Different pattern of PD-L1, IDO, and FOXP3 Tregs expression with survival in thymoma and thymic carcinoma

Immune checkpoints in thymic epithelial tumors: challenges and opportunities

“…Immune-related biomarkers in the thymus and thymic tumors PD-L1 expression, while observed in more than 90% of epithelial cells of the normal thymus with a medullar tropism respecting Hassall's corpuscles [28], has also been identified in thymomas and thymic carcinomas using various immunohistochemistry protocols (Table 2) series of 100 thymomas and 69 thymic carcinomas [35] reported high expression of PD-L1, IDO and FOXP3 Tregs in 36%, 13% and 16% of cases of thymoma, respectively. High expression of PD-L1, IDO and FOXP3 Tregs was associated with a higher grade of tumor histology.…”

“…Data from the Cancer Genome Atlas and Foundation Medicine indicated a low tumor mutation burden in thymomas and thymic carcinomas; only 6% of carcinoma cases had >10 mutations/Mb and 3% had >20 mutations/Mb (Figure 2) [13,15]. [30] TMA, clone 5H1 (intensity high) 65 44 (68%) 4 3 (75%) Arbour et al [31] Slides, clone E1L3 (25% of tumor cells cut off) 12 11 (94%) 11 4 (34%) Yokohama et al [32,33] Slides, EPR1161 (H-score, 20% of tumor cells cut off) 82 44 (54%) 25 20 (80%) Weissferdt [34] Slides, clone E1L3 (5% of tumor cells cut off) 74 47 (64%) 26 14 (54%) Markevski et al [28] Slides, clone SP142 (1% of tumor cells cut off) 38 35 (92%) 8 4 (50%) Wei et al [35] TMA, clone E1L3 (% of cells and intensity) 100 100 (100%: 36% low, 64 high) 69 69 (100%: 64% low, 36% high) Guleria et al [36] TMA, clone SP263 (1-25% of tumor cells cut off) 84 69 (82%) Suster et al [37] TMA, clone SP142 (1-50% of tumour cells cut off) 21 (lymphoepithelioma like histology) 15 (71%: 67% high, 33% low) Tiseo et al [38] TMA, clone E1L3 (H-score, 1% of tumor cells cut off) 87 16 (20%) 25 13 (52%) Bagir et al [39] Slides, clone AM26531AF-N (intensity) 37 21 (57%) 6 4 (67%) Sakane et al [40] Slides…”

“…[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]; overall, expression of PD-L1 is common in thymomas and thymic carcinomas, and is usually high and intense. In the micro-environment, a large Inhibition of autoimmune regulator leads to release of autoreactive lymphocytes and autoimmune disorders.…”

Prognostic and clinicopathological roles of programmed death‐ligand 1 (PD‐L1) expression in thymic epithelial tumors: A meta‐analysis

“…2 Complete resection is the first choice of treatment for TETs; however approximately 10%-30% of patients with TETs experience recurrence after surgery. 1,3 Various treatments have been tried in patients where surgery is not an option or in whom there has been disease recurrence, but the clinical outcomes are inconclusive. 3 Programmed death-ligand 1 (PD-L1) is one of the immune checkpoint proteins, and plays important roles in the progression and microenvironment of the cancer.…”

“…6 Several studies have also shown an association between PD-L1 expression and prognosis of patients diagnosed with TETs. 1,3,4,[7][8][9] However, the association of PD-L1 expression with the prognosis of TETs has not yet been systematically analyzed.…”