Detection of disseminated tumor cells using reverse transcriptase PCR for cytokeratin 20 in peripheral blood isolates from gastric cancer patients / 대한내과학회지

ABSTRACT

BACKGROUND: The development of metastasis in cancer is one of the main problems after primary tumor resection. The identification of metastases is only possible in the follow-up investigation when there is already a solid tumor mass. Subclinical tumor cell dissemination can be detected by immunocytological staining of cells or by other molecular biological methods, like PCR. We investigated 22 peripheral blood isolates from gastric cancer patients with a cytokeratin (CK) 20 specific nested reverse transcriptase PCR (RT-PCR) for the detection of disseminated tumor cells at the time of diagnosis. METHODS: Fresh heparinized peripheral bloods (about 10 mL) were obtained from 22 gastric cancer patients and 10 healthy doctors as controls. Nucleated cells were isolated by a density gradient method. RNA was isolated and then subjected to RT-PCR with CK 20 specific primers. RESULTS: In gastric cancer, 3 of 22 (13.6%) peripheral blood isolates yielded a CK 20 mRNA positive result in a stage undependent manner. CONCLUSION: We detected disseminated tumor cells in the peripheral blood isolated using CK 20 specific nested RT-PCR method. Studies on a larger scale are needed for further investigation on the relationship between positive rates of CK 20 mRNA and survival rates of stomach cancer, according to cancer stages.