Hereditary Breast and Ovarian Cancer and BRCA Mutations
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Direct answer
Hereditary breast and ovarian cancer syndrome is an autosomal dominant predisposition, most often caused by germline mutations in BRCA1 or BRCA2, genes that repair DNA by homologous recombination. BRCA1 carries a higher ovarian cancer risk and a link to triple-negative breast cancer, while BRCA2 is more closely tied to male breast cancer. Carriers are offered genetic counselling, enhanced surveillance, risk-reducing surgery and PARP inhibitors for eligible cancers.
What you must remember
- Inheritance: autosomal dominant with incomplete penetrance; a germline mutation is present in every cell, and the second allele is usually lost in the tumour.
- BRCA1: located on chromosome 17q21; higher ovarian risk and association with triple-negative and high-grade serous tumours.
- BRCA2: located on chromosome 13q12; linked to male breast cancer, and to prostate and pancreatic cancer, with lower ovarian risk than BRCA1.
- Function: BRCA proteins repair double-strand breaks by homologous recombination, and loss of this repair causes genomic instability.
- Testing criteria: early-onset breast cancer, triple-negative breast cancer, ovarian cancer, male breast cancer, or a strong family history of these cancers.
- Surveillance: annual breast MRI from about 25 years, with annual mammography added from about 30 years.
- PARP inhibitors: olaparib, niraparib and rucaparib in BRCA-mutated ovarian cancer; olaparib and talazoparib in germline BRCA-mutated breast cancer.
Deciding who is tested and how carriers are followed
Testing is a family decision, not only an individual one, so the sequence begins with the pedigree. Each step below shapes the next, and counselling runs through all of them.
- Take the family history. Count affected relatives on both sides, their ages at diagnosis, and any male breast, prostate or pancreatic cancer.
- Apply the testing criteria. A strong family history or a triple-negative or early-onset cancer justifies testing, and the affected relative is usually tested first.
- Counsel before and after testing. Genetic counselling covers the meaning of results, insurance concerns and implications for relatives, who are informed with consent.
- Start surveillance. Carriers without cancer have annual breast MRI from about 25 years, with mammography added from about 30 years.
- Discuss risk-reducing surgery. Bilateral mastectomy and salpingo-oophorectomy are options after childbearing is complete, with the hormonal effects of oophorectomy explained.
- Plan treatment with PARP inhibitors. Germline status guides the choice of PARP inhibitor in eligible cancers, and it also shapes surgery and chemotherapy decisions.
Where the exam tries to catch you
Questions test whether the genetic result is read in its family context, not as a single lab value.
- Trap: BRCA testing is ordered for every breast cancer patient. Correct: testing follows criteria such as early onset, triple-negative subtype or family history, and the result changes surgery, surveillance and drug choice for relatives.
- Trap: A negative BRCA test rules out hereditary risk. Correct: other genes such as PALB2, TP53 and CHEK2 also predispose, and a negative result in an affected person does not cancel the family history.
- Trap: PARP inhibitors are used for any ovarian cancer. Correct: they work best in BRCA-mutated or homologous recombination-deficient tumours, so germline or tumour testing is needed.
Frequently asked questions
Which BRCA gene carries the higher ovarian cancer risk?
BRCA1 carries a higher lifetime ovarian cancer risk than BRCA2, and it is also linked to triple-negative breast cancer. BRCA2 is more closely linked to male breast cancer.
What are the main criteria for BRCA genetic testing?
Genetic testing for BRCA mutations is considered for early-onset breast cancer, triple-negative breast cancer, ovarian cancer, male breast cancer and a strong family history of these cancers. Testing is usually offered first to the affected family member, with genetic counselling before and after.
At what age does surveillance start for BRCA mutation carriers?
Breast surveillance for BRCA mutation carriers usually starts with annual breast MRI from about 25 years, and annual mammography is added from about 30 years. Risk-reducing salpingo-oophorectomy is discussed once childbearing is complete.
Which PARP inhibitors are used in BRCA-mutated cancers?
Olaparib, niraparib and rucaparib are used in BRCA-mutated ovarian cancer, and olaparib or talazoparib are used in germline BRCA-mutated breast cancer. They exploit synthetic lethality in tumours with defective homologous recombination repair.
Is a negative BRCA test enough to rule out hereditary cancer risk?
No. A negative BRCA test does not rule out hereditary risk, because other genes such as PALB2, TP53 and CHEK2 also predispose to breast cancer. Family history and any mutation already identified in the family still guide surveillance.