S100A4 and breast cancer: Zhao et al. [131] loaded S100A4 siRNA (siS100A4) onto cationic bovine serum albumin (CBSA) and coated it with a breast cancer cell-derived exosome membrane to produce pharmaceutical nanoparticles (CBSA/siS100A4@Exosome) that targeted the lungs and silenced the S100A4 expression to avoid metastasis of triple-negative breast cancer (TNBC) to the lungs and inhibit tumorigenesis (Figure 5).