World J Oncol

World Journal of Oncology, ISSN 1920-4531 print, 1920-454X online, Open Access

Article copyright, the authors; Journal compilation copyright, World J Oncol and Elmer Press Inc

Journal website https://wjon.elmerpub.com

Original Article

Volume 17, Number 4, August 2026, pages 547-555

Human Epidermal Growth Factor Receptor 2 Negative, Low, and Overexpression in Breast Cancer Patients: Study on Recurrence-Free and Overall Survival

Figures

↓ Figure 1. Flow chart of the study process.

↓ Figure 2. Kaplan–Meier survival probability according to HER2 status. The curves show the probability of overall survival among patients with HER2-negative (blue), HER2-low (red), and HER2-overexpression (green) breast cancer over an 11-year follow-up period. Tick marks indicate censored observations. HER2: human epidermal growth factor receptor 2.

↓ Figure 3. Cox proportional hazards regression analysis of overall survival based on HER2 expression. The curves illustrate the cumulative hazard of death among patients with HER2-negative (blue), HER2-low (red), and HER2-overexpression (green) breast cancer over the 11-year follow-up period. Higher values on the y-axis indicate a greater accumulated risk of mortality. HER2: human epidermal growth factor receptor 2.

Tables

↓ **Table 1.** Patients’ Characteristic
	Total study population
	N	%
HER2: human epidermal growth factor receptor 2.
Age
< 45	305	13.2
45–55	821	35.5
> 55	1,184	51.2
Stadium
1	59	2.6
2	571	24.7
3	1,666	72.1
4	14	0.6
HER2 status
Negative	1,007	43.6
Low	491	21.3
Overexpression	812	35.2
Outcome
Death	1,450	62.7
Alive	860	37.2

↓ **Table 2.** Mean and Median Overall Survival According to HER2-Negative, HER2-Low, and HER2-Overexpression Status and Pairwise Log-Rank Comparisons of Overall Survival Between HER2-Negative, HER2-Low, and HER2-Overexpression Status
HER2	Mean				Median
	Estimate	Standard error	95% Confidence interval		Estimate	Standard error	95% Confidence interval
	Estimate	Standard error	Lower bound	Upper bound	Estimate	Standard error	Lower bound	Upper bound
HER2: human epidermal growth factor receptor 2.
Negative	6.382	0.169	6.050	6.713
Low	5.585	0.251	5.092	6.078	4.000	0.803	2.426	5.574
Overexpression	4.793	0.187	4.427	5.160	3.000	0.372	2.271	3.729
Overall	6.134	0.140	5.858	6.409	3.000	0.383	2.249	3.751
			0			1
			HER2	Chi-square	Sig.	Chi-square		Sig.
Log-rank (Mantel–Cox)			0			5.863		0.015
			1	5.863	0.015	0.852		0.356
			2	0.852	0.356