BRCA1 and BRCA2 founder mutations and the risk of colorectal cancer

BRCA genes as candidates for colorectal cancer genetic testing panel: systematic review and meta-analysis

BACKGROUND

Breast cancer susceptibility gene (BRCA) mutation carriers are at an increased risk for breast, ovarian, prostate and pancreatic cancers. However, the role of BRCA is unclear in colorectal cancer; the results regarding the association between BRCA gene mutations and colorectal cancer risk are inconsistent and even controversial. This study aimed to investigate whether BRCA1 and BRCA2 gene mutations are associated with colorectal cancer risk.

METHODS

In this systematic review, we searched PubMed/MEDLINE, Embase and Cochrane Library databases, adhering to PRISMA guidelines. Study quality was assessed using the Newcastle-Ottawa Scale (NOS). Unadjusted odds ratios (ORs) were used to estimate the probability of Breast Cancer Type 1 Susceptibility gene (BRCA1) and Breast Cancer Type 2 Susceptibility gene (BRCA2) mutations in colorectal cancer patients. The associations were evaluated using fixed effect models.

RESULTS

Fourteen studies were included in the systematic review. Twelve studies, including seven case-control and five cohort studies, were included in the meta-analysis. A significant increase in the frequency of BRCA1 and BRCA2 mutations was observed in patients with colorectal cancer [OR = 1.34, 95% confidence interval (CI) = 1.02-1.76, P = 0.04]. In subgroup analysis, colorectal cancer patients had an increased odds of BRCA1 (OR = 1.48, 95% CI = 1.10-2.01, P = 0.01) and BRCA2 (OR = 1.56, 95% CI = 1.06-2.30, P = 0.02) mutations.

CONCLUSIONS

BRCA genes are one of the genes that may increase the risk of developing colorectal cancer. Thus, BRCA genes could be potential candidates that may be included in the colorectal cancer genetic testing panel.

Implementation of BRCA mutations testing in formalin-fixed paraffin-embedded (FFPE) samples of different cancer types

BRCA1 and BRCA2 are onco-suppressor genes involved in the DNA repair mechanism. The presence of BRCA1/2 mutations confers a higher risk of developing several cancer types. To date, the FDA approved various PARP inhibitors to treat selected BRCA1/2 mutated oncologic patients. At first, PARP inhibitors were approved for patients with ovarian and breast cancers, and subsequently for metastatic pancreatic adenocarcinoma and metastatic castration-resistant prostate cancer after the treatment with chemotherapy. The current guidelines for BRCA testing are very heterogeneous between the different types of tumors regarding the diagnostic algorithm and the type of sample to analyze, such as the blood for the germline mutations and the tumoral tissue for the somatic mutations. Few data have currently been described regarding the detection of BRCA1/2 somatic mutations in formalin-fixed paraffin-embedded (FFPE) samples. In this review, we propose an overview of the BRCA mutations in FFPE samples of several cancers, including breast, ovarian, fallopian tube, primary peritoneal, prostate, and pancreatic cancer. We summarize the types and the frequency of BRCA mutations, the guidelines approved for the test, the molecular assays used for the detection and the PARP inhibitors approved for each tumor type.

Population-based Screening for Hereditary Colorectal Cancer Variants in Japan

BACKGROUND & AIMS

Colorectal cancer (CRC) is one of the most common cancers in the world. A small proportion of CRCs can be attributed to recognizable hereditary germline variants of known CRC susceptibility genes. To better understand cancer risk, it is necessary to explore the prevalence of hereditary CRC and pathogenic variants of multiple cancer-predisposing genes in non-European populations.

METHODS

We analyzed the coding regions of 27 cancer-predisposing genes in 12,503 unselected Japanese CRC patients and 23,705 controls by target sequencing and genome-wide SNP chip. Their clinical significance was assessed using ClinVar and the guidelines by ACMG/AMP.

RESULTS

We identified 4,804 variants in the 27 genes and annotated them as pathogenic in 397 and benign variants in 941, of which 43.6% were novel. In total, 3.3% of the unselected CRC patients and 1.5% of the controls had a pathogenic variant. The pathogenic variants of MSH2 (odds ratio (OR) = 18.1), MLH1 (OR = 8.6), MSH6 (OR = 4.9), APC (OR = 49.4), BRIP1 (OR=3.6), BRCA1 (OR = 2.6), BRCA2 (OR = 1.9), and TP53 (OR = 1.7) were significantly associated with CRC development in the Japanese population (P-values<0.01, FDR<0.05). These pathogenic variants were significantly associated with diagnosis age and personal/family history of cancer. In total, at least 3.5% of the Japanese CRC population had a pathogenic variant or CNV of the 27 cancer-predisposing genes, indicating hereditary cancers.

CONCLUSIONS

This largest study of CRC heredity in Asia can contribute to the development of guidelines for genetic testing and variant interpretation for heritable CRCs.

Correlation between the number of false positive variants and the quality of results using Ion Torrent PGM™ sequencing to screen BRCA genes

Introduction:

Next Generation Sequencing (NGS) is cost-effective and a faster method to study genes, but its protocol is challenging.

Objective:

To analyze different adjustments to the protocol for screening the BRCA genes using Ion Torrent PGM sequencing and correlate the results with the number of false positive (FP) variants.

Material and methods:

We conducted a library preparation process and analyzed the number of FP InDels, the library concentration, the number of cycles in the target amplification step, the purity of the nucleic acid, the input, and the number of samples/Ion 314 chips in association with the results obtained by NGS.

Results:

We carried out 51 reactions and nine adjustments of protocols and observed eight FP InDels in homopolymer regions. No FP Single-Nucleotide Polymorphism variant was observed; 67.5% of protocol variables were jointly associated with the quality of the results obtained (p<0.05). The number of FP InDels decreased when the quality of results increased.

Conclusion:

The Ion AmpliSeq BRCA1/BRCA2 Community Panel had a better performance using four samples per Ion-314 chip instead of eight and the optimum number of cycles in the amplification step, even when using high-quality DNA, was 23. We observed better results with the manual equalization process and not using the Ion Library Equalizer kit. These adjustments provided a higher coverage of the variants and fewer artifacts (6.7-fold). Laboratories must perform internal validation because FP InDel variants can vary according to the quality of results while the NGS assay should be validated with Sanger.

Surgical Management of Hereditary Breast Cancer

The identification that breast cancer is hereditary was first described in the nineteenth century. With the identification of the BRCA1 and BRCA 2 breast/ovarian cancer susceptibility genes in the mid-1990s and the introduction of genetic testing, significant advancements have been made in tailoring surveillance, guiding decisions on medical or surgical risk reduction and cancer treatments for genetic variant carriers. This review discusses various medical and surgical management options for hereditary breast cancers.

BRCA mutations and gastrointestinal cancers: When to expect the unexpected?

BRCA1/2 pathogenic variants are widely known as major risk factors mainly for breast and ovarian cancer, while their role in gastrointestinal (GI) malignancies such as colorectal cancer (CRC), gastric cancer and oesophageal cancer (OeC) is still not well established. The main objective of this review is to summarise the available evidence on this matter. The studies included in the review were selected from PubMed/GoogleScholar/ScienceDirect databases to identify published articles where BRCA1/2 pathogenic variants were assessed either as a risk factor or a prognostic/predictive factor in these malignancies. Our review suggests that BRCA1/2 might have a role as a risk factor for colorectal, gastric and OeC, albeit with differences among these diseases: In particular BRCA1 seems to be much more frequently mutated in CRC whereas BRCA2 appears to be much more closely associated with gastric and OeC. Early-onset cancer seems to be also associated with BRCA1/2 mutations and a few studies suggest a positive prognostic role of these mutations. The assessment of a potentially predictive role of these mutations is hampered by the fact that most patients with these diseases have been treated with platinum compounds, where it is expected that a higher probability of response should be seen. A few clinical trials focused on poly (ADP-ribose) polymerase inhibitors use in GI cancers are currently ongoing.

The role of pathologists in recognition of morphologic and biologic features of genetically mutated breast cancer

The recent introduction of genomic medicine and emphasis on optimizing breast cancer risk reduction mortalities has provided opportunities for pathologists to partner with clinicians in advancing the diagnosis and management of breast cancer patients. The discovery of breast cancer genes BRCA1, BRCA2, and other breast cancer genes is considered a major breakthrough in the understanding of hereditary breast cancer. These discoveries have contributed to investigate the nature of tumorigenesis and the genetic and molecular pathology in multistep tumor development, as well as their relationship to endocrine and environmental factors. The recognition of unique morphologic and biological features associated with genetically mutated breast cancer by pathologists may have an impact on appropriate follow-up management of breast cancer patients.

BRCA in Gastrointestinal Cancers: Current Treatments and Future Perspectives

A strong association between pancreatic cancer and BRCA1 and BRCA2 mutations is documented. Based on promising results of breast and ovarian cancers, several clinical trials with poly (ADP-ribose) polymerase inhibitors (PARPi) are ongoing for gastrointestinal (GI) malignancies, especially for pancreatic cancer. Indeed, the POLO trial results provide promising and awaited changes for the pancreatic cancer therapeutic landscape. Contrariwise, for other gastrointestinal tumors, the rationale is currently only alleged. The role of BRCA mutation in gastrointestinal cancers is the subject of this review. In particular, we aim to provide the latest updates about novel therapeutic strategies that, exploiting DNA repair defects, promise to shape the future therapeutic scenario of GI cancers.

Dominantly Inherited Hereditary Nonpolyposis Colorectal Cancer Not Caused by MMR Genes

In the past two decades, multiple studies have been undertaken to elucidate the genetic cause of the predisposition to mismatch repair (MMR)-proficient nonpolyposis colorectal cancer (CRC). Here, we present the proposed candidate genes according to their involvement in specific pathways considered relevant in hereditary CRC and/or colorectal carcinogenesis. To date, only pathogenic variants in RPS20 may be convincedly linked to hereditary CRC. Nevertheless, accumulated evidence supports the involvement in the CRC predisposition of other genes, including MRE11, BARD1, POT1, BUB1B, POLE2, BRF1, IL12RB1, PTPN12, or the epigenetic alteration of PTPRJ. The contribution of the identified candidate genes to familial/early onset MMR-proficient nonpolyposis CRC, if any, is extremely small, suggesting that other factors, such as the accumulation of low risk CRC alleles, shared environmental exposures, and/or gene-environmental interactions, may explain the missing heritability in CRC.

Comparison of suspected Lynch syndrome patients carrying BRCA and BRCA-like variants with Lynch syndrome probands: Phenotypic characteristics and pedigree analyses

Background

Colorectal cancer (CRC) patients diagnosed with Lynch syndrome (LS) are recommended genetic testing. Increasing numbers of germline variants involved in homologous recombination have been identified in suspected LS patients. This study compared phenotypic the characteristics of suspected LS patients carrying BRCA and BRCA‐like variants with those of LS patients.

Methods

Forty‐two patients carrying pathogenic variants of DNA mismatch repair (MMR) genes (MMR group), 9 carrying BRCA variants, and 11 carrying BRCA‐like variants (BRCA/BRCA‐like group) who met LS clinical criteria were enrolled in this study. Clinical characteristics, pedigrees, and survival rates were compared and BRCA variants were analyzed.

Results

The earliest CRC‐onset age and tumor differentiation were higher in the BRCA/BRCA‐like group than in the MMR group. Metachronous CRCs were more numerous in the MMR group, resulting in a higher progression‐free survival rate in the BRCA/BRCA‐like group. Extra‐colorectal cancers were more frequently observed in the BRCA/BRCA‐like group. BRCA2 and BRCA1 variants were clustered in exons 11 and 4/7, respectively.

Conclusion

BRCA and BRCA‐like variants in CRC patients with LS showed moderate penetrance. BRCA/BRCA‐like variant carriers had a higher risk for extra‐colorectal cancers. Surveillance of susceptible organs other than the intestine should be performed for probands and affected family members.

Risk of colorectal cancer associated with BRCA1 and/or BRCA2 mutation carriers: systematic review and meta-analysis

BACKGROUND

Carriers of the BRCA1 and/or BRCA2 mutation incur a lifetime risk of up to 85 per cent for breast cancer, and between 20 and 40 per cent for ovarian cancer. Efforts to estimate the lifetime risk of developing colorectal cancer for BRCA mutation carriers have produced conflicting results. Consequently, there are no formal guidelines regarding the need for bowel screening for individuals with BRCA1 and/or BRCA2 mutations. This systematic review and meta-analysis determined the risk of colorectal cancer associated with BRCA carrier mutations.

METHODS

The primary outcome was incidence of colorectal cancer in BRCA mutation carriers. Secondary outcomes were the incidence in BRCA1 and BRCA2 carriers, Ashkenazi Jews, and age- and sex-matched cohorts.

RESULTS

Eleven studies were included in the review, with an overall population of 14 252 and 4831 colorectal cancers identified. Nine studies were included in the meta-analysis. There was no increase in colorectal cancer among patients carrying a BRCA mutation (odds ratio 1·03, 95 per cent c.i. 0·80 to 1·32; P = 0·82). After adjustment for Ashkenazi heritage, and age and sex estimates, there was no increased odds of developing colorectal cancer (with no heterogeneity, I²  = 0 per cent).

CONCLUSION

BRCA1 and/or BRCA2 mutation carriers are not at a higher risk of colorectal cancer.

BRCA1/BRCA2 Pathogenic Variant Breast Cancer: Treatment and Prevention Strategies

Hereditary breast cancer is known for its strong tendency of inheritance. Most hereditary breast cancers are related to BRCA1/BRCA2 pathogenic variants. The lifelong risk of breast cancer in pathogenic BRCA1 and BRCA2 variant carriers is approximately 65% and 45%, respectively, whereas that of ovarian cancer is estimated to be 39% and 11%, respectively. Therefore, understanding these variants and clinical knowledge on their occurrence in breast cancers and carriers are important. BRCA1 pathogenic variant breast cancer shows more aggressive clinicopathological features than the BRCA2 pathogenic variant breast cancer. Compared with sporadic breast cancer, their prognosis is still debated. Treatments of BRCA1/BRCA2 pathogenic variant breast cancer are similar to those for BRCA-negative breast cancer, mainly including surgery, radiotherapy, and chemotherapy. Recently, various clinical trials have investigated poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitor treatment for advanced-stage BRCA1/BRCA2 pathogenic variant breast cancer. Among the various PARP inhibitors, olaparib and talazoparib, which reached phase III clinical trials, showed improvement of median progression-free survival around three months. Preventive and surveillance strategies for BRCA pathogenic variant breast cancer to reduce cancer recurrence and improve treatment outcomes have recently received increasing attention. In this review, we provide an information on the clinical features of BRCA1/BRCA2 pathogenic variant breast cancer and clinical recommendations for BRCA pathogenic variant carriers, with a focus on treatment and prevention strategies. With this knowledge, clinicians could manage the BRCA1/BRCA2 pathogenic variant breast cancer patients more effectively.

BRCA1 and BRCA2 Gene Mutations and Colorectal Cancer Risk: Systematic Review and Meta-analysis

Background

Investigations of the associations with colorectal cancer have yielded conflicting results. The aim of our study was to synthesize the research on colorectal cancer risks in BRCA mutation carriers by means of a systematic review and quantitatively by means of meta-analyses overall and in subgroups of BRCA mutation carriers.

Methods

We searched PubMed/MEDLINE, Embase, Cochrane, Scopus, and ProQuest Dissertation & Theses. Unadjusted odds ratios (ORs) were used to derive pooled estimates of colorectal cancer risk overall and in subgroups defined by mutation type (BRCA1 or BRCA2), cancer type (colorectal or colon cancer), study design (age-sex-adjusted or crude), and ascertainment method (ascertained or inferred genotyping). The associations were evaluated using random-effect models. All statistical tests were two-sided.

Results

Eighteen studies were included in the systematic review: five cohort studies with ascertained BRCA mutation, six cohort studies involving pedigree analysis, five case-control studies, and two kin-cohort studies. Of these, 14 were used in the meta-analysis, which revealed a statistically significant increased risk of colorectal cancer in overall BRCA mutation carriers (OR = 1.24, 95% confidence interval (CI) = 1.02 to 1.51, P = .03). In subgroup meta-analyses by BRCA type, BRCA1 mutation was associated with increased risk of colorectal cancer (OR = 1.49, 95% CI = 1.19 to 1.85, P < .001), but BRCA2 was not (OR = 1.10, 95% CI = 0.77 to 1.58, P = .61). In subgroup meta-analyses of studies reporting estimates adjusted for age and sex, an increased risk of colorectal cancer for BRCA1 (OR = 1.56, 95% CI = 1.23 to 1.98, P < .001), but not for BRCA2 (OR = 1.09, 95% CI = 0.75 to 1.58, P = .66) was observed. Analyses stratified by ascertainment method found no association between BRCA mutation and colorectal cancer risk.

Conclusion

The meta-analysis results provide clinicians and health-care regulatory agencies with evidence of the increased risk of colorectal cancer in BRCA1 mutation carriers, but not in BRCA2.

Update on genetic predisposition to colorectal cancer and polyposis

The present article summarizes recent developments in the characterization of genetic predisposition to colorectal cancer (CRC). The main themes covered include new hereditary CRC and polyposis syndromes, non-CRC hereditary cancer genes found mutated in CRC patients, strategies used to identify novel causal genes, and review of candidate genes that have been proposed to predispose to CRC and/or colonic polyposis. We provide an overview of newly described genes and syndromes associated with predisposition to CRC and polyposis, including: polymerase proofreading-associated polyposis, NTHL1-associated polyposis, mismatch repair gene biallelic inactivation-related adenomatous polyposis (including MSH3- and MLH3-associated polyposes), GREM1-associated mixed polyposis, RNF43-associated serrated polyposis, and RPS20 mutations as a rare cause of hereditary nonpolyposis CRC. The implementation of next generation sequencing approaches for genetic testing has exposed the presence of pathogenic germline variants in genes associated with hereditary cancer syndromes not traditionally linked to CRC, which may have an impact on genetic testing, counseling and surveillance. The identification of new hereditary CRC and polyposis genes has not deemed an easy endeavor, even though known CRC-related genes explain a small proportion of the estimated familial risk. Whole-genome sequencing may offer a technology for increasing this proportion, particularly if applied on pedigree data allowing linkage type of analysis. The final section critically surveys the large number of candidate genes that have been recently proposed for CRC predisposition.

Clinical importance of DNA repair in sporadic colorectal cancer

Colorectal cancer (CRC) is the third major cause of cancer-related deaths worldwide. However, despite the scientific efforts to provide a molecular classification to improve CRC clinical practice management, prognosis and therapeutic decision are still strongly dependent on the TNM staging system. Mismatch repair system deficiencies can occur in many organs, but it is mainly a hallmark of CRC influencing clinical outcomes and response to therapy. This review will discuss the effect of the modulation of other DNA repair pathways (direct, excision and double strand break repairs) in the clinical and pathological aspects of colorectal cancer and its potential as prognostic and predictive biomarkers.

Phenotypic characteristics of colorectal cancer in BRCA1/2 mutation carriers

Mutations in the BRCA1/2 genes were recently shown to be associated with an increased risk for colorectal cancer. We characterized the largest cohort available of BRCA1/2 mutation carriers with colorectal cancer. We analyzed 32 patients with lower gastrointestinal cancers and germline BRCA1/2 mutations from two large academic hospital registries; 91% of patients were of Ashkenazi ancestry, 78% were women, and 62.5% were carriers of BRCA1 gene mutations. A high percentage of colorectal tumors (34.5%) had a mucinous histology and were located atypically in the left colon. Two patients had anal cancer with unusual histology and an additional patient had mucinous small bowel carcinoma. Gene expression analysis showed significant correlation between the gene signatures of left mucinous colorectal cancer and basal-like breast cancer. Our results imply that Ashkenazi BRCA1/2 mutation carriers with colorectal cancer might have unique characteristics with a high rate of left-sided, mucinous histology colorectal cancer, and possibly anal carcinoma. This report suggests a phenotypic influence of defects in DNA repair genes on colorectal tumors.

Cancer Susceptibility Gene Mutations in Individuals With Colorectal Cancer

Purpose Hereditary factors play an important role in colorectal cancer (CRC) risk, yet the prevalence of germline cancer susceptibility gene mutations in patients with CRC unselected for high-risk features (eg, early age at diagnosis, personal/family history of cancer or polyps, tumor microsatellite instability [MSI], mismatch repair [MMR] deficiency) is unknown. Patients and Methods We recruited 1,058 participants who received CRC care in a clinic-based setting without preselection for age at diagnosis, personal/family history, or MSI/MMR results. All participants underwent germline testing for mutations in 25 genes associated with inherited cancer risk. Each gene was categorized as high penetrance or moderate penetrance on the basis of published estimates of the lifetime cancer risks conferred by pathogenic germline mutations in that gene. Results One hundred five (9.9%; 95% CI, 8.2% to 11.9%) of 1,058 participants carried one or more pathogenic mutations, including 33 (3.1%) with Lynch syndrome (LS). Twenty-eight (96.6%) of 29 available LS CRCs demonstrated abnormal MSI/MMR results. Seventy-four (7.0%) of 1,058 participants carried non-LS gene mutations, including 23 (2.2%) with mutations in high-penetrance genes (five APC, three biallelic MUTYH, 11 BRCA1/2, two PALB2, one CDKN2A, and one TP53), 15 of whom lacked clinical histories suggestive of their underlying mutation. Thirty-eight (3.6%) participants had moderate-penetrance CRC risk gene mutations (19 monoallelic MUTYH, 17 APC*I1307K, two CHEK2). Neither proband age at CRC diagnosis, family history of CRC, nor personal history of other cancers significantly predicted the presence of pathogenic mutations in non-LS genes. Conclusion Germline cancer susceptibility gene mutations are carried by 9.9% of patients with CRC. MSI/MMR testing reliably identifies LS probands, although 7.0% of patients with CRC carry non-LS mutations, including 1.0% with BRCA1/2 mutations.

Linking uterine serous carcinoma to BRCA1/2-associated cancer syndrome: A meta-analysis and case report

BACKGROUND

Uterine serous carcinoma (USC) shows greater morphological, clinical and molecular similarities to high-grade ovarian tubal serous carcinoma than to other types of endometrial cancer. As high-grade ovarian tubal serous carcinoma is known to be associated with BRCA1/2 pathogenic germline mutations (PMs), we aimed to explore whether USC is also a constituent of hereditary breast and ovarian cancer syndrome.

METHODS

Pubmed, EMBASE and Web of Science were searched in July 2016 for articles assessing the association between USC and germline BRCA1/2-PMs. Pooled analysis and comparisons were performed using a random effects logistic model, stratifying for ethnicity (Ashkenazi versus non-Ashkenazi). In addition, tumour tissue from an USC case with a hereditary BRCA1-PM was analysed for loss of heterozygosity at the BRCA1 locus and was functionally analysed for homologous recombination proficiency.

RESULTS

The search yielded 1893 citations, 10 studies were included describing 345 USC patients. For Ashkenazi Jews, the pooled odds ratio of having a germline BRCA1/2-PM was increased in USC patients compared with the general Ashkenazi population: odds ratio 5.4 (95%confidence interval: 2.2-13.1). In the patient with USC, we identified the known germline BRCA1-PM in the tumour DNA. Furthermore, we showed both loss of heterozygosity of the wild-type allele and a deficiency of homologous recombination.

CONCLUSION

This study suggests that USC may be an overlooked component of BRCA1/2-associated hereditary breast and ovarian cancer syndrome. Screening for germline BRCA1/2-PMs should be considered in patients diagnosed with USC, especially in cases with a positive first-degree family history for breast and/or ovarian cancer.

Secondary Primary Malignancy Risk in Patients With Ovarian Cancer in Taiwan: A Nationwide Population-Based Study

To evaluate the incidence of secondary primary malignancy (SPM) in patients with ovarian cancer using a nationwide retrospective population-based dataset. Patients newly diagnosed with ovarian cancer between 1997 and 2010 were identified using Taiwan's National Health Insurance database. Patients with antecedent malignancies were excluded. Standardized incidence ratios (SIRs) for SPM were calculated and compared with the cancer incidence in the general population. Risk factors for cancer development were analyzed using Cox proportional hazard models. Effects of surgery, chemotherapy, and radiotherapy after ovarian cancer diagnosis were regarded as time-dependent variables to prevent immortal time bias. During the 14-year study period (follow-up of 56,214 person-years), 707 cancers developed in 12,127 patients with ovarian cancer. The SIR for all cancers was 2.78 (95% confidence interval 2.58-3.00). SIRs for follow-up periods of >5, 1-5, and <1 year were 1.87, 2.04, and 6.40, respectively. After the exclusion of SPM occurring within 1 year of ovarian cancer diagnosis, SIRs were significantly higher for cancers of the colon, rectum, and anus (2.14); lung and mediastinum (1.58); breast (1.68); cervix (1.65); uterus (7.96); bladder (3.17), and thyroid (2.23); as well as for leukemia (3.98) and others (3.83). Multivariate analysis showed that age ≥ 50 years was a significant SPM risk factor (hazard ratio [HR] 1.60). Different treatments for ovarian cancer, including radiotherapy (HR 2.07) and chemotherapy (HR 1.27), had different impacts on SPM risk. Patients with ovarian cancer are at increased risk of SPM development. Age ≥ 50 years, radiotherapy, and chemotherapy are independent risk factors. Close surveillance of patients at high risk should be considered for the early detection of SPM.

Incidence of colorectal cancer in BRCA1 and BRCA2 mutation carriers: results from a follow-up study

BACKGROUND

The BRCA1 and BRCA2 genes confer increased susceptibility to breast and ovarian cancer and to a spectrum of other cancers. There is controversy regarding the risk of colorectal cancer conferred by germline mutations in these two genes.

METHODS

We followed 7015 women with a BRCA mutation for new cases of colorectal cancer. Incidence rates in carriers were compared with population-specific incidence rates, and standardised incidence ratios (SIRs) were estimated. The expected numbers of cancers were computed by multiplying person-years at risk by the appropriate age-, sex- and country-specific incidence rates from the five countries.

RESULTS

Twenty-one incident colorectal cancer cases were observed among all mutation carriers, compared with 23.6 cases expected. The SIR for BRCA1 carriers was 0.92 (95% confidence interval (CI), 0.54-1.40, P=0.7) and for BRCA2 carriers was 0.82 (95% CI, 0.30-1.81, P=0.7). The SIR for colon cancer was 3.81 (95% CI 1.77-7.23) for women below the age of 50 years (both genes combined) and was 0.60 (95% CI 0.33-1.00) for women aged 50 years and above.

CONCLUSION

The risk of colorectal cancer is increased in female carriers of BRCA1 mutations below the age of 50 years but not in women with BRCA2 mutations or in older women.

Risk of cancer other than breast or ovarian in individuals with BRCA1 and BRCA2 mutations

The risks of cancers other than breast and ovarian amongst BRCA1 and BRCA2 mutation carriers are based on relatively few family based studies with the risk of specific cancers tested in population based samples of cancers from founder populations. We assessed risks of "other cancers" in 268 BRCA1 families and 222 BRCA2 families using a person years at risk analysis from 1975 to 2005. Cancer confirmations were overall higher than in previous family based studies at 64%. There was no overall increase in risk for BRCA1 carriers although oesophagus had a significant increased RR of 2.9 (95% CI 1.1-6.0) and stomach at 2.4 (95% CI 1.2-4.3), these were based mainly on unconfirmed cases. For BRCA2 increased risks for cancers of the pancreas (RR 4.1, 95% CI 1.9-7.8) and prostate (RR 6.3, 95% CI 4.3-9.0) and uveal melanoma (RR 99.4, 95% CI 11.1-359.8) were confirmed. Possible new associations with oesophagus (RR 4.1, 95% CI 1.9-7.8) and stomach (RR 2.7, 95% CI 1.3-4.8) were detected but these findings should be treated with caution due to lower confirmation rates. In contrast to previous research a higher risk of prostate cancer was found in males with mutations in the BRCA2 OCCR region. The present study strengthens the known links between BRCA2 and pancreatic and prostate cancer, but throws further doubt onto any association with BRCA1. New associations with upper gastro-intestinal malignancy need to be treated with caution and confirmed by large prospective studies.

Expression of oncogenic BARD1 isoforms affects colon cancer progression and correlates with clinical outcome

Background:

Colon cancer predisposition is associated with mutations in BRCA1. BRCA1 protein stability depends on binding to BARD1. In different cancers, expression of differentially spliced BARD1 isoforms is correlated with poor prognosis and decreased patient survival. We therefore suspected a role of BARD1 isoforms in colon cancer.

Methods:

We performed immunohistochemistry in 168 colorectal cancers, using four antibodies directed against differentially expressed regions of BARD1. We determined structure and relative expression of BARD1 mRNA isoforms in 40 tumour and paired normal peri-tumour tissues. BARD1 expression was correlated with clinical outcome.

Results:

BARD1 isoforms were expressed in 98% of cases and not correlated with BRCA1. BARD1 mRNA isoforms were upregulated in all tumours as compared with paired normal peri-tumour tissues. Non-correlated expression and localisation of different epitopes suggested insignificant expression of full-length (FL) BARD1. Expression of N- and C-terminal epitopes correlated with increased survival, but expression of epitopes mapping to the middle of BARD1 correlated with decreased survival. Middle epitopes are present in oncogenic BARD1 isoforms, which have pro-proliferative functions. Correlated upregulation of only N- and C-terminal epitopes reflects the expression of isoforms BARD1δ and BARD1φ.

Conclusion:

Our results suggest that BARD1 isoforms, but not FL BARD1, are expressed in colon cancer and affect its progression and clinical outcome.

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.

Issues related to colorectal cancer and colorectal cancer screening practices in women

Studies have shown that colorectal cancer (CRC) incidence is equal between men and women. However, several studies have demonstrated lower adenoma detection rates in women than in men. Many questions arise about differences in adenomas, CRC, and screening practices between men and women: should screening be the same for both sexes, are there differences in risk factors in the formation of colon cancer, should special groups of women be screened differently from the general population, are colonoscopies tolerated differently in women and why, and what determines if a woman will undergo colonoscopy? This article reviews these issues.

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.

The contribution of founder mutations in BRCA1 to breast and ovarian cancer in Lithuania

We evaluated the prevalence of BRCA1 founder mutations in unselected cases of breast, ovarian and colon cancer from Lithuania. We identified a founder mutation (4153delA, 5382insC or C61G) in 6% of 235 unselected cases of breast cancer and in 19% of 43 unselected cases of ovarian cancer. Only one patient with a mutation was identified among 178 cases of colon cancer. No mutation was identified among 422 newborn controls. This data indicates that the genetic burden of breast and ovarian cancer attributable to BRCA1 mutations in Lithuania is very high and supports the recommendation that all cases of breast and ovarian cancer in Lithuania be offered genetic testing.

Pathology of hereditary breast cancer

Background

Hereditary breast cancer runs in families where several members in different generations are affected. Most of these breast cancers are caused by mutations in the high penetrance genes BRCA1 and BRCA2 accounting for about 5% of all breast cancers. Other genes that include CHEK2, PTEN, TP53, ATM, STK11/LKB1, CDH1, NBS1, RAD50, BRIP1 and PALB2 have been described to be high or moderate penetrance breast cancer susceptibility genes, all contributing to the hereditary breast cancer spectrum. However, in still a part of familial hereditary breast cancers no relationship to any of these breast cancer susceptibility genes can be found. Research on new susceptibility genes is therefore ongoing.

Design

In this review we will describe the function of the today known high or moderate penetrance breast cancer susceptibility genes and the consequences of their mutated status. Furthermore, we will focus on the histology, the immunophenotype and genotype of breast cancers caused by mutations in BRCA1 and BRCA2 genes and the other high or moderate penetrance breast cancer susceptibility genes. Finally, an overview of the clinical implications of hereditary breast cancer patients will be provided.

Conclusion

This information leads to a better understanding of the morphological, immunohistochemical and molecular characteristics of different types of hereditary breast cancers. Further, these characteristics offer clues for diagnosis and new therapeutic approaches.

Clinical and pathological characteristics of Chinese patients with BRCA related breast cancer

Breast cancers related to BRCA mutations are associated with particular biological features. Here we report the clinical and pathological characteristics of breast cancer in Chinese women with and without BRCA mutations and of carriers of BRCA1 mutations compared to BRCA2 mutations. Two hundred and 26 high-risk Hong Kong Chinese women were tested for BRCA mutations, medical information was obtained from medical records, and risk and demographic information was obtained from personal interviews. In this cohort, 28 (12.4%) women were BRCA mutation carriers and among these carriers, 39.3% were BRCA1 and 60.7% were BRCA2 mutations. Mutation carriers were more likely to have a familial history of breast and ovarian cancer, high-grade cancers, and triple negative (TN) cancers. Prevalence of TN was 48.3% in BRCA carriers and 25.6% in non-carriers and was 67.7% in BRCA1 and 35.3% in BRCA2 carriers. Estrogen receptor (ER) negative cancer was significantly associated with BRCA1 mutations, especially in those under 40 years of age. BRCA-related breast cancer in this Chinese population is associated with family history and adverse pathological/prognostic features, with BRCA2 mutations being more prevalent but BRCA1 carriers having more aggressive and TN cancers. Compared to Caucasian populations, prevalence of BRCA2 mutations and TN cancer in BRCA2 mutation carriers in Chinese population are elevated.

Predictors of endoscopic colorectal cancer screening over time in 11 states

Objectives

We study a cohort of Medicare-insured men and women aged 65+ in the year 2000, who lived in 11 states covered by Surveillance, Epidemiology, and End Results (SEER) cancer registries, to better understand various predictors of endoscopic colorectal cancer (CRC) screening.

Methods

We use multilevel probit regression on two cross-sectional periods (2000–2002, 2003–2005) and include people diagnosed with breast cancer, CRC, or inflammatory bowel disease (IBD) and a reference sample without cancer.

Results

Men are not universally more likely to be screened than women, and African Americans, Native Americans, and Hispanics are not universally less likely to be screened than whites. Disparities decrease over time, suggesting that whites were first to take advantage of an expansion in Medicare benefits to cover endoscopic screening for CRC. Higher-risk persons had much higher utilization, while older persons and beneficiaries receiving financial assistance for Part B coverage had lower utilization and the gap widened over time.

Conclusions

Screening for CRC in our Medicare-insured sample was less than optimal, and reasons varied considerably across states. Negative managed care spillovers were observed, demonstrating that policy interventions to improve screening rates should reflect local market conditions as well as population diversity.

Family history of hormonal cancers and colorectal cancer risk: a case-control study conducted in Ontario

Aggregation of cancers among families with highly penetrant genetic mutations such as hereditary nonpolyposis colorectal cancer is well-described. However, there is a paucity of data regarding familial aggregation of hormonal cancers (cancers of the breast, endometrial, ovarian and prostate) and colorectal cancer (CRC) in the general population. We investigated the association between having a first-degree family history of breast, endometrial, ovarian, or prostate cancer and CRC risk. Population-based CRC cases and controls were recruited by the Ontario Familial Colorectal Cancer Registry (OFCCR). Logistic regression was conducted to obtain odds ratio (OR) estimates and 95% confidence intervals (95% CIs). First-degree family history of breast cancer was associated with a modest, borderline statistically significant increased CRC risk (age-, sex-adjusted OR = 1.2, 95% CI = 1.0, 1.5). The magnitude of CRC risk was greatest if more than one first-degree kin had breast cancer (age-, sex-adjusted OR = 1.7, 95% CI = 1.0, 2.0), as well as if the kin was diagnosed at >50 years of age (age-, sex-adjusted OR = 1.4, 95% CI = 1.1, 1.8). Family history of ovarian cancer was associated with reduced CRC risk (multivariate-adjusted OR = 0.6, 95% CI = 0.3, 1.0). Although statistically significant increases in CRC risk were observed in the age-, sex-adjusted OR estimates for family history of endometrial and prostate cancers, the associations were no longer significant after multivariate-adjustment. In conclusion, individuals with a first-degree kin with breast cancer may have a modest increased risk for CRC compared to individuals without.

Unusual presentation of Lynch Syndrome

Lynch Syndrome/HNPCC is a syndrome of cancer predisposition linked to inherited mutations of genes participating in post-replicative DNA mismatch repair (MMR). The spectrum of cancer associated with Lynch Syndrome includes tumours of the colorectum, endometrium, ovary, upper gastrointestinal tract and the urothelium although other cancers are rarely described. We describe a family of Lynch Syndrome with an hMLH1 mutation, that harbours an unusual tumour spectrum and its diagnostic and management challenges.

Associations of high-grade prostate cancer with BRCA1 and BRCA2 founder mutations

PURPOSE

Protein-truncating mutations in BRCA1 and in particular BRCA2 genes have been associated with prostate cancer. However, there is still uncertainty about the magnitude of association particularly with Gleason score, and family history of prostate, breast, and ovary cancers.

EXPERIMENTAL DESIGN

To further examine associations between three founder mutations located in BRCA1 (185delAG, 5382insC) or BRCA2 (6174delT) genes and prostate cancer, we conducted a study of 979 prostate cancer cases and 1,251 controls among Ashkenazi Jewish men. Detailed information was obtained on prostate cancer pathology, age at diagnosis, and family history of all cancers. Odds ratios (OR) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

Prostate cancer risk was increased (OR, 1.9; 95% CI 0.9-4.1) for BRCA2 mutation carriers but not for BRCA1 mutation carriers. BRCA2 mutation carriers had an OR of 3.2 (95% CI, 1.4-7.3) for Gleason score of 7 to 10, but no association was observed for Gleason score of < 7. Carriers of BRCA1-185delAG mutation also had an OR of 3.5 (95% CI, 1.2-10.3) for Gleason score of > or =7 tumors; however, the association of either BRCA1-185delAG or 5382insC mutation was not statistically significant. Associations between founder mutations and prostate cancer were stronger in men with no first-degree family history of breast and/or ovarian cancers but were unaffected by family history of prostate cancer.

CONCLUSION

These results indicate that the BRCA2 founder mutation confers a 3-fold elevated risk of high-grade prostate cancer. Although BRCA1 mutations were not associated with prostate cancer, the BRCA1-185delAG was associated with high Gleason score tumors. These findings should be carefully considered in genetic counseling and/or evaluating therapeutic options.

Twenty questions in genetic medicine--an assessment of World Wide Web databases for genetics information at the point of care

PURPOSE

The aim of this article was to determine the accuracy and efficiency of World Wide Web ("Web") resources to help nongeneticists answer four clinical questions about each of five common genetic conditions.

METHODS

Correct answers were established by literature review. Two open-access genetics resources and seven general subscription resources were reviewed. Scoring criteria were established to define complete, partial, vague, inconsistent, not found, and wrong answers. The main outcome measures were number of answers found, accuracy, and completeness of answers. Efficiency (time per answer found) was a secondary measure.

RESULTS

Overall, the databases contained complete answers 33.3% of the time but contained no information as frequently (33.9%). The best database had complete answers 70% of the time, whereas the worst contained no complete answers. Five of the seven subscription databases had a total of eight wrong answers. The other two subscription databases and the two open-access genetics databases had no wrong answers. Search time ranged from 3.2 to 18.3 minutes per complete answer.

CONCLUSIONS

Nongeneticist providers do not have a Web resource that is accessible, accurate, and efficient to answer genetic questions that might arise in practice.

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.

"Are you at risk for hereditary breast cancer?": development of a personal risk assessment tool for hereditary breast and ovarian cancer

Identification of risk for the hereditary breast and ovarian cancer syndrome (HBOC) is important, as research has demonstrated the benefits of risk-reducing interventions for women with or at risk for this disorder. Knowledge among women regarding risk factors for hereditary breast cancer and the existence of cancer genetics services appears limited. The goal of this project was to develop a tool to broaden women's awareness regarding their potential risk for HBOC. A formal instructional design process was used to develop a brochure to facilitate recognition of HBOC risk among women attending a no-cost breast and cervical cancer screening clinic. Brochure development was guided by gathering feedback from potential users early and often. The resulting brochure included four parts: (1) a brief description of the impact of hereditary breast cancer risk on one's health; (2) a personal and family history collection table; (3) a series of questions enabling the user to self-assess HBOC risk; (4) a list of resources for women at risk for HBOC. User feedback indicated that the brochure was easy to use. The project demonstrated that women can self-evaluate their risk for HBOC. Future work will evaluate this tool among a broader population of women.

Familial breast cancer: double heterozygosity for BRCA1 and BRCA2 mutations with differing phenotypes

The co-existence of mutations in the BRCA1 and BRCA2 genes is unusual, and to date almost all cases reported have had at least one of the Ashkenazi founder mutations. We report on a family in whom individuals are double heterozygotes for a mutation in BRCA1 and a novel splice site mutation in BRCA2. The phenotypes are discordant, where one sister has had multiple cancers in the BRCA spectrum, while the other is unaffected at 65 years of age. The utility of testing is discussed, and the completion of diagnostic testing despite the finding of a potentially causal mutation is validated.

Familial breast/ovarian cancer and BRCA1/2 genetic screening: the role of immunohistochemistry as an additional method in the selection of patients

Only 20-25% of families screened for BRCA1/2 mutations are found positive. Because only a positive result is informative, we studied the role of BRCA1/2 immunohistochemistry as an additional method for patient selection. From 53 high-risk-affected probands, 18 (34%) had available paraffin blocks of their tumors and were selected for this study. Mutation screening was done by conformation-sensitive gel electrophoresis and multiplex ligation-dependent probe amplification. For immunohistochemistry, 21 neoplastic specimens (15 breast carcinomas, 5 ovary neoplasms, and 1 rectal adenocarcinoma) were analyzed with BRCA1 (monoclonal antibody, Ab-1, oncogene) and BRCA2 (polyclonal antibody, Ab-2, oncogene) antibodies. Absence of the BRCA1 protein was confirmed in negative tumors by Western blotting. Seven patients were positive for BRCA1/2 mutations: 5 for BRCA1 and 2 for BRCA2. Four out of five positive patients had tumors negative for BRCA1 immunostaining, and the remaining 13 BRCA1-negative patients had positive BRCA1 immunostaining in all tumor samples. Sensitivity to predict for BRCA1 mutation carriers was 80%, and specificity was 100%, with a positive predictive value of 100% and a negative predictive value of 93%. This correlation was statistically significant (p=0.001). No correlation was observed for BRCA2. If larger studies confirm these results, high-risk patients with BRCA1-negative tumors should be screened first for this gene.

Cancer risks in carriers of the BRCA1/2 Ashkenazi founder mutations

BACKGROUND

The risks for cancers other than breast (BC) or ovarian (OC) cancer in breast cancer gene 1 and 2 (BRCA1/2) mutation carriers were elevated in studies of carrier families. However, case-control studies did not confirm this observation.

OBJECTIVE

To compare the risks for other cancers in BRCA1/2 mutation carriers and non-carriers, all affected with BC and/or OC. Both groups share risk modifiers of BC/OC, which enabled assessment of the role of BRCA1/2 mutations.

METHODS

1098 Ashkenazi Jewish women affected with BC and/or OC were ascertained during 1995-2003; molecular testing revealed 229 BRCA1 and 100 BRCA2 carriers and 769 non-carriers. COX proportional hazard models were used to evaluate the risk of other cancers. Analyses were conducted including all other cancers or only those diagnosed after BC/OC diagnosis.

RESULTS

The HRs for any other cancer were 2.6 (95% CI 1.7 to 4.2, p<0.001) and 1.8 (95% CI 0.95 to 3.6, p = 0.07) in BRCA1 and BRCA2 carriers, respectively. The corresponding colon cancer HRs were 3.9 (95% CI 1.3 to 12.1, p = 0.02) and 2.3 (95% CI 0.5 to 11.3, p = 0.3) in BRCA1 and BRCA2 carriers. The HR for lymphoma was 11.9 (95% CI 3.1 to 46.2, p = 0.001) in BRCA2 carriers. Risk estimates for other cancers after the onset of BC/OC were similar.

CONCLUSION

A 2.5-fold increase in any other cancer and a fourfold risk of colon cancer were found among BRCA1 carriers. The corresponding HRs in BRCA2 carriers were non-significant, except for the markedly elevated risk of lymphoma. These results suggest a role for BRCA1/2 mutations in colorectal cancer risk in a subgroup of BC/OC-affected carriers.

Cancer risks among BRCA1 and BRCA2 mutation carriers

BRCA1 and BRCA2 mutations increase breast and ovarian cancer risks substantially enough to warrant risk reduction surgery, despite variable risk estimates. Underlying this variability are methodological issues, and also complex genetic and nongenetic effects. Although many modifying factors are unidentified, known factors can already be incorporated in individualised risk prediction.

Inherited association of breast and colorectal cancer: limited role of CHEK2 compared with high-penetrance genes

We assessed the association between breast cancer (BC) and colorectal cancer (CRC) from referral pattern to the Regional Genetics Service including molecular analysis. Hospital computer records and/or department referral books were used to identify cases referred to the Regional Genetic Service during a 16-year period (1990-2005 inclusive). All files were reviewed along with associated demographic data, risk assessments, referral details and results from mutation testing. Families were assessed for hereditary breast and colorectal cancer (HBCC) criteria, and all families with eligible individuals were tested for the 1100delC mutation in CHEK2. A total of 8,612 families were identified. One hundred and sixteen of 1,631 (7.5%) families with a primary referral for CRC fulfilled the criteria for HBCC, whereas only 68/6981 (1%) BC referrals fulfilled these criteria. Blood samples were obtained from 113 individuals from 83/184 families. Only 1/113 (1%) has screened positive for the CHEK2 mutation, whereas 14 (17%) families segregate BRCA1/2 mutations and at least 7 (8.5%) carry MLH1/MSH2 mutations. HBCC syndrome, if it exists as a separate entity, is not likely to be due to CHEK2 mutations. Many families are explicable by existing high-penetrance genes, and further work is necessary to elucidate whether the remainder is due to chance or as yet undiscovered genes.

Expression of DNA double-strand break repair proteins ATM and BRCA1 predicts survival in colorectal cancer

PURPOSE

The double-strand break (DSB) is the major DNA lesion leading to chromosomal aberrations and faithful repair is crucial for maintaining genomic instability. Very little is known about the expression of DNA DSB repair proteins in colorectal cancer. To address this issue, we examined the expression pattern of DSB repair key proteins ATM, BRCA1, BRCA2, Ku70, and Ku80 and their putative role in patients survival in a large series of colorectal cancer.

EXPERIMENTAL DESIGN

342 sporadic colorectal cancer were subjected to immunohistochemistry by using specific antibodies for the various proteins investigated. Staining results were compared with clinicopathologic data, patient survival, as well as expression of mismatch repair proteins MLH1 and MSH2.

RESULTS

The expression pattern of both ATM and BRCA1 predicted survival in all colorectal cancer patients as well as in the small subgroup of patients that received adjuvant therapy. Low expression of ATM and BRCA1 was associated with loss of MLH1 or MSH2 expression.

CONCLUSIONS

This is the first study to show a relationship between the expression of DNA DSB repair proteins ATM and BRCA1 and survival in colorectal cancer patients. Studies in tumors from large randomized trials are now necessary to validate our pilot data and establish the clinical usefulness of the immunohistochemical assay in predicting response to a particular adjuvant therapy regimen. Furthermore, our results indicate a possible link between expression of DNA mismatch repair and DNA DSB repair proteins in sporadic colorectal cancer, which warrants further investigation.

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.