Diagnostic value of negative enrichment and immune fluorescence in situ hybridization for intraperitoneal free cancer cells of gastric cancer

OBJECTIVE: To explore the intraperitoneal free cancer cell (IFCC) detection value of negative enrichment and immune fluorescence in situ hybridization (NEimFISH) on chromosomes (CEN) 8/17. METHODS: To verify the reliability of NEimFISH, 29 gastric cancer tumors, their adjacent tissues and greater omental tissues were tested. Our study then included 105 gastric cancer patients for IFCC. We defined patients as IFCC-positive if a signal was detected, regardless of the detailed cancer cell numbers. A comparison of clinicopathological features was conducted among IFCC groups. We also compared the diagnosis value and peritoneal recurrence predictive value among different detection methods. The comparison of IFCC number was also conducted among different groups. RESULTS: A cutoff of 2.5 positive cells could distinguish all benign tissue samples and 97% of malignant tissue samples in our study. Compared to intestinal gastric cancer, patients with diffuse gastric cancer tended to have more IFCCs (6 vs. 4, P=0.002). The IFCC counts were often higher in the lymphovascular invasion positive group than negative group (3 vs. 1, P=0.022). All IFCC samples that were considered positive using conventional cytology were also found to be positive using NEimFISH. When compared to conventional cytology and paraffin pathology, NEimFISH had a higher IFCC positive rate (68.9%) and higher one-year peritoneal recurrence predictive value with area under the curve (AUC) of 0.922. CONCLUSIONS: Gastric cancer could be effectively diagnosed by NEimFISH. The IFCC number found using NEimFISH on CEN8/17 is closely associated with Lauren type and vascular invasion of cancer. NEimFISH is a reliable detection modality with a higher positive detection rate, higher one-year peritoneal recurrence predictive value and quantitative features for IFCC of gastric cancer.