Abstract:Objective：To study a method for the detection of peritoneal micrometastasis of gastric cancer (GC) and its significance.
Methods ：During operation,peritoneal washings were collected before tumor resection in patients with various stages of gastric cancer, and the tumor cells in the peritoneal lavage were enriched, collected and analyzed using magnetic activated cell sorting (MACS) technique. The cells were labeled by anti-cytokeratin(CK)antibody with magntic microbeads and passed through magnetic columns. The CK+epithelial cells were quantified by flow cytometry and the differences of amount of CK+epithelial cells collected before and after magentic enrichment in the gastric cancer group and the control group, and between different stages of gastric cancer were compared. There were 50 cases in gastric cancer group and 10 cases of gastric leiomyoma in the control group.
Results：CK+CD45- cells were rarely detected in the samples without MACS; in the samples treated by MACS, the concentrations of CK+CD45- cells were significantly higher in GC group than in control group（41/50vs1/10，P<0.001）, and lower in pTNM stage Ⅰ-Ⅱ group than in stage Ⅲ-Ⅳ group.( 0.67% vs 3.42%, P<0.001)
Conclusions：MACS can effectively enrich epithelial tumor cells in peritoneal lavage, increase the detection rate of epithelial-derived cells, and close relationships were found between CK+CD45- cell concentrations with free tumor cells and clinicopathologic stages. The technique could become a valuable tool to evaluate the risk of cancer metastasis and prognosis and to guide therapy.