CD274 and neoplasm: CTCs were detected in 59 of 66 patients. PD-L1 positive CTCs were detected in 22 out of the 41 initially treated patients, and 18 of 41 patients showed positive PD-L1 expression in tumour tissue. The Cohen kappa coefficient of CTC and paired tumour tissue was 0.613. The PFS time of initially treated patients with positive PD-L1 expression was shorter than for those with negative PD-L1 expression in CTCs or tumour tissue.