Table 2.

Univariate and multivariate analysis of the risk factors for DSS, DFI, and PFI among patients with HER2-low TCGA-EBC.

Variables	DSS				DFI				PFI
	Univariable analysis		Multivariable analysis		Univariable analysis		Multivariable analysis		Univariable analysis		Multivariable analysis
	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value
Age: ≥60 vs <60	1.20 (0.61-2.33)	0.598	—	—	1.67 (0.77-3.63)	0.194	—	—	1.89 (1.14-3.15)	0.014	2.41 (1.43-4.06)	0.001
Tumor size: T3-T4 vs T1-T2	2.23 (0.96-5.14)	0.061	—	—	1.945 (0.87-4.34)	0.104	—	—	1.62 (0.90-2.92)	0.106	—	—
Lymph nodes: N2-N3 vs N0-N1	2.63 (1.17-5.91)	0.019	2.91 (1.25-6.78)	0.013	3.57 (1.81-7.02)	<0.001	4.23 (2.12-8.45)	<0.001	2.21 (1.29-3.80)	0.004	2.55 (1.46-4.44)	0.001
IHC: 2 + vs 1+	0.54 (0.25-1.18)	0.124	—	—	0.66 (0.34-1.29)	0.225	—	—	0.74 (0.45-1.23)	0.241	—	—
HR status: positive vs negative	0.42 (0.19-0.94)	0.035	0.39 (0.15-1.01)	0.052	0.41 (0.21-0.82)	0.012	0.33 (0.17-0.67)	0.002	0.55 (0.32-0.95)	0.033	0.46 (0.24-0.87)	0.016
HRD status: medium vs low	2.80 (0.80-9.85)	0.108	/	/	1.62 (0.63-4.14)	0.317	/	/	2.11 (1.04-4.30)	0.040	2.15 (1.04-4.41)	0.038
HRD status: high vs low	3.74 (1.03-13.60)	0.045	2.04 (0.51-8.20)	0.315	2.41 (0.92-6.36)	0.075	—	—	2.21 (1.03-4.76)	0.042	2.71 (0.73-4.03)	0.217
HRR mutations status: YES vs NO	1.42 (0.46-4.41)	0.543	—	—	1.07 (0.40-2.83)	0.895	—	—	0.72 (0.30-1.70)	0.451	—	—
BRCA1/2 mutations status: YES vs NO	1.58 (0.21-12.00)	0.657	—	—	1.49 (0.69-3.20)	0.215	—	—	1.38 (0.33-5.71)	0.657	—	—

Abbreviations: DSS, disease-specific survival; DFI, disease-free interval; PFI, progression-free interval; TCGA, The Cancer Genome Atlas dataset; HRD, homologous recombination defect score; HER2, human epidermal growth factor receptor 2; IHC, immunohistochemistry; HR, hormone receptor; HRRGs, homologous recombination repair genes; BRCA, breast cancer susceptibility gene.