Clinical consequences of BRCA2 hypomorphism

AbstractThe tumor suppressor FANCD1/BRCA2 is crucial for DNA homologous recombination repair (HRR). BRCA2 biallelic pathogenic variants result in a severe form of Fanconi anemia (FA) syndrome, whereas monoallelic pathogenic variants cause mainly hereditary breast and ovarian cancer predisposition. For decades, the co-occurrence in trans with a clearly pathogenic variant led to assume that the other allele was benign. However, here we show a patient with biallelic BRCA2 (c.1813dup and c.7796 A > G) diagnosed at age 33 with FA after a hypertoxic reaction to chemotherapy during breast cancer treatment. After DNA damage, patient cells displayed intermediate chromosome fragility, reduced survival, cell cycle defects, and significantly decreased RAD51 foci formation. With a newly developed cell-based flow cytometric assay, we measured single BRCA2 allele contributions to HRR, and found that expression of the missense allele in a BRCA2 KO cellular background partially recovered HRR activity. Our data suggest that a hypomorphic BRCA2 allele retaining 37–54% of normal HRR function can prevent FA clinical phenotype, but not the early onset of breast cancer and severe hypersensitivity to chemotherapy.

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An ultrasensitive tumor enriched flow-cytometric assay for detection of isolated tumor cells in bone marrow of patients with breast cancer

The American Journal of Surgery ◽

10.1016/s0002-9610(02)01015-2 ◽

2002 ◽

Vol 184 (5) ◽

pp. 414-417 ◽

Cited By ~ 14

Author(s):

Neslihan Cabioglu ◽

Abdullah Igci ◽

Engin O Yildirim ◽

Esin Aktas ◽

Sema Bilgic ◽

...

Keyword(s):

Breast Cancer ◽

Bone Marrow ◽

Tumor Cells ◽

Isolated Tumor Cells ◽

Flow Cytometric Assay ◽

Flow Cytometric

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Flow Cytometric Assay of c-erbB-2 Protein in Fine Needle Aspirates of Fresh and Frozen Human Breast Cancer Tissues

Breast Cancer ◽

10.1007/bf02966971 ◽

1996 ◽

Vol 3 (2) ◽

pp. 111-117 ◽

Cited By ~ 1

Author(s):

Hiroji Iwata ◽

Shunzo Kobayashi ◽

Hirotaka Iwase ◽

Yukashi Itoh ◽

Tatsuya Kuzushima ◽

...

Keyword(s):

Breast Cancer ◽

Human Breast Cancer ◽

Human Breast ◽

Flow Cytometric Assay ◽

Fine Needle ◽

Fine Needle Aspirates ◽

Flow Cytometric ◽

Cancer Tissues

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Apoptotic Effects of Melittin on 4T1 Breast Cancer Cell Line is associated with Up Regulation of Mfn1 and Drp1 mRNA Expression

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200211091451 ◽

2020 ◽

Vol 20 (7) ◽

pp. 790-799 ◽

Cited By ~ 2

Author(s):

Farnaz D. Moghaddam ◽

Pejman Mortazavi ◽

Somayeh Hamedi ◽

Mohammad Nabiuni ◽

Nasim H. Roodbari

Keyword(s):

Breast Cancer ◽

Mrna Expression ◽

Hemolytic Activity ◽

Breast Cancer Cells ◽

Flow Cytometric Analysis ◽

Control Group ◽

Flow Cytometric ◽

4T1 Cells ◽

4T1 Breast Cancer ◽

Apoptotic Effects

Background and Purpose: Melittin, as the main ingredient of honeybee venom, that has shown anticancer properties. The present study aimed at investigating the cytotoxic impacts of melittin on 4T1 breast cancer cells. Methods: Hemolytic activity of different concentrations (0.125, 0.25, 0.5, 1, 2, 4, 8μg/ml) of melittin was assayed and then cytotoxicity of selected concentrations of melittin (2, 4, 8, 16, 32, and 64μg/ml), 2 and 4μg/ml of cisplatin and 0.513, 0.295 and 0.123μg/ml of doxorubicin was evaluated on 4T1 cells using MTT assay. We used Morphological evaluation and flow cytometric analysis was used. Real time PCR was also used to determine mRNA expression of Mfn1 and Drp1 genes. Results: All compounds showed anti-proliferative effects on the tumor cell line with different potencies. Melittin had higher cytotoxicity against 4T1 breast cancer cells (IC50= 32μg/ml-72h) and higher hemolytic activity (HD50= 1μg/ml), as compared to cisplatin and doxorubicin. Mellitin at 16 and 32μg/ml showed apoptotic effects on 4T1 cells according to the flow cytometric analysis. The Real time PCR analysis of Drp1 and Mfn1 expression in cells treated with 16μg/ml of melittin revealed an up-regulation in Drp1 and Mfn1 genes mRNA expression in comparison with control group. Treatment with 32μg/ml of melittin was also associated with a rise in mRNA expression of Drp1 and Mfn1 as compared to the control group. Conclusion: The results of this study showed that melittin has anticancer effects on 4T1 cell lines in a dose and time dependent manner and can be a good candidate for further research on breast cancer treatment.

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A comparison between flow cytometric assessment of S-phase fraction and Nottingham histologic grade as prognostic instruments in breast cancer

Breast Cancer Research and Treatment ◽

10.1023/a:1006494625644 ◽

2000 ◽

Vol 63 (1) ◽

pp. 11-15 ◽

Cited By ~ 5

Author(s):

Marie Sundquist ◽

Sten Thorstenson ◽

Lars Brudin ◽

Olle Stål ◽

Bo Nordenskjöld

Keyword(s):

Breast Cancer ◽

S Phase ◽

Histologic Grade ◽

Phase Fraction ◽

Flow Cytometric

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Investigation of monogenic causes of familial breast cancer: data from the BEACCON case-control study

npj Breast Cancer ◽

10.1038/s41523-021-00279-9 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Na Li ◽

Belle W. X. Lim ◽

Ella R. Thompson ◽

Simone McInerny ◽

Magnus Zethoven ◽

...

Keyword(s):

Breast Cancer ◽

High Risk ◽

Candidate Genes ◽

Familial Aggregation ◽

Loss Of Function ◽

Cancer Data ◽

Pathogenic Variants ◽

New Genes ◽

Predisposing Genes ◽

Predisposition Genes

AbstractBreast cancer (BC) has a significant heritable component but the genetic contribution remains unresolved in the majority of high-risk BC families. This study aims to investigate the monogenic causes underlying the familial aggregation of BC beyond BRCA1 and BRCA2, including the identification of new predisposing genes. A total of 11,511 non-BRCA familial BC cases and population-matched cancer-free female controls in the BEACCON study were investigated in two sequencing phases: 1303 candidate genes in up to 3892 cases and controls, followed by validation of 145 shortlisted genes in an additional 7619 subjects. The coding regions and exon–intron boundaries of all candidate genes and 14 previously proposed BC genes were sequenced using custom designed sequencing panels. Pedigree and pathology data were analysed to identify genotype-specific associations. The contribution of ATM, PALB2 and CHEK2 to BC predisposition was confirmed, but not RAD50 and NBN. An overall excess of loss-of-function (LoF) (OR 1.27, p = 9.05 × 10−9) and missense (OR 1.27, p = 3.96 × 10−73) variants was observed in the cases for the 145 candidate genes. Leading candidates harbored LoF variants with observed ORs of 2–4 and individually accounted for no more than 0.79% of the cases. New genes proposed by this study include NTHL1, WRN, PARP2, CTH and CDK9. The new candidate BC predisposition genes identified in BEACCON indicate that much of the remaining genetic causes of high-risk BC families are due to genes in which pathogenic variants are both very rare and convey only low to moderate risk.

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Analysis of Italian BRCA1/2 Pathogenic Variants Identifies a Private Spectrum in the Population from the Bergamo Province in Northern Italy

Cancers ◽

10.3390/cancers13030532 ◽

2021 ◽

Vol 13 (3) ◽

pp. 532

Author(s):

Gisella Figlioli ◽

Arcangela De Nicolo ◽

Irene Catucci ◽

Siranoush Manoukian ◽

Bernard Peissel ◽

...

Keyword(s):

Breast Cancer ◽

Breast Cancer Risk ◽

Cancer Risk ◽

Disease Risk ◽

Northern Italy ◽

Genetic Isolate ◽

National Population ◽

Pathogenic Variants ◽

High Breast Cancer Risk

Germline pathogenic variants (PVs) in the BRCA1 or BRCA2 genes cause high breast cancer risk. Recurrent or founder PVs have been described worldwide including some in the Bergamo province in Northern Italy. The aim of this study was to compare the BRCA1/2 PV spectra of the Bergamo and of the general Italian populations. We retrospectively identified at five Italian centers 1019 BRCA1/2 PVs carrier individuals affected with breast cancer and representative of the heterogeneous national population. Each individual was assigned to the Bergamo or non-Bergamo cohort based on self-reported birthplace. Our data indicate that the Bergamo BRCA1/2 PV spectrum shows less heterogeneity with fewer different variants and an average higher frequency compared to that of the rest of Italy. Consistently, four PVs explained about 60% of all carriers. The majority of the Bergamo PVs originated locally with only two PVs clearly imported. The Bergamo BRCA1/2 PV spectrum appears to be private. Hence, the Bergamo population would be ideal to study the disease risk associated with local PVs in breast cancer and other disease-causing genes. Finally, our data suggest that the Bergamo population is a genetic isolate and further analyses are warranted to prove this notion.

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Multi-Gene Testing Overview with a Clinical Perspective in Metastatic Triple-Negative Breast Cancer

International Journal of Molecular Sciences ◽

10.3390/ijms22137154 ◽

2021 ◽

Vol 22 (13) ◽

pp. 7154

Author(s):

Martina Dameri ◽

Lorenzo Ferrando ◽

Gabriella Cirmena ◽

Claudio Vernieri ◽

Giancarlo Pruneri ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative Breast Cancer ◽

Triple Negative ◽

Checkpoint Inhibitors ◽

Gene Testing ◽

Repair Deficiency ◽

Targeted Treatments ◽

Recombination Repair ◽

Tumor Mutational Burden ◽

Next Generation Sequencing Ngs

Next-generation sequencing (NGS) is the technology of choice for the routine screening of tumor samples in clinical practice. In this setting, the targeted sequencing of a restricted number of clinically relevant genes represents the most practical option when looking for genetic variants associated with cancer, as well as for the choice of targeted treatments. In this review, we analyze available NGS platforms and clinical applications of multi-gene testing in breast cancer, with a focus on metastatic triple-negative breast cancer (mTNBC). We make an overview of the clinical utility of multi-gene testing in mTNBC, and then, as immunotherapy is emerging as a possible targeted therapy for mTNBC, we also briefly report on the results of the latest clinical trials involving immune checkpoint inhibitors (ICIs) and TNBC, where NGS could play a role for the potential predictive utility of homologous recombination repair deficiency (HRD) and tumor mutational burden (TMB).

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High likelihood of actionable pathogenic variant detection in breast cancer genes in women with very early onset breast cancer

Journal of Medical Genetics ◽

10.1136/jmedgenet-2020-107347 ◽

2021 ◽

pp. jmedgenet-2020-107347

Author(s):

D Gareth Evans ◽

Elke Maria van Veen ◽

Helen J Byers ◽

Sarah J Evans ◽

George J Burghel ◽

...

Keyword(s):

Breast Cancer ◽

Early Onset ◽

Ductal Carcinoma ◽

Cancer Genes ◽

Early Onset Breast Cancer ◽

Younger Women ◽

Pathogenic Variants ◽

Younger Age ◽

Predisposition Genes

BackgroundWhile the likelihood of identifying constitutional breast cancer-associated BRCA1, BRCA2 and TP53 pathogenic variants (PVs) increases with earlier diagnosis age, little is known about the correlation with age at diagnosis in other predisposition genes. Here, we assessed the contribution of known breast cancer-associated genes to very early onset disease.MethodsSequencing of BRCA1, BRCA2, TP53 and CHEK2 c.1100delC was undertaken in women with breast cancer diagnosed ≤30 years. Those testing negative were screened for PVs in a minimum of eight additional breast cancer-associated genes. Rates of PVs were compared with cases ≤30 years from the Prospective study of Outcomes in Sporadic vs Hereditary breast cancer (POSH) study.ResultsTesting 379 women with breast cancer aged ≤30 years identified 75 PVs (19.7%) in BRCA1, 35 (9.2%) in BRCA2, 22 (5.8%) in TP53 and 2 (0.5%) CHEK2 c.1100delC. Extended screening of 184 PV negative women only identified eight additional actionable PVs. BRCA1/2 PVs were more common in women aged 26–30 years than in younger women (p=0.0083) although the younger age group had rates more similar to those in the POSH cohort. Out of 26 women with ductal carcinoma in situ (DCIS) alone, most were high-grade and 11/26 (42.3%) had a PV (TP53=6, BRCA2=2, BRCA1=2, PALB2=1). This PV yield is similar to the 61 (48.8%) BRCA1/2 PVs identified in 125 women with triple-negative breast cancer. The POSH cohort specifically excluded pure DCIS which may explain lower TP53 PV rates in this group (1.7%).ConclusionThe rates of BRCA1, BRCA2 and TP53 PVs are high in very early onset breast cancer, with limited benefit from testing of additional breast cancer-associated genes.

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Extended gene panel testing in lobular breast cancer

Familial Cancer ◽

10.1007/s10689-021-00241-5 ◽

2021 ◽

Author(s):

Elke M. van Veen ◽

D. Gareth Evans ◽

Elaine F. Harkness ◽

Helen J. Byers ◽

Jamie M. Ellingford ◽

...

Keyword(s):

Breast Cancer ◽

Genetic Testing ◽

Detection Rate ◽

Gene Panel ◽

Lobular Breast Cancer ◽

Germline Variants ◽

Panel Testing ◽

Pathogenic Variants ◽

Gene Panel Testing ◽

Increased Risk

AbstractPurpose: Lobular breast cancer (LBC) accounts for ~ 15% of breast cancer. Here, we studied the frequency of pathogenic germline variants (PGVs) in an extended panel of genes in women affected with LBC. Methods: 302 women with LBC and 1567 without breast cancer were tested for BRCA1/2 PGVs. A subset of 134 LBC affected women who tested negative for BRCA1/2 PGVs underwent extended screening, including: ATM, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51D, and TP53.Results: 35 PGVs were identified in the group with LBC, of which 22 were in BRCA1/2. Ten actionable PGVs were identified in additional genes (ATM(4), CDH1(1), CHEK2(1), PALB2(2) and TP53(2)). Overall, PGVs in three genes conferred a significant increased risk for LBC. Odds ratios (ORs) were: BRCA1: OR = 13.17 (95%CI 2.83–66.38; P = 0.0017), BRCA2: OR = 10.33 (95%CI 4.58–23.95; P < 0.0001); and ATM: OR = 8.01 (95%CI 2.52–29.92; P = 0.0053). We did not detect an increased risk of LBC for PALB2, CDH1 or CHEK2. Conclusion: The overall PGV detection rate was 11.59%, with similar rates of BRCA1/2 (7.28%) PGVs as for other actionable PGVs (7.46%), indicating a benefit for extended panel genetic testing in LBC. We also report a previously unrecognised association of pathogenic variants in ATM with LBC.

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Current gene panels account for nearly all homologous recombination repair-associated multiple-case breast cancer families

npj Breast Cancer ◽

10.1038/s41523-021-00315-8 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Thibaut S. Matis ◽

Nadia Zayed ◽

Bouchra Labraki ◽

Manon de Ladurantaye ◽

Théophane A. Matis ◽

...

Keyword(s):

Breast Cancer ◽

Homologous Recombination ◽

Large Fraction ◽

Homologous Recombination Repair ◽

Mutational Signatures ◽

Recombination Repair ◽

Multiple Case ◽

Gene Panels ◽

Tumor Dna

AbstractIt was hypothesized that variants in underexplored homologous recombination repair (HR) genes could explain unsolved multiple-case breast cancer (BC) families. We investigated HR deficiency (HRD)-associated mutational signatures and second hits in tumor DNA from familial BC cases. No candidates genes were associated with HRD in 38 probands previously tested negative with gene panels. We conclude it is unlikely that unknown HRD-associated genes explain a large fraction of unsolved familial BC.

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