摘要Background Accurate intraoperative diagnosis of sentinel lymph node (SLN) metastases enables the selection of patients for axillary lymph node dissections during the same operation, reducing the need for a second operation. The present study aimed to prospectively compare the GeneSearchTM Breast Lymph Node (BLN) Assay with touch imprint cytology (TIC) for intraoperative evaluation of SLNs.Methods SLNs were sectioned in 1.5-3.0 mm pieces. TIC was performed on all pieces and the BLN Assay and postoperative histology evaluations were performed on different alternating node pieces. Overall performance of the BLN Assay was compared with that of TIC relative to the postoperative histology results.Results A total of 90 patients enrolled in the study. Complete intraoperative data for both the BLN Assay and TIC were collected in 86 patients. The sensitivity, specificity, and overall accuracy of the BLN Assay were 82%, 97%, and 92%,respectively on a per patient basis compared with those of TIC which were 67%, 100%, and 90%.Conclusions Performance of the BLN Assay was superior to that of TIC and the additional application of TIC did not help improve the total sensitivity and accuracy of the intraoperative assessment. The existence of ectopic breast tissue might be a possible cause of false positive for the BLN assay. In addition, the BLN Assay complements histopathology assessment and can minimize sampling error without increasing pathologists' workload.