Prognostic significance of circulating tumor cells in patients with gastric cancer: Epithelial mesenchymal transition and perioperative kinetics.

Abstract

59 Background: Circulating tumor cells (CTCs) have been shown to be heterogeneous. This study aimed to identify the prognostic significance of CTCs in patients with gastric cancer, focusing on epithelial mesenchymal transition and perioperative kinetics. Methods: Peripheral blood (7.5 ml) was taken from patients (n = 54) before curative resection, and at 7 days, 1 and 6 months postoperatively. CTCs were enriched using density gradient centrifugation and magnetic-activated cell sorting (negative selection). Cell suspensions were characterized by multi-immunofluorescence staining against cytokeratin (CK) and N-cadherin, and by DAPI staining. CTCs were defined as nucleated cells expressing CK or N-cadherin. Threshold analysis identified 1 CTC/7.5 ml as an optimal cut-off value. The median observation period was 735 days. Results: CTCs were detected in seven patients (24%) with early cancer and 14 patients (56%) with advanced cancer (p < 0.05). Cells were identified as either N-cadherin+/CK−/CD45− or N-cadherin+/CK+/CD45−, but no N-cadherin−/CK+/CD45− cells were observed. The median follow-up period was 24.5 months. After 2 years, postoperative recurrence was detected in nine patients, all of whom had advanced gastric cancer and N-cadherin+/CK−/CD45− CTCs preoperatively. In terms of perioperative kinetics (just before, 7 days and 1 month after surgery), we divided patients with advanced cancer into three risk groups: A, preoperative CTCs ≥1 and increased postoperatively; B, preoperative CTCs ≥1 and decreased postoperatively; C; no preoperative CTCs. The recurrence rates in the above groups were 80% (4/5), 44% (4/9), and 0% (0/11), respectively. Conclusions: Numerous CTCs expressed N-cadherin but not CK. Perioperative measurement of CTCs may be a useful surrogate marker for recurrence risk.

Emerging Role of Circulating Tumor Cells in Gastric Cancer

“…A cut-off value of 1 CTC/7.5 mL was chosen for CTC measurement. Advanced GC patients with preoperative CTCs ≥1 and increased postoperatively had the poorest prognosis [82].…”

“…Despites promising perspectives of using CTCs as one type of liquid biopsy for GC diagnosis and prognosis, there are still remarkable challenges for translating them into clinical practice. Notably, there are controversies on the cut-off value of CTC positivity, since a wide range of CTC levels have been used in various studies [55,61,81,82]. Critical reasons for this include the unavailability of consensus in technical approaches ranging from sampling, storage conditions, and CTC molecular markers, along with a lack of relevant enrichment and detection techniques.…”