Results obtained with IMS were compared to the pathological staging obtained by histopathology. and samples from 83?% of the patients with lymph node metastases (pN1-2) experienced detectable DTCs. In the group of patients who were unfavorable N-Desethyl amodiaquine dihydrochloride for lymph node metastases by standard histopathology (pN0) DTCs were detected in 32?%. The presence of DTCs was not associated with any other clinicopathological variables. Patients with IMS-positive samples showed decreased relapse free survival compared to patients with IMS-negative samples, N-Desethyl amodiaquine dihydrochloride N-Desethyl amodiaquine dihydrochloride but the difference was not statistically significant. The pN status was significantly associated with both relapse free and overall survival, but the presence of DTCs experienced no prognostic impact in the subcategory of patients with pN0 status. Conclusion Our findings do not support further development of lymph node DTC detection N-Desethyl amodiaquine dihydrochloride for clinical use in early stage NSCLC. strong class=”kwd-title” Keywords: NSCLC, Disseminated tumour cells, Lymph nodes, Immunomagnetic selection, Prognosis Background Curatively intended surgical resection is the standard therapy for operable patients with early-stage non-small cell lung malignancy (NSCLC), and the prognosis of these patients is usually closely related to disease stage . The regional lymph node involvement is a major prognostic factor, and for total surgical resection of NSCLC a systematic nodal dissection is recommended . This allows pathological staging of the disease according to standardized definitions, and thereby decision of further treatment strategies. The fact that approximately half of the patients undergoing medical procedures experience disease relapse, suggests that disseminated tumor cells (DTCs) may be present already at the time of medical procedures . In routine clinical practice, pathological evaluation of resected lymph nodes is done by standard histopathology, a method by which DTCs cannot be recognized. The high recurrence rate after surgical resection of NSCLC indicates that current staging classifications are not able to accurately predict individual outcome and that the nodal staging might be suboptimal. Detection of DTCs to regional lymph nodes at the time of surgery could possibly facilitate identification of subcategories of patients with high risk of disease relapse, and thereby stratification of individual groups for adjuvant therapy. Occult metastatic spread to the lymph nodes or distant sites has been the focus of research over many years, and has been reported under different terminology. The Union for International Malignancy Control (UICC) has defined micrometastasis as clusters of tumor cells measuring between 0.2 and 2?mm in diameter, and isolated tumor cells as single tumor cells N-Desethyl amodiaquine dihydrochloride or small clusters of cells smaller than 0.2?mm . Tumor cells that have spread to lymph nodes or bone marrow are often referred to as DTCs, whereas circulating tumor cells (CTCs) are used for single cells in blood . A number of previous studies have resolved the prognostic value of detecting micrometastasis and DTCs in lymph nodes of NSCLC patients [6C23], but due to considerable differences in terminology, methodology and results, no conclusion can be drawn based on the existing literature. The methods used for detection have traditionally been immunohistochemistry (IHC) with antibodies targeting epithelial-specific proteins FGD4 like cytokeratins [6C18], and molecular methods using RT-PCR for detection of tumor- or epithelial cell specific mRNA transcripts [3, 19C25]. Our group has previously published a study where we investigated the presence of DTCs in bone marrow aspirates from patients undergoing lung malignancy surgery by the use of immunomagnetic selection (IMS) . In the present study we have used IMS to investigate the presence of DTCs in lymph node tissue prospectively collected from patients with early stage NSCLC undergoing curatively intended medical procedures. In the IMS method small magnetic particles coated with the antibody MOC31 which recognizes the epithelial marker EpCAM, are used to isolate tumor cells from your lymph nodes, allowing fast screening of as.