Further studies revealed that in the TME, increased IGFBP7 secretion by CAFs further promoted the expression and secretion of fibroblast growth factor 2 (FGF2) in CAFs, and FGF2 acted on the fibroblast growth factor receptor (FGFR1) on the surface of TAMs, which in turn activated the PI3K/AKT signaling pathway to promote the infiltration and polarization of TAMs.[58] Wang and colleagues reported that collagen-containing triple helical repeat sequence-1 (CTHRC1) was highly expressed in breast cancer cells and that its high expression was associated with poor prognosis. This evidence concerns the gene FGF2 and breast cancer.