PDCD1 and neoplasm: Among these DEGs, 11 genes (NGFR, TNFSF11, PDCD1LG2, CD274, TNFRSF1A, TNFRSF11B, TMIGD2, FAS, TNFRSF10D, TNFSF13 and CD86) were down-regulated while 29 genes (TNFRSF17, TNFRSF13B, CD276, TNFRSF12A, LTBR, TNFSF18, EDAR, TNFRSF14, ICOSLG, RELT, CD28, ICOS, LTA, TNFRSF21, TNFRSF10C, VTCN1, TNFRSF11A, LTB, EDA2RC, TLA4, TNFSF9, TNFRSF25, PDCD1, CD70, TNFSF4, TNFRSF9, TNFRSF18, TNFSF15 and TNFRSF4) were up-regulated in tumor tissues (Fig. 2A and Additional file 1: Table S1).