Prevalence of BRCA1 and BRCA2 gene mutations in patients with early-onset breast cancer

Co-treatment of birinapant with TRAIL synergistically induces apoptosis by downregulating cFLIP(L) in MDA-MB-453 cell lines

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has received much attention owing to its ability to specifically induce cell death in cancer. However, several types of cancer, including some forms of breast cancer, are resistant to TRAIL. Various chemotherapeutic agents, phytochemicals, and TRAIL combination therapies have been proposed to resolve TRAIL resistance. Here, we explored the sensitization effect of birinapant on TRAIL-induced apoptosis in the MDA-MB-453 cell line. Although neither birinapant nor TRAIL showed any cytotoxic effect when used alone, apoptosis was induced when birinapant and TRAIL were used together. Our data suggest that the combination of birinapant and TRAIL induces downregulation of FLICE-like inhibitory protein (cFLIP) (L) protein expression. Interestingly, cFLIP(L) overexpression reversed apoptosis caused by co-treatment with TRAIL. Taken together, our results indicate that a combination of birinapant and TRAIL may be a promising treatment for TRAIL-resistant breast cancer.

Canada follows the US in the rise of bilateral mastectomies for unilateral breast cancer: a 23-year population cohort study

INTRODUCTION

The use of contralateral prophylactic mastectomy (CPM) continues to grow despite the absence of evidence supporting a survival benefit. This study's objectives were to (1) describe the trends in the rates of unilateral and bilateral mastectomy (BM) in women diagnosed with unilateral breast cancer (UBC) in Ontario, Canada from 1991 to 2013, and (2) identify factors associated with BM to treat UBC.

METHODS

This retrospective cohort analysis included all women aged 18 and older diagnosed with UBC between January 1991 and December 2013. Health administrative data from the Institute for Clinical Evaluative Sciences, the Ontario Cancer Registry, and the Discharge Abstract Database were used to identify all breast cancer and mastectomy cases. Age-adjusted mastectomy rates were plotted over time. Univariable and multivariable analyses included clinically significant covariates.

RESULTS

From 1991 to 2013 there were 172,165 cases of UBC and 64,886 mastectomies (37.7%) performed in Ontario. 13.6% of the mastectomies were bilateral. BM rates increased over sixfold (from 4 to 25%) across all age groups under age 70 over a 23-year period. On multivariable analysis, younger age, higher income, rural community, earlier breast cancer stage, lobular histology, availability of reconstruction and teaching hospitals were associated with increased odds of BM.

CONCLUSIONS

This is the largest population study of breast cancer patients in Canada and shows an increasing rate of BM for UBC. The results are similar to those already described in the US and highlight the importance of continued efforts to promote efficient communication and evidence-based decision-making prior to breast surgery.

Haplotype analysis of the internationally distributed BRCA1 c.3331_3334delCAAG founder mutation reveals a common ancestral origin in Iberia

BACKGROUND

The BRCA1 c.3331_3334delCAAG founder mutation has been reported in hereditary breast and ovarian cancer families from multiple Hispanic groups. We aimed to evaluate BRCA1 c.3331_3334delCAAG haplotype diversity in cases of European, African, and Latin American ancestry.

METHODS

BC mutation carrier cases from Colombia (n = 32), Spain (n = 13), Portugal (n = 2), Chile (n = 10), Africa (n = 1), and Brazil (n = 2) were genotyped with the genome-wide single nucleotide polymorphism (SNP) arrays to evaluate haplotype diversity around BRCA1 c.3331_3334delCAAG. Additional Portuguese (n = 13) and Brazilian (n = 18) BC mutation carriers were genotyped for 15 informative SNPs surrounding BRCA1. Data were phased using SHAPEIT2, and identical by descent regions were determined using BEAGLE and GERMLINE. DMLE+ was used to date the mutation in Colombia and Iberia.

RESULTS

The haplotype reconstruction revealed a shared 264.4-kb region among carriers from all six countries. The estimated mutation age was ~ 100 generations in Iberia and that it was introduced to South America early during the European colonization period.

CONCLUSIONS

Our results suggest that this mutation originated in Iberia and later introduced to Colombia and South America at the time of Spanish colonization during the early 1500s. We also found that the Colombian mutation carriers had higher European ancestry, at the BRCA1 gene harboring chromosome 17, than controls, which further supported the European origin of the mutation. Understanding founder mutations in diverse populations has implications in implementing cost-effective, ancestry-informed screening.

DNA helicases and their roles in cancer

DNA helicases, known for their fundamentally important roles in genomic stability, are high profile players in cancer. Not only are there monogenic helicase disorders with a strong disposition to cancer, it is well appreciated that helicase variants are associated with specific cancers (e.g., breast cancer). Flipping the coin, DNA helicases are frequently overexpressed in cancerous tissues and reduction in helicase gene expression results in reduced proliferation and growth capacity, as well as DNA damage induction and apoptosis of cancer cells. The seminal roles of helicases in the DNA damage and replication stress responses, as well as DNA repair pathways, validate their vital importance in cancer biology and suggest their potential values as targets in anti-cancer therapy. In recent years, many laboratories have characterized the specialized roles of helicase to resolve transcription-replication conflicts, maintain telomeres, mediate cell cycle checkpoints, remodel stalled replication forks, and regulate transcription. In vivo models, particularly mice, have been used to interrogate helicase function and serve as a bridge for preclinical studies that may lead to novel therapeutic approaches. In this review, we will summarize our current knowledge of DNA helicases and their roles in cancer, emphasizing the latest developments.

Veliparib with carboplatin and paclitaxel in BRCA-mutated advanced breast cancer (BROCADE3): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

BRCA1 or BRCA2-mutated breast cancers are sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors and platinum agents owing to deficiency in homologous recombination repair of DNA damage. In this trial, we compared veliparib versus placebo in combination with carboplatin and paclitaxel, and continued as monotherapy if carboplatin and paclitaxel were discontinued before progression, in patients with HER2-negative advanced breast cancer and a germline BRCA1 or BRCA2 mutation.

METHODS

BROCADE3 was a randomised, double-blind, placebo-controlled, phase 3 trial done at 147 hospitals in 36 countries. Eligible patients (aged ≥18 years) had deleterious germline BRCA1 or BRCA2 mutation-associated, histologically or cytologically confirmed advanced HER2-negative breast cancer, an Eastern Cooperative Oncology Group performance status of 0-2, and had received up to two previous lines of chemotherapy for metastatic disease. Patients were randomly assigned (2:1) by interactive response technology by means of permuted blocks within strata (block size of 3 or 6) to carboplatin (area under the concentration curve 6 mg/mL per min intravenously) on day 1 and paclitaxel (80 mg/m2 intravenously) on days 1, 8, and 15 of 21-day cycles combined with either veliparib (120 mg orally twice daily, on days -2 to 5) or matching placebo. If patients discontinued carboplatin and paclitaxel before progression, they could continue veliparib or placebo at an intensified dose (300 mg twice daily continuously, escalating to 400 mg twice daily if tolerated) until disease progression. Patients in the control group could receive open-label veliparib monotherapy after disease progression. Randomisation was stratified by previous platinum use, history of CNS metastases, and oestrogen and progesterone receptor status. The primary endpoint was investigator-assessed progression-free survival per Response Evaluation Criteria in Solid Tumors version 1.1. Efficacy analyses were done by intention to treat, which included all randomly assigned patients with a centrally confirmed BRCA mutation, and safety analyses included all patients who received at least one dose of velilparib or placebo. This study is ongoing and is registered with ClinicalTrials.gov, NCT02163694.

FINDINGS

Between July 30, 2014, and Jan 17, 2018, 2202 patients were screened, of whom 513 eligible patients were enrolled and randomly assigned. In the intention-to-treat population (n=509), 337 patients were assigned to receive veliparib plus carboplatin-paclitaxel (veliparib group) and 172 were assigned to receive placebo plus carboplatin-paclitaxel (control group). Median follow-up at data cutoff (April 5, 2019) was 35·7 months (IQR 24·9-43·6) in the veliparib group and 35·5 months (23·1-45·9) in the control group. Median progression-free survival was 14·5 months (95% CI 12·5-17·7) in the veliparib group versus 12·6 months (10·6-14·4) in the control group (hazard ratio 0·71 [95% CI 0·57-0·88], p=0·0016). The most common grade 3 or worse adverse events were neutropenia (272 [81%] of 336 patients in the veliparib group vs 143 [84%] of 171 patients in the control group), anaemia (142 [42%] vs 68 [40%]), and thrombocytopenia (134 [40%] vs 48 [28%]). Serious adverse events occurred in 115 (34%) patients in the veliparib group versus 49 (29%) patients in the control group. There were no study drug-related deaths.

INTERPRETATION

The addition of veliparib to a highly active platinum doublet, with continuation as monotherapy if the doublet were discontinued, resulted in significant and durable improvement in progression-free survival in patients with germline BRCA mutation-associated advanced breast cancer. These data indicate the utility of combining platinum and PARP inhibitors in this patient population.

FUNDING

AbbVie.

Prevalence of BRCA1 and BRCA2 Mutations in Patients with Primary Ovarian Cancer - Does the German Checklist for Detecting the Risk of Hereditary Breast and Ovarian Cancer Adequately Depict the Need for Consultation?

BackgroundBRCA1/2 mutations are the leading cause of hereditary epithelial ovarian cancer (EOC). The German Consortium for Hereditary Breast and Ovarian Cancer has defined inclusion criteria, which are retrievable as a checklist and facilitate genetic counselling/testing for affected persons with a mutation probability of ≥ 10%. Our objective was to evaluate the prevalence of the BRCA1/2 mutation(s) based on the checklist score (CLS).

Methods A retrospective data analysis was performed on EOC patients with a primary diagnosis treated between 1/2011 – 5/2019 at the Central Essen Clinics, where a BRCA1/2 genetic analysis result and a CLS was available. Out of 545 cases with a BRCA1/2 result (cohort A), 453 cases additionally had an extended gene panel result (cohort B).

Results A BRCA1/2 mutation was identified in 23.3% (127/545) in cohort A, pathogenic mutations in non- BRCA1/2 genes were revealed in a further 6.2% in cohort B. In cohort A, 23.3% (127/545) of patients had a BRCA1 (n = 92) or BRCA2 (n = 35) mutation. Singular EOC (CLS 2) was present in 40.9%. The prevalence for a BRCA1/2 mutation in cohort A was 10.8%, 17.2%, 25.0%, 35.1%, 51.4% and 66.7% for patients with CLS 2, 3, 4, 5, 6 and ≥ 7 respectively. The mutation prevalence in cohort B was 15.9%, 16.4%, 28.2%, 40.4%, 44.8% and 62.5% for patients with CLS 2, 3, 4, 5, 6 and ≥ 7 respectively.

Conclusions The BRCA1/2 mutation prevalence in EOC patients positively correlates with a rising checklist score. Already with singular EOC, the prevalence of a BRCA1/2 mutation exceeds the required 10% threshold. Our data support the recommendation of the S3 guidelines Ovarian Cancer of offering genetic testing to all patients with EOC. Optimisation of the checklist with clear identification of the testing indication in this population should therefore be aimed for.

Contribution of BRCA1 and BRCA2 germline mutations to early onset breast cancer: a series from north of Morocco

BACKGROUND

To date, the contribution of BRCA1/2 mutations in Moroccan early onset breast cancer patients remains unknown. Here we assess these genetic alterations for the first time in a cohort from North of Morocco.

METHODS

Thirty-three patients diagnosed with breast cancer at the age of ≤40 years were recruited irrespective of breast and/or ovarian cancer family history. Coding regions and intron-exon boundaries of BRCA1 and BRCA2 genes were sequenced from peripheral blood DNA using Ion Proton (Thermo Fisher Scientific) next generation sequencing platform.

RESULTS

Overall, five BRCA germline mutations were identified (15.1%). The frequency of mutations among patients with family history of breast cancer was 16.7%. Three mutations were found in BRCA1 (9%) and two within the BRCA2 gene (6%). These are three frameshift mutations (c.798_799del, c.2125_2126insA, c.5116_5119delAATA), one missense (c.116G > A) and one nonsense mutation (c.289G > T). The mutation c.5116_5119delAATA has a founder effect in North Africa. Moreover, one variant of unknown significance was identified in BRCA2 (c.4090A > G). Most BRCA mutations carriers (80%) had no family history of breast cancer.

CONCLUSION

Our data do not support the hypothesis that BRCA mutations alone explain the higher frequency of breast cancer in Moroccan young women. The young age (≤40 years) for breast cancer diagnosis seems to be strongly predictive of BRCA mutation status in Moroccan patients. These results will help in decision making with regard to genetic counseling and testing in the national scale.

Nomograms for prediction of overall and cancer-specific survival in young breast cancer

PURPOSE

To assess the prognostic risk factors and establish prognostic nomograms based on lymph node ratio (LNR) to predict the survival of young patients with breast cancer (BC).

METHODS

Patients aged < 40 years and diagnosed with BC between 2010 and 2016 from the Surveillance, Epidemiology and End Results database were assessed. Nomograms incorporating LNR were constructed to predict overall survival (OS) and breast cancer-specific survival (BCSS) based on Cox proportional hazards model. The performance of the nomograms was assessed by C-index, calibration curves, receiver operating characteristic (ROC) curves, decision curve analysis (DCA), and risk group stratification and compared with the TNM staging system.

RESULTS

Based on the univariate and multivariate Cox regression analysis, significant prognostic factors were identified and integrated to create the nomograms for OS and BCSS. The calibration curves indicated optimal agreement between model predictions and actual observations. The nomograms showed favorable sensitivity with a C-index of 0.8351 (95% CI 0.8234-0.8469) for OS and 0.8474 (95% CI 0.8355-0.8594) for BCSS. The ROC curves of the nomograms showed better predictive ability than those of the TNM staging system for OS (AUC: 0.8503 vs. 0.7819) and BSCC (AUC: 0.8607 vs. 0.8081). Significant differences in Kaplan-Meier curves were observed in patients stratified into different risk groups (p < 0.001).

CONCLUSIONS

These nomograms provided more accurate individualized risk prediction of OS and BCSS and may assist clinicians in making decisions for young patients with BC.

Genetic Counseling, Testing, and Management of HBOC in India: An Expert Consensus Document from Indian Society of Medical and Pediatric Oncology

PURPOSE

Hereditary breast and ovarian cancer (HBOC) syndrome is primarily characterized by mutations in the BRCA1/2 genes. There are several barriers to the implementation of genetic testing and counseling in India that may affect clinical decisions. These consensus recommendations were therefore convened as a collaborative effort to improve testing and management of HBOC in India.

DESIGN

Recommendations were developed by a multidisciplinary group of experts from the Indian Society of Medical and Pediatric Oncology and some invited experts on the basis of graded evidence from the literature and using a formal Delphi process to help reach consensus. PubMed and Google Scholar databases were searched to source relevant articles.

RESULTS

This consensus statement provides practical insight into identifying patients who should undergo genetic counseling and testing on the basis of assessments of family and ancestry and personal history of HBOC. It discusses the need and significance of genetic counselors and medical professionals who have the necessary expertise in genetic counseling and testing. Recommendations elucidate requirements of pretest counseling, including discussions on genetic variants of uncertain significance and risk reduction options. The group of experts recommended single-site mutation testing in families with a known mutation and next-generation sequencing coupled with multiplex ligation probe amplification for the detection of large genomic rearrangements for unknown mutations. Recommendations for surgical and lifestyle-related risk reduction approaches and management using poly (ADP-ribose) polymerase inhibitors are also detailed.

CONCLUSION

With rapid strides being made in the field of genetic testing/counseling in India, more oncologists are expected to include genetic testing/counseling as part of their clinical practice. These consensus recommendations are anticipated to help homogenize genetic testing and management of HBOC in India for improved patient care.

Development and Validation of a Clinical Polygenic Risk Score to Predict Breast Cancer Risk

PURPOSE

Women with a family history of breast cancer are frequently referred for hereditary cancer genetic testing, yet < 10% are found to have pathogenic variants in known breast cancer susceptibility genes. Large-scale genotyping studies have identified common variants (primarily single-nucleotide polymorphisms [SNPs]) with individually modest breast cancer risk that, in aggregate, account for considerable breast cancer susceptibility. Here, we describe the development and empirical validation of an SNP-based polygenic breast cancer risk score.

METHODS

A panel of 94 SNPs was examined for association with breast cancer in women of European ancestry undergoing hereditary cancer genetic testing and negative for pathogenic variants in breast cancer susceptibility genes. Candidate polygenic risk scores (PRSs) as predictors of personal breast cancer history were developed through multivariable logistic regression models adjusted for age, cancer history, and ancestry. An optimized PRS was validated in 2 independent cohorts (n = 13,174; n = 141,160).

RESULTS

Within the training cohort (n = 24,259), 4,291 women (18%) had a personal history of breast cancer and 8,725 women (36%) reported breast cancer in a first-degree relative. The optimized PRS included 86 variants and was highly predictive of breast cancer status in both validation cohorts (P = 6.4 × 10-66; P < 10-325). The odds ratio (OR) per unit standard deviation was consistent between validations (OR, 1.45 [95% CI, 1.39 to 1.52]; OR 1.47 [95% CI, 1.45 to 1.49]). In a direct comparison, the 86-SNP PRS outperformed a previously described PRS of 77 SNPs.

CONCLUSION

The validation and implementation of a PRS for women without pathogenic variants in known breast cancer susceptibility genes offers potential for risk stratification to guide surveillance recommendations.

PARP Inhibitors in the Treatment of Early Breast Cancer: The Step Beyond?

Exquisitely exploiting defects in homologous recombination process, poly(ADP-ribose) polymerase (PARP) inhibitors have recently emerged as a promising class of therapeutics in human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer with germline breast cancer 1 (BRCA1) or breast cancer 2 (BRCA2) mutations (gBRCA1/2m). In this setting, PARP inhibitors, either as single agent or in combination with platinum-based chemotherapy, significantly increased progression-free survival, as compared to conventional chemotherapy. Accordingly, further therapeutic advances are expected at an earlier stage of the disease. In the neoadjuvant setting, veliparib failed to increase the pathological complete response rate when added to a carboplatin-based regimen, in unselected triple-negative breast cancer patients. Similarly, when administered before anthracycline-cyclophosphamide, the neoadjuvant olaparib-paclitaxel combination was not superior to carboplatin–paclitaxel, in patients with HER2-negative breast cancer and BRCA1/2 mutation, or homologous recombination defect. Yet, neoadjuvant talazoparib, administered as a single-agent in patients with HER2-negative breast cancer and germline BRCA1/2 mutation, achieved an impressive pathological complete response rate of nearly 50%. In the adjuvant setting, the results from the OlympiA phase III study, evaluating adjuvant olaparib in HER2-negative early breast cancer and germline BRCA1/2 mutations, are eagerly awaited. Ongoing trials should clarify whether PARP inhibitors might improve outcome when administered in the adjuvant or neoadjuvant setting in early breast cancer patients with BRCA1/2 mutation or homologous recombination defect.

Clinicopathological characteristics of BRCA-associated breast cancer in Asian patients

BRCA1/2 germline mutations account for the majority of hereditary breast cancers. Since the identification of the BRCA genes, several attempts have been made to define the clinicopathological characteristics of BRCA-associated breast cancer in comparison with sporadic breast cancer. Asians constitute 60% of the world population, and although the incidence of breast cancer in Asia remains low compared to the West, breast cancer is the most prevalent female cancer in the region. The epidemiological aspects of breast cancer are different between Asians and Caucasians. Asian patients present with breast cancer at a younger age than Western patients. The contributions of BRCA1/2 mutations to breast cancer incidence are expected to differ between Asians and Caucasians, and the different genetic backgrounds among races are likely to influence the breast cancer phenotypes. However, most large-scale studies on the clinicopathological characteristics of BRCA-associated breast cancer have been on Western patients, while studies on Asian populations were small and sporadic. In this review, we provide an overview of the clinical and pathological characteristics of BRCA-associated breast cancer, incorporating findings on Asian patients.

The spectrum of BRCA1 and BRCA2 mutations and clinicopathological characteristics in Chinese women with early-onset breast cancer

PURPOSE

BRCA1/2 mutations represent a high risk of breast cancer and are related to early-onset breast cancer. However, few studies have reported the relationship between BRCA1/2 mutations and their clinical characteristics in early-onset breast cancers. This study is the first article that characterizes the risk factor profiles in Chinese patients selected by the age of onset (≤ 40 years old). We found some differences in the prevalence of germline BRCA1/2 mutations between Asian and Western countries.

METHODS

A total of 1371 consecutive unselected Chinese early-onset breast cancer patients were enrolled from the Fujian Medical University Union Hospital, China, and screened for germline BRCA1/2 mutations. Full-exome sequencing in next-generation sequencing technology was performed in all patients to examine BRCA1/2 mutations.

RESULTS

In our study, 25 (1.8%) and 61 (4.4%) patients were identified with BRCA1 and BRCA2 mutations, respectively, among the unselected early-onset breast cancer patients. BRCA1 mutations were associated with pregnancies (p = 0.026), and BRCA1 carriers had a higher likelihood of being HR positive (p < 0.001), HER2 negative (p < 0.001), or high grade (p = 0.002) than noncarriers. Among BRCA2 mutations, the age of onset was younger in carriers than in noncarriers (p = 0.017), and BRCA2 carriers were more likely to have lymph node metastasis (p = 0.004). HR-positive or HER2-negative patients were likely to be positive for BRCA2 mutations (p < 0.001). Overall, 14 BRCA1 mutations and 8 BRCA2 mutations were first reported in our study CONCLUSION: This study provided some information about the spectrum of BRCA1/2 mutations and characterized the risk factors for early-onset breast cancer in China.

Population frequencies of pathogenic alleles of BRCA1 and BRCA2: analysis of 173 Danish breast cancer pedigrees using the BOADICEA model

The Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) calculates the probability that a woman carries a pathogenic variant in BRCA1 or BRCA2 based on her pedigree and the population frequencies of pathogenic alleles of BRCA1 (0.0006394) and BRCA2 (0.00102) in the United Kingdom (UK). BOADICEA allows the clinician to define the population frequencies of pathogenic alleles of BRCA1 and BRCA2 for other populations but only includes preset values for the Ashkenazy Jewish and Icelandic populations. Among 173 early-onset breast cancer pedigrees in Denmark, BOADICEA discriminated well between carriers and non-carriers of pathogenic variants (area under the receiver operating characteristics curve: 0.81; 95% CI 0.74-0.86) but underestimated the frequency of carriers of pathogenic variants in BRCA1 or BRCA2 as measured by the observed-to-expected ratio (O/E 1.83; 95% CI 1.18-2.84). This reflects findings from older studies of BOADICEA in UK, German, Italian, and Chinese populations, all accounting for the different calibration for different carrier probabilities. To improve the performance of BOADICEA for non-UK populations, we developed a method to derive population frequencies of pathogenic alleles of BRCA1 and BRCA2. Compared to the UK population frequencies, we estimated the Danish population frequencies of pathogenic alleles to be higher for BRCA1 (0.0015; 95% CI 0.00064-0.0034) and lower for BRCA2 (0.00052; 95% CI 0.00018-0.0017) after adjusting for the different calibration of BOADICEA for different carrier probabilities. Incorporating additional population frequencies into BOADICEA could improve its performance for non-UK populations.

Breast Cancer Care in Jordan

Breast cancer is the most common malignancy in Jordan and the third leading cause of cancer death after lung and colorectal cancers. Although the incidence of breast cancer in Jordan is lower than that in industrialized nations, the number of new cases has been significantly increasing, and women present with breast cancer at a younger age and with more advanced disease than women in Western countries. Jordan is a medium-income country with limited resources and a young population structure. Therefore, breast cancer poses a particularly challenging burden on the country's health care system. Despite ongoing endeavors to improve breast cancer care at both public and private levels, more work is needed to achieve downstaging of the disease and improve access, awareness, and participation in early detection. Multimodality treatment facilities and supportive care are available; however, the quality of care varies widely according to where the patient is treated, and most treatment facilities remain located centrally, thus, creating access difficulties. The King Hussein Cancer Center, the only comprehensive cancer center in Jordan, has changed the practice of oncology in the country via implementation of a multidisciplinary approach to treatment, monitoring of treatment outcomes, and investments in ongoing cancer research. However, there remains no national system for ensuring provision of high-quality cancer care nationwide. Here, we review the epidemiology of breast cancer and the current status of breast cancer care in Jordan, we compare our treatment outcomes with international ones, and we highlight challenges and improvement opportunities.

Prevalence of Inherited Mutations in Breast Cancer Predisposition Genes among Women in Uganda and Cameroon

BACKGROUND

Sub-Saharan Africa (SSA) has a high proportion of premenopausal hormone receptor negative breast cancer. Previous studies reported a strikingly high prevalence of germline mutations in BRCA1 and BRCA2 among Nigerian patients with breast cancer. It is unknown if this exists in other SSA countries.

METHODS

Breast cancer cases, unselected for age at diagnosis and family history, were recruited from tertiary hospitals in Kampala, Uganda and Yaoundé, Cameroon. Controls were women without breast cancer recruited from the same hospitals and age-matched to cases. A multigene sequencing panel was used to test for germline mutations.

RESULTS

There were 196 cases and 185 controls with a mean age of 46.2 and 46.6 years for cases and controls, respectively. Among cases, 15.8% carried a pathogenic or likely pathogenic mutation in a breast cancer susceptibility gene: 5.6% in BRCA1, 5.6% in BRCA2, 1.5% in ATM, 1% in PALB2, 0.5% in BARD1, 0.5% in CDH1, and 0.5% in TP53. Among controls, 1.6% carried a mutation in one of these genes. Cases were 11-fold more likely to carry a mutation compared with controls (OR = 11.34; 95% confidence interval, 3.44-59.06; P < 0.001). The mean age of cases with BRCA1 mutations was 38.3 years compared with 46.7 years among other cases without such mutations (P = 0.03).

CONCLUSIONS

Our findings replicate the earlier report of a high proportion of mutations in BRCA1/2 among patients with symptomatic breast cancer in SSA.

IMPACT

Given the high burden of inherited breast cancer in SSA countries, genetic risk assessment could be integrated into national cancer control plans.

Sampling-based Markov regression model for multistate disease progression: Applications to population-based cancer screening program

To develop personalized screening and surveillance strategies, the information required to superimpose state-specific covariates into the multi-step progression of disease natural history often relies on the entire population-based screening data, which are costly and infeasible particularly when a new biomarker is proposed. Following Prentice's case-cohort concept, a non-standard case-cohort design from a previous study has been adapted for constructing multistate disease natural history with two-stage sampling. Nonetheless, the use of data only from first screens may invoke length-bias and fail to consider the test sensitivity. Therefore, a new sampling-based Markov regression model and its variants are proposed to accommodate additional subsequent follow-up data on various detection modes to construct state-specific covariate-based multistate disease natural history with accuracy and efficiency. Computer simulation algorithms for determining the required sample size and the sampling fraction of each detection mode were developed either through power function or the capacity of screening program. The former is illustrated with breast cancer screening data from which the effect size and the required sample size regarding the effect of BRCA on multistate outcome of breast cancer were estimated. The latter is applied to population-based colorectal cancer screening data to identify the optimal sampling fraction of each detection mode.

DNA damage responses in ageing

Ageing appears to be a nearly universal feature of life, ranging from unicellular microorganisms to humans. Longevity depends on the maintenance of cellular functionality, and an organism's ability to respond to stress has been linked to functional maintenance and longevity. Stress response pathways might indeed become therapeutic targets of therapies aimed at extending the healthy lifespan. Various progeroid syndromes have been linked to genome instability, indicating an important causal role of DNA damage accumulation in the ageing process and the development of age-related pathologies. Recently, non-cell-autonomous mechanisms including the systemic consequences of cellular senescence have been implicated in regulating organismal ageing. We discuss here the role of cellular and systemic mechanisms of ageing and their role in ageing-associated diseases.

Cost effectiveness of bilateral risk-reducing mastectomy and salpingo-oophorectomy

Background

Growing demand for risk-reducing surgery in individuals with inherited susceptibility to cancer leads to the question whether these procedures are cost effective for the executing hospitals. This study compared the clinical costs for bilateral risk-reducing mastectomy (BRRM) with and without different types of reconstruction, risk-reducing salpingo-oophorectomy (RRSO), and their combinations with corresponding reimbursements in the statutory health-care system in Germany.

Patients and methods

Real total costs of care for BRRM with and without reconstruction, RRSO, and their combinations were calculated as the sum of all personnel and technical costs. These costs calculated in a German University hospital were compared with the sum of all reimbursements in the German DRG-based health-care system.

Results

While sole RRSO, BRRM without reconstruction, and BRRM with secondary DIEP (deep inferior epigastric perforator)—reconstruction still result in a small benefit, we even found shortfalls for the hospital with all other prophylactic operations under consideration. The calculated deficits were especially high for BRRM with implant-based breast reconstruction and for combined operations when the risk reduction is achieved with a minimum of separate operations.

Conclusions

Risk-reducing surgery in BRCA-mutation carriers is frequently not cost-covering for the executing hospitals in the German health-care system. Thus, appropriate concepts are required to ensure a nationwide care.

Owens DK, Davidson KW, Krist AH, Barry MJ, Cabana M, Caughey AB, Doubeni CA, Epling JW, Kubik M, Landefeld CS, Mangione CM, Pbert L, Silverstein M, Simon MA, Tseng CW, Wong JB. Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-Related Cancer: US Preventive Services Task Force Recommendation Statement

IMPORTANCE

Potentially harmful mutations of the breast cancer susceptibility 1 and 2 genes (BRCA1/2) are associated with increased risk for breast, ovarian, fallopian tube, and peritoneal cancer. For women in the United States, breast cancer is the most common cancer after nonmelanoma skin cancer and the second leading cause of cancer death. In the general population, BRCA1/2 mutations occur in an estimated 1 in 300 to 500 women and account for 5% to 10% of breast cancer cases and 15% of ovarian cancer cases.

OBJECTIVE

To update the 2013 US Preventive Services Task Force (USPSTF) recommendation on risk assessment, genetic counseling, and genetic testing for BRCA-related cancer.

EVIDENCE REVIEW

The USPSTF reviewed the evidence on risk assessment, genetic counseling, and genetic testing for potentially harmful BRCA1/2 mutations in asymptomatic women who have never been diagnosed with BRCA-related cancer, as well as those with a previous diagnosis of breast, ovarian, tubal, or peritoneal cancer who have completed treatment and are considered cancer free. In addition, the USPSTF reviewed interventions to reduce the risk for breast, ovarian, tubal, or peritoneal cancer in women with potentially harmful BRCA1/2 mutations, including intensive cancer screening, medications, and risk-reducing surgery.

FINDINGS

For women whose family or personal history is associated with an increased risk for harmful mutations in the BRCA1/2 genes, or who have an ancestry associated with BRCA1/2 gene mutations, there is adequate evidence that the benefits of risk assessment, genetic counseling, genetic testing, and interventions are moderate. For women whose personal or family history or ancestry is not associated with an increased risk for harmful mutations in the BRCA1/2 genes, there is adequate evidence that the benefits of risk assessment, genetic counseling, genetic testing, and interventions are small to none. Regardless of family or personal history, the USPSTF found adequate evidence that the overall harms of risk assessment, genetic counseling, genetic testing, and interventions are small to moderate.

CONCLUSIONS AND RECOMMENDATION

The USPSTF recommends that primary care clinicians assess women with a personal or family history of breast, ovarian, tubal, or peritoneal cancer or who have an ancestry associated with BRCA1/2 gene mutations with an appropriate brief familial risk assessment tool. Women with a positive result on the risk assessment tool should receive genetic counseling and, if indicated after counseling, genetic testing. (B recommendation) The USPSTF recommends against routine risk assessment, genetic counseling, or genetic testing for women whose personal or family history or ancestry is not associated with potentially harmful BRCA1/2 gene mutations. (D recommendation).

Risk Assessment, Genetic Counseling, and Genetic Testing for BRCA-Related Cancer in Women: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Pathogenic mutations in breast cancer susceptibility genes BRCA1 and BRCA2 increase risks for breast, ovarian, fallopian tube, and peritoneal cancer in women; interventions reduce risk in mutation carriers.

OBJECTIVE

To update the 2013 US Preventive Services Task Force review on benefits and harms of risk assessment, genetic counseling, and genetic testing for BRCA1/2-related cancer in women.

DATA SOURCES

Cochrane libraries; MEDLINE, PsycINFO, EMBASE (January 1, 2013, to March 6, 2019, for updates; January 1, 1994, to March 6, 2019, for new key questions and populations); reference lists.

STUDY SELECTION

Discriminatory accuracy studies, randomized clinical trials (RCTs), and observational studies of women without recently diagnosed BRCA1/2-related cancer.

DATA EXTRACTION AND SYNTHESIS

Data on study methods, setting, population characteristics, eligibility criteria, interventions, numbers enrolled and lost to follow-up, outcome ascertainment, and results were abstracted. Two reviewers independently assessed study quality.

MAIN OUTCOMES AND MEASURES

Cancer incidence and mortality; discriminatory accuracy of risk assessment tools for BRCA1/2 mutations; benefits and harms of risk assessment, genetic counseling, genetic testing, and risk-reducing interventions.

RESULTS

For this review, 103 studies (110 articles; N = 92 712) were included. No studies evaluated the effectiveness of risk assessment, genetic counseling, and genetic testing in reducing incidence and mortality of BRCA1/2-related cancer. Fourteen studies (n = 43 813) of 8 risk assessment tools to guide referrals to genetic counseling demonstrated moderate to high accuracy (area under the receiver operating characteristic curve, 0.68-0.96). Twenty-eight studies (n = 8060) indicated that genetic counseling was associated with reduced breast cancer worry, anxiety, and depression; increased understanding of risk; and decreased intention for testing. Twenty studies (n = 4322) showed that breast cancer worry and anxiety were higher after testing for women with positive results and lower for others; understanding of risk was higher after testing. In 8 RCTs (n = 54 651), tamoxifen (relative risk [RR], 0.69 [95% CI, 0.59-0.84]; 4 trials), raloxifene (RR, 0.44 [95% CI, 0.24-0.80]; 2 trials), and aromatase inhibitors (RR, 0.45 [95% CI, 0.26-0.70]; 2 trials) were associated with lower risks of invasive breast cancer compared with placebo; results were not specific to mutation carriers. Mastectomy was associated with 90% to 100% reduction in breast cancer incidence (6 studies; n = 2546) and 81% to 100% reduction in breast cancer mortality (1 study; n = 639); oophorectomy was associated with 69% to 100% reduction in ovarian cancer (2 studies; n = 2108); complications were common with mastectomy.

CONCLUSIONS AND RELEVANCE

Among women without recently diagnosed BRCA1/2-related cancer, the benefits and harms of risk assessment, genetic counseling, and genetic testing to reduce cancer incidence and mortality have not been directly evaluated by current research.

How latent viruses cause breast cancer: An explanation based on the microcompetition model

Most breast cancer cases show a decrease in the concentration of the breast cancer type 1 susceptibility protein (BRCA1). However, only a small portion of these cases have a mutated BRCA1 gene. Although many attempts have been made to identify the reason for the decrease in BRCA1 concentration in sporadic, non-heritable breast cancer cases, the cause is still unknown. In this review, we use the Microcompetition Model to explain how certain latent viruses, which are frequently detected in breast cancer tumors, can decrease the expression of the BRCA1 gene and cause the development of breast tumors.

Two-Staged Implant-Based Breast Reconstruction: A Long-Term Outcome Study in a Young Population

Background and objectives: Differences in patient anatomy and physiology exist between young and older patients undergoing breast reconstruction after mastectomy. Breast cancer has been described as being more aggressive, more likely to receive radiation, contralateral mastectomy, as well as bilateral reconstruction in young patients. Our purpose is to report long-term experience on two-staged implant-based breast reconstruction (IBR) in young females, with complication sub-analysis based on obesity and adjuvant radiation. Materials and Methods: Retrospective chart review of all consecutive young patients who underwent two-staged IBR at our institution, between 2000 and 2016, was performed. Patients between 15 and 40 years old with least 1-year follow-up were included. Univariate logistic regression models and receiver operating characteristic (ROC) curves were created. Results: Overall 594 breasts met our inclusion criteria. The mean age was 34 years, and the median follow-up was 29.6 months. Final IBR was achieved in 98% of breasts. Overall, 12% of breasts had complications, leading to explantations of 5% of the devices. Adjuvant radiation was followed by higher rates of total device explantations (p = 0.003), while obese patients had higher rates of total complications (p < 0.001). For each point increase in BMI, the odds of developing complications increased 8.1% (p < 0.001); the cutoff BMI to predict higher complications was 24.81 kg/m². Conclusions: This population demonstrates high successful IBR completion and low explantation rates. These data suggest that obese women and those with planned adjuvant radiation deserve special counseling about their higher risk of complications.

Effectiveness of decision aids for female BRCA1 and BRCA2 mutation carriers: a systematic review

BACKGROUND

Female BRCA1 and BRCA2 mutation carriers have an increased lifetime risk of developing breast and/or ovarian cancer. Hence, they face the difficult decision of choosing a preventive strategy such as risk-reducing surgeries or intensified breast screening. To help these women during their decision process, several patient decision aids (DA) were developed and evaluated in the last 15 years. Until now, there is no conclusive evidence on the effectiveness of these DA. This study aims 1) to provide the first systematic literature review about DA addressing preventive strategy decisions for female BRCA1 and BRCA2 mutation carriers, 2) to analyze the quality of the existing evidence, 3) to evaluate the effects of DA on decision and information related outcomes, on the actual choice for preventive measure and on health outcomes.

METHODS

A systematic literature review was conducted using six electronic databases (inclusion criteria: DA addressing preventive strategies, female BRCA1 and BRCA2 mutation carriers, 18 to 75 years, knowledge of test result). The quality of the included randomized controlled trials (RCT) was evaluated with the Cochrane Collaboration's risk of bias tool. The quality of included one-group pretest-posttest design studies was evaluated with the ROBINS-I tool. Outcomes of included studies were extracted and qualitatively summarized.

RESULTS

A total of 2093 records were identified. Six studies were included for further evaluation (5 RCT, 1 one-group pretest-posttest design study). One RCT was formally included, but data presentation did not allow for further analyses. The risk of bias was high in three RCT and unclear in one RCT. The risk of bias in the one-group pretest-posttest study was serious. The outcome assessment showed that the main advantages of DA are linked to the actual decision process: Female BRCA1 and BRCA2 mutation carriers using a DA had less decisional conflict, were more likely to reach a decision and were more satisfied with their decision.

CONCLUSIONS

Decision aids can support female BRCA1 and BRCA2 mutation carriers during their decision process by significantly improving decision related outcomes. More high-quality evidence is needed to evaluate possible effects on information related outcomes, health outcomes and the actual choice for preventive measures.

Gail Model Underestimates Breast Cancer Risk in Thai Population

Background: The Gail model is the most widely used method for breast cancer risk estimation. This model has been studied and verified for its validity in many groups but there has yet to be a study to validate the Gail model in a Thai population. This study aims to evaluate whether the Gail model can accurately calculate the risk of breast cancer among Thai women. Methods: The subjects were recruited from the Division of Head, Neck, and Breast Surgery, Department of Surgery, Siriraj Hospital. The patients attending the division were asked to enroll in the study and complete questionnaires. Gail model scores were then calculated. Relationships between parameters were examined using the Pearson’s chi-square test, Fisher’s exact test, and independent-samples t-test. Results: There were 514 women recruited. Age, parity, age at first-live birth, and history of atypical ductal hyperplasia (ADH) were significant risk factors for breast cancer. The 5-year and lifetime risk score for breast cancer calculated by the Gail model were not significantly different between the patient and the control subjects. The proportions of the subjects with lifetime risk ≥20% were significantly higher in breast cancer patients (p=0.049). Conclusion: The Gail model underestimated the risk of breast cancer in Thai women. Calibration of the model is still required before adoption in Thai population.

Genomics applied to the treatment of breast cancer

Breast cancer remains a major health issue in the world with 1.7 million new cases in 2012 worldwide. It is the second cause of death from cancer in western countries. Genomics have started to modify the treatment of breast cancer, and the developments should become more and more significant, especially in the present era of treatment personalization and with the implementation of new technologies. With molecular signatures, genomics enabled a de-escalation of chemotherapy and personalized treatments of localized forms of estrogen-dependent breast cancers. Genomics can also make a real contribution to constitutional genetics, so as to identify mutations in a panel of candidate genes. In this review, we will discuss the contributions of genomics applied to the treatment of breast cancer, whether already validated contributions or possible future applications linked to research data.

BRCA2 abrogation triggers innate immune responses potentiated by treatment with PARP inhibitors

Heterozygous germline mutations in BRCA2 predispose to breast and ovarian cancer. Contrary to non-cancerous cells, where BRCA2 deletion causes cell cycle arrest or cell death, tumors carrying BRCA2 inactivation continue to proliferate. Here we set out to investigate adaptation to loss of BRCA2 focusing on genome-wide transcriptome alterations. Human cells in which BRCA2 expression is inhibited for 4 or 28 days are subjected to RNA-seq analyses revealing a biphasic response to BRCA2 abrogation. The early, acute response consists of downregulation of genes involved in cell cycle progression, DNA replication and repair and is associated with cell cycle arrest in G1. Surprisingly, the late, chronic response consists predominantly of upregulation of interferon-stimulated genes (ISGs). Activation of the cGAS-STING-STAT pathway detected in these cells further substantiates the concept that BRCA2 abrogation triggers cell-intrinsic immune signaling. Importantly, we find that treatment with PARP inhibitors stimulates the interferon response in cells and tumors lacking BRCA2.

Multi gene panel testing for hereditary breast cancer - is it ready to be used?

Breast cancer is one of the most common malignancies and the leading cause of death among women worldwide. About 20% of breast cancers are hereditary. Approximately 30% of the mutations have remained negative after testing BRCA1/2 even in families with a Mendelian inheritance pattern for breast cancer. Additional non-BRCA genes have been identified as predisposing for breast cancer. Multi gene panel testing tries to cover and explain the BRCA negative inherited breast cancer, improving efficiency, speed and costs of the breast cancer screening. We identified 23 studies reporting results from individuals who have undergone multi gene panel testing for hereditary breast cancer and noticed a prevalence of 1-12% of non-BRCA genes, but also a high level of variants of uncertain significance. A result with a high level of variants of uncertain significance is likely to be more costly than bring benefits, as well as increase the anxiety for patients. Regarding further development of multi gene panel testing, more research is required to establish both the optimal care of patients with cancer (specific treatments like PARP inhibitors) and the management of unaffected individuals (chemoprevention and/or prophylactic surgeries). Early detection in these patients as well as prophylactic measures will significantly increase the chance of survival. Therefore, multi gene panel testing is not yet ready to be used outside clear guidelines. In conclusion, studies on additional cohorts will be needed to better define the real prevalence, penetrance and the variants of these genes, as well as to describe clear evidence-based guidelines for these patients.

Familial aggregation of early-onset cancers

This registry‐linkage study evaluates familial aggregation of cancer among relatives of a population‐based series of early‐onset (≤40 years) cancer patients in Finland. A cohort of 376,762 relatives of early‐onset cancer patients diagnosed between 1970 and 2012 in 40,538 families was identified. Familial aggregation of early‐onset breast, colorectal, brain and other central nervous system (CNS) cancer and melanoma was explored by standardized incidence ratios (SIR), stratified by relatedness. Gender‐, age‐ and period‐specific population cancer incidences were used as reference. Cumulative risks for siblings and offspring of the proband up to age ≤40 years were also estimated. Almost all early‐onset cancers were sporadic (98% or more). Among first‐degree relatives, SIR was largest in colorectal cancer (14, 95% confidence interval 9.72–18), and lowest in melanoma (1.93, 1.05–3.23). Highest relative‐specific SIRs were observed for siblings in families, where also parent had concordant cancer, 90 (43–165) for colorectal cancer and 29 (11–64) for CNS cancer. In spouses, all SIRs were at population level. Cumulative risk of colorectal cancer by age 41 was 0.98% in siblings and 0.10% in population, while in breast cancer the corresponding risks were 2.05% and 0.56%. In conclusion, early‐onset cancers are mainly sporadic. Findings support high familial aggregation in early‐onset colorectal and CNS cancers. Familial aggregation in multiplex families with CNS cancers was mainly attributed to neurofibromatosis and in colorectal cancer to FAP‐ and HNPCC‐syndromes. The pattern of familial aggregation of early‐onset breast cancer could be seen to support very early exposure to environmental factors and/or rare genetic factors.

What's new?

The tendency for certain cancer types to cluster in families generally is explained by shared environmental exposures or inherited mutations. In particular, early‐onset cancer, diagnosed between ages 0 and 40, is considered indicative of familial factors. Here, investigation of cancer risk among more than 376,760 relatives of probands, or individuals with early‐onset cancer, shows that the likelihood of early‐onset cancer affecting even just one other relative in addition to the proband is exceedingly rare. Nearly all early‐onset cancers in the study population were sporadic. Estimated cumulative risks observed for specific cancers may prove useful in the context of genetic counseling.

Overexpression of Kynurenine 3-Monooxygenase Correlates with Cancer Malignancy and Predicts Poor Prognosis in Canine Mammary Gland Tumors

Tumor biomarkers are developed to indicate tumor status, clinical outcome, or prognosis. Since currently there are no effective biomarkers for canine mammary tumor (CMT), this study intended to verify whether kynurenine 3-monooxygenase (KMO), one of the key enzymes involved in tryptophan catabolism, is competent for predicting prognosis in patients with CMT. By investigating a series of 86 CMT clinical cases, we found that both gene and protein expression of KMO discriminated malignant from benign CMTs and was significantly higher in stage IV and V tumors than in lower-stage CMTs. About 73.7% of malignant CMTs showed strong expression of KMO which correlated with lower overall survival rates in patients. Further, downregulation of KMO activity significantly inhibited cell proliferation of CMT cells. Taken together, the findings indicated that KMO is a potential biomarker for tumor diagnosis, and this might open up new perspectives for clinical applications of CMT.

Identifying a BRCA2 c.5722_5723del mutation in a Han-Chinese family with breast cancer

Breast cancer (BC) is the most common female cancer found worldwide. It is responsible for 25% of all cancer patients in females. Hereditary BC accounts for about 5–10% of all BC cases. The breast cancer 1 gene (BRCA1) and the breast cancer 2 gene (BRCA2) are the two most-studied BC susceptibility genes. Genetic testing for disease-causing mutations in BRCA1, BRCA2, and other BC susceptibility genes is strongly recommended for members of families having a BC family history. The present study found a heterozygous c.5722_5723del mutation in the BRCA2 exon 11 of a large Han-Chinese BC family using whole exome sequencing and Sanger sequencing. It may cause DNA double-strand breaks repair dysfunction by disturbing homologous recombination, further resulting in BC. The study findings may help supplement and further improve genetic testing strategies and BC risk estimation methodologies in China.

Germline Missense Variants in BRCA1: New Trends and Challenges for Clinical Annotation

Genetic testing allows for the identification of germline DNA variations, which are associated with a significant increase in the risk of developing breast cancer (BC) and ovarian cancer (OC). Detection of a BRCA1 or BRCA2 pathogenic variant triggers several clinical management actions, which may include increased surveillance and prophylactic surgery for healthy carriers or treatment with the PARP inhibitor therapy for carriers diagnosed with cancer. Thus, standardized validated criteria for the annotation of BRCA1 and BRCA2 variants according to their pathogenicity are necessary to support clinical decision-making and ensure improved outcomes. Upon detection, variants whose pathogenicity can be inferred by the genetic code are typically classified as pathogenic, likely pathogenic, likely benign, or benign. Variants whose impact on function cannot be directly inferred by the genetic code are labeled as variants of uncertain clinical significance (VUS) and are evaluated by multifactorial likelihood models that use personal and family history of cancer, segregation data, prediction tools, and co-occurrence with a pathogenic BRCA variant. Missense variants, coding alterations that replace a single amino acid residue with another, are a class of variants for which determination of clinical relevance is particularly challenging. Here, we discuss current issues in the missense variant classification by following a typical life cycle of a BRCA1 missense variant through detection, annotation and information dissemination. Advances in massively parallel sequencing have led to a substantial increase in VUS findings. Although the comprehensive assessment and classification of missense variants according to their pathogenicity remains the bottleneck, new developments in functional analysis, high throughput assays, data sharing, and statistical models are rapidly changing this scenario.

Genetic Epidemiology of Breast Cancer in Latin America

The last 10 years witnessed an acceleration of our understanding of what genetic factors underpin the risk of breast cancer. Rare high- and moderate-penetrance variants such as those in the BRCA genes account for a small proportion of the familial risk of breast cancer. Low-penetrance alleles are expected to underlie the remaining heritability. By now, there are about 180 genetic polymorphisms that are associated with risk, most of them of modest effect. In combination, they can be used to identify women at the lowest or highest ends of the risk spectrum, which might lead to more efficient cancer prevention strategies. Most of these variants were discovered in populations of European descent. As a result, we might be failing to discover additional polymorphisms that could explain risk in other groups. This review highlights breast cancer genetic epidemiology studies conducted in Latin America, and summarizes the information that they provide, with special attention to similarities and differences with studies in other populations. It includes studies of common variants, as well as moderate- and high-penetrance variants. In addition, it addresses the gaps that need to be bridged in order to better understand breast cancer genetic risk in Latin America.

Women's cancers: how the discovery of BRCA genes is driving current concepts of cancer biology and therapeutics

Over the last two decades, discoveries related to the breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2) have profoundly changed our understanding and management of hereditary breast and ovarian cancers. The concept of synthetic lethality, which arises when cells become vulnerable to a combination of deficiencies in DNA repair, has driven the expanding roles of poly (adenosine diphosphate (ADP)-ribose) polymerase inhibitors in breast and ovarian cancers, and prevention strategies are taking into account the tissue specificity, natural history (fallopian tube origin of some high-grade serous ovarian cancers) and hormone sensitivity of BRCA-associated cancers. Current research has focussed on further elucidating the roles of BRCA proteins in DNA repair, investigating other key DNA repair processes and proteins and linking aberrant DNA repair with carcinogenesis. The ultimate goal is to translate this evolving knowledge into improving the clinical care and treatment of patients with pathogenic BRCA variants or other deficiencies in homologous recombination (HR). In this review, we will discuss 1) the role of BRCA proteins in DNA repair; 2) emerging concepts in the biology of HR deficiency and 3) implications for prevention and treatment.

Identifying breast cancer susceptibility genes - a review of the genetic background in familial breast cancer

INTRODUCTION

Heritage is the most important risk factor for breast cancer. About 15-20% of breast cancer is familial, referring to affected women who have one or more first- or second-degree relatives with the disease. The heritable component in these families is substantial, especially in families with aggregation of breast cancer with low age at onset. Identifying breast cancer susceptibility genes: Since the discovery of the highly penetrant autosomal dominant susceptibility genes BRCA1 and BRCA2 in the 1990s, several more breast cancer genes that confer a moderate to high risk of breast cancer have been identified. Furthermore, during the last decade, advances in genomic technologies have led to large scale genotyping in genome-wide association studies that have identified a considerable amount of common low penetrance loci. In total, the high risk genes, BRCA1, BRCA2, TP53, STK11, CD1 and PTEN account for approximately 20% of the familial risk. Moderate risk variants account for up to 5% of the inherited familial risk. The more than 180 identified low-risk loci explain 18% of the familial risk. Altogether more than half of the genetic background in familial breast cancer remains unclear. Other genes and low risk loci that explain a part the remaining fraction will probably be identified. Clinical aspects and future perspectives: Definitive clinical recommendations can be drawn only for carriers of germline variants in a limited number of high and moderate risk genes for which an association with breast cancer has been established. Future progress in evaluating previously identified breast cancer candidate variants and low risk loci as well as exploring new ones can play an important role in improving individual risk prediction in familial breast cancer.

Central body fatness is a stronger predictor of cancer risk than overall body size

The importance of body size versus weight distribution for cancer risk is unclear. We investigated associations between measures of body size and shape and the risk of developing cancer. The study population consisted of 26,607 participants from the Alberta’s Tomorrow Project cohort. Two main measures of body shape and size were examined: i) body mass index (BMI) and ii) waist circumference (WC). Incident cancers were identified via linkage to the Alberta Cancer Registry. Cox proportional hazards models were used. Males and females classified as obese (BMI ≥ 30 kg /m⁻²) have a 33% and 22% increased risk of all-cancer, respectively, than their normal weight counterparts. Similar all-cancer risk increases are observed for those above sex-specific WC guidelines. Mutual adjustment for WC attenuates the association between BMI and all-cancer risk, especially among females. Central adiposity appears to be a stronger predictor of all-cancer risk than body size.

Obesity is linked to increased cancer risk but the impact of body size versus weight distribution in determining the increased risk is unclear. Here the authors examined body mass index, waist circumference, and waist to hip ratio in relation to all-cancer incidence and incidence of seven individual cancers in a population of approximately 26,000 individual and conclude that central adiposity appears to be a stronger predictor of all-cancer risk than body size.

Overview of the genetic basis toward early detection of breast cancer

Cancer is a socioeconomical burden in any nation. Out of that, breast cancer is identified as the most common malignancy worldwide among women irrespective of age. As women are an important segment in a community, the weakening of their strength toward the development of a nation is a critical problem in each nation. In this review, it was aimed to discuss the characteristics of cancer genome, cancer genetics, and cancer epigenetics in general and then focus on discussing both genetic and nongenetic factors responsible for the predisposition of breast cancer in humans. More emphasis was placed on genes responsible for the early onset of the disease and which can be used as genetic tools in the identification of the disease at an early stage. Then the context of genetic involvement toward the breast cancer occurrence before age of 40 years was highlighted accordingly. In addition to genetic testing, the review paid adequate attention to mention novel liquid biopsy techniques and other clinical, laboratory, and radiologic assessments. These techniques can be used in early detection and recurrence as well as the surveillance of the patients after primary therapies.

Potentially pathogenic germline CHEK2 c.319+2T>A among multiple early-onset cancer families

To study the potential contribution of genes other than BRCA1/2, PTEN, and TP53 to the biological and clinical characteristics of multiple early-onset cancers in Norwegian families, including early-onset breast cancer, Cowden-like and Li-Fraumeni-like syndromes (BC, CSL and LFL, respectively). The Hereditary Cancer Biobank from the Norwegian Radium Hospital was used to identify early-onset BC, CSL or LFL for whom no pathogenic variants in BRCA1/2, PTEN, or TP53 had been found in routine diagnostic DNA sequencing. Forty-four cancer susceptibility genes were selected and analyzed by our in-house designed TruSeq amplicon-based assay for targeted sequencing. Protein- and RNA splicing-dedicated in silico analyses were performed for all variants of unknown significance (VUS). Variants predicted as the more likely to affect splicing were experimentally analyzed by minigene assay. We identified a CSL individual carrying a variant in CHEK2 (c.319+2T>A, IVS2), here considered as likely pathogenic. Out of the five VUS (BRCA2, CDH1, CHEK2, MAP3K1, NOTCH3) tested in the minigene splicing assay, only NOTCH3 c.14090C>T (p.Ser497Leu) showed a significant effect on RNA splicing, notably by inducing partial skipping of exon 9. Among 13 early-onset BC, CSL and LFL patients, gene panel sequencing identified a potentially pathogenic variant in CHEK2 that affects a canonical RNA splicing signal. Our study provides new information on genetic loci that may affect the risk of developing cancer in these patients and their families, demonstrating that genes presently not routinely tested in molecular diagnostic settings may be important for capturing cancer predisposition in these families.

Germline Mutations in BRCA1 and BRCA2 in Breast Cancer Patients with High Genetic Risk in Turkish Population

Background

The guidelines recommend considering the BRCA1 and BRCA2 germline mutations in female patients with breast carcinomas. In this retrospective study, the BRCA1/2 mutation prevalence in high-risk breast carcinoma patients in a Turkish population was investigated.

Materials and Methods

In high genetic risk breast carcinoma patients, the BRCA1 and BRCA2 germline mutations were identified by applying next-generation sequencing.

Results

The results showed BRCA1/2 mutations in 19% of the total patients. In those with first-degree relatives with breast carcinoma histories, the BRCA1/2 mutation prevalence was also 19%. In the patients younger than 40 years old, the BRCA1/2 mutation prevalence was 19.5%. In the triple-negative breast carcinoma patients younger than 60 years old, the BRCA1/2 mutation prevalence was 24.2%. In the patients younger than 40 years old with triple-negative breast carcinomas, BRCA1/2 mutation positivity was found in 37.5% of the patients. Overall, in the Turkish population, the BRCA1/2 mutation prevalence ranges from 19% to 37% in patients with high-risk breast carcinomas.

Conclusion

It is recommended to check for BRCA1/2 mutations in all high-risk breast carcinoma patients in the Turkish population.

Targeting BRCA Deficiency in Breast Cancer: What are the Clinical Evidences and the Next Perspectives?

Breast cancers (BC) associated with germline mutations of BRCA1/2 represent 3–5% of cases. BRCA1/2-associated BC have biological features leading to genomic instability and potential sensitivity to DNA damaging agents, including poly(ADP-ribose) polymerase (PARP) and platinum agents. In this review, we will summarize clinical trials of chemotherapy and PARP inhibitors (PARPi), alone or in combination, at the early or late stage of BRCA1/2-associated BC. We will also present the mechanisms of resistance to PARPi as well as the new therapeutic strategies of association with PARPi. Finally, we will discuss under which conditions the use of DNA damaging agents can be extended to the BRCA1/2-wild type population, the BRCAness concept.

Germline mutations in 40 cancer susceptibility genes among Chinese patients with high hereditary risk breast cancer

Multigene panel testing of breast cancer predisposition genes have been extensively conducted in Europe and America, which is relatively rare in Asia however. In this study, we assessed the frequency of germline mutations in 40 cancer predisposition genes, including BRCA1 and BRCA2, among a large cohort of Chinese patients with high hereditary risk of BC. From 2015 to 2016, consecutive BC patients from 26 centers of China with high hereditary risk were recruited (n = 937). Clinical information was collected and next-generation sequencing (NGS) was performed using blood samples of participants to identify germline mutations. In total, we acquired 223 patients with putative germline mutations, including 159 in BRCA1/2, 61 in 15 other BC susceptibility genes and 3 in both BRCA1/2 and non-BRCA1/2 gene. Major mutant non-BRCA1/2 genes were TP53 (n = 18), PALB2 (n = 11), CHEK2 (n = 6), ATM (n = 6) and BARD1 (n = 5). No factors predicted pathologic mutations in non-BRCA1/2 genes when treated as a whole. TP53 mutations were associated with HER-2 positive BC and younger age at diagnosis; and CHEK2 and PALB2 mutations were enriched in patients with luminal BC. Among high hereditary risk Chinese BC patients, 23.8% contained germline mutations, including 6.8% in non-BRCA1/2 genes. TP53 and PALB2 had a relatively high mutation rate (1.9 and 1.2%). Although no factors predicted for detrimental mutations in non-BRCA1/2 genes, some clinical features were associated with mutations of several particular genes.

Role of the general practitioner in the care of BRCA1 and BRCA2 mutation carriers: General practitioner and patient perspectives

BACKGROUND

General practitioners (GPs) have an increasing role in referring patients with putative mutation in BRCA1/2 genes for genetics consultation and for long-term follow-up of mutation carriers.

METHODS

We compared the expectations of the GPs' role according to BRCA1/2 mutation carriers and to GPs themselves.

RESULTS

Overall, 38% (58/152) of eligible GPs and 70% (176/252) of eligible patients were surveyed. Although 81% of GPs collected the family history, only 24% considered that they know criteria indicating genetics consultation and 39% sufficient knowledge of BRCA1/2 guidelines to answer patients' questions. Twelve% of GPs were aware of the French national guidelines. Among unsatisfied patients, 40% felt that their GP was able to answer (moderately, sufficiently, or completely) specific questions about BRCA1/2 care as compared with 81% in satisfied patients. Only 33% of GPs reported being informed directly by the geneticist about the patients' results. GPs' main expectations for their role in BRCA1/2 carrier care were psychological support and informing relatives about screening (72% and 71%, respectively), which contrasts with the perceptions of patients, who mainly requested medical advice for BRCA1/2-related care (51%).

CONCLUSION

There is an important need for GP training and enhancing interactions between GPs and geneticists to improve the GP's role in BRCA1/2 screening and management.

BRCA mutation in breast cancer patients: Prognostic impact and implications on clinical management

BRCA1/2 mutations are involved in breast cancer (BC) susceptibility but their influence on outcome is unclear. We reviewed BC patients tested for BRCA to determine biological features and influence on outcome. BRCA-1 was correlated to younger age (P = 0.035), nodal involvement (P = 0.030), higher tumor grade (P = 0.0022) and Ki-67 (P = 0.014), ER/PgR negative status (P = 0.00042 and 0.0091, respectively), and use of adjuvant chemotherapy (P = 0.000038); BRCA was neither predictive for chemotherapy administration nor resulted in impaired outcome or occurrence of secondary BC. BRCA status did not influence outcome despite higher biological aggressiveness and younger age at presentation.

Germline Variation and Breast Cancer Incidence: A Gene-Based Association Study and Whole-Genome Prediction of Early-Onset Breast Cancer

Background: Although germline genetics influences breast cancer incidence, published research only explains approximately half of the expected association. Moreover, the accuracy of prediction models remains low. For women who develop breast cancer early, the genetic architecture is less established.Methods: To identify loci associated with early-onset breast cancer, gene-based tests were carried out using exome array data from 3,479 women with breast cancer diagnosed before age 50 and 973 age-matched controls. Replication was undertaken in a population that developed breast cancer at all ages of onset.Results: Three gene regions were associated with breast cancer incidence: FGFR2 (P = 1.23 × 10^-5; replication P < 1.00 × 10^-6), NEK10 (P = 3.57 × 10^-4; replication P < 1.00 × 10^-6), and SIVA1 (P = 5.49 × 10^-4; replication P < 1.00 × 10^-6). Of the 151 gene regions reported in previous literature, 19 (12.5%) showed evidence of association (P < 0.05) with the risk of early-onset breast cancer in the early-onset population. To predict incidence, whole-genome prediction was implemented on a subset of 3,076 participants who were additionally genotyped on a genome wide array. The whole-genome prediction outperformed a polygenic risk score [AUC, 0.636; 95% confidence interval (CI), 0.614-0.659 compared with 0.601; 95% CI, 0.578-0.623], and when combined with known epidemiologic risk factors, the AUC rose to 0.662 (95% CI, 0.640-0.684).Conclusions: This research supports a role for variation within FGFR2 and NEK10 in breast cancer incidence, and suggests SIVA1 as a novel risk locus.Impact: This analysis supports a shared genetic etiology between women with early- and late-onset breast cancer, and suggests whole-genome data can improve risk assessment. Cancer Epidemiol Biomarkers Prev; 27(9); 1057-64. ©2018 AACR.

Mutational spectrum in a worldwide study of 29,700 families with BRCA1 or BRCA2 mutations

The prevalence and spectrum of germline mutations in BRCA1 and BRCA2 have been reported in single populations, with the majority of reports focused on White in Europe and North America. The Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) has assembled data on 18,435 families with BRCA1 mutations and 11,351 families with BRCA2 mutations ascertained from 69 centers in 49 countries on six continents. This study comprehensively describes the characteristics of the 1,650 unique BRCA1 and 1,731 unique BRCA2 deleterious (disease-associated) mutations identified in the CIMBA database. We observed substantial variation in mutation type and frequency by geographical region and race/ethnicity. In addition to known founder mutations, mutations of relatively high frequency were identified in specific racial/ethnic or geographic groups that may reflect founder mutations and which could be used in targeted (panel) first pass genotyping for specific populations. Knowledge of the population-specific mutational spectrum in BRCA1 and BRCA2 could inform efficient strategies for genetic testing and may justify a more broad-based oncogenetic testing in some populations.

Multicenter cross-sectional screening of the BRCA gene for Chinese high hereditary risk breast cancer populations

Due to lack of systematic reviews, BRCA, DNA Repair Associated (BRCA) mutations in the Chinese population are not completely understood. The following study investigates the prevalence and type of BRCA mutations in Chinese patients with high hereditary risk of breast cancer (BC). Patients Drwere recruited from 14 cities between October 2015 and February 2016, and were selected based on family and personal medical history. BRCA mutations were analyzed by collecting blood samples from all participants. 437 BC patients were included. A total of seventy-six (17.4%) mutation carriers were identified with no geographic difference. The mutation rate in the early-onset BC patients was lower compared to family history of breast/ovarian cancer (OC), bilateral BC, male BC, BC&OC or meeting ≥2 criteria (9.2 vs. 21.7, 24.0, 22.2, 16.7 and 24.3%, respectively, P=0.007). A total of 61 mutation sites were identified (BRCA1 32, BRCA2 29) including 47.5% novel sites and extra 10 variants of uncertain significance. A total of five sites were repeated in more than one unrelated patient. A total of 11 sites were associated with hereditary breast and ovarian cancer syndrome, two of which were confirmed by family pedigrees. Compared with BRCA^- patients, patients with BRCA1 mutation tended to be triple-negative BC (P<0.001), whereas patients with BRCA2 mutation were more likely to be hormone receptor positive BC (P=0.02). The present study provides a general BRCA mutation profile in the Chinese population. The prevalence of BRCA mutation in BC patients with high hereditary risk is lower compared with Western populations. Chinese mutation type is different with Western people, without obvious founder mutation.

BRCA mutation carrier detection. A model-based cost-effectiveness analysis comparing the traditional family history approach and the testing of all patients with breast cancer

Background

Identification of BRCA mutation carriers among patients with breast cancer (BC) involves costs and gains. Testing has been performed according to international guidelines, focusing on family history (FH) of breast and/or ovarian cancer. An alternative is testing all patients with BC employing sequencing of the BRCA genes and Multiplex Ligation Probe Amplification (MLPA).

Patients and methods

A model-based cost-effectiveness analysis, employing data from Oslo University Hospital, Ullevål (OUH-U) and a decision tree, was done. The societal and the healthcare perspectives were focused and a lifetime perspective employed. The comparators were the traditional FH approach used as standard of care at OUH-U in 2013 and the intervention (testing all patients with BC) performed in 2014 and 2015 at the same hospital. During the latter period, 535 patients with BC were offered BRCA testing with sequencing and MLPA. National 2014 data on mortality rates and costs were implemented, a 3% discount rate used and the costing year was 2015. The incremental cost-effectiveness ratio was calculated in euros (€) per life-year gained (LYG).

Results

The net healthcare cost (healthcare perspective) was €40 503/LYG. Including all resource use (societal perspective), the cost was €5669/LYG. The univariate sensitivity analysis documented the unit cost of the BRCA test and the number of LYGs the prominent parameters affecting the result.

Diagnostic BRCA testing of all patients with BC was superior to the FH approach and cost-effective within the frequently used thresholds (healthcare perspective) in Norway (€60 000–€80 000/LYG).