CD274 and neoplasm: By liquid biopsy monitoring of tumor subclones over treatment, Stein at al found ctDNA showed rapid clearance in the majority of patients mirroring a high rate of early tumor shrinkage and loss of PD-L1 on the tumor cell surface by PD-L1 mutations abrogated direct antitumor effects of PD-L1 antibody, avelumab [96].