancer were observed regardless of relationship, age at diagnosis, or type of cancer examined. These observations from a large cancer patient population may be useful when making recommendations for cost-effective prostate cancer screening and for directing investigators to the potentially most informative subjects.

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 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.

BRCA2 is a moderate penetrance gene contributing to young-onset prostate cancer: implications for genetic testing in prostate cancer patients

BACKGROUND

A family history of prostate cancer (PrCa) is a strong risk factor for the disease, indicating that inherited factors are important in this disease. We previously estimated that about 2% of PrCa cases diagnosed ≤ 55 years harbour a BRCA2 mutation and PrCa among BRCA2 carriers has been shown to be more aggressive, with poorer survival.

METHODS

To further evaluate the role of BRCA2 in PrCa predisposition, we screened 1864 men with PrCa aged between 36 and 88 years. We analysed the BRCA2 gene using a novel high-throughput multiplex fluorescence heteroduplex detection system developed for the ABI3130xl genetic analyzer.

RESULTS

We identified 19 protein-truncating mutations, 3 in-frame deletions and 69 missense variants of uncertain significance (UV) in our sample set. All the carriers of truncating mutations developed PrCa at ≤ 65 years, with a prevalence of BRCA2 mutation of 1.20% for cases in this age group.

CONCLUSION

Based on the estimated frequency of BRCA2 mutations in the United Kingdom we estimate that germline mutations in the BRCA2 gene confer an ∼ 8.6-fold increased risk of PrCa by age 65, corresponding to an absolute risk of ∼ 15% by age 65. These results suggest that routine testing of early onset PrCa cases for germline BRCA2 mutations will further help to refine the prevalence and risk associated with BRCA2 mutations and may be useful for guiding management options.

Prostate cancer in BRCA2 germline mutation carriers is associated with poorer prognosis

Background:

The germline BRCA2 mutation is associated with increased prostate cancer (PrCa) risk. We have assessed survival in young PrCa cases with a germline mutation in BRCA2 and investigated loss of heterozygosity at BRCA2 in their tumours.

Methods:

Two cohorts were compared: one was a group with young-onset PrCa, tested for germline BRCA2 mutations (6 of 263 cases had a germline BRAC2 mutation), and the second was a validation set consisting of a clinical set from Manchester of known BRCA2 mutuation carriers (15 cases) with PrCa. Survival data were compared with a control series of patients in a single clinic as determined by Kaplan–Meier estimates. Loss of heterozygosity was tested for in the DNA of tumour tissue of the young-onset group by typing four microsatellite markers that flanked the BRCA2 gene, followed by sequencing.

Results:

Median survival of all PrCa cases with a germline BRCA2 mutation was shorter at 4.8 years than was survival in controls at 8.5 years (P=0.002). Loss of heterozygosity was found in the majority of tumours of BRCA2 mutation carriers. Multivariate analysis confirmed that the poorer survival of PrCa in BRCA2 mutation carriers is associated with the germline BRCA2 mutation per se.

Conclusion:

BRCA2 germline mutation is an independent prognostic factor for survival in PrCa. Such patients should not be managed with active surveillance as they have more aggressive disease.

Brca2 and Trp53 deficiency cooperate in the progression of mouse prostate tumourigenesis

Epidemiological studies have shown that one of the strongest risk factors for prostate cancer is a family history of the disease, suggesting that inherited factors play a major role in prostate cancer susceptibility. Germline mutations in BRCA2 predispose to breast and ovarian cancer with its predominant tumour suppressor function thought to be the repair of DNA double-strand breaks. BRCA2 has also been implicated in prostate cancer etiology, but it is unclear the impact that mutations in this gene have on prostate tumourigenesis. Here we have undertaken a genetic analysis in the mouse to determine the role of Brca2 in the adult prostate. We show that deletion of Brca2 specifically in prostate epithelia results in focal hyperplasia and low-grade prostate intraepithelial neoplasia (PIN) in animals over 12 months of age. Simultaneous deletion of Brca2 and the tumour suppressor Trp53 in prostate epithelia gave rise to focal hyperplasia and atypical cells at 6 months, leading to high-grade PIN in animals from 12 months. Epithelial cells in these lesions show an increase in DNA damage and have higher levels of proliferation, but also elevated apoptosis. Castration of Brca2;Trp53 mutant animals led to regression of PIN lesions, but atypical cells persisted that continued to proliferate and express nuclear androgen receptor. This study provides evidence that Brca2 can act as a tumour suppressor in the prostate, and the model we describe should prove useful in the development of new therapeutic approaches.

In Western countries, prostate cancer is the most common male cancer and the second biggest cause of cancer-related deaths in men. Men with a familial history of either breast or ovarian cancer have an elevated predisposition to prostate cancer, suggesting there is a genetic element to this disease. Indeed, the inheritance of a mutated form of the breast cancer susceptibility gene BRCA2 has been linked to the development of prostate cancer, although the precise role that BRCA2 dysfunction plays in the development of prostate cancer is unclear. To address this, we have generated an animal model in which the mouse Brca2 gene is specifically deleted in the adult prostate. These mice develop precancerous prostate lesions, which progress in severity and incidence with the loss-of-function of an additional tumour suppressor, Trp53. Importantly, blocking male steroidal hormone production by castration leads to partial regression of the prostate lesions, however cells continue to proliferate after androgen withdrawal. This suggests human BRCA2 mutant prostate tumours, like the majority of prostate cancers, will respond to hormone therapy, but will relapse, as frequently occurs in this disease. In summary, our model suggests that BRCA2 acts as a tumour suppressor in the prostate and provides a pre-invasive model to test novel therapeutics.

Prolonged survival in a patient with BRCA2 associated metastatic pancreatic cancer after exposure to camptothecin: a case report and review of literature

Germline mutations in the tumor suppressor genes BRCA1 and BRCA2 have been proven to predict a drastically increased lifetime risk of breast and ovarian cancers in the individuals who carry them. A number of studies have shown that the third most common cancer associated with these mutations is pancreatic cancer. There is evidence of in vivo therapeutic response to the cross-linking agents; such as mitomycin C (MMC) in BRCA2 mutated pancreatic cell lines. We present the 'first patient' who achieved a prolonged survival on irinotecan, a topoisomerase I poison, administered alone and then in combination with cetuximab. Our patient presented at the age of 71 years with a dual diagnosis of prostate carcinoma and pancreatic carcinoma on the background of a significant family history of cancer. On genetic testing, he was found to have the common Ashkenazi Jewish BRCA2 mutation, 6174delT. To date, he has received 22 cycles of docetaxel, capecitabine, and gemcitibine followed by single agent irinotecan every 3 weeks for 27 cycles, and then weekly cetuximab was added to the regimen at cycle 28. His disease then remained stable for an additional 13 months. He did not have mutated KRAS. MMC and oxaliplatin was then introduced upon progression. His current treatment is MMC plus irinotecan as oxaliplatin was removed because of a hypersensitivity reaction. This patient is stable with an Eastern Cooperative Oncology Group performance status of 0, four and a half years (56 months) after his initial diagnosis. DNA topoisomerases are nuclear enzymes responsible for the regulation of DNA topology. They are involved in basic DNA transactions during replication, transcription, and recombination. BRCA2-deficient human cells are deficient in the repair of double-strand breaks and DNA cross-links through homologous recombination. Active poisons of topoisomerase I include derivatives of camptothecin. Our case is the first clinical piece of evidence that demonstrates an increased sensitivity to camptothecin-11 and a reduced topoisomerase I relaxation activity in BRCA2 associated pancreatic cancer. This case shows that patients with metastatic pancreatic carcinoma and BRCA2 mutations may have disease that is biologically more chemosensitive and consequently prolong survival despite prognostically unfavorable disease.

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.

A compendium of familial relative risks of cancer among first degree relatives: a population-based study

Familial clustering of cancer is expected to occur at practically all anatomical sites. However, few studies have had sufficient size to investigate different sites simultaneously and with adjustment for confounders. We evaluated familial clustering in the Netherlands Cohort Study in which 120,852 men and women, aged 55-69 years in 1986 were followed up for 13.3 years. 14,025 Probands, 6,629 parents and 4,271 siblings were diagnosed with cancer. Relative Risks (RR) of cancer in first degree family members were calculated by using multivariable Cox regression analyses. We also calculated false-positive reporting probabilities. Significant concordant familial clustering was observed for stomach (RR(father) = 1.89, RR(parent) = 1.66, RR(sister) = 3.33, RR(sibling) = 2.38, RR(1st degree) = 1.69), colon/rectum (RR(father) = 1.82, RR(mother) = 1.83, RR(parent) = 1.88, RR(1st degree) = 1.56), lung (RR(brother) = 1.50) and breast cancer (RR(mother) = 1.65, RR(sister) = 1.72, RR(1st degree) = 1.72) with low false-positive reporting probabilities. Significant discordant familial clustering has been observed for combinations of pancreas-colon/rectum (RR(mother) = 2.42, RR(parent) = 1.89, RR(1st degree) = 1.73), larynx-lung (RR(father) = 3.35, RR(parent) = 2.84, RR(1st degree) = 2.30), lung-oesophagus (RR(sibling) = 3.49), breast-bladder (RR(father) = 2.79, RR(parent) = 2.61), endometrium-stomach (RR(mother) = 2.32), ovarium-oesophagus (RR(1stdegree) = 4.19), prostate-colon/rectum (RR(parent) = 1.46) and bladder-larynx/pharynx (RR(father) = 2.49) cancer, although false-positive reporting probabilities were higher for these associations. Familial clustering of cancer occurs at most sites but is generally modest. Some observed discordant familial clustering is surprising but should be interpreted with caution as their prior probability is low.

Prostate cancer progression and survival in BRCA2 mutation carriers

BACKGROUND

Mutations in the BRCA2 gene are associated with an increased risk of prostate cancer, but it is not known whether they are associated with progression of the disease. We compared prostate cancer-specific survival, disease stage, and tumor grade between prostate cancer patients carrying the Icelandic BRCA2 999del5 founder mutation and noncarriers.

METHODS

Using population-based registries, we identified all 596 prostate cancer patients who were diagnosed in Iceland during 1955 through 2004 among 29603 male relatives of unselected breast cancer probands. BRCA2 mutation status could be determined for 527 patients (88.4%). Stage and grade were abstracted from original records, blindly with respect to mutation status, for a subgroup of 89 patients that included all mutation carriers and, for each carrier, two control patients without the BRCA2 999del5 mutation who were matched to the carrier on years of diagnosis and birth. Hazard ratios (HRs) and 95% confidence intervals (CIs) for prostate cancer-specific survival were estimated using multivariable regression models. All statistical tests were two-sided.

RESULTS

The mutation was carried by 30 patients (5.7%). Compared with noncarriers, BRCA2 999del5 mutation carriers had a lower mean age at diagnosis (69.0 years versus 74.0 years; P = .002), more advanced tumor stage (stages 3 or 4, 79.3% versus 38.6%; P < .001), higher tumor grade (grades G3-4, 84.0% versus 52.7%, P = .007), and shorter median survival time (2.1 years, 95% CI = 1.4 to 3.6 years, versus 12.4 years, 95% CI = 9.9 to 19.7 years). Carrying the BRCA2 999del5 mutation was also associated with an increased risk of dying from prostate cancer (adjusting for year of diagnosis and birth, HR = 3.42, 95% CI = 2.12 to 5.51); the association remained after adjustment for stage and grade (HR = 2.35, 95% CI = 1.08 to 5.11). The prognosis of BRCA2 999del5 mutation carriers was not associated with period of diagnosis or with relatedness to breast cancer probands.

CONCLUSIONS

The Icelandic BRCA2 999del5 founder mutation was strongly associated with rapidly progressing lethal prostate cancer.

Germline mutations in the BRCA2 gene and susceptibility to hereditary prostate cancer

PURPOSE

Several epidemiologic studies have reported that carriers of germline mutations in the BRCA2 gene have an increased risk of prostate cancer, with the highest risk observed in men diagnosed at earlier ages. However, studies of the contribution of BRCA2 mutations to the etiology of hereditary prostate cancer (HPC) have been inconsistent.

EXPERIMENTAL DESIGN

To further address this issue, 266 subjects from 194 HPC families participating in the Seattle-based Prostate Cancer Genetic Research Study were screened for BRCA2 mutations by sequencing the coding regions, intron-exon boundaries, and suspected regulatory elements of this gene. Of selected HPC families, 32 had multiple breast or ovarian cancer cases, 16 were Jewish, 8 had a pancreatic cancer case, and 138 had at least one affected man diagnosed with prostate cancer at an early age (<60 years).

RESULTS

No disease-associated protein truncating BRCA2 mutations were found in 266 subjects from HPC families. There were 61 DNA sequence variants, of which 31 (50.8%) changed the predicted amino acids. No associations were found between these missense changes and family characteristics. Among affected men with prostate cancer, there were no statistically significant differences between the genotype frequencies of DNA variants with a minor allele frequency of 1% or higher and between the strata defined by median age at diagnosis or by clinical features.

CONCLUSION

No evidence was found in this study for an association between BRCA2 mutations and susceptibility to HPC in men selected from high-risk families.

Effect of familial history and smoking on common cancer risks in Japan

BACKGROUND

Inherited genetic predispositions are important risk factors for the development of cancer in general. To determine genetic susceptibility for 14 common cancers, a case-control study of the impact of a family history of cancer in first-degree relatives was conducted. The authors further evaluated the effect modification by habitual smoking with adjustment for other confounding environmental factors.

METHODS

In total, 18,836 cancer cases and 28,125 age-matched and sex-matched controls, confirmed as being free of cancer, were recruited. Odds ratios (ORs) and 95% confidence intervals were determined by multiple logistic regression analysis, including stratification by family history for 14 cancer sites and interactions with a smoking history.

RESULTS

The associations between family history and risk of cancer were generally stronger at the same sites than across cancer sites. Risks to first-degree relatives at the same sites were found to be significantly elevated with 8 of 14 cancer sites; especially high ORs were found for prostate and thyroid cancers. Some across-site associations were observed; in particular, a reciprocal association between breast and prostate cancer was found. The interaction between family history and smoking history for breast cancer was found to be statistically significant. There was no statistical evidence for the interactions in other sites, but among subjects with a family history, the ORs were found to be higher in smokers compared with nonsmokers.

CONCLUSIONS

The results of the current study support the hypothesis of a genetic susceptibility to cancers in family members. For breast cancer, the interaction between family history and smoking history was observed to be significant.

An observational study of cancers among female partners of UK-resident prostate cancer patients

Epidemiological studies suggest that environment plays an important role in the aetiology of cancer. Thus, if a cancer (e.g. prostate cancer (CaP)) arises in males, one could hypothesize that risk in co-habiting partners might be elevated. We conducted an observational-questionnaire study in NorthWest England evaluating the medical histories of CaP males and their female partners. Details regarding previous partners (>10y) were also sought. Self-filled questionnaires were obtained from 548 males, 81 of whom provided information on previous female partners (PFPs) and 448 current female partners (CFPs). Observed rates over a 30-y period (1971-2001) of common cancers (breast, colorectal or lung) in female partners and colorectal cancer in males were compared to the cumulative expected probability (estimated using crude incidence rates for England provided by the Office of National Statistics, UK) using a Chi-Square Goodness-of-Fit test. Colorectal cancers in males were similar to national estimates. Rates for breast, colorectal or lung cancer among CFPs and the total female cohort (CFPs plus PFPs) were also similar to estimates. However, observed rates for breast or lung cancers among PFPs were significantly (P< or =0.001) elevated. Our results suggest no evidence of elevated risk among female partners of CaP males.

Cancer incidence in first-degree relatives of a population-based set of cases of early-onset breast cancer

Reliable determination of familial risks for cancer is important for clinical counselling, cancer prevention and understanding cancer aetiology. Family-based gene identification efforts may be targeted if the risks are well characterised and the mode of inheritance is identified. Early-onset breast cancer in a family member is a risk indicator for cancer among first-degree relatives; however, the familial risk pattern has not been assessed fully in population-based incidence studies. We estimated the risks for cancers of the breast, ovary and other sites among the first-degree relatives of 8868 patients in whom breast cancer was diagnosed before they reached the age of 50 years (diagnosed during the period 1943-1999). Population registers and parish records were used to identify 31,235 first-degree relatives, who were followed up to 31 December 2002 for occurrence of cancer by linkage to the Danish Cancer Registry. The observed incidence rates were compared with national rates adjusted for age, sex and calendar period. Overall, 39% of the 674 cases of breast cancer and 43% of the 143 cases of ovarian cancer among relatives were associated with a diagnosis of early-onset breast cancer in a family member. Among relatives under 50 years of age, the proportions were 56% and 58%, respectively, and among relatives 50 years or above the proportions were approximately 30% and 10%. In addition, a slightly but significantly increased risk for cancer of the cervix uteri was observed among relatives, and among those under 50 years of age, we found significantly increased risks for cancers of the colon and gall-bladder. In conclusion, the excess risk for breast cancer in first-degree relatives is large and remains sizable in the subgroup of female relatives aged 50 years or older, and that mutations in BRCA1/2 seem to explain only half of breast cancer cases attributable to family history.

A history of cancer in the husband does not increase the risk of breast cancer

Spouses share the home environment, and dietary and other lifestyle habits. Furthermore, a cancer diagnosis in the husband is a stressful event for the wife also. Thus, a history of cancer in the husband may be an indicator of breast cancer risk. We investigated the issue in a large Italian multicentric case-control study on 2,588 women with incident breast cancer and 2,569 female hospital controls, admitted for acute, non neoplastic diseases. The adjusted odds ratio (OR) was 1.0 (95% confidence interval, CI, 0.7-1.4) for a history of any type of cancer in the husband, 1.0 (95% 0.4-2.7) for stomach, 0.7 (95% 0.2-2.3) for intestinal (chiefly colorectal), 0.9 (95% CI 0.5-1.7) for lung, and 1.3 (95% CI 0.4-4.3) for prostate cancer. The OR was close to unity also when data were analyzed in separate strata of patient's or husband's age, patient's education, or vital status of the husband. This study suggests that women whose husband had a diagnosis of cancer are not at increased risk of breast cancer, although results for individual cancer sites should be interpreted with caution, due to small numbers.

Molecular changes in prostatic cancer

Prostate cancer is one of the most commonly diagnosed and potentially devastating cancers in men, throughout the world. However, the clinical manifestation of this disease varies greatly, from indolent tumours, requiring little or no treatment, to those aggressive cancers which require radical therapies. Prostate cancer, like all other cancers, develops and progresses as a consequence of an accumulation of genetic changes. While several putative genes have been isolated for the development of breast, ovarian and colon cancer, the aetiology and pathogenesis of prostate cancer remains poorly understood. In this review, we discuss important genetic markers in early, metastatic and hormone refractory prostate cancer which may, in the future, be used as markers for diagnosis and prognosis, as well as targets for therapeutic intervention.

Cancer as a complex phenotype: pattern of cancer distribution within and beyond the nuclear family

BACKGROUND

The contribution of low-penetrant susceptibility variants to cancer is not clear. With the aim of searching for genetic factors that contribute to cancer at one or more sites in the body, we have analyzed familial aggregation of cancer in extended families based on all cancer cases diagnosed in Iceland over almost half a century.

METHODS AND FINDINGS

We have estimated risk ratios (RRs) of cancer for first- and up to fifth-degree relatives both within and between all types of cancers diagnosed in Iceland from 1955 to 2002 by linking patient information from the Icelandic Cancer Registry to an extensive genealogical database, containing all living Icelanders and most of their ancestors since the settlement of Iceland. We evaluated the significance of the familial clustering for each relationship separately, all relationships combined (first- to fifth-degree relatives) and for close (first- and second-degree) and distant (third- to fifth-degree) relatives. Most cancer sites demonstrate a significantly increased RR for the same cancer, beyond the nuclear family. Significantly increased familial clustering between different cancer sites is also documented in both close and distant relatives. Some of these associations have been suggested previously but others not.

CONCLUSION

We conclude that genetic factors are involved in the etiology of many cancers and that these factors are in some cases shared by different cancer sites. However, a significantly increased RR conferred upon mates of patients with cancer at some sites indicates that shared environment or nonrandom mating for certain risk factors also play a role in the familial clustering of cancer. Our results indicate that cancer is a complex, often non-site-specific disease for which increased risk extends beyond the nuclear family.

Unravelling the genetics of prostate cancer

This review describes what is currently known about the genetics of prostate cancer. Traditionally, the genetics of a suspected inherited cancer predisposition have generally been thought of in terms of a single, high-risk gene with a dominant mode of inheritance. Such a gene might be observed in families, as has been documented in familial breast cancer (BRCA1/2), familial colorectal cancer (HNPCC), retinoblastoma (RB1), and Wilms tumor (WT1). This review investigates the evidence for the existence, first of familial prostate cancer, and second, for the presence of such a high-risk gene in those families by epidemiological and experimental approaches. Another current area of interest in prostate cancer is the investigation of the contribution of common lower penetrance genes to the disease. This alternative approach has become popular, as it raises the issue of frequently seen genetic variations such as single nucleotide polymorphisms (SNPs) having relevance to the risk of developing the disease. Finally, this article will explore the way forward, with emphasis on worldwide collaboration from teams attempting to find the genes responsible for the disease and investment in new technologies that will aid in their discovery.

Familial association of histology specific breast cancers with cancers at other sites

Breast cancer histologies show important differences in their incidence pattern, method of detection and management. Aggregation of breast cancer occurs also in families diagnosed for cancer at sites different from the breast. Therefore, the familial association of histology specific breast cancers with cancers at other sites is of great interest. The nationwide Swedish Family-Cancer Database was used to calculate standardised incidence ratios (SIRs) for breast cancer when parents or sibling were diagnosed with cancer at the most common sites. Significant SIRs were found when parents had breast, ovarian, laryngeal, endometrial, prostate, lung and colon cancers. If women were diagnosed before the age of 50 years, the SIRs were significant when parents were diagnosed with breast, ovarian, and prostate cancers, and leukaemia, and when siblings were diagnosed with squamous cell skin, pancreatic, breast and endometrial cancers. If mothers were diagnosed with breast cancer, histology-specific SIRs were ranked as comedo > tubular > ductal > lobular; SIR for medullary carcinoma was not significant but it was high when mothers presented with ovarian cancer. Other associations were between the upper aerodigestive tract and lobular, colon and comedo, larynx and ductal cancer. Moreover, cervical cancer was associated with comedo and endometrial cancer with the medullary histology. In conclusion, histology-specific breast cancers were associated with specific cancer sites and the strength of the association varied among histologies.

Familial risk of prostate cancer in Iceland

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

Novel perspective: focusing on the X chromosome in reproductive cancers

In an XX female, one of the two X chromosomes has been inactivated during early embryonic life to achieve a compensation of X-linked gene products between males and females, leaving only one allele of X-linked genes functional. There are some X-linked genes escaping the X-inactivation, i.e., being expressed from both alleles. Escape from X-inactivation varies at different levels; some genes have both alleles active in some women but only one allele active in others, whereas some other genes have both alleles active in neoplastic tissue but only one allele active normally. The X-inactivation may be considered functionally equivalent to a loss of heterozygosity (LOH) for some genes, whereas escape from X-inactivation may be equivalent to functional gene amplification for others. The physiological LOH may make X-linked tumor suppressor genes lose their function more easily, compared with autosomal tumor suppressor genes, thus predisposing women to cancer formation more easily. Moreover, the human X chromosome contains many genes related to cancer or to sex and reproduction. All these properties of the X chromosome suggest that it may play more important roles than any autosomal chromosome in the development and progression of reproductive and urologic cancers.

BRCA2 and pancreatic cancer

Many factors, including a family history of cancer, have been implicated in the development of pancreatic cancer. Among these factors, germline BRCA2 mutations have been clearly associated with the development of this disease, while mutations in BRCA1 appear to have a limited role. Patients with pancreatic cancer and germline BRCA2 mutations tend to be Ashkenazi Jewish, have a younger than average age of onset, and in many cases, lack family history for breast, ovarian, or pancreatic cancers. In addition, somatic mutations of BRCA2 appear to be rare in tumors of the pancreas. The mechanism by which mutant BRCA2 contributes to development of pancreatic cancers is not well understood. However, it appears that inactivation of several independent functions of BRCA2 including regulation of gene transcription, chromatin remodeling, cell growth, DNA damage repair, and chromosomal instability may provide a pathophysiological basis for the association of BRCA2 mutations and pancreatic cancer.

Cancer incidence in relatives of a population-based set of cases of early-onset breast cancer with a known BRCA1 and BRCA2 mutation status

BACKGROUND

Relatives of breast cancer cases have an increased risk of the disease. The risk increases with increasing numbers and decreasing age of onset of affected relatives. In families with a BRCA1 or a BRCA2 mutation, individual carrier status predicts the risk of breast cancer. In relatives of cases where both BRCA1 and BRCA2 mutations are excluded, the risk remains undetermined.

METHODS

Standardized incidence ratios (SIRs) and cumulative cancer incidences were calculated for relatives of a population-based set of early-onset breast cancer index cases (younger than age 41 years) with a defined BRCA mutation status (n = 203).

RESULTS

In first-degree relatives (FDRs) of mutation-negative cases, breast cancer incidences (SIR = 2.3), prostate cancer incidences (SIR = 1.7), cervix cancer incidences (SIR = 3.3) and nonmelanoma skin cancer incidences (SIR = 2.8) were increased. The risks of breast cancer, prostate cancer and nonmelanoma skin cancer were further increased in FDRs of breast cancer cases younger than 36 years of age. In high-risk individuals with at least one relative with breast cancer apart from the index case, but no BRCA mutation in the family, breast cancer incidence was increased (SIR = 5.3); again the prostate cancer incidence was elevated (SIR = 2.5). The cumulative incidence of breast cancer at ages 50 and 70 years for FDRs of index cases without a BRCA mutation was 3.6% and 12.8%, respectively. Similarly, the cumulative incidence of breast cancer for high-risk women was 6.3% and 21.1% at ages 50 and 70 years, and that for FDRs of BRCA mutation carriers was 17.2% and 27.7% at the same ages.

CONCLUSION

The incidence of breast cancer is increased for FDRs of women with early-onset breast cancer irrespective of the BRCA status in the family. Risk increases with decreasing age and with increasing number of affected relatives. The incidences of prostate cancer, cervix cancer and nonmelanoma skin cancer are elevated for FDRs of early-onset breast cancer cases without a BRCA mutation, indicating a possible association between these cancers and early-onset breast cancer.

BRCA2 mutation carriers, reproductive factors and breast cancer risk

BACKGROUND

Germline mutations in the BRCA genes dramatically increase the risk of breast cancer. In the general population, breast cancer risk is affected by age at menarche, by age at first birth, by the number of births and by the duration of breast feeding. Whether this is true for mutation carriers is not clear.

METHODS

In a case-control study, nested in a population-based cohort of the Icelandic Cancer Detection Clinic, two groups of cases were defined, matched on year of birth, on age at diagnosis and on age when giving information on reproductive factors: 100 carriers of the Icelandic founder BRCA2 mutation 999del5, and 361 BRCA2-negative cases. The mean age at diagnosis was 48 years. There were 1000 women in a matched group of unaffected controls. Conditional logistic regression was used for the analysis.

RESULTS

An increased number of births was associated with a decreased risk of breast cancer in BRCA2-negative cases but not in BRCA2-positive cases. A negative association between risk and duration of breast feeding was observed only in the mutation carriers. These associations were not statistically significant, but the effects of the two variables differed significantly according to mutation status (P = 0.007 and P = 0.045 for interaction with number of births and with duration of breast feeding, respectively). This was maintained when limiting the analysis to women diagnosed older than the age of 40 years.

CONCLUSION

The association between breast cancer and the number of pregnancies and between breast cancer and the duration of breast feeding was not the same for carriers and noncarriers of a detrimental BRCA2 mutation. In the context of other epidemiological and laboratory studies, this may indicate that the product of the BRCA2 gene has a function relating to the differentiation of epithelial tissue in the breast.

Segregation analysis of 389 Icelandic pedigrees with Breast and prostate cancer

Breast cancer and prostate cancer are the most commonly occurring cancers in females and males, respectively. The objective of this project was to test the hypothesis that breast cancer in females and prostate cancer in males represent homologous cancers that may be controlled by one or more common unidentified genes that may explain some of the observed familial aggregation. We modeled the transmission of a breast-prostate cancer phenotype in 389 pedigrees ascertained through a breast cancer proband drawn from the Icelandic Cancer Registry. Assuming that age at diagnosis of this combined phenotype followed a logistic distribution, segregation analyses were performed to evaluate residual parental effects, a sibship covariate, and a dichotomous cohort effect. The most parsimonious model was a Mendelian codominant model, which could partly explain the familial aggregation of both cancers. Inheritance of a putative high-risk allele (A) predicted gender-specific mean ages of onset for females as 53.8 years, 59.7 years, and 65.6 years for the putative AA, AB, and BB genotypes, respectively. Similarly, the predicted means were 73.7 years, 75.6 years, and 78.3 years, respectively, among males. Under this codominant model, the lifetime risk of a woman being affected was 19% by age 80 years. This implies that when prostate cancer among male relatives of breast cancer probands (unselected for family history or early-onset disease) is considered a pleiotrophic effect of the same gene that increases the risk for breast cancer, women are predicted to have a less than 1 in 5 risk of developing breast cancer when they carry the putative high-risk allele. However, this is a higher risk than in the general Icelandic population. Our results suggest that BRCA2 mutations alone are inadequate to explain all of the excess clustering of prostate cancer cases in families of breast cancer probands, and that additional genes conferring excess risk to both breast and prostate cancer may exist in this population.

Immunohistological detection of BRAF25 in human prostate tumor and cancer specimens

BRAF25 is an alternatively spliced protein of BRAF35 (see associated paper). We have mapped the BRAF25 gene to chromosome sub-band 19p13.3, a region where loss of chromosomal heterozygosity has been reported in about 50% of ovarian cancers. Because of the high incidence of genetic links of prostate cancer to breast and ovarian cancers, we investigated the BRAF25 expression in the prostate specimens. Immunohistochemical analysis using antibodies specific for BRAF25 revealed a strong immunostaining in sections of the benign prostatic hyperplasia (BPH). The staining was concentrated on the nuclei of cells facing the lumen of prostatic glands, even though the sporadic nuclei of cells in stromas were also stained. However, the expression of BRAF25 was dramatically reduced in intermediate prostate cancer and absent in advanced prostate cancer. Preincubation of the antibody with the immunizing peptide abolished immunostaining in BPH specimens. Therefore, the expression of BRAF25 was gradually lost in prostate cancer.

The effect of a single BRCA2 mutation on cancer in Iceland

OBJECTIVE

To estimate the risk of malignant diseases in families of probands with the same mutation in the BRCA2 gene.

DESIGN

A cohort study using record linkage of a breast cancer family resource and the Icelandic Cancer Registry.

SETTING

Iceland.

SUBJECTS

Families of 995 breast cancer patients, from which 887 were tested for a single founder 999del5 mutation; 90 had the mutation and 797 did not.

RESULTS

Relatives of probands with the mutation had significantly increased relative risk (RR) of breast cancer. For first degree relatives, the RR was 7.55 (95% CI 6.04 to 9.03) but was 1.72 (95% CI 1.49 to 1.96) in first degree relatives of probands without the mutation. For prostate and ovarian cancer, the first and second degree relatives of probands with the mutation had a significantly increased RR, but in families of probands without the mutation no significant familial risk was found.

CONCLUSIONS

The 999del5 mutation in the BRCA2 gene explains a substantial proportion of familial risk of breast cancer in Iceland, but significant familial risk remains in relatives of probands without the mutation. For prostate and ovarian cancer, the mutation accounts for most of the familiality observed in families of breast cancer patients.

Perspective: prostate cancer susceptibility genes

In many developed countries, prostate cancer is the most frequently diagnosed malignancy in men. The extent to which the marked racial/ethnic difference in its incidence rate is attributable to screening methods, environmental, hormonal, and/or genetic factors remains unknown. A positive family history is among the strongest epidemiological risk factors for prostate cancer. It is now well recognized that association of candidate genetic markers to this multifactorial malignancy is more difficult than the identification of susceptibility genes for some common cancers such as breast, ovary, and colon cancer. Several reasons may explain such a difficulty: 1) prostate cancer is diagnosed at a late age, thus often making it impossible to obtain DNA samples from living affected men for more than one generation; 2) the presence within high-risk pedigrees of phenocopies, associated with the lack of distinguishing features between hereditary and sporadic forms; and 3) the genetic heterogeneity of this complex disease along with the accompanying difficulty of developing appropriate statistical transmission models taking into account simultaneously multiple susceptibility genes, frequently showing moderate or low penetrance. Despite the localization of seven susceptibility loci, there has been limited confirmatory evidence of linkage for currently known candidate genes. Nonetheless, the discovery of the first prostate cancer susceptibility gene characterized by positional cloning, ELAC2 was achieved taking advantage of the Utah Family Resource. Moreover, common missense mutations in the ELAC2 gene were found to be significantly associated with an increased risk of diagnosis of prostate cancer in some studies. More recently, recombination map-ping and candidate gene analysis were used to map several genes, including the 2'-5'-oligoadenylate-dependent ribonuclease L (RNASEL) gene, to the critical region of HPC1. Two deleterious mutations in RNASEL segregate independently with the disease in two of the eight HPC1-linked families. Additional studies using larger cohorts are needed to fully evaluate the role of these two susceptibility genes in prostate cancer risk. Although a number of rare highly penetrant loci contribute to the Mendelian inheritance of prostate cancer, some of the familial risks may be due to shared environment and more specifically to common low-penetrance genetic variants. In this regard, it is not surprising that analyses of genes encoding key proteins involved in androgen biosynthesis and action, led to the observation of a significant association between a susceptibility to prostate cancer and common genetic variants, such as those found in 5alpha-reductase type 2 and AR genes.

[Analysis of mutations in genes BRCA1 and BRCA2 among patients with breast and ovarian cancer in northern Portugal and Galicia]

OBJECTIVE

To detect mutations in the BRCA1 and BRCA2 genes by means of the protein truncation test (PTT) in a population in northern Portugal and Galicia with breast and ovarian cancer.

DESIGN

Prospective study.

SETTING

Patients in northern Portugal and Galicia with family history of breast and/or ovarian cancer.Patients. A total of 76 women with family history of breast cancer according to the BCLC criteria (Breast Cancer Linkage Consortium) were studied at IPATIMUP.

MAIN RESULTS

Five cases (6.5%) with changes in the normal sequence in genes BRCA1 and BRCA2 were identified; three of these mutations occurred in the gene BRCA1 and the other two in the gene BRCA2. Two out of the three mutations found in the gene BRCA1 were de novo mutations. Changes detected in the normal sequence in the gene BRCA2 were mutations reported for the first time among the study population, according to the information obtained through the BCIC database (Breast Cancer Information Core).

CONCLUSIONS

This was the first study in detecting individuals carrying mutations in the susceptibility breast cancer genes BRCA1 and BRCA2 among the population of northern Portugal and Galicia.

A follow-up study of breast and other cancers in families of an unselected series of breast cancer patients

The cancer experience among relatives of an unselected cohort of 402 breast cancer patients was previously reported. Cases and their first degree relatives were flagged at the National Health Service Central Register for continuous notification of cancer registrations and deaths. More than 10 years of follow-up data have been analysed to update cancer risks overall and to estimate breast cancer risk in relatives prospectively according to family history at the time of breast cancer diagnosis in the index case. Significant excesses of breast cancer (RR 2.24, P<0.0001), prostate cancer (RR 1.71, P=0.039) and bone sarcoma (RR 6.564, P=0.042) overall and soft tissue sarcoma in mothers only (RR 15.44, P=0.001) were found. There was no excess of any other cancer, including ovarian. High breast cancer risk in relatives was associated with young age at diagnosis in the index (index <40 years at diagnosis, RR in relatives 3.76, P=0.004). Prospective risk of breast cancer was higher in relatives of index patients who had an affected first degree relative at the time of their diagnosis (no family history, RR 1.87, P=0.012; with a family history, RR 3.72, P=0.015). These prospective risk estimates are valuable in advising relatives of newly diagnosed breast cancer patients.

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.

BRCA1 and prostate cancer

The breast cancer susceptibility gene BRCA1 on chromosome 17q21 encodes an 1863 amino acid protein that is important for normal embryonic development. Germline mutations of this gene are linked to a significantly increased lifetime risk for breast and/or ovarian cancer, and recent studies suggest that the same may be true for prostate cancer. Several activities that may contribute to the tumor suppressor function of BRCA1 have been identified via in vitro and experimental animal studies. These include (i) regulation of cell proliferation; (ii) participation in DNA repair/recombination processes related to the maintenance of genomic integrity; (iii) induction of apoptosis in damaged cells; and (iv) regulation of transcription. A second breast cancer susceptibility gene (BRCA2) operates in some of the same molecular pathways as BRCA1, and mutations of this gene predispose to breast and ovarian cancer and probably to other tumor types, including prostate cancer. Finally, recent studies from our laboratory suggest that BRCA1 modulates proliferation, chemosensitivity, repair of DNA strand breaks, apoptosis induction, and expression of certain key cellular regulatory proteins (including BRCA2 and p300) in human prostate cancer cells. These activities are consistent with a putative prostate tumor suppressor function of BRCA1.

A key to understanding postoperative lymphoedema: a study on the evolution and consistency of oedema of the arm using ultrasound imaging

Post-mastectomy oedema is a very serious complication that, in the course of time, will transform into fibrotic tissue. The aim of our study is to evaluate when and in which layer liquid oedema transforms into fibrotic tissue. To do so, ultrasonographic images were taken of 22 patients and 9 control women at the shoulder and 10 cm proximal and distal from the olecranon, with the images then being scanned and imported into a computer program to determine echogenicity of the dermis, subcutis, subcutis on dermal side and subcutis on fascial side. Statistical analyses were performed by means of the Wilcoxon test and a Student's t-test. No significant differences (P< or =0.05) were found for the different parameters in the control group. In the experimental group: significant differences in perimeter, skinfold, thickness of dermis and subcutis were found. Although not significant, subcutaneous tissue was more echogenic on the oedematous side, with significant hyperechogenicity at the fascial subcutaneous layer. This indicates that fibrotic tissue develops distally in the forearm.

Heterogeneity in genetic susceptibility to prostate cancer

The incidence of prostate cancer is related to aging. Its increase in the last 10 years, varies from country to country and according to ethnic group, with its greatest incidence among African-American males and the least among Asian males. Only two risk factors have thus far been clearly established for prostate cancer: familial aggregation and ethnic origin. No dietary or environmental cause has yet been identified for prostate cancer. However, some variations in endogenous factors, such as sex steroids or IGF1 circulating levels, may partly explain differences in risk observed between different populations. Genetic polymorphisms of genes encoding for 5alpha-reductase, androgen receptor, or vitamin D receptor have been associated with different degrees of risk for prostate cancer and may explain variations in risk among ethnic groups or within geographic areas. Different studies support the theory that familial prostate cancer may be hereditary and not due to a similar lifestyle. Thus, familial inheritance is a parameter that must be considered when advising screening in high-risk families. Indeed, the relative risk for first-degree relatives of prostate cancer patients can reach 2, 5 and 11 when, respectively, 1, 2 and 3 first-degree relatives are affected. Some familial forms appear to be associated with transmission of a rare, putative, autosomal dominant gene (0.003-0.06 allele frequency) with a high penetrance (88% at age 85). Using this transmission model and linkage analysis, three predisposing loci on chromosome 1: HPC-1 (hereditary prostate cancer 1: 1q24-25), PCaP (predisposing for prostate cancer: 1q42-43) and CAPB (predisposing for prostate and brain tumor: 1p36) and one locus on chromosome 20 (HPC20: 20q13) have been described. Moreover, X-linked transmission has been suggested and related to another predisposing gene locus: HPCX (Xq27-28). It is possible that a large proportion of familial prostate cancer is due not to segregation of a few major gene mutations transmitted according to a monogenic inheritance, but rather to familial sharing of alleles at many loci, each contributing to a small increase in cancer risk.

Germ line mutations associated with breast cancer susceptibility

Laboratory-based research in germ line mutations associated with breast cancer susceptibility is rapidly being integrated into clinical practice with profound implications. A Medline search was performed for all relevant articles published since 1990. Where appropriate, historical articles referenced in those identified were also reviewed. The results suggested that while mutations in the BRCA1 and BRCA2 genes are the most clinically relevant, much of the data on which clinical decisions are based must be interpreted with wide confidence intervals. Between 1 in 152 and 1 in 833 individuals carry such mutations. They account for less than 5% of all breast cancer, but up to 10% of cancers in those under the age of 40 years. Founder mutations are responsible for a larger proportion of breast cancer cases within certain inbred communities. Phenotypic expression and penetrance of different mutations is not currently predictable and estimates of penetrance are largely based on highly selected populations. BRCA1 mutations are more commonly associated with ovarian cancer than BRCA2 mutations. BRCA1 cancers tend to have more distinct pathological features and are usually oestrogen receptor (ER)-negative. To conclude, the evidence in this review suggests that caution should be exercised when translating scientific progress in breast cancer germ line genetics into clinical practice. Most of the available data are derived from studies on highly selected populations. The importance of other less penetrant, but more prevalent, germ line mutations may be realised in the future.