Expression of Topoisomerase 1 and carboxylesterase 2 correlates with irinotecan treatment response in metastatic colorectal cancer

Topoisomerase 1 (TOPO-1) and carboxylesterase 2 (CES-2) are found to play crucial roles in the pathogenesis of various cancers. The prognostic role of TOPO-1 and CES-2 in patients with metastatic colorectal cancer (mCRC) who underwent irinotecan chemotherapy was largely unknown. In the current study, we assessed the expression of TOPO-1 and CES-2 in mCRC and analyzed its potential relevance to irinotecan based therapy. A total of 98 patients with mCRC were included in this study. The expression of TOPO-1 and CES-2 in mCRC tissues was evaluated by immunohistochemistry. For TOPO-1, 46 patients showed high expression and 52 patients showed low expression. For CES-2, 53 patients showed high expression and 45 patients showed low expression. The correlation between TOPO-1 or CES-2 expression and clinicopathological characteristics of mCRC patients was analyzed. Neither TOPO-1 nor CES-2 had significant correlation with age, gender, tumor site, tumor grade and metastatic sites in mCRC patients. However, high expression of CES-2 but not TOP-1 was positively correlated with better curative effect. Kaplan-Meier and log-rank test were applied to assess the correlation between progression-free survival (PFS)/overall survival (OS) and TOPO-1 or CES-2 expression in mCRC patients. High expression of TOPO-1 and CES-2 are correlated with longer PFS and OS. In summary, our findings suggest that TOPO-1 and CES-2 may play important roles irinotecan sensitivity in mCRC patients. Evaluation of expression of TOPO-1 and CES-2 may provide preliminary clinical evidence for the management of irinotecan-based therapy in mCRC patients.