A family history of cancers other than breast may influence risk of breast cancer (BC) and associations may differ by subtype, according to a study of 3,023 African American women with estrogen receptor positive (ER+) BC, 1,497 with estrogen receptor negative (ER-) BC (including 696 triple negative cases), and 17,420 controls. Researchers found:

• First degree family history of BC was associated with 1.76-fold increased risk of ER+ BC, 1.67-fold increased risk of ER-, and 1.72-fold increased risk of triple negative BC.

• Family history of cervical cancer was associated with 2.39-fold increased risk of ER- BC, but not ER+ cancer.

• Family history of both BC and prostate cancer was associated with 3.40-fold increased risk of ER+ BC and 2.09-fold increased risk of ER- BC.

• Family history of both breast and lung cancer was associated only with 2.11-fold increased risk of ER- BC.

Citation: Bethea TN, Rosenberg L, Castro-Webb N, et al. Family history of cancer in relation to breast cancer subtypes in African American women. [Published online ahead of print December 31, 2015]. Cancer Epidemiol Biomarkers Prev. doi: 10.1158/1055-9965.EPI-15-1068.