PDCD1 and cancer: In addition, KEGG pathway enrichment analysis showed that the DMDGs were enriched in programmed cell death ligand 1 expression and programmed cell death protein 1(PD-1) checkpoint pathway in cancer, cellular senescence, and advanced glycation end product (AGE)-receptor for AGE (RAGE) signaling pathway in diabetic complication phenotype-related pathways (Figure 3B).