Normal Breast-Cancer Gene Keeps Cancer at Bay by Blocking DNA Replication
The protein encoded by the tumour-suppressor gene BRCA1 may keep breast and ovarian cancer in check by preventing transcription of repetitive DNA sequences, says a study published today in Nature . This explanation brings together many disparate theories about how the gene functions and could also shed light on how other tumour suppressors work.Since the discovery in the mid-1990s that defects in BRCA1 strongly predispose women to breast and ovarian cancer, researchers have suggested numerous ways in which the protein might stop cells from becoming cancerous. Some have focused on its ability to repair DNA damage, whereas others have studied how it regulates cell-cycle checkpoints, transcription or cell proliferation. But until now, no unifying theory of how these different functions might prevent breast and ovarian cancer has emerged....