Clinical Significance Of Immunohistochemically Detecting Positve Expression Of Cytokeratin In Lymph Nodes Of Patients With Stage Ⅰ Non-Small-Cell Lung Cancer

Objective: This study was designed to detect positive expression ofcytokeratin(CK) in lymph nodes of patients with stage I non-small-celllung cancer(NSCLC) to confirm the presence of micrometastasis and tostudy the correlation with recurrence, metastases and prognosis and toprovide theoretical evidence for synthetic therapy of stage I NSCLCpatients. Methods: A total of 246 hilar and mediastinal lymph nodes(LNs)indicated to be tumor cells free by conventional histopathologic methodswere removed during surgery from 33 patients with completely resectedstage I NSCLC. The LNs were analyzed for micrometastasis byimmunohistochemistry using CK as a micrometastatic marker. Results: CK-positive cells were detected in 12 (4.9%) of 246 LNs, in10 (30.3%) of 33 patients. There was significant difference between therecurrence and metastases rate of patients with and without positiveexpression of CK(80.0% vs 26.1%,P=0.016).The median survival ofpatients with positive expression of CK was significantly shorter than thosewith negative expression of CK(21month vs 60month, P=0.016,Log ranktest).The patients with positive expression of CK in the LNs had a poorprognosis by both univariate (P=0.004) and multivariate analyses(P=0.004). Conclusions: Immunohistochemical stain for CK is a valid methodfor detecting and assessing micrometastasis in lymph nodes of lung cancerpatients.The detection of lymph nodal micrometastatic tumor cells byimmunohistochemistry using CK provides an accurate assessment of tumorstaging and has powerful prognostic implications for completely resectedstage I NSCLC patients and provides theoretical evidence for synthetictherapy of stage I NSCLC patients.