Table 1.
Frequency of Histopathologic Characteristics of BRCA1, BRCA2, and Sporadic Tumors
| Characteristic | Sporadic Frequency (%)
|
BRCA1 Frequency (%)
|
BRCA2 Frequency (%)
|
|||
|---|---|---|---|---|---|---|
| Range Reported in Literature | Frequency Used for Weighting | Range Reported in Literature | Frequency Used for Weighting | Range Reported in Literature | Frequency Used for Weighting | |
| Breast | ||||||
| BRCA1 loss | 20-40 | 30 | 68-100 | 80 | NA | |
| BRCA2 loss | 22-50 | 30 | NA | 38-100 | 70 | |
| Medullary | 1-3 | 1.5 | 11-13 | 12 | ND | |
| Triple negative | 10-25 | 16 | 80 | 80 | ND | |
| ER negative | 13-37 | 26 | 63-90 | 83 | ND | |
| PR positive | 58-68 | 65 | 16-21 | 20 | ND | |
| HER-2 positive | 12-35 | 20 | 0-3 | 3 | 0-3 | 3 |
| HER-2 negative | 70-88 | 80 | 97-100 | 97 | 97-100 | 97 |
| ER positive/grade 1 | 27-42 | 30 | 0-2.4 | 2 | 5-17 | 7 |
| ER positive/grade 2 | 11-28 | 27 | 10-17 | 10 | 22-45 | 41 |
| ER positive/grade 3 | 9-17 | 13 | 12-28 | 13 | 28-30 | 28 |
| ER negative/grade 1 | 3-14 | 5 | 0-1 | 1 | 1-4 | 2 |
| ER negative/grade 2 | 12-13 | 13 | 9-13 | 13 | 2-17 | 5 |
| ER negative/grade 3 | 12-16 | 16 | 62-91 | 65 | 9-18 | 16 |
| Grade 1 | 18-56 | 22 | 0-9 | 2.5 | 11-22 | 17 |
| Grade 2 | 23-49 | 42 | 16-26 | 23 | 29-49 | 43 |
| Grade 3 | 21-49 | 36 | 66-100 | 71 | 38-64 | 47 |
| Ovarian | ||||||
| BRCA1 loss | 40-66 | 40 | 72-100 | 90 | NA | |
| BRCA2 loss | 30-42 | 30 | NA | 80-100 | 80 | |
| Serous | 29-47 | 34 | 40-100 | 50 | 39-100 | 60 |
| Mucinous | 11-36 | 17 | 0-3 | 2 | 0-2 | 1 |
| Endometrioid | 5-33 | 26 | NA | 0-29 | 18 | |
| Grade 1 | 10-19 | 13 | 1-3 | 2 | 0-3 | 3 |
| Grade 2 | 21-34 | 31 | 22-27 | 26 | 13-14 | 14 |
| Grade 3 | 50-55 | 54 | 72-75 | 72 | 81-87 | 87 |
| Stage I | 24 | 3-17 | 17 | 0-6 | 6 | |
| Stage II | 17 | 10-16 | 10 | 0-6 | 6 | |
| Stage III | 40 | 69-70 | 69 | 82-100 | 82 | |
| Stage IV | 19 | 3-11 | 6 | 0-7 | 5 | |
Abbreviations: NA, not applicable comparison; ND, not calculated because the literature suggests no differences from sporadic rates; ER, estrogen receptor; PR, progesterone receptor; HER-2, human epidermal growth factor receptor 2.