Abstract
The current study clarified the accuracy of a circulating tumor cell (CTC) detection system to diagnose colorectal cancer using blood samples. The system uses the 'polymeric CTC-chip,' (CTC-chip), which is a microfluidic device that is used for CTC isolation. CTCs are considered sensitive diagnostic biomarkers. However, their concentration in the peripheral blood is low and requires highly sensitive and specific capturing techniques. The capture efficiency of the polymeric CTC-chip was first assessed using cell suspensions of the colorectal cancer cell line HCT-116, which was reported as 90.9% in a phosphate-buffered saline suspension and 65.0% in the blood. The CTC-chip was then used to detect CTCs in blood samples obtained from 13 patients with stage II-IV colorectal cancer. On average, the CTCs/ml was lower in patients with stages II and III colorectal cancer (3.3±2.3) than in those with stage IV (7.0±6.2). In patients with stages II-IV, 92% had ≥1 CTC per ml, which was significantly higher than the positive rate (15%) detected using the carbohydrate antigen 19-9 test (CA19-9). Furthermore, CTCs were detected in all patients with stage II and III colorectal cancer, including a number of patients with negative results for the carcinoembryonic antigen (CEA) and CA19-9 tests. With the polymeric CTC-chip detection system, CTCs can be effective cancer markers, particularly for patients with stage II and III colorectal cancer who often exhibit negative conventional serum marker test results. The CTC-chip system may also facilitate the detection of cancer progression based on CTC concentration.