Abstract P1-01-17: Comparative Analysis of Metastatic Tumor Cells within the Sentinel Lymph Nodes of Breast Cancer Patients Utilizing a Novel Approach

Abstract

Abstract Background and Objective: The intrinsic high false negative rate associated with intraoperative analysis of SLN may result in a second surgical procedure for the patient. We attempt to improve the intraoperative and the pathologic and molecular evaluation of SLN by utilizing novel immunobead methods for detection and assessment of tumor cell expression of Her2, CD44 and Muc1. Methods: During the operation of breast cancer patients, gived sentinel lymph node biopsy firstly, and the SLN will each be divided in four quadrants, and two quadrants (B,C) will be brought to the pathologist for routine intraoperative analysis and further immunhistochemical (H&E and CK) examination often 2 mm thick sections of each quadrant. The other (A,D) quadrants will be immediately mechanically disaggregated and filtered in order to remove stromal elements and cellular debris. The resulting cell suspension will be incubated with 4.5 µm magnetic beads coated with MOC31 antibody, and simultaneously with different nonmagnetic, fluorescent microparticles coated with either anti-Her2, anti-CD44, or anti-Muc1 by flow-cytometry. Results: 62 cases from 2009.1 to 2009.9 in our hospital has been studied, and results as follows: 1. Immunomagnetic evaluation of alive tumor cells in SLNs is rapidly and easily performed using the MOC-31 antibody that binds to the vast majority of breast cancer cells. The novel technologies will demonstrate higher detection sensitivity (96%) and lower false negative rate (4.0%). 2. For the intraoperative frozen HE staining, the sensitivity was 68%, false negative rate was 32%; and for CK-IHC, the sensitivity was 76.0%, and the false negative rate was 24%. 3.To compare to standard intraoperative procedures and histopathologic techniques of analyzing the SLN to that of the novel approach, it could get higher sensitivity (96%vs 68%,P=0.023;96%vs76%,P=0.049), lower false negative rate (4%vs32% ,P=0.023;4%vs24%,P=0.049) and higher micrometastasis detection rate. 4.Expession of Her2,CD44 and Muc1 in SLN is 32.5%±2.2%,83.4± 4.1% and 86.6%±3.4%, and each has positively correlated with the expression of that in primary tumor (P<0.5). Conclusion: Our novel approach that utilizing immunobead detection of metastatic breast cancer cells, and simultaneously characterize the isolated cells for membrane markers coated with antibodies targeting Her2, Muc1 or CD44 by flow-cytometry, has rapid speed and high accuracy. Compared to traditional HE and CK-IHC, it has higher sensitivity and lower false negative rate, and could be used more widely and easily. Expression of CD44, Her2 and Muc1 in sentinel lymph nodes were positively correlated with the expression of those in primary tumor. It is suggested that the three biomarkers above could predict metastasis of sentinel lymph nodes, and maybe direct treatment after operation. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-17.