High Ki67 Expression has Prognostic Value in Surgically-Resected T3 Gastric Adenocarcinoma.

Abstract

Antigen KI-67 (Ki67) plays a critical role in regulation of cell proliferation and has prognostic value in several types of cancer; however, the relationship between Ki67 expression and prognosis in resected T3 gastric adenocarcinoma (GA) has not yet been investigated. Retrospective analysis of 693 patients with T3 GA who underwent surgical resection at a single institution between July 2003 and December 2009 was performed. Ki67 expression in tumor tissues was examined using immunohistochemistry (IHC); the associations between Ki67 and prognosis/survival outcomes were assessed using the Chi-square test, Kaplan-Meier survival analysis, log-rank test, and univariate and multivariate analysis. High Ki67 expression (IHC score > or = 3+) was observed in 335/693 (48.34%) of cases. Ki67 expression was significantly associated with distant metastasis, 5-year median recurrence-free survival time in months (MRFST), and 5-year median overall survival time in months (MOST). Median recurrence and overall survival were 20 and 28 months. High Ki67 expression was associated with shorter MRFST (13 vs. 27 months, p < 0.001) and MOST (21 vs. 35 months, p < 0.001 compared to low K67 expression). Multivariate analysis demonstrated that high K167 expression was an independent prognostic factor for an increased risk of recurrence (p = 0.001) and distant metastasis (p = 0.003) and poorer overall survival (p = 5.33 x 10(-5)). High Ki67 expression was frequently observed in resected T3 GA and was a significant prognostic factor for poor outcome with respect to recurrence, distant metastasis and overall survival. Ki67 may represent a useful prognostic biomarker for resected T3 GA.