Table 1.
The frequencies of BRCA1 and BRCA2 mutationsa in high-risk breast cancer patients according to familial and personal risk factors (N = 478)
| Risk category | Total | BRCA1 mutation | BRCA2 mutation | BRCA1/2 mutation |
|---|---|---|---|---|
| N (%d) | N (%e) | N (%e) | N (%e) | |
| Family history | ||||
| Breast cancer family only (without ovarian cancer)§ | 303 (63.4) | 14 (4.6) | 29 (9.6) | 43 (14.2) |
| 1 breast cancer family | 253 (52.9) | 11 (4.4) | 17 (6.7) | 28 (11.1) |
| 2 ≤breast cancer families*,§ | 50 (10.5) | 3 (6.0) | 12 (24.0) | 15 (30.0) |
| Breast cancer families in 1st degree relativesb | 217 (45.4) | 13 (6.0) | 20 (9.2) | 33 (15.2) |
| Breast cancer families in second/third degree relativesb,§ | 86 (18.0) | 1 (1.2) | 9 (10.5) | 10 (11.6) |
| Ovarian cancer familyb | ||||
| Without breast cancer§ | 29 (6.1) | 6 (20.7) | 0 (0.0) | 6 (20.7) |
| With breast cancer* | 13 (2.7) | 4 (30.8) | 2 (15.4) | 6 (46.2) |
| Any of breast/ovarian cancer familiesc,* | 345 (72.2) | 24 (7.0) | 31 (9.0) | 55 (15.9) |
| No family history* | 133 (27.8) | 6 (4.5) | 2 (1.5) | 8 (6.0) |
| Personal history | ||||
| Early-onset breast cancer (age < 40) | 199 (41.6) | 12 (6.0) | 11 (5.5) | 23 (11.6) |
| Bilateral breast cancer | 47 (9.8) | 2 (4.3) | 5 (10.6) | 7 (14.9) |
| Multiple organ cancersf | 27 (5.6) | 0 (0.0) | 2 (7.4) | 2 (7.4) |
| Both breast and ovarian cancer* | 6 (1.3) | 3 (50.0) | 1 (16.7) | 4 (66.7) |
| Male breast cancer | 4 (0.8) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Clinicopathological factor | ||||
| Age at diagnosis | ||||
| <40 | 186 (38.9) | 12 (6.5) | 11 (6.8) | 23 (14.3) |
| 40–49 | 172 (36.0) | 10 (5.8) | 15 (8.7) | 25 (14.5) |
| 50–59 | 89 (18.6) | 7 (7.9) | 6 (6.7) | 13 (14.6) |
| 60–79 | 31 (6.5) | 1 (3.3) | 1 (3.3) | 2 (6.5) |
| Stage* | ||||
| 0 | 55 (11.5) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| I | 173 (36.2) | 12 (6.9) | 12 (6.9) | 24 (13.9) |
| II | 159 (33.3) | 12 (7.6) | 18 (11.3) | 30 (18.9) |
| III+ | 88 (18.4) | 5 (7.4) | 2 (2.9) | 7 (10.3) |
| Unknown | 3 (0.6) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Hormone receptor status*,§ | ||||
| ER+ & PR+ | 307 (64.2) | 5 (1.6) | 25 (8.1) | 20 (9.8) |
| ER+ & PR− | 44 (9.2) | 1 (2.3) | 4 (9.1) | 5 (11.4) |
| ER− & PR+ | 7 (1.5) | 1 (14.3) | 0 (0.0) | 1 (14.3) |
| ER− & PR− | 115 (24.1) | 23 (20.0) | 4 (3.5) | 27 (23.5) |
| Unknown | 5 (1.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Subtype according to hormone receptor and HER2 status*,§ | ||||
| HR+ & HER2− | 252 (52.7) | 6 (2.4) | 19 (7.5) | 25 (9.9) |
| HR− & HER2+ | 28 (5.9) | 1 (3.6) | 0 (0.0) | 1 (3.6) |
| HR+ & HER2+ | 37 (7.7) | 0 (0.0) | 2 (5.4) | 2 (5.4) |
| Triple-negative | 76 (15.9) | 19 (25.0) | 3 (4.0) | 22 (29.0) |
| Unclassifiable | 85 (17.8) | 4 (4.7) | 9 (10.6) | 13 (15.3) |
| Total | 478 (100.0) | 30 (6.3) | 33 (6.9) | 63 (13.2) |
HR hormone receptor, HER2 human epidermal growth factor receptor 2
* P value <0.05 for BRCA1/2 mutation prevalence between those included in each category and those not
§ P value <0.05 between BRCA1 and BRCA2 ratio in carriers
aIncluding three patients with large genomic rearrangements in BRCA1 gene
bAmong 42 patients who had family history of ovarian cancer, 40 had one family member with ovarian cancer history and 2 had two family members with ovarian cancer history
cClosest degree of relatives with breast cancer
dPercent among all subjects (column percent)
ePercent among subjects with each risk category (row percent)
fMultiple organ cancer was defined as breast cancer patients with other primary organ cancer except ovarian cancer