A differential gene analysis was performed between the high and low PTGDS expression groups (divided by mean PTGDS mRNA level), which indicated that PTGDS was positively correlated with immune-related pathways in breast cancer, including the lymphocyte transmembrane migration pathway, T cell signalling pathway, B cell signalling pathway and NK cell-mediated cytotoxicity (Figure S8A). The gene discussed is PTGDS; the disease is breast cancer.