Background:The breast imaging-reporting and data system (BI-RADS) grading has a great advantage in diagnosing breast diseases, but with some limitations.Aims:The study analyzed the value of ultrasound-guided core needle biopsy (CNB) in diagnosing BI-RADS grades 3, 4, and 5 breast cancer.Methods:Breast cancer patients at BI-RADS grades 3 to 5 received breast ultrasonography, ultrasound-guided CNB and immunohistochemical examination. Receiver operating characteristic (ROC) curve was made to test diagnostic efficiency of regression model.Results:Calcification was positively correlated with expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (HER)-2. The areas of 4 ROC curves were 0.752, 0.805, 0.758, and 0.847, and the 95%CI was 0.660 to 0.844, 0.723 to 0.887, 0.667 to 0.849, and 0.776 to 0.918, respectively. BI-RADS grades 3 to 5 were positively correlated with expression of ER, PR and human epidermal growth factor receptor-2 (HER-2). Statistical significance existed between grade 5 and expression of ER, PR and HER-2, and between grade 4 and expression of HER-2.Conclusions:The study demonstrates that BI-RADS can be used as an effective evaluation method in the diagnosis of breast diseases before invasive operation, and it has higher diagnostic accuracy if combined with pathological examinations.