Detection of circulating tumor cells by cytokeratin 20 and prostate stem cell antigen RT-PCR in blood of patients with gastrointestinal cancers

Background: Detection of circulating tumor cells in blood may be an important diagnostic and prognostic factor in the management of tumor patients. The present study aimed to examine whether cytokeratin 20 (CK-20) and prostate stem cell antigen (PSCA) are useful markers for the detection of disseminated cancer cells in the blood of tumor patients. Materials and Methods: A nested RT-PCR assay was used to detect CK-20 and PSCA mRNA in blood samples from 18 healthy donors, 15 patients with non-malignant disease, 9 patients with benign tumors and 47 patients with malignant tumors (11 pancreatic carcinoma, 8 gastric cancer, 15 colorectal carcinoma and 13 miscellaneous tumors). Results: CK-20 expression was observed in the peripheral blood of 19 out of 47 (40.4%) patients with malignant tumors, 2 out of 9 (22.2%) patients with benign tumors and 3 out of 15 (20%) patients with non-tumor diseases. PSCA expression was present in the blood of 22 out of 47 (46.8%) patients with malignant tumors and particularly in 7 out of 11 (63.6%) patients with pancreatic cancer. CK-20 and PSCA expression was not observed in blood samples from healthy donors. There was a relationship between PSCA expression and tumor stage. Conclusion: The present results demonstrate that it is possible to apply a simple and reliable method for the detection of circulating tumor cells based on CK-20 and PSCA RT-PCR assays.