Table 4.
Proportions of BRCA1 and BRCA2 mutations in 117 female breast/ovarian cancer probands, classified by number of cancer patients in the family, age at disease diagnosis, site-specific breast or breast-ovarian/ovarian cancer
| Age of proband at disease diagnosis | |||||||||
| 40 years or less | 41-50 years | 51 years or more | All ages | ||||||
| Cancer patients | BRCA1 | BRCA2 | BRCA1 | BRCA2 | BRCA1 | BRCA2 | BRCA1 | BRCA2 | |
| in family† | [% (n)] | [% (n)] | [% (n)] | [% (n)] | [% (n)] | [% (n)] | [% (n)] | [% (n)] | |
| Breast | |||||||||
| One | 4 (1/28) | 4 (1/28) | 0 (0/9)* | 0 (0/9)* | 0 (0/10)* | 0 (0/10)* | 2 (1/47)* | 2 (1/47)* | |
| Two or three | 25 (2/8) | 0 (0/8) | 0 (0/13) | 0 (0/13) | 3 (1/34) | 9 (3/34) | 5 (3/55) | 5 (3/55) | |
| Total | 8 (3/36) | 3 (1/36) | 0 (0/22) | 0 (0/22) | 2 (1/44) | 7 (3/44) | 4 (4/102) | 4 (4/102) | |
| Breast/ovary | |||||||||
| None/one | 0 (0/1) | 0 (0/1) | 0 (0/1) | 0 (0/1) | 0 (0/3) | 0 (0/3) | 0 (0/5) | 0 (0/5) | |
| None to two/ | - | - | 25 (1/4) | 0 (0/4) | 0 (0/6) | 0 (0/6) | 10 (1/10) | 0 (0/10) | |
| one or two | |||||||||
| Total | 0 (0/1) | 0 (0/1) | 20 (1/5) | 0 (0/5) | 0 (0/9) | 0 (0/9) | 7 (1/15) | 0 (0/15) | |
†Including proband; numbers of BRCA1- and BRCA2-positive cases over number of cases in each age subset are given in parentheses. *The 19 breast cancer patients with no familial clustering of breast/ovarian cancer diagnosed above age 40 years included 10 cases with bilateral breast cancer and nine patients with breast cancer associated with gastrointestinal, pancreatic or endometrial cancer (synchronous/metachronous, four cases; in a first-degree relative, five cases).