Molecular detection of disseminated tumor cells in the peripheral blood in patients with gastrointestinal cancer

Purpose: In this study, 62 preoperative peripheral blood samples from patients with gastrointestinal carcinomas, 12 healthy volunteers, and ten patients with inflammatory gastrointestinal diseases were analyzed for the determination of CEA, CK19, and CK20 mRNA expression in peripheral blood, and its clinical significance was evaluated. Methods: Nested reverse transcriptase-polymerase chain reaction (nested RTPCR) was used to analyze CEA, CK19, and CK20 mRNA expression in peripheral blood. Fresh tumor tissues from patients with colorectal cancer (n=15) were used as a positive control. Results: Among 62 blood samples from patients with gastrointestinal cancer, the expression of CEA, CK19, and CK20 mRNA was 51.6% (32/62), 35.5% (22/62), and 48.4% (30/62), respectively. 74.2% (46/62) were positive for at least one marker. Fifteen tumor tissues were all positive for CEA, CK19, and CK20 mRNA. Only one blood sample from patients with no gastrointestinal carcinoma was positive for CEA mRNA. Conclusion: Our results indicate that the molecular detection of circulating tumor cells in peripheral blood in patients with gastrointestinal carcinoma was significantly correlated with its malignant biological properties, and may be helpful in the selection of clinical treatment and judgment of prognosis.