Topoisomerase I Protein Expression and Prognosis of Patients with Colorectal Cancer

Topoisomerase I (Topo I) is known as a target for chemotherapy in advanced or recurrent colorectal cancer. In order to prolong the survival of patients with colorectal cancer or to prevent ineffective chemotherapy, we evaluated clinicopathological characteristics of Topo I protein in colorectal cancer. Also, we estimated whether Topo I protein expression of primary tumors could be a parameter for chemosensitivity of Topo I inhibitor in patients with cancer recurrence. Immunohistochemical detection of Topo I protein was performed in 104 surgically obtained specimens. Topo I protein was detected in 45 of 104 patients (43.2%). Topo I protein expression closely correlated with tumor progression, histpathological differentiation and poor prognosis of patients. Sixteen patients with recurrent cancer had been treated with Topo I inhibitor. Topo I inhibitor significantly prolonged the survival of 12 patients who had Topo I-positive primary tumors. Topo I protein expression in colorectal cancer may be a biological marker for chemosensitivity of tumors against Topo I inhibitors.