<Emphasis Type="Italic">BRCA1</Emphasis> deficiency is a recurrent event in early-onset triple-negative breast cancer: a comprehensive analysis of germline mutations and somatic promoter methylation

Purpose

BRCA1 germline mutation is closely associated with triple-negative breast cancer. BRCA deficiency leads to impaired DNA repair and tumor development, and understanding this deficiency, in both hereditary and sporadic scenarios, is of great clinical and biological interest. Here, we investigated germline or somatic events that might lead to BRCA1 impairment in triple-negative breast cancer. We also analyzed the clinical implications associated with BRCA deficiency.

Methods

Next-generation sequencing for the BRCA1/2 genes and multiplex ligation-dependent probe amplification (MLPA) for the BRCA1 gene were performed for mutation screening. A customized bisulfite next-generation sequencing approach was used for assessing BRCA1 promoter methylation status in tumor tissue.

Results

A total of 131 triple-negative cases were assessed, and germline pathogenic variants were detected in 13.0% of all cases and in 26% of cases diagnosed in young women. Most germline pathogenic variants (88.2%) occurred in the BRCA1 gene. BRCA1 promoter hypermethylation was detected in 20.6% of tumors; none of these tumors were in BRCA1/2 pathogenic variant carriers. BRCA1 impairment by either germline or somatic events was significantly more frequent in young women (55% in those ≤ 40 years; 33% in those 41–50 years; 22% in those > 50 years of age) and associated with better overall and disease-free survival rates in this group of patients.

Conclusions

BRCA1 deficiency was recurrent in early-onset triple-negative breast cancer in Brazilian patients and associated with improved survival. With the new treatment modalities being investigated, including poly (ADP-ribose)-polymerase (PARP) inhibitor therapy, our results suggest that a significant proportion of young women with this subtype of tumor might benefit from PARP inhibitor treatment, which warrants further investigation.

     

Revisiting breast cancer patients who previously tested negative for <Emphasis Type="Italic">BRCA</Emphasis> mutations using a 12-gene panel

Purpose

BRCA mutations contribute to about 20% of all hereditary breast cancers. With full-genome sequencing as the emerging standard for genetic testing, other breast cancer susceptibility genes have been identified and may collectively contribute to up to 30% of all hereditary breast cancers. We re-assessed women who had previously tested negative for a BRCA mutation when outdated techniques were used, and discuss the implications of identifying a mutation several years after initial genetic testing.

Methods

We evaluated the prevalence of mutations in 12 breast cancer susceptibility genes (including BRCA1 and BRCA2) in 190 breast cancer patients with a strong family history of breast cancer. These women had previously tested negative for mutations in the large coding exons of BRCA1 and BRCA2 using the protein truncation test (PTT) between the years of 1996 and 2013.

Results

We identified pathogenic mutations in 17 of 190 (9%) women. Six mutations were detected in BRCA1 (n = 2) and BRCA2 (n = 4). Eleven mutations were found in other breast cancer susceptibility genes including CHEK2 (n = 5), PALB2 (n = 2), BLM (n = 2), ATM (n = 1) and TP53 (n = 1).

Conclusion

Among 190 breast cancer patients with a family history of the disease, and who previously received a negative result for BRCA mutations using the PTT, 17 (9%) women were found to carry a high-risk pathogenic mutation in a breast cancer susceptibility gene. Six of these women were BRCA mutation carriers who were missed previously. These findings support the rationale for updated genetic testing in patients who tested BRCA mutation negative using outdated techniques.

     

Young age at first pregnancy does protect against early onset breast cancer in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> mutation carriers

Purpose

Previous research assessing the impact of pregnancy and age at first pregnancy on breast cancer risk in BRCA1 and BRCA2 mutation carriers has produced conflicting results, with some studies showing an increased risk following early first pregnancy in contrast to the reduced risk in the general population of women. The present study addresses these inconsistencies.

Methods

Female BRCA1 and BRCA2 carriers from North West England were assessed for breast cancer incidence prior to 50 years of age comparing those with an early first full-term pregnancy (< 21 years) to those without a full-term pregnancy. Breast cancer incidence per decade from 20 years and Kaplan–Meier analyses were performed.

Results

2424 female mutation carriers (1278 BRCA1; 1146 BRCA2) developed 990 breast cancers under the age of 50 years. Women who had their first term pregnancy prior to age 21 (n = 441) had a lower cancer incidence especially between age 30–39 years. Kaplan–Meier analysis showed an odds ratio of 0.78 for BRCA1 (p = 0.005) and 0.73 for BRCA2 (p = 0.002).

Conclusions

The present study demonstrates a clear protective effect of early first pregnancy on breast cancer risk in both BRCA1 and BRCA2 mutation carriers.

     

Male breast cancer in a multi-gene panel testing cohort: insights and unexpected results

Purpose

Genetic predisposition to male breast cancer (MBC) is not well understood. The aim of this study was to better define the predisposition genes contributing to MBC and the utility of germline multi-gene panel testing (MGPT) for explaining the etiology of MBCs.

Methods

Clinical histories and molecular results were retrospectively reviewed for 715 MBC patients who underwent MGPT from March 2012 to June 2016.

Results

The detection rate of MGPT was 18.1% for patients tested for variants in 16 breast cancer susceptibility genes and with no prior BRCA1/2 testing. BRCA2 and CHEK2 were the most frequently mutated genes (11.0 and 4.1% of patients with no prior BRCA1/2 testing, respectively). Pathogenic variants in BRCA2 [odds ratio (OR) = 13.9; p = 1.92 × 10^?16], CHEK2 (OR = 3.7; p = 6.24 × 10^?24), and PALB2 (OR = 6.6, p = 0.01) were associated with significantly increased risks of MBC. The average age at diagnosis of MBC was similar for patients with (64 years) and without (62 years) pathogenic variants. CHEK2 1100delC carriers had a significantly lower average age of diagnosis (n = 7; 54 years) than all others with pathogenic variants (p = 0.03). No significant differences were observed between history of additional primary cancers (non-breast) and family history of male breast cancer for patients with and without pathogenic variants. However, patients with pathogenic variants in BRCA2 were more likely to have a history of multiple primary breast cancers.

Conclusion

These data suggest that all MBC patients regardless of age of diagnosis, history of multiple primary cancers, or family history of MBC should be offered MGPT.

     

The incidence of cardiomyopathy in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> mutation carriers after anthracycline-based adjuvant chemotherapy

Purpose

Breast cancer remains the fourth-leading cause of death in the United States. Nearly 10% of breast cancers are hereditary, with deleterious mutations in BRCA1 and BRCA2 genes being the leading cause. Anthracycline chemotherapy, used commonly for breast cancer, carries cardiotoxicity risk. Recent studies demonstrated anthracycline-induced cardiac failure in homozygous BRCA2-deficient mice and increased rates of heart failure in homozygous BRCA1-deficient mice following ischemic insult. Therefore, we conducted a retrospective matched cohort study to determine the rates of anthracycline-induced cardiomyopathy in breast cancer patients with germline mutation in BRCA1 or BRCA2 genes compared to age-matched patients without a BRCA1 or BRCA2 gene mutation.

Methods

The primary endpoint was to determine the rate of cardiomyopathy defined as either congestive heart failure or asymptomatic decline in ejection fraction to <50%. A total of 102 breast cancer patients who were BRCA gene mutation carriers (55 BRCA1, 45 BRCA2, and two with both), who received anthracycline-based chemotherapy were compared to a matched cohort of breast cancer patients with wild-type BRCA gene status.

Results

We found a 4.9% rate of cardiomyopathy in the BRCA mutation carriers and 5.2% in the matched controls (p = 0.99). Cox proportional hazards model showed that only trastuzumab and hypertension were significantly associated with the development of cardiomyopathy in both groups (p < 0.05).

Conclusions

Given the limitations of a retrospective study, we saw no increased risk of cardiotoxicity among breast cancer patients with BRCA1 and/or BRCA2 gene mutations treated with standard doses of anthracycline compared to the general population.

     

Ovarian cancer patients at high risk of <Emphasis Type="Italic">BRCA</Emphasis> mutation: the constitutional genetic characterization does not change prognosis

Ovarian neoplasms secondary to germline BRCA mutations had been described to have a more favourable survival. There is only few data concerning the prognosis of non mutated patients presenting clinical features evocative of BRCA alterations. We retrospectively collected data from patients treated in our institution for an invasive ovarian carcinoma between 1995 and 2011. Patients considered at high risk of BRCA mutation were tested for BRCA1/2 germline mutations. We described clinical, pathological and therapeutic features and compared prognosis of BRCA mutation carriers and non-mutated patients. Out of 617 ovarian cancer patients, we identified 104 patients who were considered at high risk of mutation. The 33 mutated patients were more likely to present a personal (33 vs. 10 %, p = 0.003) or a family (42 vs. 24 %, p = 0.06) history of breast/ovarian cancers. BRCA1/2 mutation carriers and wild type patients displayed similar prognosis: median progression–free survival (PFS) of 20.9 versus 37.7 months (p = 0.21); median overall survival (OS) of 151.2 versus 122.5 months (p = 0.52). Personal history of breast cancer increased both PFS [HR = 0.45 (95CI 0.25–0.81)] and OS [HR = 0.35 (95CI 0.16–0.75)]. In multivariate analysis, this parameter was an independent prognostic feature, whereas the identification of a BRCA1/2 mutation was not. In our cohort, all patients at high risk of BRCA mutation share a similar prognosis, whatever is their germline mutation status. Prognosis seems to be more influenced by clinical history than by germline mutations identification. If it is confirmed in larger and independent series, this result suggests that the hypothesis of other BRCA pathway alterations (BRCAness phenotype) deserves to be deeply explored.     

No evidence of increased breast cancer risk for proven noncarriers from <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> families

In families screened for mutations in the BRCA1 or BRCA2 genes and found to have a segregating mutation the breast cancer risk for women shown not to carry the family-specific mutation might be at above “average” risk. We assessed the risk of breast cancer in a clinic based cohort of 725 female proven noncarriers in 239 BRCA1 and BRCA2 families compared with birth-matched controls from the Danish Civil Registration System. Prospective analysis showed no significantly increased risk for breast cancer in noncarriers with a hazard ratio of 0.67 [95 % confidence interval (CI) 0.32–1.42, p = 0.29] for all family members who tested negative and 0.87 (95 % CI 0.38–1.97, p = 0.73) for non-carries who were first-degree relatives of mutation carriers. Proven noncarriers from BRCA1 and BRCA2 families have no markedly increased risk for breast cancer compared to the general population, and our data do not suggest targeted breast cancer surveillance for noncarriers from BRCA1 and BRCA2 families.     

Mammographic breast density decreases after bariatric surgery

Purpose

To describe imaging findings, detection rates, and tumor characteristics of breast cancers in a large series of patients with BRCA1 and BRCA2 mutations to potentially streamline screening strategies.

Methods

An IRB-approved, HIPAA-compliant retrospective analysis of 496 BRCA mutation carriers diagnosed with breast carcinoma from 1999 to 2013 was performed. Institutional database and electronic medical records were reviewed for mammography and MRI imaging. Patient and tumor characteristics including age at diagnosis, tumor histology, grade, receptor, and nodal status were recorded.

Results

Tumors in BRCA1 mutation carriers were associated exhibited significantly higher nuclear and histological grade compared to BRCA2 (p < 0.001). Triple-negative tumors were more frequent in BRCA1 mutation carriers, whereas hormone receptor-positive tumors were more frequent in BRCA2 mutation carriers (p < 0.001). BRCA2 mutation carriers more frequently presented with ductal carcinoma in situ (DCIS) alone 14% (35/246) and cancers more frequently exhibiting calcifications (p < 0.001). Mammography detected fewer cancers in BRCA1 mutation carriers compared to BRCA2 (p = 0.04): 81% (186/231) BRCA1 versus 89% (212/237) BRCA2. MRI detected 99% cancers in each group. Mammography detected cancer in two patients with false-negative MRI (1 invasive cancer, 1 DCIS). Detection rates on both mammography and MRI did not significantly differ for women over 40 years and women below 40 years.

Conclusions

Breast cancers in BRCA1 mutation carriers are associated with more aggressive tumor characteristics compared to BRCA2 and are less well seen on mammography. Mammography rarely identified cancers not visible on MRI. Thus, the omission of mammography in BRCA1 mutation carriers screened with MRI can be considered.

     

Are <Emphasis Type="Italic">BRCA1</Emphasis>- and <Emphasis Type="Italic">BRCA2</Emphasis>-related breast cancers associated with increased mortality?

There has been contradictory evidence as to whether BRCA1 associated breast cancers have a poorer prognosis than non-BRCA1 cancers. In this issue of Breast Cancer Research Robson and colleagues provide further evidence for poorer survival in BRCA1 carriers and show that it could be attributed to failure to treat small node-negative grade 3 breast cancers with chemotherapy. There still remains little evidence for a survival difference for BRCA2 related breast cancers. Although the high contralateral breast cancer risk is confirmed by this study there is no real evidence for an increase in ipsilateral recurrence or new primary breast cancers in mutation carriers up to the 10-year point.     

Psychosocial factors associated with the uptake of contralateral prophylactic mastectomy among <Emphasis Type="Italic">BRCA1/2</Emphasis> mutation noncarriers with newly diagnosed breast cancer

Purpose

Women who are newly diagnosed with breast cancer may consider contralateral prophylactic mastectomy (CPM) to reduce their future risk of cancer in their unaffected breast. Pre-surgical BRCA1/2 genetic testing can provide valuable risk information to guide this choice. However, little is understood about why BRCA1/2 mutation noncarriers, who are generally not at substantially elevated risk of contralateral disease, select CPM.

Methods

We examined the uptake of CPM among breast cancer patients identified as BRCA1/2 mutation noncarriers (n = 92) as part of a larger prospective study of the impact of pre-surgical BRCA1/2 testing. Data obtained from self-report questionnaires and patient medical records were used to examine associations between theoretically relevant background and psychosocial factors and BRCA1/2 mutation noncarriers’ decisions to undergo CPM.

Results

Among BRCA1/2 mutation noncarriers, 25% (n = 23) elected to undergo CPM. Psychosocial factors including a self-reported physician recommendation for CPM, greater perceived contralateral breast cancer risk, and greater perceived benefits of CPM were all significantly associated with the uptake of CPM.

Conclusions

A sizeable minority of BRCA1/2 mutation noncarriers choose to undergo CPM after learning their mutation status through pre-surgical genetic testing. BRCA1/2 mutation noncarriers’ cognitive perceptions and social influences appear to be important in shaping their decisions regarding CPM. This work highlights the importance of several psychosocial factors in influencing patients’ surgical decisions. Future research is needed that examines the formation of BRCA1/2 mutation noncarriers’ beliefs regarding their disease and available treatment options, and that characterizes the physician-patient communication that occurs in this complex decision-making context.

     

Dissimilarity between sporadic,non-BRCA1/2 families and hereditary breast cancer,linked to BRCA genes,in the Tunisian population

Background

Most breast cancers (90 %) are sporadic. Only 5–10 % of all cancer cases can be attributed to genetic defects. BRCA genes are strongly incriminated in the hereditary predisposition to the disease. The purpose of our study was to provide more efficient approach to identify pathogenic BRCA mutation carriers and to determine subgroups within the non-BRCA tumor class.

Methods

Different clinicopathological features, reproductive factors, as well as psychosocial ones were compared in women carrying mutations in the BRCA1/BRCA2 genes (12 cases) with non-BRCA1/2 family tumors (36 cases) and age-matched sporadic cases, unselected for family history (44 cases).

Results

A BRCA‐related class was yielded based on age at diagnosis (age ≤ 35 years; p = 0.1), molecular subtypes(the triple-negative subtype was predominant: 43 % of cases; p = 0.025) and age at menarche (p = 0.04). Furthermore, a “probably sporadic” class was distinguished using hormonal contraceptive use (through 30–40 years of age; p = 0.039), the number of full-term pregnancies (age ≥40 years; p = 0.01), age at menopause(age > 50 years; p = 0.04) and psychosocial factors (age ≥ 40 years; p = 0.01). However, analysis of non-BRCA1/2 family tumors indicated that they constitute a heterogeneous class, showing few perceptible differences with sporadic group, but distinct from BRCA1/2 tumors.

Conclusions

In Tunisian population, breast cancer can be classified with a high level of accuracy as sporadic or related to BRCA germline mutations by combining different clinicopathological features and reproductive factors. This can be clinically useful in genetic counseling and decision making for BRCA genetic test.

     

<Emphasis Type="Italic">BRCA1</Emphasis>-like profile is not significantly associated with survival benefit of non-myeloablative intensified chemotherapy in the GAIN randomized controlled trial

Purpose

The BRCA1-like profile identifies tumors with a defect in homologous recombination due to inactivation of BRCA1. This profile has been shown to predict which stage III breast cancer patients benefit from myeloablative, DNA double-strand-break-inducing chemotherapy. We tested the predictive potential of the BRCA1-like profile for adjuvant non-myeloablative, intensified dose-dense chemotherapy in the GAIN trial.

Methods

Lymph node positive breast cancer patients were randomized to 3 × 3 dose-dense cycles of intensified epirubicin, paclitaxel, and cyclophosphamide (ETC) or 4 cycles concurrent epirubicin and cyclophosphamide followed by 10 cycles of weekly paclitaxel combined with 4 cycles capecitabine (EC-TX). Only triple negative breast cancer patients (TNBC) for whom tissue was available were included in these planned analyses. BRCA1-like or non-BRCA1-like copy number profiles were derived from low coverage sequencing data.

Results

119 out of 163 TNBC patients (73%) had a BRCA1-like profile. After median follow-up of 83 months, disease free survival (DFS) was not significantly different between BRCA1-like and non-BRCA1-like patients [adjusted hazard ratio (adj.HR) 1.02; 95% confidence interval (CI) 0.55–1.86], neither was overall survival (OS; adj.HR 1.26; 95% CI 0.58–2.71). When split by BRCA1-like status, DFS and OS were not significantly different between treatments. However, EC-TX seemed to result in a trend to an improvement in DFS in patients with a BRCA1-like tumor, while the reverse accounted for ETC treatment in patients with a non-BRCA1-like tumor (p for interaction = 0.094).

Conclusions

The BRCA1-like profile is not associated with survival benefit for a non-myeloablative, intensified regimen in this study population. Considering the limited cohort size, capecitabine might have additional benefit for TNBC patients.

     

<Emphasis Type="Italic">BRCA1/BRCA2</Emphasis> founder mutations and cancer risks: impact in the western Danish population

Mutations in the BRCA1 and BRCA2 genes significantly contribute to hereditary breast cancer and ovarian cancer, but the phenotypic effect from different mutations is insufficiently recognized. We used a western Danish clinic-based cohort of 299 BRCA families to study the female cancer risk in mutation carriers and their untested first-degree relatives. Founder mutations were characterized and the risk of cancer was assessed in relation to the specific mutations. In BRCA1, the cumulative cancer risk at age 70 was 35 % for breast cancer and 29 % for ovarian cancer. In BRCA2, the cumulative risk was 44 % for breast cancer and 15 % for ovarian cancer. We identified 47 distinct BRCA1 mutations and 48 distinct mutations in BRCA2. Among these, 8 founder mutations [BRCA1 c.81-?_4986+?del, c.3319G>T (p.Glu1107*), c.3874delT and c.5213G>A (p.Gly1738Glu) and BRCA2 c.6373delA, c.7008?1G>A, c.7617+1G>A and c.8474delC] were found to account for 23 % of the BRCA1 mutations and for 32 % of the BRCA2 mutations. The BRCA1 mutation c.3319G>T was, compared to other BRCA1 mutations, associated with a higher risk for ovarian cancer. In conclusion, founder mutations in BRCA1 and BRCA2 contribute to up to one-third of the families in western Denmark and among these the BRCA1 c.3319G>T mutation is potentially linked to an increased risk of ovarian cancer.     

A single-institution experience of salvage therapy for patients with early and locally advanced breast cancer who progress during neoadjuvant chemotherapy

BRCA1 mutation carriers face a high lifetime risk of breast cancer, estimated at 60 % compared to 10 % in the general population. BRCA1 breast cancers typically have an aggressive course (i.e., high-grade, triple-negative) and are associated with a poor prognosis. At present, primary prevention is limited to prophylactic removal of the unaffected breasts. Effective chemopreventive strategies are not yet available. Emerging evidence suggests that BRCA1 mutation carriers have high circulating levels of progesterone which may play a role in their susceptibility to breast cancer. Recently, the RANK/RANKL system was found to be dysregulated in women with a BRCA1 mutation. Mutation carriers had significantly lower endogenous levels of osteoprotegerin (OPG) than women without a BRCA1 mutation. OPG is an endogenous decoy receptor for RANKL and inhibits RANKL-mediated signaling. RANKL binds to RANK on mammary epithelial cells and stimulates their proliferation and maturation. Low OPG levels may contribute to mammary tumorigenesis through increased proliferation and may explain in part the increased breast cancer risk in BRCA1 mutation carriers. Denosumab is an anti-RANKL monoclonal antibody which is approved to treat osteoporosis and to prevent skeletal damage caused by bone metastases. The emerging role of aberrant RANK-signaling in BRCA1 tumorigenesis suggests that targeting of RANKL may prevent breast cancer among women with germline BRCA1 mutations. Clinical investigations of denosumab are warranted and may lead to a novel chemopreventive approach for breast cancer for high-risk women.     

Relationship of immunohistochemistry,copy number aberrations and epigenetic disorders with BRCAness pattern in hereditary and sporadic breast cancer

The study aims to identify the relevance of immunohistochemistry (IHC), copy number aberrations (CNA) and epigenetic disorders in BRCAness breast cancers (BCs). We studied 95 paraffin included BCs, of which 41 carried BRCA1/BRCA2 germline mutations and 54 were non hereditary (BRCAX/Sporadic). Samples were assessed for BRCA1ness and CNAs by Multiplex Ligation-dependent Probe Amplification (MLPA); promoter methylation (PM) was assessed by methylation-specific-MLPA and the expression of miR-4417, miR-423-3p, miR-590-5p and miR-187-3p by quantitative RT-PCR. IHC markers Ki67, ER, PR, HER2, CK5/6, EGFR and CK18 were detected with specific primary antibodies (DAKO, Denmark). BRCAness association with covariates was performed using multivariate binary logistic regression (stepwise backwards Wald option). BRCA1/2 mutational status (p = 0.027), large tumor size (p = 0.041) and advanced histological grade (p = 0.017) among clinic-pathological variables; ER (p < 0.001) among IHC markers; MYC (p < 0.001) among CNA; APC (p = 0.065), ATM (p = 0.014) and RASSF1 (p = 0.044) among PM; and miR-590-5p (p = 0.001), miR-4417 (p = 0.019) and miR-423 (p = 0.013) among microRNA expression, were the selected parameters significantly related with the BRCAness status. The logistic regression performed with all these parameters selected ER+ as linked with the lack of BRCAness (p = 0.001) and MYC CNA, APC PM and miR-590-5p expression with BRCAness (p = 0.014, 0.045 and 0.007, respectively). In conclusion, the parameters ER expression, APC PM, MYC CNA and miR-590-5p expression, allowed detection of most BRCAness BCs. The identification of BRCAness can help establish a personalized medicine addressed to predict the response to specific treatments.     

Tamoxifen therapy improves overall survival in luminal A subtype of ductal carcinoma in situ: a study based on nationwide Korean Breast Cancer Registry database

Purpose

The molecular mechanism of breast and/or ovarian cancer susceptibility remains unclear in the majority of patients. While germline mutations in the regulatory non-coding regions of BRCA1 and BRCA2 genes have been described, screening has generally been limited to coding regions. The aim of this study was to evaluate the contribution of BRCA1/2 non-coding variants.

Methods

Four BRCA1/2 non-coding regions were screened using high-resolution melting analysis/Sanger sequencing or next-generation sequencing on DNA extracted from index cases with breast and ovarian cancer predisposition (3926 for BRCA1 and 3910 for BRCA2). The impact of a set of variants on BRCA1/2 gene regulation was evaluated by site-directed mutagenesis, transfection, followed by Luciferase gene reporter assay.

Results

We identified a total of 117 variants and tested twelve BRCA1 and 8 BRCA2 variants mapping to promoter and intronic regions. We highlighted two neighboring BRCA1 promoter variants (c.-130del; c.-125C > T) and one BRCA2 promoter variants (c.-296C > T) inhibiting significantly the promoter activity. In the functional assays, a regulating region within the intron 12 was found with the same enhancing impact as within the intron 2. Furthermore, the variants c.81-3980A > G and c.4186-2022C > T suppress the positive effect of the introns 2 and 12, respectively, on the BRCA1 promoter activity. We also found some variants inducing the promoter activities.

Conclusion

In this study, we highlighted some variants among many, modulating negatively the promoter activity of BRCA1 or 2 and thus having a potential impact on the risk of developing cancer. This selection makes it possible to conduct future validation studies on a limited number of variants.

     

Simultaneous <Emphasis Type="Italic">ATM/BRCA1/RAD51</Emphasis> expression variations associated with prognostic factors in Iranian sporadic breast cancer patients

Background

DNA double-strand breaks (DSBs) as a serious lesion are repaired by non-homologous end-joining and homologous recombination pathways. ATM, BRCA1, RAD51 genes are involved in HR pathways. While some studies have revealed individual expression changes of these genes in different types of cancer, there are limited studies attempting to evaluate correlation of expression variations of these genes in breast cancer pathogenesis. This study aimed to determine RAD51, ATM and BRCA1 gene expression level and its association with clinicopathological factors in fresh breast cancer tissues. Moreover, this study evaluates potential correlations among expression levels of these genes.

Methods

50 breast cancer tissues were collected and examined for BRCA1, RAD51 and ATM gene expression by Real Time PCR. Expression changes were analyzed with REST software version 2009.

Results

mRNA expression was reduced in all these three genes when compared with β-Actin as a control gene (P _value < 0.001). Spearman’s test demonstrated a significant positive correlation among ATM, BRCA1 and RAD51 gene down expression (P _value < 0.0001). There was a significant association between down expression of ATM with stage (P _value < 0.05), necrosis (P _value < 0.05), perineural invasion (P _value < 0.05), vascular invasion (P _value < 0.01), malignancy (P _value ≤ 0.001), PR (P _value < 0.05) and ER status (P _value < 0.01). In addition, there was a significant association between down expression of BRCA1 with Ki67 (P _value ≤ 0.001). Moreover, there was a significant association between down expression of RAD51 with lymph node involvement (P _value < 0.01), auxiliary lymph node metastasis (P _value = 0.01), age (P = 0.001), grade (P _value < 0.05) and PR status (P _value < 0.05).

Conclusion

This study suggests association between expression changes in several DSB repair genes in a common functional pathway in breast cancer and the significant association between abnormal expression of these genes and important clinical prognostic factors.

     

Homologous recombination deficiency (HRD) status predicts response to standard neoadjuvant chemotherapy in patients with triple-negative or BRCA1/2 mutation-associated breast cancer

Purpose

Defects in the homologous recombination (HR) DNA repair pathway sensitize tumors to therapeutics that target this pathway. A significant proportion of triple-negative breast cancers (TNBC) carry HR defects. The HRD assay is highly associated with sensitivity to neoadjuvant platinum-based chemotherapy in TNBC. Standard chemotherapy consists of some combination of an anthracycline, cyclophosphamide, and taxane. This study assesses the association of HR deficiency status with response to standard neoadjuvant chemotherapy in TNBC or BRCA1/2 mutation-associated breast cancer.

Methods

Tumor samples were retrospectively obtained from 45 TNBC patients and 2 BRCA1/2 mutant, hormone receptor-positive/HER2-negative breast cancer patients who received anthracycline- and/or taxane-based neoadjuvant chemotherapy at Stanford University or Cedars-Sinai Medical Centers. The HRD score and tumor BRCA1/2 mutation status were determined from baseline tumor biopsies. HR deficient tumors were those with a HRD score of ≥ 42 or a tumor BRCA1/2 mutation. Response was categorized by the residual cancer burden (RCB) index.

Results

HR deficient patients were more likely to achieve a pathologic complete response (pCR) compared with non-deficient patients (OR 13.06, CI 1.52–11.241, p = 0.0028). Among BRCA1/2 mutation wild-type patients, HR deficient patients were more likely to achieve a pCR (OR 16, 95% CI 1.65–160.41, p = 0.0041) compared with HR non-deficient patients. Further, HRD scores were highly concordant pre- and post-therapy (Spearman correlation > 99%).

Conclusions

HR deficiency status is significantly associated with response to standard neoadjuvant chemotherapy in TNBC. This observation is consistent with the mechanisms of action of doxorubicin and cyclophosphamide as DNA damaging agents.

     

Feasibility study of contralateral risk-reducing mastectomy with breast reconstruction for breast cancer patients with <Emphasis Type="Italic">BRCA</Emphasis> mutations in Japan

Background

Contralateral risk-reducing mastectomy (CRRM) for breast cancer patients with BRCA mutations has been reported to not only reduce breast cancer incidence but also to improve survival. The National Comprehensive Cancer Network guidelines recommend providing CRRM to women with BRCA mutations who desire CRRM after risk-reduction counseling. However, in Japan, CRRM cannot be performed generally because it is not covered by health insurance. Thus, we conducted a feasibility study to confirm the safety of CRRM.

Methods

CRRM with bilateral breast reconstructions were performed for breast cancer patients with BRCA mutations. The primary endpoint was early adverse events within 3 months, and secondary endpoints were late adverse events.

Results

Between August 2014 and November 2016, ten patients were enrolled. The median age was 37.5 years, and five of the patients had the BRCA1 mutation while five had the BRCA2 mutation. Six patients received neoadjuvant chemotherapy. Eight patients selected silicone breast implants, and two patients selected transverse rectus abdominis myocutaneous flap reconstruction. Pathological findings showed no evidence of occult breast cancers in any of the patients. At a median of 25.5 months follow-up time, CRRM-related early adverse events were hematoma (subsequently removed by re-operation; grade 2, n?=?1), wound infection (grade 2, n?=?1), skin ulceration (grade 1, n?=?2) and wound pain (grade 1, n?=?1). Overall, there were no grade 3 or more severe adverse events.

Conclusion

Our results confirm that CRRM with reconstruction could be performed safely.

     

ATM-depletion in breast cancer cells confers sensitivity to PARP inhibition

Background

Mutations in the DNA damage response (DDR) factors, breast cancer 1 (BRCA1) and BRCA2, sensitize tumor cells to poly(ADP-ribose) polymerase (PARP) inhibitors. The ataxia telangiectasia mutated (ATM) kinase is a key DDR protein whose heterozygous germline mutation is a moderate–risk factor for developing breast cancer. In this study, we examined whether ATM inactivation in breast cancer cell lines confers sensitivity to PARP inhibitors.

Methods

Wild-type BRCA1/2 breast cancer cells (i.e., MCF-7 and ZR-75-1 lines) were genetically manipulated to downregulate ATM expression then assayed for cytostaticity/cytotoxicity upon treatment with PARP inhibitors, olaparib and iniparib.

Results

When ATM-depleted cells and their relative controls were treated with olaparib (a competitive PARP-1/2 inhibitor) and iniparib (a molecule originally described as a covalent PARP-1 inhibitor) a different response to the two compounds was observed. ATM-depletion sensitized both MCF-7 and ZR-75-1 cells to olaparib-treatment, as assessed by short and long survival assays and cell cycle profiles. In contrast, iniparib induced only a mild, ATM-dependent cytostatic effect in MCF-7 cells whereas ZR-75-1 cells were sensitive to this drug, independently of ATM inactivation. These latest results might be explained by recent observations indicating that iniparib acts with mechanisms other than PARP inhibition.

Conclusions

These data indicate that ATM-depletion can sensitize breast cancer cells to PARP inhibition, suggesting a potential in the treatment of breast cancers low in ATM protein expression/activity, such as those arising in mutant ATM heterozygous carriers.