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# Hereditary breast and ovarian cancer syndrome (BRCA1/BRCA2)

Inherited BRCA1 or BRCA2 variants that sharply raise the risk of breast and ovarian cancer, and also of [prostate](https://durgical.com/en/anatomy/prostate/) and pancreatic cancer.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Mammary gland lobes](https://durgical.com/en/anatomy/mammary-gland/)
- [Lactiferous ducts](https://durgical.com/en/anatomy/lactiferous-ducts/)
- [Ovaries](https://durgical.com/en/anatomy/ovary/)
- [Breast fat](https://durgical.com/en/anatomy/body-of-breast/)
- [Uterine tubes](https://durgical.com/en/anatomy/uterine-tube/)
- [Prostate](https://durgical.com/en/anatomy/prostate/)
- [Pancreas](https://durgical.com/en/anatomy/pancreas/)

## In biochemistry

- [DNA repair](https://durgical.com/en/biochemistry/topics/dna-repair/)
- [DNA sequencing](https://durgical.com/en/biochemistry/topics/dna-sequencing/)

## In the clinical exam

- [Past medical, surgical, family and social history](https://durgical.com/en/clinical-exam/past-medical-surgical-family-and-social-history/)
- [Clinical breast examination](https://durgical.com/en/clinical-exam/clinical-breast-examination/)

## Why it happens

- [Genomic instability: mismatch repair, BRCA and xeroderma pigmentosum](https://durgical.com/en/general-pathology/genomic-instability-mismatch-repair-brca-and-xeroderma-pigmentosum/)
- [Hereditary cancer syndromes: the table to know](https://durgical.com/en/general-pathology/hereditary-cancer-syndromes-the-table-to-know/)
- [Tumour suppressor genes: RB, TP53, APC, BRCA and the two-hit hypothesis](https://durgical.com/en/general-pathology/tumour-suppressor-genes-rb-tp53-apc-brca-and-the-two-hit-hypothesis/)
- [Molecular pathology: PCR, FISH, sequencing and liquid biopsy](https://durgical.com/en/general-pathology/molecular-pathology-pcr-fish-sequencing-and-liquid-biopsy/)

## What it is

An autosomal dominant cancer predisposition caused by germline variants in BRCA1 or BRCA2, genes of double-strand break repair by homologous recombination.

## Who gets it

BRCA variants explain a small but important share of breast cancer (about 5–10% of cases have a hereditary cause) and a larger share of high-grade serous ovarian cancer. They are more common in some founder populations (such as Ashkenazi Jewish). Founder BRCA1 and BRCA2 variants have been described in Colombia in regional studies; no population prevalence is established.

## Causes

- Inherited pathogenic variant in BRCA1 (chromosome 17) or BRCA2 (chromosome 13)
- Loss of the second copy in the tissue (two hits)
- Other homologous recombination genes with lower risk: PALB2, RAD51C, RAD51D, ATM, CHEK2

## Risk factors

- Relatives with breast cancer before 50, bilateral or in men
- Ovarian cancer in the family
- Ancestry with founder variants
- Triple-negative breast cancer at a young age

## Pathophysiology

BRCA1 helps detect and resect double-strand breaks and BRCA2 loads the RAD51 recombinase onto single-stranded DNA. Without them, the cell cannot use the sister chromatid as a template and repairs by error-prone routes (NHEJ, microhomology-mediated joining). Deletions and rearrangements build up (chromosomal instability), which favours cancer in hormone-sensitive tissues. The same defect makes them sensitive to platinum and PARP inhibitors (synthetic lethality).

## Classification

- BRCA1: more triple-negative breast cancer and ovarian cancer
- BRCA2: more hormone receptor-positive breast cancer, male breast, prostate and pancreatic cancer
- Two altered BRCA2 copies: Fanconi anaemia (group D1)

## Symptoms and signs

- No symptoms until a cancer appears
- Breast lump, [nipple](https://durgical.com/en/anatomy/nipple/) retraction or bloody discharge
- Abdominal bloating, early satiety or persistent pelvic pain ([ovary](https://durgical.com/en/anatomy/ovary/))

## Red flags

- A new breast lump or breast [skin](https://durgical.com/en/anatomy/skin/) change
- Ascites or a pelvic mass
- A breast lump in a man

## Diagnosis

**Clinical**
Suspected from personal and family history criteria; testing is offered to all patients with epithelial ovarian cancer and many with young-onset or triple-negative breast cancer.

**Tests**
Hereditary cancer gene panel by sequencing (BRCA1, BRCA2, PALB2 and others) with large-deletion analysis; CA-125 in ovarian cancer follow-up.

**Imaging**
Breast MRI and mammography for surveillance; transvaginal ultrasound when pelvic symptoms are evaluated.

## Treatment

**Follow-up**
Intensive breast surveillance: yearly MRI from a young age and mammography later, by age and gene.

**Surgical**
Risk-reducing bilateral mastectomy (optional, shared decision).

**Surgical**
Risk-reducing bilateral salpingo-oophorectomy once childbearing is complete, because ovarian cancer screening is not effective.

**Medical**
PARP inhibitors and platinum chemotherapy in BRCA-deficient tumours.

**Follow-up**
Genetic counselling and cascade testing of relatives, men included.

## Complications

- Breast cancer (often early and bilateral)
- Ovarian, fallopian tube and peritoneal cancer
- Aggressive prostate cancer (BRCA2)
- Pancreatic cancer and melanoma (BRCA2)

## Prognosis

Surveillance and risk-reducing surgery greatly lower mortality. Salpingo-oophorectomy cuts ovarian cancer risk by more than 80%.

## Prevention

- Genetic counselling before and after testing
- Risk-reducing surgery in carriers
- Surveillance by gene and age

## Test yourself

Think of the answer, then tap the question to see it.

## Which DNA repair pathway depends on BRCA1 and BRCA2?

Homologous recombination, which repairs double-strand breaks using the sister chromatid.

## Why do BRCA-deficient tumours respond to PARP inhibitors?

Without homologous recombination they rely on PARP for repair; blocking both routes kills the tumour cell (synthetic lethality).

## Which cancers are more typical in men with BRCA2 variants?

Male breast cancer, aggressive prostate cancer and pancreatic cancer.

## Why is risk-reducing salpingo-oophorectomy advised instead of ovarian screening?

Because there is no effective screening for ovarian cancer, which is usually found late.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/hereditary-breast-and-ovarian-cancer-syndrome/)

## Related conditions

- [Breast cancer](https://durgical.com/en/conditions/breast-cancer/)
- [Ovarian cancer](https://durgical.com/en/conditions/ovarian-cancer/)
- [Prostate cancer](https://durgical.com/en/conditions/prostate-cancer/)
- [Pancreatic cancer](https://durgical.com/en/conditions/pancreatic-cancer/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Breast cancer: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/breast-cancer/) (MedlinePlus, US National Library of Medicine, 2026); [Ovarian cancer: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/ovarian-cancer/) (MedlinePlus, US National Library of Medicine, 2026); [BRCA1 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/brca1/) (MedlinePlus, US National Library of Medicine, 2026); [BRCA2 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/brca2/) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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Source: https://durgical.com/en/conditions/hereditary-breast-and-ovarian-cancer-syndrome/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/hereditary-breast-and-ovarian-cancer-syndrome/