Abstract:ObjectiveTo analyze multimodal ultrasonic characteristics of human epidermal growth factor receptor 2 (HER-2) positive breast cancer patients in different hormone receptor (HR) expression states, so as to provide a reference for the early diagnosis and treatment of HER-2 positive breast cancer. Methods The clinical data of 160 patients with HER-2 positive breast cancer who were diagnosed and treated in the First Affiliated Hospital with Nanjing Medical University and Jurong Peoples Hospital from January 2017 to December 2023 were collected retrospectively. According to immunohistochemical results, patients were divided into HR positive group (n=89) and HR negative group (n=71). General data, pathological characteristics and multimodal ultrasonic characteristics of the two groups were compared. Logistic regression analysis was performed to analyze the relationship between multimodal ultrasonic characteristics and HR expression in HER-2 positive breast cancer. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of multimodal ultrasonic characteristics for HR expression in HER-2 positive breast cancer patients. Results Compared with HR negative group, proportions of routine ultrasound signs (irregular shape, edge anomaly or fuzziness, microcalcification, internal uneven echo) significantly decreased in HR positive group, and proportions of contrast-enhanced ultrasound signs (irregular shape, fuzzy boundary and non-filling defect after enhancement) significantly decreased (P＜0.05). Compared with HR negative group, difference value of lesion diameter in contrast-enhanced ultrasound sign ［(3.29±0.36) mm vs (4.30±0.44) mm, t=15.971, P＜0.01］, elasticity score ［(3.15±0.33) points vs (4.56±0.47) points, t=21.416, P＜0.01］ and hardness ratio ［(0.24±0.04) points vs (0.33±0.05) points, t=12.340, P＜0.01］ in elastography signs significantly decreased in HR positive group. Logistic regression analysis showed that difference value of lesion diameter, elasticity score and hardness ratio after enhancement were closely related to HR expression (P＜0.05). ROC curve analysis showed that the area under the curve of three characteristics of ultrasoud multimodality combined to predict the HR expression status in patients with HER-2 positive breast cancer (0.895) was larger than that of the lesion diameter difference (0.641), elasticity score (0.833) and hardness ratio (0.783) (Z=7.524, 3.405, 4.420, P＜0.05), and the specificity and Youden index of combined prediction were also the highest. Conclusion HR positive expression in patients with HER-2 positive breast cancer is closely related to multimodal ultrasonic characteristics. Multimodal ultrasonic characteristics have a high predictive value for HR positive expression in HER-2 positive patients.