Clinical significance of circulating tumor cells and their expression of cyclooxygenase-2 in patients with nasopharyngeal carcinoma

OBJECTIVE: To explore the expression of circulating tumor cells (CTCs) and cyclooxygenase-2 (COX-2) in CTCs and to assess their association with clinical parameters and treatment. PATIENTS AND METHODS: Peripheral blood samples from 50 patients with nasopharyngeal carcinoma (NPC) were included. We applied advanced CanPatrolTM CTC enrichment technique and in situ hybridization assay to isolate, identify, and classify CTCs and COX-2 in CTCs. Epstein-Barr virus DNA was detected by Real Time-quantitative PCR (RT-qPCR). RESULTS: No CTCs were identified in ten healthy volunteers (100%). Of the total patients, 48 (96%) had positive CTCs counts and 36 (72%) had positive mesenchymal CTCs counts before treatment. CTCs cells were highly expressed in different NPC stages, and the positive ratio of mesenchymal CTCs in stage IV was higher than that in other stages. The proportion of mesenchymal cells was higher expressed in metastasis patients. The expression of COX-2 was different in different types of CTCs. The positivity of COX-2 in CTCs was higher in stage IV patients than that in stage II and stage III patients. Decreased mesenchymal CTCs and that express COX-2 indicated a favorable curative effect in NPC patients. The positivity of mesenchymal CTCs and COX-2 was higher in EBV DNA positive patients compared with EBV DNA negative patients (p<0.05). Meanwhile. the mean number of CTCs, mesenchymal CTCs, CTCs that express COX-2, hybrid CTCs that express COX2 and mesenchymal CTCs that express COX-2 was significantly higher in the EBV DNA positive patients than negative patients before treatment (p<0.05). CONCLUSIONS: CTCs and their expression of COX-2 were correlated with NPC clinical characteristics, and have relation with Epstein-Barr virus DNA. Decreased mesenchymal CTCs and that express COX-2 indicated a favorable curative effect in NPC patients.