1. Clinical consequences of BRCA2 hypomorphism
- Author
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Castells-Roca, Laia, Gutiérrez-Enríquez, Sara, Bonache, Sandra, Bogliolo, Massimo, Carrasco, E., Aza-Carmona, Miriam, Montalban, G., Muñoz-Subirana, N., Pujol, Roser, Cruz Zambrano, Cristina, Llop-Guevara, A., Ramírez de Haro, Ma. José, Saura, Cristina, Lasa, Adriana, Serra, V., Diez, Orland, Balmaña Gelpí, Judith, Surrallés i Calonge, Jordi, Universitat Autònoma de Barcelona, Institut Català de la Salut, [Castells-Roca L] Genome Instability and DNA repair Syndromes Group and Join Unit UAB-IR Sant Pau on Genomic Medicine, Biomedical Research Institute IIB-Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. Genetics Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. [Gutiérrez-Enríquez S, Bonache S, Carrasco E, Diez O, Balmaña J] Hereditary Cancer Genetics Group, Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain. Vall d’Hebron Hospital Universitari, Barcelona, Spain. [Bogliolo M] Genome Instability and DNA repair Syndromes Group and Join Unit UAB-IR Sant Pau on Genomic Medicine, Biomedical Research Institute IIB-Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. Genetics Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. Center for Biomedical Network Research on Rare Diseases (CIBERER) U-745, Barcelona, Spain. [Aza-Carmona M] Genome Instability and DNA repair Syndromes Group and Join Unit UAB-IR Sant Pau on Genomic Medicine, Biomedical Research Institute IIB-Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. [Montalban G] Hereditary Cancer Genetics Group, Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain. Vall d’Hebron Hospital Universitari, Barcelona, Spain. Rue McMahon, Québec city G1R 3S3 Québec, Canada. [Cruz C, Llop-Guevara A, Serra V] Experimental Therapeutics Group, Vall d’Hebron Institute of Oncology (VHIO), Vall d’Hebron Hospital Universitari, Barcelona, Spain. [Saura C] Breast Cancer and Melanoma Group, Vall d’Hebron Institute of Oncology (VHIO), Vall d’Hebron Hospital Universitari, Barcelona, Spain, and Vall d'Hebron Barcelona Hospital Campus
- Subjects
DNA damage ,Neoplasms::Neoplasms by Site::Breast Neoplasms [DISEASES] ,RAD51 ,Case Report ,Amino Acids, Peptides, and Proteins::Proteins::Fanconi Anemia Complementation Group Proteins::BRCA2 Protein [CHEMICALS AND DRUGS] ,Breast cancer ,Mama - Càncer ,Fanconi anemia ,medicine ,Missense mutation ,Pharmacology (medical) ,Radiology, Nuclear Medicine and imaging ,Allele ,skin and connective tissue diseases ,Cancer genetics ,RC254-282 ,Gens del càncer ,neoplasias::neoplasias por localización::neoplasias de la mama [ENFERMEDADES] ,business.industry ,aminoácidos, péptidos y proteínas::proteínas::proteínas de grupos de complementación de la anemia de Fanconi::proteína BRCA2 [COMPUESTOS QUÍMICOS Y DROGAS] ,Hemic and Lymphatic Diseases::Hematologic Diseases::Anemia::Anemia, Aplastic::Anemia, Hypoplastic, Congenital::Fanconi Anemia [DISEASES] ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,Cell cycle ,medicine.disease ,Oncology ,Cancer research ,business ,Ovarian cancer ,Anèmia de Fanconi ,enfermedades hematológicas y linfáticas::enfermedades hematológicas::anemia::anemia aplásica::anemia hipoplásica congénita::anemia de Fanconi [ENFERMEDADES] - Abstract
The 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.
- Published
- 2021