• BRIEF REPORTS • Detection of micrometastasis in peripheral blood by multi-sampling in patients with colorectal cancer

AIM: To evaluate the reverse transcriptase-PCR assay and multiple sampling for detection of cytokeratin-positive cells in peripheral blood of colorectal carcinoma patients and to investigate the clinical significance of micrometastasis in peripheral blood. METHODS: The expression of CK20 mRNA by RT-PCR was investigated in bone marrow, portal vein and peripheral blood in 58 colorectal cancer patients and 12 controls without known cancer. The peripheral blood was sampled twice at intervals of 3 d before operation. All the patients were followed up for one year. RESULTS: There was no positive expression of CK20mRNA in 12 volunteers. The positive expression of CK20mRNA was 77.6 % (45/58) in bone marrow, and that in porta