Breast cancer susceptibility gene, BRCA2, is a tumor suppressor and individuals who inherit one defected copy of BRCA2 allele experience early onset breast cancer or ovarian cancer accompanied by the loss of the wild type allele. Mouse model for Brca2 mutation shows growth retardation and paradoxical occurrence of thymic lymphomas. Thymic lymphomas from Brca2-mutant mice harbor mutations in p53, Bub1, and BubR1, which function as mitotic checkpoint proteins. Therefore, interplay between Brca2 and mitotic checkpoint has been suggested in the maintenance of genetic fidelity, although it has not been assessed whether the unique mutations in Bub1 and BubR1 found in Brca2-mutant mice are responsible for the abolishment of mitotic checkpoint function. This report demonstrates that Bub1 and BubR1 mutant proteins from Brca2(-/-)thymic lymphomas have defects in the phosphorylation and kinetochore localization after spindle damage. Thus, the mutations of Bub1 and BubR1 found in Brca2- mutant mice indeed are responsible for the chromosome instability in Brca2-mutated tumors.
Animals ; BRCA2 Protein/*genetics/*metabolism ; Cell Cycle Proteins ; Cell Transformation, Neoplastic/metabolism ; Mice ; *Mitosis ; Mutation/*genetics ; Phosphorylation ; Protein Kinases/*metabolism ; Protein Transport ; Support, Non-U.S. Gov't ; T-Lymphocytes/metabolism ; Thymus Neoplasms/genetics/*pathology

OBJECTIVETo detect the mutations of BRCA1 and BRCA2 in sporadic breast cancer and study the relationship between BRCA1 and BRCA2 mutations and breast cancer.

METHODSBreast cancer tissues of 144 patients and breast tissues of 30 cases of healthy people who were treated from December 2000 to September 2005 were studied. DNA was extracted by the phenol-chloroform method. Fragments of exon 2, exon 3, exon 5, exon 6, exon 7, exon 8, exon 9, exon 10, exon 11, exon 12, exon 13, exon 14, exon 15, exon 16, exon 17, exon 18, exon 19, exon 20, exon 21, exon 22, exon 23 and exon 24 in the BRCA1 gene and exon 10 and exon 14 in the BRCA2 gene were amplified by polymerase chain reaction. Mutation screening was performed by single-strand conformation polymorphism analysis and alterations were confirmed by DNA sequencing.

RESULTSA total of 20 single nucleotide changes in BRCA1 were detected in the 144 cases of breast cancer patients. The total mutation rate was 13.9% and missense mutation rate was 11.1%. No mutation was detected in the BRCA2 and controls.

CONCLUSIONSMutations in BRCA1 may play an important role in evaluation of sick risk, earlier diagnosis and gene therapy of breast cancer in southern Chinese populations.

Adult ; Aged ; Apoptosis Regulatory Proteins ; BRCA1 Protein ; genetics ; metabolism ; BRCA2 Protein ; genetics ; metabolism ; Base Sequence ; Blotting, Western ; Breast Neoplasms ; genetics ; metabolism ; pathology ; DNA Mutational Analysis ; Female ; Humans ; Middle Aged ; Mutation ; Polymerase Chain Reaction ; Polymorphism, Single-Stranded Conformational

Age of Onset ; Cystadenocarcinoma, Serous ; genetics ; metabolism ; pathology ; Female ; Genes, BRCA1 ; Genes, BRCA2 ; Humans ; Immunohistochemistry ; Neoplasm Staging ; Ovarian Neoplasms ; genetics ; metabolism ; pathology ; Receptors, Progesterone ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo identify molecular markers of lung squamous cell carcinoma by cDNA microarray technique.

METHODScDNA expression profiles were examined by microarrays of 6 surgical specimens of stage I lung squamous cell carcinomas. Those genes, either up-regulated or down-regulated in every specimen studied, were identified. The expression levels of nm23 and BRCA2 by the squamous cell carcinoma of the lung were further examined by immunohistochemical techniques.

RESULTSA total of 107 genes were identified, of which 26 were up-regulated and 81 were down-regulated in all six specimens. Immunohistochemical staining showed that, compared with normal lung tissues, the intensity of nm23 expression by the squamous cell carcinoma of lung was significantly increased while that of BRCA-2 was decreased.

CONCLUSIONcDNA microarrays can be used to identify gene expression profile of lung cancer, some of which may be used as markers of lung squamous cell carcinoma.

BRCA2 Protein ; metabolism ; Biomarkers, Tumor ; Carcinoma, Squamous Cell ; genetics ; metabolism ; Gene Expression Profiling ; Humans ; Lung Neoplasms ; genetics ; metabolism ; Male ; NM23 Nucleoside Diphosphate Kinases ; Nucleoside-Diphosphate Kinase ; metabolism ; Oligonucleotide Array Sequence Analysis

Breast cancer is one of the leading causes of death in women today. Some of the patients are hereditary, with a large proportion characterized by mutation in BRCA1 and/or BRCA2 genes. In this review, we provide an overview of these two genes, focusing on their relationship with hereditary breast cancers. BRCA1/2 associated hereditary breast cancers have unique features that differ from the general breast cancers, including alterations in cellular molecules, pathological bases, biological behavior, and a different prevention strategy. But the outcome of BRCA1/2 associated hereditary breast cancers still remains controversial; further studies are needed to elucidate the nature of BRCA1/2 associated hereditary breast cancers.
Apoptosis Regulatory Proteins ; BRCA1 Protein ; genetics ; physiology ; BRCA2 Protein ; genetics ; physiology ; Breast Neoplasms ; genetics ; metabolism ; Disease Progression ; Female ; Gene Expression Regulation, Neoplastic ; Genetic Diseases, Inborn ; Genetic Predisposition to Disease ; Humans ; Mutation ; Prognosis

Alterations of genes are known to be critical for the induction of tumorigenesis, but the mechanism of ovarian carcinogenesis is little understood and remains to be elucidated. In this study, we investigated the roles of brca1, brca2 and p53 genes in the development of ovarian cancer using conditional knockout mice generated by a Cre-loxP recombinant system. Following the application of recombinant adenovirus expressing Cre in vitro, the proliferation of ovarian surface epithelium (OSE) was increased. For instance, a significant increase in cell growth was observed in OSE cells in vitro by conditional knockout isolated from the mice bearing concurrent floxed copies of brca1 and brca2/p53. However, the proliferative effect of the ovarian cells was not observed in concurrent brca1/brca2 or p53 knockout mice in vivo, indicating that we could not observe the direct evidence of the involvement of brca1, brca2, and p53 in ovarian carcinogenesis. Since morphological changes including tumor formation were not observed in mice bearing floxed copies of concurrent brca1/brca2 or p53, the inactivation of brca1/2 or p53 is not sufficient for the induction of tumor formation. Taken together, these results suggest that the deficiency of these genes may not be involved directly in the mechanism of ovarian carcinogenesis.
Animals ; BRCA1 Protein/*genetics/metabolism ; BRCA2 Protein/*genetics/metabolism ; Cell Proliferation ; Cell Transformation, Neoplastic/*genetics ; Epithelium/*pathology ; Extracellular Matrix Proteins/genetics ; Female ; Gene Silencing ; Mice ; Mice, Knockout ; Ovarian Neoplasms/*genetics ; Protein-Lysine 6-Oxidase/genetics ; Tumor Cells, Cultured ; Tumor Suppressor Protein p53/*genetics/metabolism

OBJECTIVETo investigate the effect of PARP1 inhibitor PJ34 on multi-drug resistance in a human multiple myeloma cell line and its connection with FA/BRCA pathway in DNA damage repair.

METHODSA CCK8 assay was used to measure the inhibition rate. Real-time quantitative PCR was used to detect expression changes of DNA repair genes involved in the FA/BRCA pathway. Western blotting assay was used to detect expression of key protein FANCD2 in the FA/BRCA pathway. Annexin VFITC/PI double staining flow cytometry was used to measure cell apoptosis induced by PJ34. A COMET assay was used to detect the effect of PJ34 on DNA damage repair.

RESULTSPJ34 could significantly enhance the sensitivity of RPMI8226/R cells to melphalan. The IC50 value of melphalan was dropped from 20.43 mol/L to 7.8 mol/L. PJ34 could inhibit the DNA damage repair, and the effect was related with the inhibition of FA/BRCA pathway. PJ34 and melphalan showed a synergistic effect in promoting the apoptosis of RPMI8226/R cells.

CONCLUSIONPJ34 can reverse the resistance of RPMI8226/R cells to melphalan by inhibiting the FA/BRCA pathway, which in turn can induce suppression of DNA damage repair. Therefore, PJ34 may have clinical value in overcoming the multi-drug resistance of multiple myeloma.

Antineoplastic Agents ; pharmacology ; BRCA2 Protein ; genetics ; metabolism ; Cell Line, Tumor ; Drug Resistance, Neoplasm ; Fanconi Anemia Complementation Group D2 Protein ; genetics ; metabolism ; Humans ; Multiple Myeloma ; drug therapy ; enzymology ; genetics ; metabolism ; Phenanthrenes ; pharmacology ; Poly (ADP-Ribose) Polymerase-1 ; Poly(ADP-ribose) Polymerase Inhibitors ; Poly(ADP-ribose) Polymerases ; genetics ; metabolism

Germ-line mutations in BRCA2 predispose to early-onset cancer. Homozygous mutant mouse, which has Brca2 truncated in exon 11 exhibit paradoxic occurrence of growth retardation and development of thymic lymphomas. However, due to its large embryonic lethality, cohort studies on the thymic lymphomas were not feasible. With the aid of Cre-loxP system, we demonstrate here that thymus-specific disruption of Brca2 allele without crossing it to p53-mutant background leads to the development of thymic lymphomas. Varying from 16 weeks to 66 weeks after birth, 25% of mice disrupted of Brca2 in the thymus died of thymic lymphomas, whereas previous report did not observe lymphomagenesis using similar Cre-loxP system. Future analysis of thymic lymphomas from these mice presented here will provide information on the cooperative mutations that are required for the BRCA2-associated pathogenesis of cancer.
Animals ; BRCA2 Protein/deficiency/*genetics ; CD4-CD8 Ratio ; Cell Separation ; Flow Cytometry ; Integrases/*genetics/immunology ; Lymphoma/*genetics/immunology/metabolism/pathology ; Mice ; Mice, Knockout ; Organ Specificity ; *Sequence Deletion ; T-Lymphocytes/enzymology/*immunology ; Thymus Gland/immunology/metabolism/pathology ; Thymus Neoplasms/*genetics/immunology/metabolism/pathology ; Tumor Suppressor Protein p53/deficiency/genetics/immunology

OBJECTIVETo investigate the expression of a novel metastasis-inducing protein human anterior gradient-2 (AGR2) in breast cancer and its clinical and prognostic significance.

METHODSAGR2 expression was assessed in 160 cases of breast cancer and 20 cases of benign breast diseases by immunohistochemistry using tissue chip technology. In addition the expression of ERa, PR and c-erbB-2 in breast cancer was also evaluated. Follow-up information of 5-year duration was available in 127 patients with breast cancer. Kaplan-Meier analysis and COX regression model were used to analyze the correlation between AGR2 expression and the follow-up clinical data.

RESULTSThe expression of AGR2 was significantly higher in breast cancers than that in benign diseases (68.3% vs. 25.0% , P < 0.01). There was a negative correlation between AGR2 expression and the histological grade of breast cancer (P <0.05) , whereas positive correlations was found between the expression of AGR2 and ERalpha (P <0.05), and between the expression of AGR2 and PR (P <0.01). In the subgroup of ERalpha-positive breast cancer, Logistic regression model demonstrated AGR2 and TNM stage were important factors affecting lymph node metastasis (both P < 0.01). Kaplan-Meier analysis demonstrated that a positive expression of AGR2 was associated with poor overall survival and relapse-free survival (both P <0.01). Moreover, COX regression model confirmed the expression of AGR2 as an independent prognostic factor among patients with ERa-positive breast cancer (P <0.01).

CONCLUSIONSThe abnormal expression of AGR2 may play a role in the pathogenesis and progression of breast cancer. The metastasis-inducing capability of AGR2 may be partly regulated through the ER pathway. Therefore, AGR2 may be a useful molecular marker for prognostication for patient with hormone-responsive breast cancer.

Antineoplastic Agents, Hormonal ; analysis ; BRCA2 Protein ; genetics ; metabolism ; Biomarkers, Tumor ; analysis ; Breast Neoplasms ; diagnosis ; genetics ; metabolism ; Estrogen Receptor alpha ; metabolism ; Female ; Gene Expression Regulation, Neoplastic ; genetics ; Humans ; Immunohistochemistry ; Neoplasm Metastasis ; diagnosis ; Neoplasm Staging ; Prognosis ; Proteins ; genetics ; metabolism ; Receptor, ErbB-2 ; analysis ; metabolism

OBJECTIVETo investigate the possible relationship between defects in the FA/BRCA pathway of genomic stability and potential pathogenesis of T and B cell lymphoma.

METHODSNineteen cell lines derived from diverse subtypes of lymphoma for possible FA pathway defects were screened.

RESULTSNo defect in FANCD2 ubiquitination was observed. However, the FANCN protein was absent in cell lines HT and Sudhl4. This absence was correlated with enhanced MMC-induced G2 arrest, growth inhibition and high chromosomal breakage rate in both cell lines. In addition, in exon-5a of FANCN gene, a mutation of c.1769 C>T, p. A590V was found in cell line HT, but not in cell line Sudhl4.

CONCLUSIONThis mutation may be the reason causing the absence of the FANCN protein expression or making the protein unstable and losing its function.

Animals ; Antibiotics, Antineoplastic ; pharmacology ; BRCA2 Protein ; metabolism ; Base Sequence ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Chromosome Breakage ; drug effects ; Fanconi Anemia ; metabolism ; Fanconi Anemia Complementation Group D2 Protein ; metabolism ; Fanconi Anemia Complementation Group N Protein ; Gene Expression Regulation, Neoplastic ; Genomic Instability ; Humans ; Lymphoma ; genetics ; pathology ; Mitomycin ; pharmacology ; Molecular Sequence Data ; Mutation ; Nuclear Proteins ; chemistry ; deficiency ; genetics ; metabolism ; Protein Stability ; Sequence Analysis, DNA ; Signal Transduction ; Tumor Suppressor Proteins ; chemistry ; deficiency ; genetics ; metabolism