Association between HER2 expression levels and sonographic features in triple-negative breast cancer

To investigate the association between HER2 expression levels and sonographic characteristics in patients with triple-negative breast cancer (TNBC). A retrospective analysis was performed on 173 patients with pathologically confirmed TNBC. Based on HER2 immunohistochemistry (IHC) results, patients were classified into three groups: HER2-negative (IHC 0), HER2-low (IHC 1+), and HER2-low (IHC 2 + without amplification as determined by fluorescence in situ hybridization [FISH]). Sonographic features—including tumor shape, orientation, internal echogenicity, margin, posterior acoustic features, and presence of calcification—as well as lymph node metastasis status were compared across the groups. With increasing HER2 expression levels, tumors were more likely to exhibit an irregular shape ( p < 0.001), non-circumscribed margins ( p = 0.009), reduced incidence of posterior acoustic enhancement ( p = 0.004), and higher frequency of calcification ( p = 0.026). No significant differences were observed in tumor orientation or internal echogenicity among the groups ( p > 0.05). The rate of lymph node metastasis did not differ significantly across the three groups ( p = 0.233). HER2 expression level is associated with specific sonographic features in TNBC, with higher expression correlating with more suspicious ultrasound characteristics. Although a trend toward increased lymph node metastasis was noted in the HER2-low (IHC 2+) group, this difference was not statistically significant, warranting further investigation.