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Age and Geographical Distribution in Families with BRCA1/BRCA2 Mutations in the Slovak Republic.

ABSTRACT: Molecular diagnostics of hereditary breast and/or ovarian cancer is mainly based on detection of BRCA1 and BRCA2 germline mutations in suspected families. The aim of the study was to determine the frequency, age and geographical distribution in 130 Slovak hereditary breast and ovarian cancer (HBOC) families diagnosed within the years 2000-2004. Mutation screening was performed by single-strand conformation polymorphism (SSCP), heteroduplex analysis (HDA) and sequencing of PCR products showing an abnormal migration pattern. Twenty of 130 (15.6%) HBOC suspected families were found to carry mutations in BRCA1 or BRCA2 genes. The glossary data from the National Cancer Registry of Slovakia (NCRS) were compared with the results from HBOC suspected kindreds. Age distribution of breast cancer onset in our study group showed the highest proportion of onset in HBC families within the 5th decade of life, while NCRS reports at least a ten year later onset. These findings confirmed that cases of breast cancer under 50 years of age can be used as one of the principal criteria to assign a family as a hereditary breast and/or ovarian cancer kindred. In contrast with unselected ovarian cancer cases, about 75% of all HOC index cases were diagnosed between 40 and 49 years of age. To study the geographical distribution of hereditary breast and/or ovarian cancer, Slovakia was divided into three parts. The distribution of HBOC suspected families approximately follows this division, with an increasing number in the western area of the country.

SUBMITTER: Ciernikova S

PROVIDER: S-EPMC3401926 | biostudies-literature | 2006 Dec

REPOSITORIES: biostudies-literature

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Age and Geographical Distribution in Families with BRCA1/BRCA2 Mutations in the Slovak Republic.

Ciernikova Sona S Tomka Miroslav M Kovac Michal M Stevurkova Viola V Zajac Vladimir V

Hereditary cancer in clinical practice 20061215 1

Molecular diagnostics of hereditary breast and/or ovarian cancer is mainly based on detection of BRCA1 and BRCA2 germline mutations in suspected families. The aim of the study was to determine the frequency, age and geographical distribution in 130 Slovak hereditary breast and ovarian cancer (HBOC) families diagnosed within the years 2000-2004. Mutation screening was performed by single-strand conformation polymorphism (SSCP), heteroduplex analysis (HDA) and sequencing of PCR products showing an ...[more]

PMID: 20223009

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Project description:BackgroundGermline mutations in the adenomatous polyposis gene (APC) result in familial adenomatous polyposis (FAP). FAP is an autosomal dominantly inherited disorder predisposing to colorectal cancer. Typical FAP is characterized by hundreds to thousands of colorectal adenomatous polyps and by several extracolonic manifestations. An attenuated form of polyposis (AFAP) is characterized by less than 100 adenomas and later onset of the disease.MethodsHere, we analyzed the APC gene for germline mutations in 59 Czech and 15 Slovak FAP patients. In addition, 50 apparently APC mutation negative Czech probands and 3 probands of Slovak origin were screened for large deletions encompassing the APC gene. Mutation screening was performed using denaturing gradient gel electrophoresis and/or protein truncation test. DNA fragments showing an aberrant electrophoretic banding pattern were sequenced. Screening for large deletions was performed by multiplex ligation dependent probe amplification. The extent of deletions was analyzed using following microsatellite markers: D5S299, D5S82, D5S134 and D5S346.ResultsIn the set of Czech and Slovak patients, we identified 46 germline mutations among 74 unrelated probands. Total mutation capture is 62,2% including large deletions. Thirty seven mutations were detected in 49 patients presenting a classical FAP phenotype (75,5%) and 9 mutations in 25 patients with attenuated FAP (36%). We report 20 novel germline APC mutations and 3 large deletions (6%) encompassing the whole-gene deletions and/or exon 14 deletion. In the patients with novel mutations, correlations of the mutation localization are discussed in context of the classical and/or attenuated phenotype of the disease.ConclusionThe results of the molecular genetic testing are used both in the establishment of the predictive diagnosis and in the clinical management of patients. In some cases this study has also shown the difficulty to classify clinically between the classical and the attenuated form of FAP according to the established criteria. Interfamilial and/or intrafamilial phenotype variability was also confirmed in some cases which did not fit well with predicted genotype-phenotype correlation. All these findings have to be taken into consideration both in the genetic counselling and in the patient care.

Project description:Approximately 25% of hereditary breast cancer cases associated with a strong familial history can be explained by mutations in BRCA1 or BRCA2 and other lower penetrance genes. The remaining high-risk families could be classified as BRCAX (non-BRCA1/2) families, in which no penetrant mutation has been found until now. Gene expression involving alternative splicing represents a well-known mechanism regulating the expression of multiple transcripts encoded by individual genes, which could be involved in cancer development. Thus using RNA-seq methodology, the analysis of transcriptome in immortalized lymphoblastoid cell lines of high-risk breast cancer individuals could reveal transcripts implicated in breast cancer susceptibility and development. RNA was extracted from immortalized lymphoblastoid cell lines of 117 women (affected and unaffected) coming from BRCA1, BRCA2 and BRCAX families. Anova analysis revealed a total of 95 transcripts corresponding to 85 different genes differentially expressed (Bonferroni corrected p-value <0.01) between those groups. Hierarchical clustering allowed distinctive subgrouping of BRCA1/2 subgroups from BRCAX individuals, without regard for the cancer status. We found enrichment for pathways in signaling cascades including mTOR and EIF2-related pathways. No transcripts were differentially expressed between BRCA1 and BRCA2 individuals, however out of 95 transcripts, 67 could discriminate BRCAX from combination of BRCA1 and BRCA2 individuals. On the other hand, 28 transcripts could discriminate affected from unaffected BRCAX individuals. These BRCAX-associated transcripts demonstrated enrichment in Telomere Extension by Telomerase and Double-Strand Break Repair by Non-Homologous End Joining mechanisms. To our knowledge, this represents the first study identifying transcripts differentially expressed in immortalized lymphoblastoid cell lines coming from the major classes of mutation-related breast cancer subgroups, namely BRCA1, BRCA2 and BRCAX. Moreover, some transcripts could discriminate affected from unaffected BRCAX individuals, which could represent potential therapeutic targets for breast cancer treatment.

Dataset Information

Age and Geographical Distribution in Families with BRCA1/BRCA2 Mutations in the Slovak Republic.

Publications

Age and Geographical Distribution in Families with BRCA1/BRCA2 Mutations in the Slovak Republic.

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