PDCD1 and esophageal cancer: In two cohorts of esophageal cancer, the expression of PD-1, PD-L1, TIGIT and TIM-3 was downregulated in CD3+CD4+ T and CD3+CD8+ T cells in patients well responding to 2 and 4 Gy RT while PD-1, PD-L1 and TIGIT were elevated in those poorly [127].