Table 1. Clinical characteristics of patients in the two study cohorts.

Sample type	Total no. of patients	Age mean ± S.D. (range)	Pathologic stage		No. of patients with lymph node involvement	No. of patients with metastasis	Histological grade			ER		PR
			Early*	Late**			1	2	3	Positive	Negative	Positive	Negative
Plasma samples	36	67±13.4 (38–89)	27	9	19	0	11	18	7	28	8	23	13
Triple samples	20	50±11.7 (33–77)	12	8	13	0	0	5	15	16	4	10	10

*The pathologic stage<III was considered as “Early stage”.

**The pathologic stage III and IV was considered as “Late stage”.

ER: Estrogen receptor; PR: Progesterone receptor.