Table 1.

Baseline characteristics of study participants in the training and validation set

Variable	Training set		Validation set		P
	No.	%	No.	%
Control group count	24		44
Age, years
≤50	13	54.17	25	56.82	0.833
>50	11	45.83	19	43.18
Menstruation
Pre-menopause	13	54.17	25	56.82	0.833
Post-menopause	11	45.83	19	43.18
Breast cancer group count	24		58
Age, years
≤50	13	54.17	27	46.55	0.53
>50	11	45.83	31	53.45
Menstruation
Pre-menopause	13	54.17	29	50	0.731
Post-menopause	11	45.83	29	50
Histologic tumor size (cm)
≤2	9	37.5	23	39.66	0.711
2–5	12	50	31	53.45
>5	3	12.5	4	6.89
Lymph nodes
Positive	16	66.67	30	51.72	0.215
Negative	8	33.33	28	48.28
Estrogen receptors
Positive	14	58.33	29	50	0.492
Negative	10	41.67	29	50
Progestogen receptors
Positive	14	58.33	29	50	0.492
Negative	10	41.67	29	50
HER2 status
Positive	12	50	24	41.38	0.474
Negative	12	50	34	58.62
Ki67 labeling index
≤14	1	4.17	6	10.34	0.362
>14	23	95.83	52	89.66
Histological grade
1	0	0	0	0	0.097
2	8	33.33	31	53.45
3	16	66.67	27	46.55