Researchers Home In On Possible New Breast Cancer Gene
Breast Cancer Gene
Researchers describe a new candidate breast-cancer susceptibility gene.
The Rap80 gene is required for the normal DNA-repair function of the well-known breast cancer gene BRCA1.
Cancer-causing mutations in the BRCA1 protein cause it to fail to bind to the Rap80 protein. Consequently, BRCA1 is unable to identify DNA damage sites in the genome. When BRCA1 fails to fix DNA damage, cancer-causing mutations accumulate, spawning the development of breast and ovarian malignancies.
"With this current discovery, we have made significant new insights into the molecular mechanism by which BRCA1 recognizes sites of DNA damage that breast-cancer-causing mutated forms of BRCA1 cannot recognize," says co-senior author Roger Greenberg MD, PhD, Assistant Professor of Cancer Biology at Penn. "Now we have gained a partial understanding of the molecular basis between cancer-causing BRCA1 failures to fix DNA damage versus normal BRCA1's ability to fix DNA damage."
In this study, the researchers found Rap80 binds to the region of the BRCA1 protein that is necessary for recognizing sites of DNA damage. In the 1990s, investigators discovered that BRCA1 was involved in DNA repair by maintaining the normal number and structure of chromosomes. DNA breaks that aren't repaired can lead to cancer by increasing the rate of mutations, cancer-causing changes in the gene sequence.
More specifically, modification of proteins in the cell nucleus