Clinical Significance of Increased Ki-67 Protein Expression in Non-small Cell Lung Cancers / 대한흉부외과학회지

ABSTRACT

BACKGROUND: The Ki-67 protein is a biomarker associated with cell proliferation and a valuable negative prognostic factor in non-small cell lung cancer. We investigated the Ki-67 protein expression in resected non-small cell lung cancer to evaluate the impact on clinicopathological characteristics and postoperative prognosis. MATERIAL AND METHOD: Using monoclonal antibody Ki-67, we immunohistochemically examined 38 surgically resected non-small cell lung cancers to determine Ki-67 Labeling Index (LI). We analysed the differences of clinicopathological characteristics and postoperative recurrence and survival between High Ki-67 Group (LI> or =20%) and Low Ki-67 Group (LI<20%). RESULT: The Ki-67 LIs were heterogenous and a mean values was 20.0+/-20.05%. There were no significant differences in age, sex, smoking, TNM stage, and vascular invasion between High Ki-67 Group and Low Ki-67 Group. A High Ki-67 Group was significantly associated with squamous cell type, poor differentiation, and lymphatic invasion (p< or =0.05). High Ki-67 Group showed a trend of lower survival (median 47.2 vs. 96.5 months, p=0.312) and lower disease-free survival (median 18.2 vs. 72.3 months, p=0.327) than Low Ki-67 Group. CONCLUSION: These results indicate that increased Ki-67 protein expression may be a negative prognostic factor and showed a trend of shortened survival and disease-free survival. To evaluate the pivotal role of Ki-67 protein expression, a long-term follow-up and further study are required.