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Molecular genetics of breast cancer progression
1Department of Pathology, University Hospital of Iceland, Reykjavik, Iceland.
Abstract:
Somatic changes in the genome of breast cancer cells include amplifications, deletions and gene mutations. Several chromosome regions harboring known oncogenes are found amplified in breast tumors. Despite the high number of chromosome regions deleted in breast tumors the functional relationship to known genes at these locations and cancer growth is mainly undiscovered. Mutations in two tumor suppressor genes (TSG) have been described in a subset of breast carcinomas. These TSG are the TP53, encoding the p53 transcription factor, and the CDH1, encoding the cadherin cell adhesion molecule. Breast tumors of patients with a germ-line mutation in the BRCA1 or BRCA2 gene have an increase of additional genetic defects compared with sporadic breast tumors. This higher frequency of genetic aberrations could pinpoint genes that selectively promote tumor progression in individuals predisposed to breast cancer due to BRCA1 or BRCA2 germ-line mutations. Accumulation of somatic genetic changes during tumor progression may follow a specific and more aggressive pathway of chromosome damage in these individuals. Although the sequence of molecular events in the progression of breast tumor is poorly understood the detected genetic alterations fit the model of multistep carcinogenesis in both sporadic and hereditary breast cancer. This review will focus on the genetic lesions within the breast cancer cell.
Insights
This review examines genetic alterations in breast cancer cells, including amplifications, deletions, and mutations in tumor suppressor genes like TP53 and CDH1. It highlights increased genetic defects in BRCA1/BRCA2 mutation carriers, suggesting specific pathways in hereditary breast cancer progression.
Area of Science:
- Genetics
- Oncology
- Molecular Biology
Background:
- Breast cancer involves somatic genomic changes like amplifications, deletions, and mutations.
- Tumor suppressor genes TP53 and CDH1 are mutated in some breast carcinomas.
- Hereditary breast cancer linked to BRCA1/BRCA2 mutations shows more genetic defects than sporadic tumors.
Purpose of the Study:
- To review genetic lesions within breast cancer cells.
- To explore the relationship between deleted chromosome regions and cancer growth.
- To understand genetic aberration patterns in hereditary versus sporadic breast cancer.
Main Methods:
- Review of existing literature on breast cancer genomics.
- Analysis of somatic genetic alterations (amplifications, deletions, mutations).
- Comparison of genetic defects in sporadic and hereditary (BRCA1/BRCA2) breast tumors.
Main Results:
- Amplifications of oncogene-harboring regions are common in breast tumors.
- Functional roles of many deleted regions in breast tumors remain unclear.
- Germline BRCA1/BRCA2 mutations correlate with increased somatic genetic aberrations.
Conclusions:
- Genetic alterations in breast cancer cells align with multistep carcinogenesis models.
- Hereditary breast cancer may involve distinct, potentially more aggressive, chromosomal damage pathways.
- Further research is needed to elucidate the functional impact of genetic lesions in breast cancer progression.