CD274 and neoplasm: As tumour-targeting probes, we used four types of monoclonal antibodies such as anti-HER2 antibody (Herceptin),20 anti-EGFR antibody (Erbitux),21 anti-VEGFR-2 antibody (Cyramza),22 and anti-PD-L1 antibody (anti-PD-L1 ab).23 These monoclonal antibodies are used as antibody drugs of cancer therapy for breast and skin tumours in clinical fields.