Table 5. Univariate analysis of disease-free survival.

Variable	p-value*
Entire group
T stage (1 vs. 2–3)	0.054
N stage (0 vs. 1–3)	0.009
Histologic grade (I–II vs. III)	0.357
Lymphovascular invasion (absent vs. present)	0.043
p53 overexpression (absent vs. present)	0.517
Ki-67 index ( < 20% vs. ≥ 20%)	0.202
Hormone receptor (negative vs. positive)	0.944
HER2 (negative vs. positive)	0.394
Subtype (LA vs. LB vs. HER2+ vs. TN)	0.549
Adjuvant chemotherapy (not received vs. received)	0.526
Adjuvant radiotherapy (not received vs. received)	0.242
Adjuvant hormone therapy (not received vs. received)	0.843
miR-222 expression level (low vs. high)	0.117
Hormone receptor-positive subgroup
T stage (1 vs. 2–3)	0.037
N stage (0 vs. 1–3)	0.138
Histologic grade (I–II vs. III)	0.357
Lymphovascular invasion (absent vs. present)	0.213
p53 overexpression (absent vs. present)	0.168
Ki-67 index ( < 20% vs. ≥ 20%)	0.159
HER2 (negative vs. positive)	0.467
Subtype (LA vs. LB)	0.173
Adjuvant chemotherapy (not received vs. received)	0.632
Adjuvant radiotherapy (not received vs. received)	0.320
miR-222 expression level (low vs. high)	0.021

HER2=human epidermal growth factor receptor 2; LA=luminal A; LB=luminal B; TN=triple-negative; miR-222=microRNA-222.

^*p-values were calculated by the log-rank test.