Detection of tumor cells in lymph nodes of lung cancer by immunomagnetic beads negative enrichment method

Objective To establish an enrichment and detection method by immunomagnetic beads for disseminated tumor cells in lymph node specimens of lung cancer, and to explore the feasibility of this method to improve the diagnosis rate of lymph node micrometastasis. Methods Lymph node were obtained intraoperatively from lung cancer patients and turned into digest solution. All lymph node were pathologically non-metastatic. Tumor cells were enriched by negative method and identified by immunofluorescence and immunofluorescence in situ hybridization. Only p53+ /DAPI+ /CD45- cells and CEP8+ /DAPI+ /CD45- cells were judged as positive cells. Results Thirty patients with lung cancer were enrolled and 60 lymph nodes were obtained. Positive cells were detected in 7 lymph nodes by immunofluorescence and 7 lymph nodes by immunofluorescence in situ hybridization. Both p53+ /DAPI+ /CD45- cells and CEP8+ /DAPI+ /CD45- cells were detected in 3 lymph nodes. Therefore, eleven lymph node from 10 NSCLC patients were found to be positive of micrometastasis. Conclusion Negative enrichment by immunomagnetic beads is feasible to enrich disseminated tumor cells from lymph nodes and potentially leads to a more accurate estimation of lymph nodes micrometastasis for lung cancer patients. Key words: Lung cancer; Lymph node micrometastasis; Negative enrichment