Padda et al. examined 69 TETs and found 68% of samples expressed high levels of PD-L1 using the clone 15 antibody (Sino Biological).[24] Katsuya et al. examined a larger series of 141 TETs and found high PD-L1 expression in 70% of thymic carcinoma samples but only 23% of thymoma samples stained positive for PD-L1 (Cell Signaling E1L3N clone, H-score evaluation alone)[25] and Yokoyama et al. noted high PD-L1 expression in 80% of a series of thymic carcinoma specimens (EPR1161, Abcam, H-score evaluation, included cytoplasmic expression)[26]. This evidence concerns the gene CD274 and thymoma.