| Study, year | Patients (N) | Outcomes |
| D’Avanzo, 1995 [17] | 103 | -Study design: a case-control study of 21 MBC cases and 82 controls admitted to the hospital for acute, non-neoplastic, non-hormone related disease -A history of BC in female relatives resulted in an MBC OR of 8.5 (95% CI: 1.1 - 69.0) |
| Haraldsson, 1998 [1] | 34 | -Study design: analysis of germline mutations in 34 MBC patients -1 (14%) out of 7 BRCA2 mutation carriers had a positive family history of BC -13% of cases overall had a positive family history of BC |
| Ewertz, 2001 [23] | 624 | -Study design: population-based case-control study of 156 cases and 468 controls -Increased risk of MBC associated with BC family history (OR = 3.3; 95% CI: 2.0 - 5.6) |
| Johnson, 2002 [25] | 1986 | -Study design: analysis of risk factors in a population-based case-control study of 81 newly diagnosed, histologically confirmed MBC cases and 1905 male controls -Increased breast cancer risk seen in men with a mother or sister with BC (adjusted OR = 3.65, 95% CI: 1.62 - 8.19) |
| Brinton, 2008 [16] | 324,920 | -Study design: prospective National Institutes of Health-AARP Diet and Health Study, of 324,920 men, among whom 121 developed breast cancer. -Men with a first-degree relative with BC had an increased risk of breast cancer (RR = 1.92, 95% CI: 1.19 - 3.09) |