Table 2. Estimated relative risks (RR) for breast cancer of the same histologic subgroup, and for breast cancer of any histology in first-degree relatives (FDR) of proband breast cancer cases by histologic subgroup.

CI: 95% confidence interval; Exp: expected; Obs: observed

		Same histology subgroup				Any breast cancer histology
Subgroup	#FDRs	Obs	Exp	P value	RR (CI)	Obs	Exp	P value	RR (CI)
Breast cancer	190,576	--	--	--	--	5,846	3,308.2	<0.001	1.77 (1.72,1.81)
Angiosarcoma	96	0	0			6	2.3	0.03	2.59 (1.13, 5.63)
Apocrine	436	0	0.02			20	7.84	0.0002	2.55 (1.56, 3.94)
Inflammatory	1493	0	0.2			42	26.4	0.0046	1.59 (1.14, 2.15)
Lobular	14,097	48	18.2	<0.001	2.64 (1.95, 3.50)	551	248.4	<0.001	2.22 (2.04, 2.41)
Mucinous	5,056	6	2.2	0.025	2.73 (1.19, 5.95)	168	90.4	<0.001	1.86 (1.59, 2.16)
Phyllodes	251	0	0.01			5	3.97	0.61	1.26 (0.41, 2.94)
Tubular	1264	0	0.15			47	23.6	1.8e-5	2.00 (1.47, 2.65)
Medullary	3,058	0	0.79			102	54.1	<0.001	1.88 (1.54, 2.29)
Metaplastic	313	0	0.01			9	5.43	0.099	1.66 (0.76, 3.15)