PDCD1 and breast cancer: The results revealed that differentially expressed IRGs in breast cancer were associated with PD-1/PD-L1-mediated immune escape, such as positive regulation of fibroblast proliferation, inflammatory response, positive regulation of ERK1 and ERK2 cascade, lymphocyte chemotaxis, estrogen signaling pathway, MAPK signaling pathway, NF-kappa B signaling pathway, Ras signaling pathway, and TNF signaling pathway.