Moderate-risk Breast Cancer Research Articles

An app promoting weight gain prevention via healthy behaviours amongst young women with a family history of breast cancer: Acceptability and usability assessment.

Breast cancer is the most frequent female malignancy in the UK. Around 20% of cases are linked to weight gain, excess weight and health behaviours. We designed a weight gain prevention, health behaviour intervention for young women at increased risk. The study comprised a single arm observational study over 2 months testing acceptability and usability of the intervention: online group welcome event, app and private Facebook group. Females aged 18-35 years at moderate or high risk of breast cancer (>17% lifetime risk) were recruited via invite letters and social media posts. The app included behaviour change techniques and education content. Online questionnaires were completed at baseline, as well as at 1 and 2 months. We also assessed feasibility of study procedures. Both recruitment methods were successful. Thirty-five women were recruited, 26% via social media posts. Median age was 33 (interquartile range = 28.2-34.5) years, the majority (94.1%) were of White ethnicity. Thirty-four participants were included in the analyses, of which 94% downloaded the app. Median self-monitoring logs per participant during the study period was 10.0 (interquartile range = 4.8-28.8). App quality mean (SD) score was 3.7 (0.6) at 1 and 2 months (scale: 1-5). Eighty-nine per cent rated the app at average or above at 1 month and 75.0% at 2 months. Nineteen women (55.9%) joined the Facebook group and there were 61 comments and 83 reactions and votes from participants during the study period. This first iteration of the app and intervention was well received and is suitable to progress to the next stage of refining and further testing.

Abstract PO3-07-11: Concordance between abbreviated and complete magnetic resonance protocols for screening woman at moderate and high risk for breast cancer

Abstract Introduction: Patients at high risk for developing breast cancer are potential beneficiaries of personalized screening strategies. Breast magnetic resonance imaging (MRI) has shown high sensitivity, but its broader use remains constrained by issues such as high cost and long examination time. The abbreviated magnetic resonance protocol is presented as an alternative to overcome these challenges. Our primary outcome was to evaluate the concordance of the final report between full and abbreviated protocols. Secondary outcomes included the acquisition and reading time of images from the abbreviated protocol. Methods: A cross-sectional study was conducted on asymptomatic women at moderate and high risk for breast cancer who underwent the full MRI screening protocol in private health institutions in the city of Belo Horizonte, Brazil. The abbreviated protocol was derived from the full protocol by the computer through selection of specific sequences. Each image was independently blind read, and assigned a category from the Breast Imaging - Reporting and Data System (BI-RADS) by at least two examiners. The results were then compared using the Cohen's kappa and Intraclass Correlation Coefficients. Results: The study included 170 women, and a concordance rate of 96,9% was found for the reported BI-RADS category between protocols in this population. A 21-minute reduction was observed in examination time for the abbreviated protocol. Conclusion: The significant concordance between protocols indicates that despite the reduction in acquisition time, number of acquired images, and method's complexity, the abbreviated MRI protocol meets most screening demands. It is, therefore, a viable alternative for cost reduction and improving patients tolerability for the studied population. Table 1. Clinical characteristics of the study population Absolute and percentage data about age, personal risk for breast cancer, family history, and previous genetic testing in the study population. Table 2. Concordance analysis between abbreviated and complete MRI protocols based on the ACR-BIRADS classification - Coen Kappa and Intraclass Correlation Coefficient The Kappa value of 0.9687 (95% CI 0.9426 - 0.9949, p < 0.01) indicates almost perfect concordance between the two protocols. The intraclass correlation coefficient of 0.982 (95% CI 0.97 - 0.987, p < 0.01), also indicates excellent concordance using the two-way random effect models criteria. Citation Format: Mariana Mitraud Ottoni Guedes, Agnaldo Lopes da Silva Filho, Thais Paiva Moraes, Adriene Moraes Campos, Ivie Braga de Paula, Felipe Marcondes de Oliveira Coelho, Barbara Silveira Santana, Bertha Andrade Coelho, Maria Fernanda Sperotto Valadares Gontijo, Leticia Martins De Araujo Campos Linhares, Anna Dias Salvador, Waldeir José de Almeida Junior, José Tadeu Campos de Avelar. Concordance between abbreviated and complete magnetic resonance protocols for screening woman at moderate and high risk for breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-07-11.

Bayesian meta-analysis of penetrance for cancer risk.

Multi-gene panel testing allows many cancer susceptibility genes to be tested quickly at a lower cost making such testing accessible to a broader population. Thus, more patients carrying pathogenic germline mutations in various cancer-susceptibility genes are being identified. This creates a great opportunity, as well as an urgent need, to counsel these patients about appropriate risk-reducing management strategies. Counseling hinges on accurate estimates of age-specific risks of developing various cancers associated with mutations in a specific gene, ie, penetrance estimation. We propose a meta-analysis approach based on a Bayesian hierarchical random-effects model to obtain penetrance estimates by integrating studies reporting different types of risk measures (eg, penetrance, relative risk, odds ratio) while accounting for the associated uncertainties. After estimating posterior distributions of the parameters via a Markov chain Monte Carlo algorithm, we estimate penetrance and credible intervals. We investigate the proposed method and compare with an existing approach via simulations based on studies reporting risks for two moderate-risk breast cancer susceptibility genes, ATM and PALB2. Our proposed method is far superior in terms of coverage probability of credible intervals and mean square error of estimates. Finally, we apply our method to estimate the penetrance of breast cancer among carriers of pathogenic mutations in the ATM gene.

Abstract B012: Pedigree and multi-omics analyses implicate nucleotide excision repair genes, XPA, ERCC6, and ERCC8, in susceptibility to breast cancer

Abstract Background: The majority of low- and moderate-risk [odds ratios (OR) ≤ 3] susceptibility genes for peri- and post-menopausal breast cancer (≥50 years of age), particularly those with minor allele frequency (MAF) of <30%, have not yet been identified and/or validated. We used a hypothesis-driven integrative approach to identify breast cancer susceptibility genes by analyzing pedigree and multi-omics (genomics, transcriptomics, mutation landscape) data. Methods: We conducted pedigree analysis in 31 families with DNA repair disorders, xeroderma pigmentosum (XP), trichothiodystrophy (TTD), Cockayne syndrome (CS), XP/TTD and XP/CS. These disorders can be caused by mutations in genes involved in the nucleotide excision repair (NER) pathway such as XPA-XPG, ERCC6 and ERCC8. We estimated the frequency of hereditary breast cancer, defined as the presence of at least two cases of premenopausal breast cancer (diagnosed <50 years of age) or one case of premenopausal breast cancer and one case of ovarian cancer in one side of the family, in our study. Furthermore, we conducted individual analysis of four genome-wide association studies (GWAS) datasets (totaling 2961 cases and 4335 controls), individual and meta-analysis of two gene expression microarray datasets (98 cases and 163 controls), and targeted analysis of The Cancer Genome Atlas (TCGA) (522 breast cancers). All analyses involved invasive ductal breast carcinoma in women diagnosed at ≥50 years of age. Results: In an XP family with causative mutations in XPA, there were four cases of premenopausal breast cancer (including heterozygote mutation carriers), one case of ovarian cancer, and one case of prostate cancer. Comprehensive sequencing failed to identify a BRCA1 or BRCA2 mutation in this family. Overall, 7 of 31 (22.6%) families with DNA repair disorders had a family history that was compatible with hereditary breast cancer. Hence, we selected a panel of NER genes as candidates for association studies with breast cancer. Our candidate-gene association analysis of GWAS datasets suggested an increased risk of breast cancer with ERCC6 (main effect:1.29 ≤ OR ≤ 2.91, 0.005 ≤ p ≤ 0.04, 11.8 ≤ MAF ≤ 29.7%) and implicated its interaction with ERCC8 (joint effect:3.03 ≤ OR ≤ 5.31, 0.01 ≤ pinteraction ≤ 0.03). Our transcriptomics analysis identified significant upregulation of ERCC6 (p=7.95 × 10–6) and ERCC8 (p=4.67 × 10–6) in breast cancer. Our analysis of TCGA breast tumor data showed similar mutation frequency of ERCC6 (1.8%) and ERCC8 (0.3%) as known breast cancer susceptibility genes such as BLM (1.9%) and LSP1 (0.3%). Conclusion: Our integrative analyses suggest that ERCC6 may be a previously unreported low- to moderate-risk breast cancer susceptibility gene, which may also interact with ERCC8. ERCC6 and ERCC8 code for the main components of the transcription-coupled (TC) repair sub-pathway of the NER. TC-NER protects against genotoxic agents, such as free radicals and reactive oxygen species. Our results provide a deeper biologic insight and leads for prevention of common breast cancer. Citation Format: Roxana Moslehi, Amiran Dzutsev. Pedigree and multi-omics analyses implicate nucleotide excision repair genes, XPA, ERCC6, and ERCC8, in susceptibility to breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr B012.

ASO Visual Abstract: Associationof Moderate-Risk Breast Cancer Geneswith Contralateral Prophylactic Mastectomy and Bilateral Disease.

ASO Visual Abstract: Associationof Moderate-Risk Breast Cancer Geneswith Contralateral Prophylactic Mastectomy and Bilateral Disease.

Association of Moderate-Risk Breast Cancer Genes with Contralateral Prophylactic Mastectomy and Bilateral Disease.

The impact of ATM, CHEK2, and PALB2, the three most prevalent moderate-risk breast cancer genes, on surgical decision making is not well known. Our retrospective study included patients with resectable non-metastatic breast cancer who underwent multigene panel testing between July 2014 and January 2020 with at least one genetic alteration (pathogenic or variant of uncertain significance [VUS] in ATM [n = 49], CHEK [n = 57], or PALB2 [n = 27]). Our objectives were to determine the rate of contralateral prophylactic mastectomy (CPM) and the rate of bilateral breast cancer. Univariable analyses (UVA) and multivariable analyses (MVA) were performed to identify factors associated with CPM and bilateral breast cancer. The rate of CPM was 39% (n = 49/127), with 54% (n = 25/46) of patients with a pathogenic mutation and 30% (n = 24/81) of patients with a VUS choosing CPM. On MVA, premenopausal status (odds ratio [OR] 3.46) and a pathogenic alteration (OR 3.01) were associated with increased use of CPM. Bilateral disease was noted in 16% (n = 22/138). Patients with pathogenic mutations had a 22% (n = 11/51) incidence of bilateral breast cancer, while patients with VUS had a 13% (n = 11/87) incidence, although this was not statistically significant on UVA or MVA. On MVA, premenopausal status was associated with a decreased risk of bilateral disease (OR 0.33, p = 0.022). During follow-up, a breast cancer event occurred in 16% (n = 22/138). Our study identified a high rate of CPM among those with ATM, CHEK2, and PALB2 alterations, including VUS. Further studies are needed to clarify reasons for CPM among patients with moderate-risk alterations.

Artificial intelligence-supported screen reading versus standard double reading in the Mammography Screening with Artificial Intelligence trial (MASAI): a clinical safety analysis of a randomised, controlled, non-inferiority, single-blinded, screening accuracy study

Retrospective studies have shown promising results using artificial intelligence (AI) to improve mammography screening accuracy and reduce screen-reading workload; however, to our knowledge, a randomised trial has not yet been conducted. We aimed to assess the clinical safety of an AI-supported screen-reading protocol compared with standard screen reading by radiologists following mammography. In this randomised, controlled, population-based trial, women aged 40-80 years eligible for mammography screening (including general screening with 1·5-2-year intervals and annual screening for those with moderate hereditary risk of breast cancer or a history of breast cancer) at four screening sites in Sweden were informed about the study as part of the screening invitation. Those who did not opt out were randomly allocated (1:1) to AI-supported screening (intervention group) or standard double reading without AI (control group). Screening examinations were automatically randomised by the Picture Archive and Communications System with a pseudo-random number generator after image acquisition. The participants and the radiographers acquiring the screening examinations, but not the radiologists reading the screening examinations, were masked to study group allocation. The AI system (Transpara version 1.7.0) provided an examination-based malignancy risk score on a 10-level scale that was used to triage screening examinations to single reading (score 1-9) or double reading (score 10), with AI risk scores (for all examinations) and computer-aided detection marks (for examinations with risk score 8-10) available to the radiologists doing the screen reading. Here we report the prespecified clinical safety analysis, to be done after 80 000 women were enrolled, to assess the secondary outcome measures of early screening performance (cancer detection rate, recall rate, false positive rate, positive predictive value [PPV] of recall, and type of cancer detected [invasive or in situ]) and screen-reading workload. Analyses were done in the modified intention-to-treat population (ie, all women randomly assigned to a group with one complete screening examination, excluding women recalled due to enlarged lymph nodes diagnosed with lymphoma). The lowest acceptable limit for safety in the intervention group was a cancer detection rate of more than 3 per 1000 participants screened. The trial is registered with ClinicalTrials.gov, NCT04838756, and is closed to accrual; follow-up is ongoing to assess the primary endpoint of the trial, interval cancer rate. Between April 12, 2021, and July 28, 2022, 80 033 women were randomly assigned to AI-supported screening (n=40 003) or double reading without AI (n=40 030). 13 women were excluded from the analysis. The median age was 54·0 years (IQR 46·7-63·9). Race and ethnicity data were not collected. AI-supported screening among 39 996 participants resulted in 244 screen-detected cancers, 861 recalls, and a total of 46 345 screen readings. Standard screening among 40 024 participants resulted in 203 screen-detected cancers, 817 recalls, and a total of 83 231 screen readings. Cancer detection rates were 6·1 (95% CI 5·4-6·9) per 1000 screened participants in the intervention group, above the lowest acceptable limit for safety, and 5·1 (4·4-5·8) per 1000 in the control group-a ratio of 1·2 (95% CI 1·0-1·5; p=0·052). Recall rates were 2·2% (95% CI 2·0-2·3) in the intervention group and 2·0% (1·9-2·2) in the control group. The false positive rate was 1·5% (95% CI 1·4-1·7) in both groups. The PPV of recall was 28·3% (95% CI 25·3-31·5) in the intervention group and 24·8% (21·9-28·0) in the control group. In the intervention group, 184 (75%) of 244 cancers detected were invasive and 60 (25%) were in situ; in the control group, 165 (81%) of 203 cancers were invasive and 38 (19%) were in situ. The screen-reading workload was reduced by 44·3% using AI. AI-supported mammography screening resulted in a similar cancer detection rate compared with standard double reading, with a substantially lower screen-reading workload, indicating that the use of AI in mammography screening is safe. The trial was thus not halted and the primary endpoint of interval cancer rate will be assessed in 100 000 enrolled participants after 2-years of follow up. Swedish Cancer Society, Confederation of Regional Cancer Centres, and the Swedish governmental funding for clinical research (ALF).

Impact of High-to-Moderate Penetrance Genes on Genetic Testing: Looking over Breast Cancer.

Breast cancer (BC) is the most common cancer and the leading cause of cancer death in women worldwide. Since the discovery of the highly penetrant susceptibility genes BRCA1 and BRCA2, many other predisposition genes that confer a moderate risk of BC have been identified. Advances in multigene panel testing have allowed the simultaneous sequencing of BRCA1/2 with these genes in a cost-effective way. Germline DNA from 521 cases with BC fulfilling diagnostic criteria for hereditary BC were screened with multigene NGS testing. Pathogenic (PVs) and likely pathogenic (LPVs) variants in moderate penetrance genes were identified in 15 out of 521 patients (2.9%), including 2 missense, 7 non-sense, 1 indel, and 3 splice variants, as well as two different exon deletions, as follows: ATM (n = 4), CHEK2 (n = 5), PALB2 (n = 2), RAD51C (n = 1), and RAD51D (n = 3). Moreover, the segregation analysis of PVs and LPVs into first-degree relatives allowed the detection of CHEK2 variant carriers diagnosed with in situ melanoma and clear cell renal cell carcinoma (ccRCC), respectively. Extended testing beyond BRCA1/2 identified PVs and LPVs in a further 2.9% of BC patients. In conclusion, panel testing yields more accurate genetic information for appropriate counselling, risk management, and preventive options than assessing BRCA1/2 alone.

Breast cancer genomes from CHEK2 c.1100delC mutation carriers lack somatic TP53 mutations and display a unique structural variant size distribution profile

BackgroundCHEK2 c.1100delC was the first moderate-risk breast cancer (BC) susceptibility allele discovered. Despite several genomic, transcriptomic and functional studies, however, it is still unclear how exactly CHEK2 c.1100delC promotes tumorigenesis. Since the mutational landscape of a tumor reflects the processes that have operated on its development, the aim of this study was to uncover the somatic genomic landscape of CHEK2-associated BC.MethodsWe sequenced primary BC (pBC) and normal genomes of 20 CHEK2 c.1100delC mutation carriers as well as their pBC transcriptomes. Including pre-existing cohorts, we exhaustively compared CHEK2 pBC genomes to those from BRCA1/2 mutation carriers, those that displayed homologous recombination deficiency (HRD) and ER− and ER+ pBCs, totaling to 574 pBC genomes. Findings were validated in 517 metastatic BC genomes subdivided into the same subgroups. Transcriptome data from 168 ER+ pBCs were used to derive a TP53-mutant gene expression signature and perform cluster analysis with CHEK2 BC transcriptomes. Finally, clinical outcome of CHEK2 c.1100delC carriers was compared with BC patients displaying somatic TP53 mutations in two well-described retrospective cohorts totaling to 942 independent pBC cases.ResultsBC genomes from CHEK2 mutation carriers were most similar to ER+ BC genomes and least similar to those of BRCA1/2 mutation carriers in terms of tumor mutational burden as well as mutational signatures. Moreover, CHEK2 BC genomes did not show any evidence of HRD. Somatic TP53 mutation frequency and the size distribution of structural variants (SVs), however, were different compared to ER+ BC. Interestingly, BC genomes with bi-allelic CHEK2 inactivation lacked somatic TP53 mutations and transcriptomic analysis indicated a shared biology with TP53 mutant BC. Moreover, CHEK2 BC genomes had an increased frequency of > 1 Mb deletions, inversions and tandem duplications with peaks at specific sizes. The high chromothripsis frequency among CHEK2 BC genomes appeared, however, not associated with this unique SV size distribution profile.ConclusionsCHEK2 BC genomes are most similar to ER+ BC genomes, but display unique features that may further unravel CHEK2-driven tumorigenesis. Increased insight into this mechanism could explain the shorter survival of CHEK2 mutation carriers that is likely driven by intrinsic tumor aggressiveness rather than endocrine resistance.

Awareness of symptoms, anticipated barriers and delays to help-seeking among women at higher risk of breast cancer: A UK multicentre study

Women with a family history of breast cancer have an increased lifetime risk of the disease. Delay in symptom presentation can lead to poorer outcomes. Low awareness of breast cancer symptoms and help-seeking barriers have been associated with delay in presentation in the general population. Symptom awareness and help-seeking barriers among women at increased risk of breast cancer are unknown. We conducted analysis of survey data which included women with moderate and high risk of breast cancer from 20 secondary and tertiary care clinics in England (n = 408). Women completed a validated survey assessing breast cancer symptom awareness, barriers to help-seeking and anticipated delay in help-seeking. Women recognised an average of 9.1/11 breast cancer symptoms (SD = 2.1). Nipple rash was the least recognised symptom (51.0%). Women educated to at least degree level had higher awareness than those with lower education (β = 0.14, 95% CI 0.13, 0.99, p = 0.011). Women at lower socioeconomic status (SES) had lower awareness than those at higher SES (β = -0.13, 95% CI −1.09, −0.07, p = 0.027). Women reported several anticipated help-seeking barriers (mean = 4.0/11, SD = 2.8). Waiting to see if a symptom will pass was the most commonly reported barrier to help-seeking (71.5%). Most women (376/408; 92.2%) reported that they would seek medical help within 2 weeks of discovering a breast cancer symptom. Interventions to increase awareness of non-lump breast cancer symptoms and reduce help-seeking barriers are needed, with considerations of appropriate reading levels and modalities for women with lower education and SES.

FANCM missense variants and breast cancer risk: a case-control association study of 75,156 European women

Evidence from literature, including the BRIDGES study, indicates that germline protein truncating variants (PTVs) in FANCM confer moderately increased risk of ER-negative and triple-negative breast cancer (TNBC), especially for women with a family history of the disease. Association between FANCM missense variants (MVs) and breast cancer risk has been postulated. In this study, we further used the BRIDGES study to test 689 FANCM MVs for association with breast cancer risk, overall and in ER-negative and TNBC subtypes, in 39,885 cases (7566 selected for family history) and 35,271 controls of European ancestry. Sixteen common MVs were tested individually; the remaining rare 673 MVs were tested by burden analyses considering their position and pathogenicity score. We also conducted a meta-analysis of our results and those from published studies. We did not find evidence for association for any of the 16 variants individually tested. The rare MVs were significantly associated with increased risk of ER-negative breast cancer by burden analysis comparing familial cases to controls (OR = 1.48; 95% CI 1.07–2.04; P = 0.017). Higher ORs were found for the subgroup of MVs located in functional domains or predicted to be pathogenic. The meta-analysis indicated that FANCM MVs overall are associated with breast cancer risk (OR = 1.22; 95% CI 1.08–1.38; P = 0.002). Our results support the definition from previous analyses of FANCM as a moderate-risk breast cancer gene and provide evidence that FANCM MVs could be low/moderate risk factors for ER-negative and TNBC subtypes. Further genetic and functional analyses are necessary to clarify better the increased risks due to FANCM MVs.

ATM c.7570G>C is a high-risk allele for breast cancer.

ATM is generally described as a moderate-risk breast cancer susceptibility gene. However, some of ATM variants might encounter higher risk. ATM c.7570G>C, p.Ala2524Pro, (rs769142993) is a pathogenic Finnish founder variant causative for recessively inherited ataxia-telangiectasia. At cellular level, it has been reported to have a dominant-negative effect. ATM c.7570G>C has recurrently been described in Finnish breast cancer families and unselected case cohorts collected from different parts of the country, but the rarity of the allele (MAF 0.0002772 in Finns) and lack of confirming segregation analyses have prevented any conclusive risk estimates. Here, we describe seven families from genetic counseling units with ATM c.7570G>C variant showing co-segregation with breast cancer. Further analysis of the unselected breast cancer cohort from Northern Finland (n=1822), a geographical region previously indicated to have enrichment of the variant, demonstrated that c.7570G>C significantly associates with breast cancer, and the risk is estimated as high (odds ratio [OR]=8.5, 95% confidence interval [CI]=1.04-62.46, P=.018). Altogether, these results place ATM c.7570G>C variant among the high-risk alleles for breast cancer, which should be taken into consideration in genetic counseling.

Clinical applicability of the Polygenic Risk Score for breast cancer risk prediction in familial cases

BackgroundCommon low-risk variants are presently not used to guide clinical management of familial breast cancer (BC). We explored the additive impact of a 313-variant-based Polygenic Risk Score (PRS313) relative to...

Invited Commentary: Learning about Breast Cancer Outcomes in Asian Women to Close the Health Equity Gap.

Invited Commentary: Learning about Breast Cancer Outcomes in Asian Women to Close the Health Equity Gap.

Characterization of genetic predisposition to molecular subtypes of breast cancer in Brazilian patients.

Introduction BRCA1 and BRCA2 germline pathogenic variants (GPVs) account for most of the 5-10% of breast cancer (BC) that is attributable to inherited genetic variants. BRCA1 GPVs are associated with the triple negative subtype, whereas BRCA2 GPVs are likely to result in higher grade, estrogen-receptor positive BCs. The contribution of other genes of high and moderate risk for BC has not been well defined and risk estimates to specific BC subtypes is lacking, especially for an admixed population like Brazilian.ObjectiveThe aim of this study is to evaluate the value of a multigene panel in detecting germline mutations in cancer-predisposing genes for Brazilian BC patients and its relation with molecular subtypes and the predominant molecular ancestry.Patients and methodsA total of 321 unrelated BC patients who fulfilled NCCN criteria for BRCA1/2 testing between 2016-2018 were investigated with a 94-genes panel. Molecular subtypes were retrieved from medical records and ancestry-specific variants were obtained from off-target reads obtained from the sequencing data.ResultsWe detected 83 GPVs in 81 patients (positivity rate of 25.2%). Among GPVs, 47% (39/83) were identified in high-risk BC genes (BRCA1/2, PALB2 and TP53) and 18% (15/83) in moderate-penetrance genes (ATM, CHEK2 and RAD51C). The remainder of the GPVs (35% - 29/83), were identified in lower-risk genes. As for the molecular subtypes, triple negative BC had a mutation frequency of 31.6% (25/79), with predominance in BRCA1 (12.6%; 10/79). Among the luminal subtypes, except Luminal B HER2-positive, 18.7% (29/155) had GPV with BRCA1/2 genes contributing 7.1% (11/155) and non-BRCA1/2 genes, 12.9% (20/155). For Luminal B HER2-positive subtype, 40% (16/40) had GPVs, with a predominance of ATM gene (15% - 6/40) and BRCA2 with only 2.5% (1/40). Finally, HER2-enriched subtype presented a mutation rate of 30.8% (4/13) with contribution of BRCA2 of 7.5% (1/13) and non-BRCA1/2 of 23% (3/13). Variants of uncertain significance (VUS) were identified in 77.6% (249/321) of the patients and the number of VUS was increased in patients with Asian and Native American ancestry.ConclusionThe multigene panel contributed to identify GPVs in genes other than BRCA1/2, increasing the positivity of the genetic test from 9.6% (BRCA1/2) to 25.2% and, considering only the most clinically relevant BC predisposing genes, to 16.2%. These results indicate that women with clinical criteria for hereditary BC may benefit from a multigene panel testing, as it allows identifying GPVs in genes that directly impact the clinical management of these patients and family members.

Functions of Breast Cancer Predisposition Genes: Implications for Clinical Management.

Approximately 5–10% of all breast cancer (BC) cases are caused by germline pathogenic variants (GPVs) in various cancer predisposition genes (CPGs). The most common contributors to hereditary BC are BRCA1 and BRCA2, which are associated with hereditary breast and ovarian cancer (HBOC). ATM, BARD1, CHEK2, PALB2, RAD51C, and RAD51D have also been recognized as CPGs with a high to moderate risk of BC. Primary and secondary cancer prevention strategies have been established for HBOC patients; however, optimal preventive strategies for most hereditary BCs have not yet been established. Most BC-associated CPGs participate in DNA damage repair pathways and cell cycle checkpoint mechanisms, and function jointly in such cascades; therefore, a fundamental understanding of the disease drivers in such cascades can facilitate the accurate estimation of the genetic risk of developing BC and the selection of appropriate preventive and therapeutic strategies to manage hereditary BCs. Herein, we review the functions of key BC-associated CPGs and strategies for the clinical management in individuals harboring the GPVs of such genes.

Apparent regional differences in the spectrum of BARD1 pathogenic variants in Spanish population and importance of copy number variants

Only up to 25% of the cases in which there is a familial aggregation of breast and/or ovarian cancer are explained by germline mutations in the well-known BRCA1 and BRCA2 high-risk genes. Recently, the BRCA1-associated ring domain (BARD1), that partners BRCA1 in DNA repair, has been confirmed as a moderate-risk breast cancer susceptibility gene. Taking advantage of next-generation sequencing techniques, and with the purpose of defining the whole spectrum of possible pathogenic variants (PVs) in this gene, here we have performed a comprehensive mutational analysis of BARD1 in a cohort of 1946 Spanish patients who fulfilled criteria to be tested for germline pathogenic mutations in BRCA1 and BRCA2. We identified 22 different rare germline variants, being 5 of them clearly pathogenic or likely pathogenic large deletions, which account for 0.26% of the patients tested. Our results show that the prevalence and spectrum of mutations in the BARD1 gene might vary between different regions of Spain and expose the relevance to test for copy number variations.

Spectrum and frequency of CHEK2 variants in breast cancer affected and general population in the Baltic states region, initial results and literature review

BackgroundWhile BRCA1/2 gene mutational spectrum and clinical features are widely studied, there is limited data on breast cancer-predisposing non-BRCA pathogenic/likely pathogenic variants (PV/LPVs) in the Baltic states region. According to previous studies, CHEK2 is the most frequent moderate-risk breast cancer predisposition gene. The study aimed to analyse the frequency and mutational spectrum of CHEK2 PV/LPVs in the Baltic states region and perform a literature review on the subject. MethodsThe study includes two cohorts - population-based Estonian biobank (EstBB) (N-152 349) and breast cancer affected cases from Latvia (N-105). In the cohort from Latvia, CHEK2, BRCA1, BRCA2, PALB2 testing with next-generation sequencing (NGS) was carried out in selected breast cancer cases. In the EstBB, the full SNP genotyped dataset Global Screening Array (GSA) (N-152 349) was used to screen CHEK2 PV/LPVs and variants c.319+2T > A (p.(?)), c.444+1G>A (p.(?)), c.433C > T (p.Arg145Trp), c.283C > T (p.Arg95*) in CHEK2 are reported from this dataset. In addition, a subset of the EstBB (N-4776) underwent whole-genome sequencing (WGS, N-2420) and whole-exome sequencing (WES, N-2356) and founder variants c.470T > C (p.Ile157Thr), c.444+1G>A (p.(?)), c.1100delC (p.Thr367Metfs*15) in CHEK2 were reported from this dataset. Moreover, a literature overview was performed on April 1, 2021, using the PubMed search of keywords ‘CHEK2’, ‘breast cancer’, ‘Estonia’, ‘Lithuania’, ‘Latvia’, ‘Poland’, ‘Belarus’ and ‘Russia’. ResultsIn the breast cancer affected cohort from Latvia 6 CHEK2 variants, classified as PV/LPVs, were observed (6/105; 5.7%), including recurrent ones c.470T > C (p.Ile157Thr) (1.9%) and del5395(ex9-10del; (p.Met304Leufs*16)) (1.9%), as well as single ones – c.1100delC (p.Thr367Metfs*15) (1%) and c.444+1G>A (p.(?)) (1%). From EstBB NGS data (N-4776) CHEK2 variant c.470T > C (p.Ile157Thr) was detected in 8.6% of cases, c.1100delC (p.Thr367Metfs*15) in 0.6% and c.444+1G>A (p.(?)) in 0.2% of cases. In the EstBB full cohort of SNP array data (N-152 349) CHEK2 variant c.444+1G>A (p.(?)) was detected in 0.02% of cases, c.319+2T > A (p.(?)) in 0.09% of cases, c.433C > T (p.Arg145Trp) in 0.02% of cases and c.283C > T (p.Arg95*) in <0.001% of cases. For the literature review altogether, 49 PubMed articles were found, 23 of which were relevant, representing CHEK2 PV/LPVs in the population of interest. Ten publications are from Poland, eight from Russia, three from Latvia and two from Belarus. ConclusionsThis study is the first combined report on complete CHEK2 PV/LPVs screening in selected breast cancer affected cases in Latvia and large-scale population screening in Estonia, providing insight into the CHEK2 mutational spectrum in the Baltic states region. The initial results are in line with other studies that CHEK2 PV/LPVs frequency is around 5–6% of selected breast cancer cases. Here we report three CHEK2 PV/LPV - c.319+2T > A (p.(?)), c.433C > T (p.Arg145Trp), c.283C > T (p.Arg95*), that are novel for the Baltic states region. This is also the first report on c.1100delC (p.Thr367Metfs*15) and c.444+1G>A (p.(?)) from the Baltic states. High population frequency of c.470T > C (p. Ile157Thr) (8.6%) continues to question the variant's pathogenicity in particular populations. Other findings are concordant with previous reports from Latvia and neighbouring populations.

Prevalence and Clinicopathological Characteristics of Moderate and High-Penetrance Genes in Non-BRCA1/2 Breast Cancer High-Risk Spanish Families.

(1) Background: Over the last decade, genetic counseling clinics have moved from single-gene sequencing to multigene panel sequencing. Multiple genes related to a moderate risk of breast cancer (BC) have emerged, although many questions remain regarding the risks and clinical features associated with these genes. (2) Methods: Ninety-six BC index cases (ICs) with high-risk features for hereditary breast and ovarian cancer (HBOC) and with a previous uninformative result for BRCA1/2 were tested with a panel of 41 genes associated with BC risk. The frequency of pathogenic variants (PVs) was related to the clinical characteristics of BC. (3) Results: We detected a PV rate of 13.5% (excluding two cases each of BRCA1 and MUTYH). Among the 95 assessed cases, 17 PVs were identified in 16 ICs, as follows: BRCA1 (n = 2), CHEK2 (n = 3), ATM (n = 5), MUTYH (n = 2), TP53 (n = 2), BRIP1 (n = 1), CASP8 (n = 1), and MSH2 (n = 1). We also identified a novel loss-of-function variant in CASP8, a candidate gene for increased BC risk. There was no evidence that the clinical characteristics of BC might be related to a higher chance of identifying a PV. (4) Conclusions: In our cohort, which was enriched with families with a high number of BC cases, a high proportion of mutations in ATM and CHEK2 were identified. The clinical characteristics of BC associated with moderate-risk genes were different from those related to BRCA1/2 genes.

CHEK2 Pathogenic Variants in Greek Breast Cancer Patients: Evidence for Strong Associations with Estrogen Receptor Positivity, Overuse of Risk-Reducing Procedures and Population Founder Effects.

Simple SummaryCHEK2 germline pathogenic variants are identified at a relatively high frequency among hereditary breast cancer cases and are known to be associated with intermediate breast cancer risk i.e., 2–2.5-fold increase, compared to the general population. Histopathological characteristics and clinical outcomes of breast cancer patients who are CHEK2 carriers have not been thoroughly investigated. We have therefore sought to determine the CHEK2 variant spectrum and identify variants with possible founder effect, while investigating the clinicopathological features and outcomes of Greek patients who were CHEK2 carriers. Three variants have been identified as Greek founders. The vast majority of CHEK2-associated breast tumors were hormone receptor positive, underlying a possible benefit from chemoprophylaxis with tamoxifen. A trend for longer survival was observed in patients that underwent mastectomy and received hormone-therapy. Nearly half of patients underwent a risk-reducing surgery, which was not mandated according to current guidelines or relevant risks associated with CHEK2.CHEK2 germline pathogenic variants predispose to breast cancer and possibly to other malignancies, with their spectrum and frequency being variable among populations. Τhe majority of CHEK2-associated breast tumors are hormone receptor positive; however, relevant clinical outcomes are not well defined. Herein, we illustrate the histopathological characteristics and clinical outcomes of 52 Greek breast cancer patients who are CHEK2 carriers. Genetic analysis was performed by Sanger/massively parallel sequencing, followed by MLPA. Subsequent haplotype analysis investigated possible founder effects. Blood relatives were offered cascade testing. CHEK2 variant spectrum was characterized by variability, while influenced by founder effects. The majority of carriers, i.e., 60.8%, were diagnosed with breast cancer before the age of 45. Notably, 91.5% of breast tumors were hormone receptor positive. Hormone therapy and mastectomy at diagnosis seem to have a positive trend on overall survival, after a median follow-up of 9.5 years. Remarkably, 41.9% of patients underwent risk-reducing surgery, one third of which involved salpingo-oophorectomy. Nearly half of families responded to cascade testing. Our data highlight the need for guideline-adherent choices, based on the evidence that CHEK2 carriers are at moderate risk for breast cancer and no risk for ovarian cancer, while underscore the possible role of chemoprevention with tamoxifen.