OBJECTIVE To evaluate core needle biopsy (CNB) as a mini-mally invasive method to examine breast lesions and discuss the clinical significance of subsequent immunohistochemistry (IHC)analysis.METHODS The clinical data and pathological results of 235 pa-tients with breast lesions, who Received CNB before surgery, were analyzed and compared. Based on the results of CNB done before surgery, 87 out of 204 patients diagnosed as invasive carcinoma were subjected to immunodetection for p53, c-erbB-2, ER and PR.The morphological change of cancer tissues in response to chemo-therapy was also evaluated.RESULTS In total of 235 cases receiving CNB examination, 204 were diagnosed as invasive carcinoma, reaching a 100% consistent rate with the surgical diagnosis. Sixty percent of the cases diag-nosed as non-invasive carcinoma by CNB was identified to have the presence of invading elements in surgical specimens, and simi-larly, 50% of the cases diagnosed as atypical ductal hyperplasia by CNB was confirmed to be carcinoma by the subsequent result of excision biopsy. There was no significant difference between the CNB biopsy and regular surgical samples in positive rate of im-munohistochemistry analysis (p53, c-erbB-2, ER and PR; P > 0.05).However, there was significant difference in the expression rate of p53 and c-erbB-2 between the cases with and without morphologi-cal change in response to chemotherapy (P < 0.05). In most cases with p53 and c-erbB-2 positive, there was no obvious morphologi-cal change after chemotherapy. CONCLUSION CNB is a cost-effective diagnostic method with minimal invasion for breast lesions, although it still has some limi-tations. Immunodetection on CNB tissue is expected to have great significance in clinical applications.