The inheritance of certain mutations of BRCA1 can make it much more likely that a woman will develop breast or ovarian cancer in her lifetime. In addition to inheriting a BRCA1 mutation, what else must happen for a woman to develop breast or ovarian cancer?

Verified step by step guidance

1. Understand that BRCA1 is a tumor suppressor gene, which means it helps regulate cell growth and prevent cancer by repairing DNA damage.
2. Recognize that inheriting a mutation in one copy of the BRCA1 gene (germline mutation) increases cancer risk but is not sufficient alone to cause cancer.
3. Learn about the 'two-hit hypothesis' which states that both copies of a tumor suppressor gene must be inactivated for cancer to develop.
4. Identify that the second 'hit' usually involves a somatic mutation or loss of the normal BRCA1 allele in the cells of breast or ovarian tissue.
5. Conclude that in addition to inheriting a BRCA1 mutation, a woman must acquire a second mutation or loss of function in the other BRCA1 allele in relevant cells for cancer to develop.

Key Concepts

BRCA1 Gene and Its Role in Cancer

BRCA1 is a tumor suppressor gene involved in DNA repair. Mutations in BRCA1 impair this repair function, increasing the risk of breast and ovarian cancer. However, carrying a mutation alone does not guarantee cancer development; it raises susceptibility.

Multistep Nature of Cancer Development

Cancer arises through multiple genetic and environmental changes over time. Besides inheriting a mutation like BRCA1, additional mutations or cellular changes must accumulate to trigger uncontrolled cell growth and tumor formation.

Role of Environmental and Lifestyle Factors

Environmental exposures, lifestyle choices, and hormonal factors can influence cancer risk by causing DNA damage or affecting gene expression. These factors interact with inherited mutations to increase the likelihood of cancer development.