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

•CTC was a useful biomarker for evaluating the efficacy of NK cells therapy on stage IV NSCLC is firstly showed.•A potentially effective approach for the control of tumor growth in stage IV NSCLN patients is proposed.•A new approach for double detecting CTC from PBMC is confirmed.

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. ΔCt 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.