Research Progress of PD-L1 Expression in Circulating Tumor Cells in Malignant Tumors

In recent years, with the in-depth study of PD-1 and PD-L1 and the development of immunotherapy, the first problem is how to screen the beneficiaries. Recent clinical studies have shown that the expression level of PD-L1 in circulating tumor cells (CTC) can be used as a potential biomarker to play a guiding role in immunotherapy of malignant tumors. This article reviews the latest clinical research progress on the expression of PD-L1 in circulating tumor cells in various solid tumors.