Detection and quantification of circulating tumor cells in esophageal squamous cancer by real-time fluorescent quantitative reverse transcription-polymerase chain reaction

Abstract

Objective To evaluate circulating tumor cells (CTCs) in peripheral blood of patients with primary esophageal squamous cancer by real-time fluorescent quantitative reverse transcription-polymerase chain reaction (fqRT-PCR). Methods Carcinoembryonic antigen (CEA) mRNA was detected in the peripheral blood samples of 43 patients with primary esophageal squamous cancer and 10 controls by real-time fqRT-PCR. Results Twenty of 43 (46.51%) patients with esophageal squamous cancer had detectable CEA mRNA in peripheral blood samples and there was no detectable CEA mRNA in control group.The positive expression rate of CEA mRNA was significantly higher in patients with TNM stage Ⅲ, Ⅳ than that in stage Ⅰ , Ⅱ (P＜0.05), but there was no significant difference between stage Ⅰ and Ⅱ , neither between stage Ⅲ and Ⅳ (P＞0.05). CEA mRNA copies were significantly higher in patients with stage Ⅳ than that in stage Ⅰ , Ⅱ , Ⅲ (P＜0.01), but there were no significant differences among stage Ⅰ , Ⅱ and Ⅲ (P＞0.05). There was no correlation between the expression of CEA mRNA and cancer cell differentiation. The follow-up data showed the specificity for predicting metastasis of high CEA mRNA level in peripheral blood was 81.25% (13/16). Conclusion The detection of CEA mRNA in peripheral blood by fqRT-PCR is a sensitive, specific and reliable method to monitor the CTCs in patients with esophageal squamous cancer. Key words: Esophageal cancer; Carcinoembryonic antigen; Peripheral blood