Table 5. Family history and breast cancer subtypes further stratified by DNA ploidy.

		Diploid & near-diploid			Aneuploid
	N of	ER−&PR−			ER−&PR−
	ER+/PR+ tumors1	N1	OR (95% CI)2	P 2	N1	OR (95% CI)2	P 2
Family history
No	413	21	1.00		86	1.00
Yes	91	11	2.17 (0.99–4.74)	0.053	23	1.23 (0.73–2.08)	0.43
Among <50 years old
Family history
No	98	3	1.00		16	1.00
Yes	40	7	5.87 (1.43–24.06)	0.014	14	2.21 (0.97–5.00)	0.058

¹Subjects with missing information of ER, PR, or family history were removed from analyses.

²Results were estimated from case-only logistic regressions with adjustment for age at diagnosis.