Circulating tumor cell as a biomarker for evaluating allogenic NK cell immunotherapy on stage IV non-small cell lung cancer

In this study, we determined the number of peripheral blood circulating tumor cells (CTCs) pre- and post-NK in patients with stage IV non-small cell lung cancer (NSCLC) as a reference for understanding the relevance of any changes to the efficacy of NK cells therapy. The patients were given one to three courses of immunotherapy. CTC numbers and CTC-related gene expression were measured in the peripheral blood of 31 patients with stage IV NSCLC at 1 day before and 7 and 30 d after NK cells therapy using magnetic activated cell sorting (MACS) and fluorescence activated cell sorting (FACS) combined with real-time quantitative PCR (RT-qPCR). Throughout the research, fever was the most common reaction (34.6%). The number of CTCs was 18.11 +/- 5.813, 15.13 +/- 5.984 and 10.32 +/- 5.623, respectively, and this decreased significantly over time. Delta Ct values for the CTC-related genes CEA, MAGE-3 and CK18 increased significantly after NK cells infusion. The expression of CEA, CK18 and MAGE-3 decreased significantly with time after NK. CTC was a useful biomarker for evaluating the efficacy of NK cells therapy on stage IV NSCLC.