Table 6 Summary of family characteristics and pathological characteristics of breast cancers of individuals with deleterious BRCA1 and BRCA2 mutations
| Â | Overall | BRCA1 | BRCA2 | Non-BRCA |
|---|---|---|---|---|
Age of onset | 22 to 78 | 28 to 57 | 34 to 59 | 22 to 78 |
Average age of onset (years) | 41.9 | 40.3 | 43.6 | 44.2 |
Total no. of breast and ovarian cancers in family | 1 to 7 | 1 to 7 | 1 to 7 | 1 to 6 |
Average no. of breast and ovarian cancers in family | 1.9 | 2.7 | 2.6 | 1.8 |
No. of cases of breast cancer <50 | 0 to 4 | 1 to 3 | 1 to 3 | 0 to 4 |
Average no. of cases of breast cancer <50 | 1.1 | 1.6 | 1.5 | 1.0 |
% with ER-negative tumours | 48% | 100% | 40% | 45% |