CD274 and metastatic neoplasm: Considering the expression of PD-L1 on isolated CTCs, PD-L1+ CTCs classified HCC patients at early-stage (3/39 with PD-L1+ CTCs) and advanced/metastatic disease (23/34 with PD-L1+ CTCs) with sensitivity and specificity of 67.7% and 92.3%, respectively.