Oestrogen receptor status, treatment and breast cancer prognosis in Icelandic BRCA2 mutation carriers

Characterization of HER2-low breast cancer in young women with germline BRCA1/2 pathogenetic variants: Results of a large international retrospective cohort study

BACKGROUND

Breast cancer (BC) in women aged ≤40 years carrying germline pathogenetic variants (PVs) in BRCA1/2 genes is infrequent but often associated with aggressive features. Human epidermal growth factor receptor 2 (HER2)-low-expressing BC has recently emerged as a novel therapeutic target but has not been characterized in this rare patient subset.

METHODS

Women aged ≤40 years with newly diagnosed early-stage HER2-negative BC (HER2-0 and HER2-low) and germline BRCA1/2 PVs from 78 health care centers worldwide were retrospectively included. Chi-square test and Student t-test were used to describe variable distribution between HER2-0 and HER2-low. Associations with HER2-low status were assessed with logistic regression. Kaplan-Meier method and Cox regression analysis were used to assess disease-free survival (DFS) and overall survival. Statistical significance was considered for p ≤ .05.

RESULTS

Of 3547 included patients, 32.3% had HER2-low BC, representing 46.3% of hormone receptor-positive and 21.3% of triple-negative (TN) tumors. HER2-low vs. HER2-0 BC were more often of grade 1/2 (p < .001), hormone receptor-positive (p < .001), and node-positive (p = .003). BRCA2 PVs were more often associated with HER2-low than BRCA1 PVs (p < .001). HER2-low versus HER2-0 showed better DFS (hazard ratio [HR], 0.86; 95% CI, 0.76-0.97) in the overall population and more favorable DFS (HR, 0.78; 95% CI, 0.64-0.95) and overall survival (HR, 0.65; 95% CI, 0.46-0.93) in the TN subgroup. Luminal A-like tumors in HER2-low (p = .014) and TN and luminal A-like in HER2-0 (p = .019) showed the worst DFS.

CONCLUSIONS

In young patients with HER2-negative BC and germline BRCA1/2 PVs, HER2-low disease was less frequent than expected and more frequently linked to BRCA2 PVs and associated with luminal-like disease. HER2-low status was associated with a modestly improved prognosis.

HR-positive/HER2-negative breast cancer arising in patients with or without BRCA2 mutation: different biological phenotype and similar prognosis

Background

BRCA2 plays a key role in homologous recombination. However, information regarding its mutations in Chinese patients with breast cancer remains limited.

Objectives

This study aimed to assess the clinicopathological characteristics of BRCA2 mutation breast cancer and explore the mutation's effect on hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer survival in China.

Design

This hospital-based cohort study prospectively included 629 women with breast cancer diagnosed from 2008 to 2023 at Zhejiang Cancer Hospital in China.

Methods

We compared the clinicopathological characteristics and metastatic patterns and analysed the invasive disease-free survival (iDFS), distant relapse-free survival (DRFS) and first-line progression-free survival (PFS1) of patients with HR-positive/HER2-negative breast cancer according to BRCA2 mutations.

Results

Among the 629 patients, 78 had BRCA2 mutations (12.4%) and 551 did not (87.6%). The mean age at diagnosis was lower in the BRCA2 mutation breast cancer group than in the non-mutation breast cancer group (38.91 versus 41.94 years, p = 0.016). BRCA2 mutation breast cancers were more likely to be lymph node-positive than non-mutation breast cancers (73.0% versus 56.6%, p = 0.037). The pathological grade was higher in 47.1% of BRCA2 mutation breast cancers than in 29.6% of non-mutation breast cancers (p = 0.014). The proportions of patients with BRCA2 mutations who developed contralateral breast cancer (19.2% versus 8.8%, p = 0.004), breast cancer in the family (53.8% versus 38.3%, p = 0.009) and ovarian cancer in the family (7.6% versus 2.4%, p = 0.022) were higher than those of patients without the mutation. The median follow-up time was 92.78 months. Multivariate analysis showed that BRCA2 mutation was not associated with poorer iDFS [hazard ratio = 0.9, 95% confidence interval (CI) = 0.64-1.27, p = 0.56] and poorer distant relapse-free survival (DRFS) (hazard ratio = 1.09, 95% CI = 0.61-1.93, p = 0.76). There was no significant difference between the two groups with regard to metastatic patterns in the advanced disease setting. In the first-line metastatic breast cancer setting, PFS1 expression was broadly similar between the two groups irrespective of chemotherapy or endocrine therapy.

Conclusion

HR-positive/HER2-negative breast cancer with BRCA2 mutations differs from those without mutations in clinical behaviour and reflects more aggressive tumour behaviour. Our results indicate that BRCA2 mutations have no significant effect on the survival of Chinese women with HR-positive/HER2-negative breast cancer.

ER-positive and BRCA2-mutated breast cancer: a literature review

BRCA2-mutated carriers have a high lifetime risk of breast cancer (BC), an early age of onset, and an increased risk of other cancers (including ovarian, pancreatic, and prostate cancer). Almost 70-80% of BRCA2-mutated BC are estrogen receptor (ER)-positive, which is a particular type of ER-positive BC that differs from sporadic ER-positive BC. This article reviews the clinicopathological features, treatment, and prognosis of ER-positive and BRCA2-mutated BC to provide a reference for clinical decision-making.

Estrogen receptor-positive breast cancer and adverse outcome in BRCA2 mutation carriers and young non-carrier patients

Estrogen receptor-positive (ER+) breast cancer generally confers a more favorable prognosis than ER-negative cancer, however, a different picture is emerging for BRCA2 mutation carriers and young patients. We used nationwide data from population-based registries to study prognostic effects in those two groups. Of all 2817 eligible women diagnosed with breast cancer in Iceland during 1980-2004, 85% had been tested for the Icelandic 999del5 BRCA2 (c.771_775delTCAAA) founder pathogenic variant. We compared breast cancer-specific survival, effects of ER status, other clinical parameters, and treatment, between three mutually exclusive groups: BRCA2-carriers, non-carriers diagnosed 40 years or younger, and older non-carriers. Prevalence of the BRCA2 mutation among tested patients <=40 years of age was 21.0%, but it was 5.4% among women diagnosed >40 years of age. For ER+ cancer, breast cancer-specific 15-year survival was 49.7%, 55.2%, and 74.7%, among BRCA2-carriers, young and older non-carriers, respectively, whereas for ER-negative cancer, survival was similar (64.0-69.3%) for all three groups. Neither BRCA2 carriers nor young non-carriers did tumor grade 3 predict worse survival than did tumor grade 1. The adverse outcome for the young cases cannot be explained by BRCA2 mutations, as carriers were excluded from the group. Those two clinically important patient groups need special attention with respect to treatment choices, in particular, if diagnosed with ER+ tumors. It is thus advisable to have knowledge of BRCA2 status when treatment decisions are made. Finally, it is important to understand the biological basis for the specific nature of ER+ tumors in young women and BRCA2 carriers.

PREDICT validity for prognosis of breast cancer patients with pathogenic BRCA1/2 variants

We assessed the PREDICT v 2.2 for prognosis of breast cancer patients with pathogenic germline BRCA1 and BRCA2 variants, using follow-up data from 5453 BRCA1/2 carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and the Breast Cancer Association Consortium (BCAC). PREDICT for estrogen receptor (ER)-negative breast cancer had modest discrimination for BRCA1 carrier patients overall (Gönen & Heller unbiased concordance 0.65 in CIMBA, 0.64 in BCAC), but it distinguished clearly the high-mortality group from lower risk categories. In an analysis of low to high risk categories by PREDICT score percentiles, the observed mortality was consistently lower than the expected mortality, but the confidence intervals always included the calibration slope. Altogether, our results encourage the use of the PREDICT ER-negative model in management of breast cancer patients with germline BRCA1 variants. For the PREDICT ER-positive model, the discrimination was slightly lower in BRCA2 variant carriers (concordance 0.60 in CIMBA, 0.65 in BCAC). Especially, inclusion of the tumor grade distorted the prognostic estimates. The breast cancer mortality of BRCA2 carriers was underestimated at the low end of the PREDICT score distribution, whereas at the high end, the mortality was overestimated. These data suggest that BRCA2 status should also be taken into consideration with tumor characteristics, when estimating the prognosis of ER-positive breast cancer patients.

What Is Known about Breast Cancer in Young Women?

Breast cancer (BC) is the second leading cause of cancer-related death in women under the age of 40 years worldwide. In addition, the incidence of breast cancer in young women (BCYW) has been rising. Young women are not the focus of screening programs and BC in younger women tends to be diagnosed in more advanced stages. Such patients have worse clinical outcomes and treatment complications compared to older patients. BCYW has been associated with distinct tumour biology that confers a worse prognosis, including poor tumour differentiation, increased Ki-67 expression, and more hormone-receptor negative tumours compared to women >50 years of age. Pathogenic variants in cancer predisposition genes such as BRCA1/2 are more common in early-onset BC compared to late-onset BC. Despite all these differences, BCYW remains poorly understood with a gap in research regarding the risk factors, diagnosis, prognosis, and treatment. Age-specific clinical characteristics or outcomes data for young women are lacking, and most of the standard treatments used in this subpopulation currently are derived from older patients. More age-specific clinical data and treatment options are required. In this review, we discuss the epidemiology, clinicopathologic characteristics, outcomes, treatments, and special considerations of breast cancer in young women. We also underline future directions and highlight areas that require more attention in future studies.

The impact of oophorectomy on survival from breast cancer in patients with CHEK2 mutations

BACKGROUND

To estimate the impact of oophorectomy and other treatments on the survival of breast cancer patients with a CHEK2 mutation.

METHODS

Women with Stage I-III breast cancer who were treated at 17 hospitals in Poland were tested for four founder mutations in the CHEK2 gene. 974 women (10%) were positive for a CHEK2 mutation. Control patients without a CHEK2 mutation were selected from a database of patients treated over the same time period. Information on treatments received and distant recurrences were retrieved from medical records. Treatments included chemotherapy, hormonal therapy (tamoxifen) and radiation therapy. Oophorectomies were performed for the treatment of breast cancer or for benign conditions. Dates of death were obtained from the Polish Vital Statistics Registry. Causes of death were determined by medical record review. Predictors of survival were determined using the Cox proportional hazards model.

RESULTS

In all, 839 patients with a CHEK2 mutation were matched to 839 patients without a mutation. The mean follow-up was 12.0 years. The 15-year survival for CHEK2 carriers was 76.6% and the 15-year survival for non-carrier control patients was 78.8% (adjusted HR = 1.06; 95% CI: 0.84-1.34; P = 0.61). Among CHEK2 carriers, the 15-year survival for women who had an oophorectomy was 86.3% and for women who did not have an oophorectomy was 72.1% (adjusted HR = 0.59; 95% CI: 0.38-0.90; P = 0.02). Among controls, the 15-year survival for patients who had an oophorectomy was 84.5% and for women who did not have an oophorectomy was 77.6% (adjusted HR = 1.03; 95% CI: 0.66-1.61; P = 0.90).

CONCLUSION

Among women with breast cancer and a CHEK2 mutation, oophorectomy is associated with a reduced risk of death from breast cancer.

The Effect of Estrogen Receptor Status on Survival in Breast Cancer Patients in Ethiopia. Retrospective Cohort Study

Background

There is wide global variance in survival from breast cancer, both in developed and developing country. However, the effect of estrogen receptor status has not been widely evaluated in Ethiopia where the incidence of breast cancer is rapidly increasing. Hence, the current study aimed to determine the effect of estrogen receptor status on the overall survival of breast cancer patients who were treated at Black Lion Specialized Hospital, Ethiopia.

Methods

In this institution-based retrospective cohort study a total of 368 study participants were included with a one-to-one ratio of estrogen receptor negative to estrogen receptor positive. The main outcome of interest for this study was death due to breast cancer. The authors compared the women with estrogen receptor-positive and estrogen receptor-negative breast cancer for overall survival rate using log rank test. The incidence density rate of mortality was calculated for each exposed and non-exposed variable. The effect of estrogen receptor status on breast cancer mortality was estimated using the Cox proportional hazards model.

Results

The incidence density rate of mortality among breast cancer patients for estrogen receptor positive were found to be 5.48 (95% CI=3.94–7.64) per 1,000 person years observation; while for estrogen negative receptor status the mortality rate was found to be 10.47 (95% CI=8.19–13.37) per 1,000 person years observation. In the Cox regression analysis after ful adjustments for confounder variables, the mortality event risk was 32% higher among estrogen receptor negative (HR=1.32; 95% CI=1.08–2.91) as compared to estrogen receptor positive breast cancer patients.

Conclusion

We have found that the incidence density rate of mortality among breast cancer patients was significantly higher in the estrogen receptor negative groups. Therefore, clinicians should give careful attention to the impact of estrogen receptor negative status on the overall outcome of clients.

BRCA2 Haploinsufficiency in Telomere Maintenance

Our previous studies showed an association between monoallelic BRCA2 germline mutations and dysfunctional telomeres in epithelial mammary cell lines and increased risk of breast cancer diagnosis for women with BRCA2 999del5 germline mutation and short telomeres in blood cells. In the current study, we analyzed telomere dysfunction in lymphoid cell lines from five BRCA2 999del5 mutation carriers and three Fanconi Anemia D1 patients by fluorescence in situ hybridization (FISH). Metaphase chromosomes were harvested from ten lymphoid cell lines of different BRCA2 genotype origin and analyzed for telomere loss (TL), multitelomeric signals (MTS), interstitial telomere signals (ITS) and extra chromosomal telomere signals (ECTS). TL, ITS and ECTS were separately found to be significantly increased gradually between the BRCA2^+/+, BRCA2^+/- and BRCA2^-/- lymphoid cell lines. MTS were found to be significantly increased between the BRCA2^+/+ and the BRCA2^+/- heterozygous (p < 0.0001) and the BRCA2^-/- lymphoid cell lines (p < 0.0001) but not between the BRCA2 mutated genotypes. Dysfunctional telomeres were found to be significantly increased in a stepwise manner between the BRCA2 genotypes indicating an effect of BRCA2 haploinsufficiency on telomere maintenance.

Clinicopathological features and BRCA1 and BRCA2 mutation status in a prospective cohort of young women with breast cancer

BACKGROUND

Breast cancer in young women is more likely to have higher risk features and be associated with germline BRCA1/BRCA2 mutations. We present the clinicopathologic features of breast cancers in a prospective cohort of young women, and associations between surrogate molecular subtype and BRCA1/BRCA2 mutation status.

METHODS

Histopathological features, biomarker status, tumour stage and BRCA status were collected. Invasive tumours were categorised as luminal A-like (ER + and/or PR + , HER2-, grade 1/2), luminal B-like (ER + and/or PR + , HER2 + , or ER + and/or PR + , HER2-, and grade 3), HER2-enriched (ER/PR-, HER2 + ) or triple-negative.

RESULTS

In all, 57.3% (654/1143) of invasive tumours were high grade. In total, 32.9% were luminal A-like, 42.4% luminal B-like, 8.3% HER2-enriched, and 16.4% triple-negative. Among different age groups, there were no differences in molecular phenotype, stage, grade or histopathology. 11% (131) of tumours were from BRCA mutation carriers; 64.1% BRCA1 (63.1% triple-negative), and 35.9% BRCA2 (55.3% luminal B-like).

DISCUSSION

The opportunity to provide comparisons across young age groups, BRCA mutation status, surrogate molecular phenotype, and the identification of more aggressive hormone receptor-positive phenotypes in this population provides direction for future work to further understand and improve disparate outcomes for young women with luminal B-like cancers, particularly BRCA2-associated cancers, with potential implications for tailored prevention and treatment.

Survival from breast cancer in women with a BRCA2 mutation by treatment

BACKGROUND

The impact of various breast-cancer treatments on patients with a BRCA2 mutation has not been studied. We sought to estimate the impact of bilateral oophorectomy and other treatments on breast cancer-specific survival among patients with a germline BRCA2 mutation.

METHODS

We identified 664 women with stage I-III breast cancer and a BRCA2 mutation by combining five different datasets (retrospective and prospective). Subjects were followed for 7.2 years from diagnosis to death from breast cancer. Tumour characteristics and cancer treatments were patient-reported and derived from medical records. Predictors of survival were determined using Cox proportional hazard models, adjusted for other treatments and for prognostic features.

RESULTS

The 10-year breast-cancer survival for ER-positive patients was 78.9% and for ER-negative patients was 82.3% (adjusted HR = 1.23 (95% CI, 0.62-2.45, p = 0.55)). The 10-year breast-cancer survival for women who had a bilateral oophorectomy was 89.1% and for women who did not have an oophorectomy was 59.0% (adjusted HR = 0.45; 95% CI, 0.28-0.72, p = 0.001). The adjusted hazard ratio for chemotherapy was 0.83 (95% CI, 0.65-1.53: p = 0.56).

CONCLUSIONS

For women with breast cancer and a germline BRCA2 mutation, positive ER status does not predict superior survival. Oophorectomy is associated with a reduced risk of death from breast cancer and should be considered in the treatment plan.

Management of patients with BRCA mutation from the point of view of a breast surgeon

Germ-line mutation in BRCA (BReast CAncer gene) 1 or BRCA2 are found in 3–4% of all women with breast cancer. These patients have a significant increased risk of breast and ovarian cancer. They are often younger when diagnosed with the mutation, and the possible breast cancer they get is often aggressive with inferior outcome. There are risk reducing strategies, and the most powerful strategy is risk reducing surgery, both risk reducing bilateral mastectomy (RRM) and risk reducing bilateral salpino-oophorectomy (PBSO). This review is meant to address breast surgery in patients with germline BRCA mutation. The guidelines and techniques applied is under continuous change and it is important for the clinicians to be well informed to provide the patient with the information needed for them to make an informed decision on what risk strategy to choose.

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Patients with germ-line mutation in BRCA1 or BRCA2 have a significant increased risk of breast and ovarian cancer.

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There are different risk reducing strategies and the most powerful strategy is risk-reducing surgery, both risk reducing bilateral mastectomy and risk reducing bilateral salpingo-oophorectomy.

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Guidelines and techniques for the risk reducing surgery of the breast are under continuous change and improvement.

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Breast conserving therapy is not associated with worse survival and is a good option for a BRCA mutation carrier diagnosed with breast cancer. Risk-reducing mastectomy can be performed in a later setting.

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The management of BRCA mutation carriers, both affected and unaffected, should be performed in a multidisciplinary team. Physicians need to be systematically educated and updated on the most recent literature.

PARP inhibitor treatment of advanced breast cancer beyond the BRCA-mutated type: a meta-analysis

Background: We conducted this meta-analysis to compare the efficacy and safety of PARP inhibitors with or without chemotherapy versus chemotherapy alone for advanced breast cancer. Methods: A meta-analysis and trial sequential analysis were performed using RevMan 5.2 analysis software. Results: Six eligible randomized clinical trials involving 2080 patients were included. Regimens containing PARP inhibitors were significantly associated with higher objective response rate, longer progression-free survival and overall survival. The PARP inhibitor regimen group had a significantly higher rate of grade ≥3 thrombocytopenia than the chemotherapy-only group. Conclusion: Regimens containing PARP inhibitors are effective and safe for BRCA-mutated advanced breast cancer patients. The efficacy appears to be only marginal in patients with BRCA status unselected.

Clinical behavior and outcomes of breast cancer in young women with germline BRCA pathogenic variants

Young breast cancer (BC) patients carrying a germline BRCA pathogenic variant (mBRCA) have similar outcomes as non-carriers. However, the impact of the type of gene (BRCA1 vs. BRCA2) and hormone receptor status (positive [HR+] vs. negative [HR-]) on clinical behavior and outcomes of mBRCA BC remains largely unknown. This is an international, multicenter, hospital-based, retrospective cohort study that included mBRCA patients diagnosed, between January 2000 and December 2012, with stage I-III invasive early BC at age ≤40 years. From 30 centers worldwide, 1236 young mBRCA BC patients were included. Among 808 and 428 patients with mBRCA1 or mBRCA2, 191 (23.6%) and 356 (83.2%) had HR+tumors, respectively (P < 0.001). Median follow-up was 7.9 years. Second primary BC (P = 0.009) and non-BC malignancies (P = 0.02) were more frequent among mBRCA1 patients while distant recurrences were less frequent (P = 0.02). Irrespective of hormone receptor status, mBRCA1 patients had worse disease-free survival (DFS; adjusted HR = 0.76, 95% CI = 0.60-0.96), with no difference in distant recurrence-free interval (DRFI) and overall survival (OS). Patients with HR+ disease had more frequent distant recurrences (P < 0.001) and less frequent second primary malignancies (BC: P = 0.005; non-BC: P = 0.18). No differences in DFS and OS were observed according to hormone receptor status, with a tendency for worse DRFI (adjusted HR = 1.39, 95% CI = 0.94-2.05) in patients with HR+ BC. Type of mBRCA gene and hormone receptor status strongly impact BC clinical behavior and outcomes in mBRCA young patients. These results provide important information for patients' counseling on treatment, prevention, and surveillance strategies.

Emerging role of pioneer transcription factors in targeted ERα positive breast cancer

Transcription factors (TFs) are modular protein groups that preferably bind to DNA sequences and guide genomic expression through transcription. Among these key regulators, “pioneer factors” are an emerging class of TFs that specifically interact with nucleosomal DNA and facilitate accessible genomic binding sites for the additional TFs. There is growing evidence of these specialized modulators in particular malignancies, as highlighted by agents’ clinical efficacy, specifically targeting nuclear hormone receptors. They have been implicated in multiple cancers more recently, with a high proportion inculpating on hormone influential cancers. Moreover, extended crosstalk and cooperation between ERα pioneering factors in estrogen-dependent breast cancer (BC) remain elucidated. This review discusses on the recent advances in our understanding of pioneer TFs in cancer, especially highlighting its potentiality to modulate chromatin condensation to permit ERα recruitment in BC cells. Through the study it was concluded that the highly prospected pioneer TFs in BC, including FOXA1, TLE1, PBX1, and GATA3, possess the potential therapeutic significance and further innovations in the field could yield targeted therapy in cancer treatment.

Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Genetic/Familial High-Risk Assessment: Breast, Ovarian, and Pancreatic focus primarily on assessment of pathogenic or likely pathogenic variants associated with increased risk of breast, ovarian, and pancreatic cancer and recommended approaches to genetic testing/counseling and management strategies in individuals with these pathogenic or likely pathogenic variants. This manuscript focuses on cancer risk and risk management for BRCA-related breast/ovarian cancer syndrome and Li-Fraumeni syndrome. Carriers of a BRCA1/2 pathogenic or likely pathogenic variant have an excessive risk for both breast and ovarian cancer that warrants consideration of more intensive screening and preventive strategies. There is also evidence that risks of prostate cancer and pancreatic cancer are elevated in these carriers. Li-Fraumeni syndrome is a highly penetrant cancer syndrome associated with a high lifetime risk for cancer, including soft tissue sarcomas, osteosarcomas, premenopausal breast cancer, colon cancer, gastric cancer, adrenocortical carcinoma, and brain tumors.

BRCA1 and BRCA2 associated breast cancer and the roles of current modelling systems in drug discovery

For a drug candidate to be fully developed takes years and investment of hundreds of millions of dollars. There is no doubt that drug development is difficult and risky, but vital to protecting against devastating disease. This difficulty is clearly evident in BRCA1 and BRCA2 related breast cancer, with current treatment options largely confined to invasive surgical procedures, as well as chemotherapy and radiotherapy regimes which damage healthy tissue and can leave remnant disease. Consequently, patient survival and relapse rates are far from ideal, and new candidate treatments are needed. The preclinical stages of drug discovery are crucial to get right for translation to hospital beds. Disease models must take advantage of current technologies and be accurate for rapid and translatable treatments. Careful selection of cell lines must be coupled with high throughput techniques, with promising results trialled further in highly accurate humanised patient derived xenograft models. Traditional adherent drug screening should transition to 3D culture systems amenable to high throughput techniques if the gap between in vitro and in vivo studies is to be partially bridged. The possibility of organoid, induced pluripotent stem cell, and conditionally reprogrammed in vitro models is tantalising, however protocols are yet to be fully established. This review of BRCA1 and BRCA2 cancer biology and current modelling systems will hopefully guide the design of future drug discovery endeavours and highlight areas requiring improvement.

Rapid Genetic Testing for BRCA1 and BRCA2 Mutations at the Time of Breast Cancer Diagnosis: An Observational Study

BACKGROUND

This study aimed to evaluate the impact of rapid genetic testing (RGT) for BRCA1 and BRCA2 at the time of breast cancer diagnosis on treatment choices. Bilateral mastectomy for the treatment of breast cancer in women with a BRCA1 or BRCA2 mutation offers a reduction in the risk of contralateral breast cancer. It is unclear whether offering RGT at the time of breast cancer diagnosis has an impact on women's surgical decision-making.

METHODS

Women with breast cancer diagnosed between June 2013 and May 2018 were recruited from four academic health sciences centers in Toronto, Canada. The participants completed a questionnaire before genetic testing, then one week and one year after disclosure of the genetic test result. Before surgery, RGT was performed. Diagnostic, pathologic, and treatment data were compared between those with and those without a BRCA mutation.

RESULTS

The study enrolled 1007 women who consented to RGT. The mean age of the participants was 46.3 years, and the median time to result disclosure was 10 days. A BRCA mutation was found in 6% of the women. The women with a BRCA mutation were significantly more likely to elect for bilateral mastectomy than the women without a BRCA mutation (p < 0.0001). Of the BRCA-positive patients, 95.7% reported that they used their genetic test result to make a surgical decision.

CONCLUSIONS

The women provided with RGT at the time of breast cancer diagnosis use the genetic information to make treatment decisions, and the majority of those identified with a BRCA mutation elect for a bilateral mastectomy.

Breast cancer survival in Nordic BRCA2 mutation carriers-unconventional association with oestrogen receptor status

Background

The natural history of breast cancer among BRCA2 carriers has not been clearly established. In a previous study from Iceland, positive ER status was a negative prognostic factor. We sought to identify factors that predicted survival after invasive breast cancer in an expanded cohort of BRCA2 carriers.

Methods

We studied 608 women with invasive breast cancer and a pathogenic BRCA2 mutation (variant) from four Nordic countries. Information on prognostic factors and treatment was retrieved from health records and by analysis of archived tissue specimens. Hazard ratios (HR) were estimated for breast cancer-specific survival using Cox regression.

Results

About 77% of cancers were ER-positive, with the highest proportion (83%) in patients under 40 years. ER-positive breast cancers were more likely to be node-positive (59%) than ER-negative cancers (34%) (P < 0.001). The survival analysis included 584 patients. Positive ER status was protective in the first 5 years from diagnosis (multivariate HR = 0.49; 95% CI 0.26–0.93, P = 0.03); thereafter, the effect was adverse (HR = 1.91; 95% CI 1.07–3.39, P = 0.03). The adverse effect of positive ER status was limited to women who did not undergo endocrine treatment (HR = 2.36; 95% CI 1.26–4.44, P = 0.01) and patients with intact ovaries (HR = 1.99; 95% CI 1.11–3.59, P = 0.02).

Conclusions

The adverse effect of a positive ER status in BRCA2 carriers with breast cancer may be contingent on exposure to ovarian hormones.

BRCA1 Promoter Methylation Status in 1031 Primary Breast Cancers Predicts Favorable Outcomes Following Chemotherapy

Background

Breast Cancer 1 gene (BRCA1) is known to be inactivated in breast tumors by promoter methylation. Tumor cells in patients carrying a germline mutation in BRCA1 are sensitive to cytotoxic drugs that cause DNA double strand breaks. However, very little is known on whether patients with BRCA1 promoter methylated tumors are similarly sensitive to cytotoxic drugs. In this study, we address this by making use of extensive follow-up data on patients treated with cyclophosphamide, methotrexate, and fluorouracil in Iceland between 1976 and 2007.

Methods

We analyzed BRCA1 promoter methylation by pyrosequencing DNA from tumor samples from 1031 patients with primary breast cancer. Of those, 965 were sporadic cases, 61 were BRCA2, and five were BRCA1 germline mutation carriers. All cases were examined with respect to clinicopathological parameters and breast cancer–specific survival in patients treated with cytotoxic drugs. Information on chemotherapy treatment in noncarriers was available for 26 BRCA1 methylated tumors and 857 unmethylated tumors.

Results

BRCA1 was promoter methylated in 29 sporadic tumors or in 3.0% of cases (29 of 965), whereas none of the tumors derived from BRCA germline mutation carriers were promoter methylated. Important to note, patients with BRCA1 promoter methylation receiving chemotherapeutic drug treatment show highly improved breast cancer–specific survival compared with unmethylated controls (hazard ratio = 0.10, 95% confidence interval = 0.01 to 0.75, two-sided P = .02).

Conclusions

BRCA1 promoter methylation is predictive of improved disease outcome in patients receiving cyclophosphamide, methotrexate, and fluorouracil drug treatment. Our results support the use of markers indicative of “BRCAness” in sporadic breast cancers to identify patients that are likely to benefit from the use of DNA-damaging agents.

Mechanism of Action and Clinical Efficacy of CDK4/6 Inhibitors in BRCA-Mutated, Estrogen Receptor-Positive Breast Cancers: Case Report and Literature Review

Sensitivity to endocrine therapy of patients with estrogen receptor (ER)-positive metastatic breast cancer and germline BRCA1/2 mutations is not yet fully elucidated. Furthermore, the registration trials of CDK 4/6 inhibitors in combination with endocrine therapy lacked of a pre-specified subgroup analysis in BRCA1/2 mutation carriers. We report clinical history of two patients with BRCA-mutated, ER-positive metastatic breast cancer treated with letrozole plus the CDK 4/6 inhibitor palbociclib. Biological and clinical implications of the treatment outcome observed in the two cases are discussed with the knowledge of scientific evidence to date available. Overall, biological rationale, preclinical, and clinical data support the prominent role of CDK 4/6 inhibitors plus endocrine therapy, even in combination with PARP inhibitors, in the treatment of BRCA-mutated, ER-positive breast cancers. However, the interaction between Cyclin/CDK pathway, ER and BRCA is complex and evidences reported so far, albeit reliable, await confirmation in the context of future randomized clinical trials.

CpG promoter hypo-methylation and up-regulation of microRNA-190b in hormone receptor-positive breast cancer

Estrogen receptor-positive breast cancer is subdivided into subtypes LuminalA and LuminalB, based on different expression patterns. MicroRNA-190b has been reported to be up-regulated in estrogen receptor-positive breast cancers. In this study we aimed to investigate the role of CpG promoter methylation in regulating miR-190b expression and its impact on clinical presentation and prognosis. DNA methylation analysis for the promotor of microRNA-190b was performed by pyrosequencing 549 primary breast tumors, of which 62 were carriers of the BRCA2 ^999del5 founder mutation, 71 proximal normal breast samples and 16 breast derived cell lines. MicroRNA-190b expression was analysed in 67 primary breast tumors, 14 paired normal breast samples and 16 breast derived cell lines. Tissue microarrays (TMAs) were available for ER (n = 436), PR (n = 436), HER-2 (N = 258) and Ki67 (n = 248). MiR-190b had reduced promoter methylation in estrogen receptor-positive breast cancers (P = 1.02e-12, Median values: ER+ 24.3, ER- 38.26) and miR-190b's expression was up-regulated in a correlative manner (P = 1.83e-06, Spearman's rho -0.62). Through breast cancer specific survival analysis, we demonstrated that LuminalA patients exhibiting miR-190b hypo-methylation had better survival than other patients (P = 0.034, HR = 0.29, 95% CI 0.09-0.91). We, furthermore, demonstrated that miR-190b hypo-methylation occurs less frequently in ER+ tumors from BRCA2 ^999del5 mutation carriers than in non-mutated individuals (P = 0.038, Χ ² = 4.32, n = 335). Our results suggest that upregulation of miR-190b may occur through loss of promoter DNA methylation during the development of estrogen-receptor (ER) positive breast cancers, and that miR-190b hypo-methylation leads to increased breast cancer specific survival within the LuminalA- subtype but not LuminalB.

The spectrum of mutations predisposing to familial breast cancer in Poland

To optimize genetic testing, it is necessary to establish the spectrum of breast cancer-predisposing mutations in particular ethnic groups. We studied 1,018 women with a strong family history for breast cancer (families with hereditary breast cancer; HBC) from genetically homogenous population of Poland, which is populated by ethnic Slavs, for mutations in 14 cancer susceptibility genes. Additionally, we compared the frequency of candidate pathogenic variants in breast cancer cases and controls. Germline mutations were detected in 512 of 1,018 probands with breast cancer (50.3%), including BRCA1/2 mutations detected in 420 families and non-BRCA mutations seen in 92 families. Thirteen BRCA1/2 founder mutations represented 84% of all BRCA1/2-positive cases. Seven founder mutations of CHEK2, PALB2, NBN and RECQL represented 73% of all non-BRCA-positive cases. Odds ratios for hereditary breast cancer were 87.6 for BRCA1, 15.4 for PALB2, 7.2 for CHEK2, 2.8 for NBN and 15.8 for RECQL. Odds ratios for XRCC2, BLM and BARD1 were below 1.3. In summary, we found that 20 founder mutations in six genes (BRCA1/2, CHEK2, PALB2, NBN and RECQL) are responsible for 82% of Polish hereditary breast cancer families. A simple test for these 20 mutations will facilitate genetic testing for breast cancer susceptibility in Poland. It may also facilitate genetic testing for breast cancer susceptibility in other Slavic populations and women of Slavic descent worldwide.

Estrogen Receptor Status Oppositely Modifies Breast Cancer Prognosis in BRCA1/BRCA2 Mutation Carriers Versus Non-Carriers

Breast cancer (BC) prognosis in BRCA1 and BRCA2 mutation carriers has been reported contradictorily, and the significance of variables influencing prognosis in sporadic BC is not established in BC patients with hereditary BRCA1/BRCA2 mutations. In this retrospective cohort study, we analyzed the effect of clinicopathological characteristics on BC prognosis (disease-free survival [DFS] and disease-specific survival [DSS]) in hereditary BRCA1/BRCA2 mutation carriers. We enrolled 234 BRCA1/BRCA2 mutation carriers and 899 non-carriers, of whom 191 carriers and 680 non-carriers, with complete data, were available for survival analyses. We found that patients with ER-positive tumors developed disease recurrence 2.3-times more likely when they carried a BRCA1/BRCA2 mutation (23/60; 38.3% ER-positive carriers vs. 74/445; 16.6% ER-positive non-carriers; p < 0.001). ER-positive mutation carriers also had a 3.4-times higher risk of death due to BC compared with ER-positive non-carriers (13/60; 21.7% vs. 28/445; 6.3%; p < 0.001). Moreover, prognosis in ER-negative BRCA1/BRCA2 mutation carriers was comparable with that in ER-positive non-carriers. Our study demonstrates that ER-positivity worsens BC prognosis in BRCA1/BRCA2 mutation carriers, while prognosis for carriers with ER-negative tumors (including early-onset) is significantly better and comparable with that in ER-positive, older BC non-carriers. These observations indicate that BRCA1/BRCA2 mutation carriers with ER-positive BC represent high-risk patients.

Oestrogen receptor status and survival in women with BRCA2-associated breast cancer

BACKGROUND

To evaluate the predictors of mortality, including ER status, in women with a BRCA2 mutation and breast cancer.

METHODS

Eligible participants were identified from within two longitudinal cohorts. These patients were selected because they were diagnosed with breast cancer between 1975 and 2015 and carried a BRCA2 mutation. Data were abstracted from the medical record and pathology report. We analysed the effects of ER status and other variables on breast cancer specific survival using a Cox proportional hazards model.

RESULTS

Three hundred ninety women with breast cancer and a BRCA2 mutation were included in the analysis. The mean follow-up time was 12.3 years (range 1-39 years) and 89 subjects died (22.8%). In the multivariate analysis, women with ER-positive tumours were more likely to die than women with ER-negative tumours (HR 2.08, 95% CI 0.99-4.36, p = 0.05), and this was of borderline significance. For the 233 women with ER-positive tumours the 20-year survival rate was 62.2%, compared to 83.7% for 58 women with ER-negative tumours (p = 0.03).

CONCLUSIONS

The majority of women with a BRCA2 mutation present with ER-positive breast cancer, and for these women, prognosis may be worse than for BRCA2 carriers with ER-negative breast cancer.

Whole genome sequencing of breast cancer

Breast cancer was the first to take advantage of targeted therapy using endocrine therapy, and for up to 20% of all breast cancer patients a further significant improvement has been obtained by HER2‐targeted therapy. Greater insight in precision medicine is to some extent driven by technical and computational progress, with the first wave of a true technical advancement being the application of transcriptomic analysis. Molecular subtyping further improved our understanding of breast cancer biology and has through a new tumor classification enabled allocation of personalized treatment regimens. The next wave in technical progression must be next‐generation‐sequencing which is currently providing new and exciting results. Large‐scale sequencing data unravel novel somatic and potential targetable mutations as well as allowing the identification of new candidate genes predisposing for familial breast cancer. So far, around 15% of all breast cancer patients are genetically predisposed with most genes being factors in pathways implicated in genome maintenance. This review focuses on whole‐genome sequencing and the new possibilities that this technique, together with other high‐throughput analytic approaches, provides for a more individualized treatment course of breast cancer patients.

BRCA Mutations and Breast Cancer Prevention

Women who inherit a deleterious BRCA1 or BRCA2 mutation face substantially increased risks of developing breast cancer, which is estimated at 70%. Although annual screening with magnetic resonance imaging (MRI) and mammography promotes the earlier detection of the disease, the gold standard for the primary prevention of breast cancer remains bilateral mastectomy. In the current paper, I review the evidence regarding the management of healthy BRCA mutation carriers, including key risk factors and protective factors, and also discuss potential chemoprevention options. I also provide an overview of the key findings from the literature published to date, with a focus on data from studies that are well-powered, and preferably prospective in nature.

Surgery for BRCA, TP53 and PALB2: a literature review

Introduction

The presence of a deleterious mutation, most commonly a BRCA mutation, has a tremendous impact on the management of breast cancer. We review the surgical management of BRCA mutation carriers, and two other potentially high-risk mutations, TP53 and PALB2.

Methodology

A search was done on PubMed, limited to reviews and the English language only. The search terms used were ‘BRCA’ or ‘PALB2’ or ‘TP53’ and ‘surgery’. Fifteen articles were identified by searching and one article was obtained from other sources.

Results

Breast-conserving surgery has equivalent survival, but may have an increased risk of local recurrence, compared to mastectomy among BRCA mutation carriers. Contralateral prophylactic mastectomy may not improve overall survival, despite reducing the risk of developing contralateral breast cancer. The use of preoperative genetic testing allows patients to have combined curative and prophylactic surgery. However, preoperative genetic testing may influence patients to make rash decisions. In healthy BRCA mutation carriers, bilateral prophylactic mastectomy is done to prevent breast cancer from occurring. Bilateral prophylactic mastectomy is highly effective in reducing the risk of breast cancer in healthy BRCA mutation-positive women and may have a survival benefit. Prophylactic oophorectomy reduces the risk of ovarian cancer, but may not have an effect on the risk of breast cancer. There is a lack of studies on surgery for non-BRCA mutations. TP53 and PALB2 are potentially high-risk mutations for breast cancer, which may justify the use of prophylactic surgery. Advice should be given on a case-by-case basis.

Conclusion

A comprehensive approach is needed to provide optimum treatment for breast cancer patients with deleterious mutations.

Clinical and molecular characterization of BRCA-associated breast cancer: results from the DBCG

BACKGROUND

In breast cancer (BC) patients a cancer predisposing BRCA1/2 mutation is associated with adverse tumor characteristics, risk assessment and treatment allocation. We aimed to estimate overall- (OS) and disease-free survival (DFS) according to tumor characteristics and treatment among women who within two years of definitive surgery for primary BC were shown to carry a mutation in BRCA1/2 .

MATERIAL AND METHODS

From the clinical database of the Danish Breast Cancer Group we included 141 BRCA1 and 96 BRCA2 BC patients. Estrogen receptor and HER2 status were centrally reviewed on paraffin-embedded tumor tissue. Information on risk reducing surgery was obtained from the Danish Pathology and Patient Registries and included as time-dependent variables in Cox proportional hazard models.

RESULTS

Ten-year OS and DFS for BRCA1 BC patients were 78% (95% CI 69-85) and 74% (95% CI 64-81). Ten-year OS and DFS for BRCA2 BC were 88% (95% CI 78-94) and 84% (95% CI 74-91). BRCA1 BC patients as compared to BRCA2 BC patients had a higher risk of BC relapse or non-breast cancer within ten years of follow-up, independent of ER status (adjusted HR 2.78 95% CI 1.28-6.05, p = .01), but BRCA mutation was not associated with OS (adjusted HR 1.98, 95% CI 0.87-4.52, p = .10). In multivariate analysis, including both BRCA1 and BRCA2 carriers, no chemotherapy was associated with a higher risk of death (adjusted OS HR 3.58, 95% CI 1.29-9.97, p = .01) and risk reducing contralateral mastectomy (RRCM) was associated with a significantly reduced risk of death (adjusted OS HR 0.42, 95% CI =0.21-0.84, p = .01).

CONCLUSION

Difference in OS between BRCA1 and BRCA2 BC patients could be ascribed to tumor-biology. BRCA1 BC patients may have a shorter ten-year DFS than BRCA2 BC patients. Chemotherapy and risk reducing contralateral mastectomy reduce mortality for both BRCA1 and BRCA2 BC patients.

Predictors of survival for breast cancer patients with a BRCA1 mutation

PURPOSE

To evaluate in a contemporary cohort the impacts of chemotherapy and oophorectomy on survival for breast cancer patients with a BRCA1 mutation.

EXPERIMENTAL DESIGN

We reviewed the pathology reports and medical records of 372 women with breast cancer and a BRCA1 mutation, diagnosed from 2005 to 2017, between the ages of 25 and 65 and followed them for death from all causes and death from breast cancer. Death was ascertained through the Poland vital statistics registry. We performed survival analysis to evaluate the impacts of chemotherapy (including neoadjuvant cisplatinum) and of oophorectomy on survival.

RESULTS

After a mean follow-up of 5.6 years (median 5.2), 66 of the 372 women died; 56 of the deaths were from breast cancer and 6 were from ovarian cancer. 127 women received neoadjuvant cisplatinum and 245 women received other chemotherapies. Cisplatinum (versus all other therapies) was associated with a hazard ratio of 0.42 (95%CI 0.20-0.87) on breast cancer-specific survival. The 10-year actuarial all-cause survival for women who had both cisplatinum and an oophorectomy was 94.4%. The 10-year all-cause survival for women who had neither cisplatinum nor an oophorectomy was 65.4% (p < 0.01).

CONCLUSIONS

Cisplatinum and oophorectomy are effective therapies for women with breast cancer and a BRCA1 mutation.

Genetic testing in women with breast cancer: implications for treatment

INTRODUCTION

Mutations in either the BRCA1 or BRCA2 genes are responsible for approximately 42,000 cases of breast cancer annually. Identifying these germline mutations in a woman with breast cancer is important because it can influence her immediate and long-term management and has important implications for other family members. Areas covered: This review highlights how treatment-focussed genetic testing for BRCA1 and BRCA2 mutations can potentially influence cancer treatment and secondary prevention decisions in women with breast cancer. Expert commentary: Testing women with breast cancer for BRCA1 and BRCA2 germline mutations has the potential to decrease cancer burden and improve cancer outcomes. It can help optimise surgical and systemic therapy approaches. Clinicians should actively consider whether genetic testing is appropriate for each woman with breast cancer, and if so should instigate it early in the treatment trajectory when it can most influence cancer care.