GREM1 and breast cancer: In our study, two datasets including GSE125989 and GSE100534 were applied to identify DEGs between primary BC samples and BM samples, and then 19 overlapped DEGs were observed using the Venn diagram, including COL1A1, DPT, GREM1, CILP, POSTN, IGF1, COL3A1, THBS2, COL14A1, LUM, ACTA2, COL6A3, LRRC15, CCL19, MMP11, COL5A2, AOX1, KRT14, and GAP43.