GPR37 and breast cancer: We used overall survival analysis with the Kaplan-Meier plotter database to analyze the prognostic value of seven differentially expressed hub genes (FPR2, CXCR4, FPR1, CX3CL1, GPR37, GABBR2 and PLCB1) that were common in both the lung and brain metastases from breast cancer, but only GPR37 and FPR1 genes represent significantly (log-rank P = < 0.05) values (Fig 8A, S10 Table), as well as four specific hub genes of lung cell line (SAA1, CCR5, CCR3 and CXCL11) were significantly resulted with only two SAA1 and CCR5 genes (Fig 8B, S10 Table).