BRCA1 Protein ; BRCA2 Protein ; High-Throughput Nucleotide Sequencing

OBJECTIVETo study BRCA1 gene expression in sporadic breast cancer in Han nationality and its relations to clinical pathological parameters.

METHODSImmunohistochemical method was used to detect the BRCA1 protein in paraffin embedded breast cancer tissue of 51 patients. The relationship between BRCA1 protein and clinical pathological features was analysed.

RESULTSBRCA1 protein was located in the nuclear of breast cancer cells. The rate of its down regulation of expression was 49.0% (25/51), which correlated reversely with c-erbB-2 protein, but did not correlate with histological grading, tumor size, lymph node involvement and patient age.

CONCLUSIONThe detection of BRCA1 protein expression may be a reflection of its gene alteration. So it may be a primary method for screening the susceptibility to breast cancer.

Adult ; Aged ; BRCA1 Protein ; analysis ; Breast Neoplasms ; genetics ; pathology ; Female ; Genes, BRCA1 ; Humans ; Immunohistochemistry ; Middle Aged

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

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

Breast cancer susceptibility gene 1(BRCA1) plays an important role in breast cancer development and progression. BRCA1 encodes a 1863-amino acid protein with two BRCA1 C-terminal (BRCT) domains at its C-terminus, BRCT1 and BRCT2. Many cancer-predisposing mutations are located in the BRCT domains, which have been shown to induce chromatin unfolding by use of an approach that allows visualization of large-scale chromatin structure through lac repressor/lac operator recognition. To map the important region of BRCT domain (amino acid residues 1642-1736), six deletion mutant constructs were made. The chromatin structure assay showed that amino acid residues 1691-1721 are involved in the induction of chromatin unfolding. To further localize the critical amino acid residues, ten alanine scanning mutant constructs were made. The chromatin structure assay demonstrated that the 1707IAGGK1711 region is critical for the chromatin unfolding activity. Based on the mapped important region, Blast analysis identified a novel homologous protein. Mapping of the BRCT1 domain may aid in the presymptomatic risk assessment and provide a valuable tool for further study on the BRCT1 structure and function.
BRCA1 Protein ; chemistry ; physiology ; Base Sequence ; Chromatin ; chemistry ; Cloning, Molecular ; Female ; Genes, BRCA1 ; Humans ; Molecular Sequence Data ; Mutation ; Protein Folding ; Structure-Activity Relationship

PURPOSE: To study the subcellular localization with flow-cytometry and to evaluate their prognostic values. MATERIALS AND METHODS: The breast tissues were obtained from 28 patients with breast cancer and 6 patients with benign mass. The expression of BRCA1 protein was analyzed with the flow cytometry(Coulter Epics-XL, Coulter Corps, FL, USA) using the monoclonal antibody(BRCA1(Ab-1), Calbiochem, MA, USA) before and after nuclear and cytoplasmic permeabilization in association with DNA ploidy analysis. Several BRCA1 protein indices were derived including 95 percentile channel fluorescence(95% CF) and mean channel fluorescence(MCF) and percentage of BRCA 1 positive cell population arbitarily defined as those above 0.12 channel fluorescence. RESULTS: Cytoplasmic 95% CF were higher in breast cancer(n=28, 0.65+/-0.26) than in benign mass(n=6, 0.40+/-0.13, p=0.0211). Cytoplasmic BRCAl positive cell percentages were significantly higher in malignant tissues(24.0+/-10.3) than in benign mass(43.4+/-15.2, p=0.0059). Cytoplasmic BRCA1 positive cell percentages were significantly different according to the stages(stage I vs II, 32.6+/-9.8 vs 48.3+/-18.8, p=0.048, stage I vs stage III, 32.6+/-9.8 vs 47.0+/-10.9, p=0.010). The BRCA1 protein indices were not significantly correlated with histologic grades and DNA indices(aneuploidy, S phase and proliferation fractions). CONCLUSIONS: Flowcytometric assay offers an alternative approach to evaluating BRCA1 protein status of breast cancer tissue and detection of cytoplasmic BRCA1 protein by this method may help to understand the role of BRCA1 in breast cancer cell biology. The further study on cytoplasmic or nuclear BRCA1 protein in association with clinical therapeutic response or prognosis seems to be warranted.
BRCA1 Protein* ; Breast Neoplasms* ; Breast* ; Cytoplasm ; DNA ; Flow Cytometry ; Fluorescence ; Humans ; Ploidies ; Prognosis ; S Phase

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

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

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

PURPOSE: To understand the involvement of BRCA1 gene in Korean breast and/or ovarian cancer families. MATERIALS AND METHODS: Germline mutations of BRCA1 gene were analyzed in 13 families which included 3 hereditary site-specific breast cancer families, 6 suspected breast cancer families, and 3 suspected breast-ovarian cancer family, and one Li-Fraumeni family by screening BRCA1 gene using single strand conformation polymorphism (SSCP) analysis on polymerase chain reaction (PCR) amplified genomic DNA and confirmed the results by sequencing. RESULTS: Including one family with previously reported nonsense mutation of BRCA1 gene, we detected two mutations in unrelated families. One newly identified mutation was frame shift mutation resulting from TG deletion in codon 1701, which results in a truncated BRCA1 protein, at codon 1714. CONCLUSION: The proportion of families who inherit the mutated BRCA1 gene seems to be small among Korean breast and/or ovarian cancer families.
BRCA1 Protein ; Breast Neoplasms ; Breast* ; Codon ; Codon, Nonsense ; DNA ; Frameshift Mutation ; Genes, BRCA1* ; Germ-Line Mutation* ; Humans ; Mass Screening ; Ovarian Neoplasms* ; Polymerase Chain Reaction