Objective: To investigate the germline mutation status of related genes in breast cancer patients and high-risk individuals by next-generation sequencing. To analyze the correlations between homologous recombination repair (HR) pathway gene mutation status and clinicopathological characteristics of breast cancer patients. To supplement the database of breast cancer related gene mutations in Chinese population. Methods: This study is a cross-sectional study. From October 2020 to September 2021, whole blood samples were collected from 350 breast cancer patients and 49 high-risk individuals, admitted to Peking University People's Hospital and accepted genetic testing voluntarily. Germline mutations in 32 breast cancer related genes were detected by NGS. The clinicopathological characteristics, including age at the onset, family history, unilateral/bilateral tumor, Luminal typing (Luminal A subtype, Luminal B subtype, HER2-enriched subtype and triple negative breast cancer), tumor size and metastasis, were analyzed, and the correlations between HR pathway gene mutation status and clinicopathological characteristics were analyzed by Chi-squared test and Fisher's exact probability test. Results: Among 350 breast cancer patients, 64 (18.3%) cases carried gene pathogenic mutations (including pathogenic and likely pathogenic mutations), including 47 (13.4%) in BRCA1/2, 16 (4.6%) in non-BRCA1/2 genes, 1 (0.3%) in BRCA2 and FANCL. Among 49 high-risk individuals, 7 (14.3%) cases carried gene pathogenic mutations, including 6 (12.3%) in BRCA1/2 and 1 (2%) in ATM genes. BRCA1/2 pathogenic mutations were associated with age at the onset (18%, 8.7%, χ²=6.346, P=0.012), and the BRCA1/2 pathogenic mutation frequency was higher in patients diagnosed at age ≤45 years. HR pathway gene mutations (including pathogenic, likely pathogenic and uncertain significance mutations) were correlated with unilateral/bilateral tumor (49.5%, 68.4%, χ²=4.841, P=0.028) and Luminal typing (45.7%, 62.2%, 32%, 60%, χ²=12.004, P=0.007), and the HR mutation frequencies were higher in patients with bilateral tumor, Luminal B breast cancer and triple negative breast cancer (TNBC). Conclusion: The BRCA1/2 pathogenic mutation frequency in high-risk individuals is similar to that in breast cancer patients, and BRCA1/2 testing is helpful to guide breast cancer screening and prevention in high-risk individuals. Patients with early onset breast cancer, bilateral breast cancer, Luminal B breast cancer and TNBC have higher mutation frequencies of HR pathway genes, and HR pathway genes testing should be conducted as soon as possible to provide laboratory evidence for diagnosis, treatment, prognosis and risk evaluation of breast cancer.
BRCA1 Protein/genetics* ; BRCA2 Protein/genetics* ; Breast Neoplasms/pathology* ; Cross-Sectional Studies ; Female ; Genetic Predisposition to Disease ; Germ-Line Mutation ; High-Throughput Nucleotide Sequencing ; Humans ; Middle Aged ; Mutation ; Recombinational DNA Repair ; Triple Negative Breast Neoplasms/pathology*

Asian Continental Ancestry Group/genetics* ; BRCA1 Protein/genetics* ; China ; Consensus ; Humans

Asian Continental Ancestry Group ; BRCA1 Protein/genetics* ; Breast Neoplasms/surgery* ; China ; Female ; Genetic Testing ; Humans ; Mastectomy

OBJECTIVE: To detect potential variant in an ethical Han Chinese pedigree affected with breast cancer. METHODS: The proband and her relatives were subjected to next-generation sequencing using a target capture sequencing kit containing 121 cancer-related genes. Candidate variants were selected by analysis of their type, frequency in population, and segregation with the phenotype. Candidate variant was verified by Sanger sequencing and TA cloning. RESULTS: A c.2013_2014ins GT variant was detected in the BRCA1 gene among all breast cancer patients from this pedigree but not among healthy females. The variant was not recorded in the 1000 Genome Project database or the Exome Aggregation Consortium (ExAC) database. The frameshifting insertion was predicted to form an premature stop codon in gene transcript and can give rise to a truncated protein. CONCLUSION The BRCA1 c.2013_2014ins GT variant probably underlies the pathogenesis of breast cancer in this Chinese pedigree.
Asian Continental Ancestry Group ; BRCA1 Protein ; genetics ; Breast Neoplasms ; genetics ; Exome ; Female ; High-Throughput Nucleotide Sequencing ; Humans ; Pedigree ; Phenotype

BRCA1 Protein ; BRCA2 Protein ; High-Throughput Nucleotide Sequencing

Breast cancer is the second most common cancer in Korean women. Germline mutations in the BRCA1 and BRCA2 genes cause hereditary breast cancer and are detected in 15–20% of hereditary breast cancer. We investigated the BRCA1 and BRCA2 mutations in 114 familial breast cancer patients using next-generation sequencing. We confirmed 20 different mutations of BRCA1 and BRCA2 in 25 subjects (21.9%). Two such mutations in eight patients were novel (not reported in any variant database or previous study). Six mutations have been reported as disease-causing mutations in public databases. Seven mutations were found only in a single nucleotide polymorphism database and one mutation has been reported in Korea. The BRCA1/2 mutation frequency was similar to that of other studies on familial breast cancer patients in the Korean population. Further studies should examine more cases and mutations of whole exons.
BRCA1 Protein ; BRCA2 Protein ; Breast Neoplasms ; Breast ; Exons ; Female ; Genes, BRCA2 ; Germ-Line Mutation ; Humans ; Korea ; Mutation Rate ; Polymorphism, Single Nucleotide

No abstract available.
Genes, Tumor Suppressor ; BRCA2 Protein ; BRCA1 Protein ; Ovarian Neoplasms ; Breast Neoplasms

PURPOSE: Unclassified variants (UVs) of BRCA1 and BRCA2 genes are not defined as pathogenic for breast cancer, and their clinical significance currently remains undefined. Therefore, this study was conducted to identify potentially pathogenic UVs by comparing their prevalence between breast cancer patients and controls. MATERIALS AND METHODS: A total of 328 breast cancer patients underwent BRCA1/2 genetic screening at the National Cancer Center of Korea. Genetic variants of BRCA genes that were categorized as unclassified according to the Breast Cancer Information Core database were selected based on allelic frequency, after which candidate variants were genotyped in 421 healthy controls. We also examined family members of the study participants. Finally, the effects of amino acid substitutions on protein structure and function were predicted in silico. RESULTS: Genetic tests revealed 33 UVs in BRCA1 and 47 in BRCA2. Among 15 candidates genotyped in healthy controls, c.5339T>C in BRCA1 and c.6029T>G, c.7522G>A in BRCA2 were not detected. Moreover, the c.5339T>C variant in the BRCA1 gene was detected in four patients with a family history of breast cancer. This nonsynonymous variant (Leu1780Pro) in the BRCA1 C-terminal domain was predicted to have an effect on BRCA1 protein structure/function. CONCLUSION: This study showed that comparison of genotype frequency between cases and controls could help identify UVs of BRCA genes that are potentially pathogenic. Moreover, ourfindings suggest that c.5339T>C in BRCA1 might be a pathogenic variant for patients and their families.
Amino Acid Substitution ; BRCA1 Protein ; Breast Neoplasms* ; Breast* ; Computer Simulation ; Genes, BRCA1 ; Genes, BRCA2* ; Genetic Testing ; Genotype ; Humans ; Korea ; Prevalence

Germline mutations in the BRCA1 and BRCA2 genes are strong genetic factors for predispositions to breast, ovarian, and other related cancers. This report describes a family with a history of breast and ovarian cancers that harbored a novel BRCA1 germline mutation. A single nucleotide deletion in intron 20, namely c.5332+4delA, was detected in a 43-year-old patient with breast cancer. This mutation led to the skipping of exon 20, which in turn resulted in the production of a truncated BRCA1 protein that was 1773 amino acids in length. The mother of the proband had died due to ovarian cancer and had harbored the same germline mutation. Ectopically expressed mutant BRCA1 protein interacted with the BARD1 protein, but showed a reduced transcriptional function, as demonstrated by the expression of cyclin B1. This novel germline mutation in the BRCA1 gene caused familial breast and ovarian cancers.
Adult ; Amino Acids ; BRCA1 Protein ; Breast Neoplasms* ; Breast* ; Cyclin B1 ; Exons* ; Genes, BRCA1 ; Genes, BRCA2 ; Germ-Line Mutation* ; Humans ; Introns ; Mothers ; Ovarian Neoplasms

OBJECTIVETo investigate the knowledge and willingness of breast cancers patients from Shanghai for genetic counseling and gene testing.

METHODSA total of 428 patients filled out the questionnaire and the data was statistically analyzed.

RESULTSMost of the patients were unaware of genetic counseling and gene testing. But after a brief introduction, a majority of them were willing to accept genetic counseling and recommend their family members to participate. The willingness was education- and age-related. When told that gene testing may benefit themselves, 92.1% of the patients were willing to be tested. However, when told that gene testing may only benefit their family, only 33.9% of the patients were willing to join the testing. The acceptance was also age-, education- and family income-related. The difference was statistically significant. Moreover, the willingness ratio to participate the gene testing was lower than expected. Overall, 74.1% of the patients were willing to accept cheaper preliminary gene screening, whilst only 19.2% were willing to accept genetic testing of higher price. Despite of being told that testing results will be maintained as confidential, still 43.2% worried about adverse effects. Such patients tended to younger, from low-income families, with a family history of associated cancers, or personal history of other cancers. The difference was statistically significant.

CONCLUSIONThe majorities of patients do not know but are willing to accept genetic counseling and gene testing and recommend their family to participate. Lack of genetic knowledge, cost for the testing and concerns about discrimination are the obstacles for patients to participate in genetic counseling and gene testing. To spread the knowledge about breast cancer and establish a follow-up screening system for high-risk population may improve the tertiary prevention for breast cancer.

Adult ; Aged ; Asian Continental Ancestry Group ; genetics ; statistics & numerical data ; BRCA1 Protein ; genetics ; BRCA2 Protein ; genetics ; Breast Neoplasms ; diagnosis ; ethnology ; genetics ; Chi-Square Distribution ; China ; Educational Status ; Female ; Genetic Counseling ; Genetic Predisposition to Disease ; genetics ; Genetic Testing ; Health Knowledge, Attitudes, Practice ; Humans ; Middle Aged ; Social Class