Mechanism investigations revealed that RP11-424C20.2/UHRF1 axis regulated immune escape of LIHC and THYM at least partly through IFN-γ-mediated CLTA-4 and PD-L1 pathway.
Thus, the number of cases with PD-L1 expression and the percent expression of PD-L1 were significantly higher in more aggressive thymomas (type B2 or B3).
Furthermore, we also analyzed PD-L1 expression level in different types of TETs from TCGA database and observed that higher PD-L1 expression was in thymic carcinoma than in thymoma.
PD-L1 was expressed in 90% of nonneoplastic thymi, 92% of thymomas, and 50% of carcinomas, with significantly higher scores (P < .01) in B2 and B3 thymomas and carcinomas than in AB and B1 thymomas; PD-L1 was diffuse in most B2 and B3 thymomas and focal in carcinomas.
Increases in both the PD-L1 and PD-1 scores were observed after chemotherapy in six serial pre/post chemotherapy TM specimens, with a mean PD-L1 score and a median PD-1 intensity of 42/93, and 0/2.5, respectively.