ObjectiveTo compare the clinicopathological characteristics and prognosis of young early breast cancer patients with different human epidermal growth factor receptor 2 (HER2) expression levels, and to analyze the clinicopathological characteristics and prognosis of young early breast cancer patients with low HER2 expression. MethodsA total of 1 723 breast cancer patients who were treated in the Department of Breast Surgery of the First Affiliated Hospital of Xi’an Jiaotong University between June 2016 and June 2018 were collected and divided into three groups: HER2-negative, low-expression, and high-expression. The clinicopathological characteristics of the three groups were compared, and the relationship between HER2 expression and patients’ prognosis was analyzed. ResultsThere were 512 HER2-negative patients, 748 HER2-low expression patients, and 463 HER2-high expression patients. The results of the clinical pathological characteristics analysis of the three groups of patients showed that there were no statistical differences in marital status, menopausal status, family history, single T stage (tumor size), single M stage (distant metastasis), affected side, vascular tumor thrombus, and radiotherapy in the three groups of breast cancer patients with different HER2 expression levels (P>0.05). However, there were statistical differences in age, Ki-67 expression level, N stage, TNM stage, surgical method, estrogen receptor and progesterone receptor status, histological type, histological grade, whether to receive neoadjuvant therapy and adjuvant chemotherapy in breast cancer patients with different HER2 expression levels (P<0.05). The results of survival analysis showed that the prognosis of early breast cancer patients may not be significantly correlated with the HER2 expression level, and the prognosis of young early breast cancer patients may also not be statistically correlated with the HER2 expression status. ConclusionsBreast cancer patients with different HER2 expression levels differ in multiple clinicopathological characteristics, but these differences do not significantly affect the prognosis of the patients. Especially for early-stage breast cancer, HER2 expression levels do not seem to have a significant impact on prognosis. This suggests that HER2 status may not be a decisive factor in treatment and prognosis assessment, and other pathological characteristics and treatment methods need to be considered comprehensively. The prognosis of young breast cancer patients in early stage may also not be statistically correlated with HER2 expression status.