Objective: To investigate the relationship between methylation status of APC gene in both peripheral blood and tumor tissues and clinical-pathology characteristics in patients with esophageal squamous cell carcinoma(ESCC), and to study the dynamic change of APC methylation in peripheral blood in the perioperative period.
Methods: Real-time MSP technique was used to detect methylation status of APC in tumor tissues, adjacent normal tissues and peripheral blood on the day before the surgery, intraoperative, postoperative day 7 in 76 cases with ESCC. Sixty healthy volunteers matched by age and gender were randomly selected as controls.
Results: The methylation rate of APC in tumor tissue and peripheral blood was 44.74%(34/76) and 42.11%(32/76), respectively, which were significantly higher than that in adjacent normal tissue and controls [6.58%(5/76) and 1.67%(1/60), P=0.000]. The methylation rates showed good agreement between tumor tissues and peripheral blood, which could be verified by ROC curve(A Zeta=0.849, P=0.000). APC methylation rate was significantly related to pathological staging, lymph node metastasis, depth of invasion, and invasion of nerve and vessel (P<0.05). The results demonstrated that family history of cancer was independently associated with APC methylation in peripheral blood(P<0.05). DNA methylation rates in peripheral blood showed an initial increase and then decreased in the preoperative period, intraoperative and postoperative.
Conclusion: The methylation rates of APC among free DNA in peripheral blood in patients with ESCC reflect tumor progression, and decrease with the solid tumour resection.