Circulating tumor cells in pulmonary vein and peripheral arterial provide a metric for PD-L1 diagnosis and prognosis of patients with non-small cell lung cancer

Abstract

Background Lung cancer is the leading cause of death caused by malignant tumors. PD-L1(programmed cell death protein-1) has shown tremendous achievement in treating NSCLC. We sought to find the relationship between CTCs in the pulmonary vein and postoperative PFS, besides we detected PD-L1 in CTCs. Method We enrolled 112 NSCLC patients. CTC tests were performed at four time points (preoperative, pulmonary vein, intraoperative and postoperative) on every NSCLC patient who received surgery. The RNA of PD-L1 was tested by FISH. The levels of the PD-L1 mRNA and protein in tissue samples were detected. Results The CTCs in the PV were the highest (P< 0.001), and CTCs in the PPA were the lowest (P< 0.001). The PFS in the group with PV CTCs 16/5 ml was shorter than that in the group with PV CTCs< 16/5 ml (11.1 months vs 21.2 months, respectively; P< 0.001). The PFS in the group with PPA CTCs 3/5 ml was shorter than that in the group with CTCs< 3/5 ml (14.8 months vs 20.7 months, respectively; P< 0.001). The CTCs in stage I were lower than those in stage II-IV (P = 0.025). No linear relationship was found between the CTCs and tumor size (P> 0.05) or LN metastasis (P> 0.05). In total, fifty-two (50.5%) patients had positive PD-L1 expression in CTC. In PD-L1-positive CTC patients, the value of PD-L1 tissue expression was higher than that in PD-L1-negative CTC patients (P = 0.0153). Conclusion CTCs in the pulmonary vein can be an effective prognosis indicator of NSCLC patients.