Familial cancer syndromes - BRCA1 and 2
Description
- Hereditary breast and ovarian cancer syndrome - AD, high-penetrance tumour suppressor genes
- BRCA1 chr 17q21; BRCA2 chr 13q12
Lifetime cancer risk to age 80
| BRCA1 | BRCA2 | Population | |
|---|---|---|---|
| Breast (female) | ~65-72% | ~45-69% | ~12% |
| Contralateral breast @20 yr | ~40% | ~26% | |
| Ovarian/tubal/peritoneal | ~44% | ~17% | ~1.5% |
| Male breast | ~1% | ~7% | 0.1% |
| Prostate | modest inc | inc, aggressive | |
| Pancreas | small inc | ~3-5% | |
| Melanoma | - | small inc |
Tumour phenotype - the discriminator
- BRCA1 -> triple-negative (ER-/PR-/HER2-), high grade, basal-like, younger, medullary features
- BRCA2 -> resembles sporadic: ER-positive, HER2-negative, luminal
- Ovarian: high-grade serous in both
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