Table 1.

Clinical characteristics of the patients and tumor samples used in study.

Characteristic	Both Sets		Discovery Set		Validation Set		p-value
	n	%	n	%	n	%
Number of Tumors	198		84	42	114	58
Age	192		84		108		0.02
<50 yrs	81	42	43	51	38	35
≥50 yrs	111	58	41	49	70	65
Missing	6		0		6
Race	194		80		114		0.10
Caucasian	187	96	75	94	112	98
Asian/Pacific Islander	7	4	5	6	2	2
Missing	4		4		0
Menopausal status	167		71		96		0.24
Premenopausal	62	37	31	44	31	32
Menopausal	11	7	3	4	8	8
Postmenopausal	94	56	37	52	57	59
Missing	31		13		18
Body mass index	166		65		101		0.65
Underweight (< 18.5)	3	2	2	3	1	1
Normal (18.5-24.9)	46	28	17	26	29	29
Overweight (25-29.9)	61	37	26	40	35	35
Obese (≥30)	56	33	20	31	36	35
Missing	32		19		13
Tumor size	195		83		112		0.01
<2 cm	35	18	10	12	25	22
2-5 cm	139	71	60	72	79	71
>5 cm	12	6	10	12	2	2
Any size with direct extension	9	5	3	4	6	5
Cannot be assessed	3		1		2
Positive lymph nodes	150		66		84		0.14
0	74	49	29	44	45	54
1-3	49	33	28	42	21	25
4-9	17	11	6	9	11	13
>10	10	7	3	5	7	8
Unknown	48		18		30
Metastases	146		64		82		0.86
No metastases	144	99	63	98	81	99
Metastases found	2	1	1	2	1	1
Unknown	52		20		32
Histology	198		84		114
Infiltrating ductal carcinoma (IDC)	188	95	82	98	106	93	0.41
Infiltrative lobular carcinoma (ILC)	1	0.5	0	0	1	1
Adenocarcinoma/carcinoma, not otherwise specified	7	3.5	2	2	5	4
Medullary carcinoma	2	1	0	0	2	2