S100A4 and cancer: These differences may be a result of the tumor microenvironment heterogeneity of diverse cancer types and mutation types such as BRCA1 or BRCA2. Furthermore, a study that tracked the evolution of CAFs after injecting TNBC 4T1 fibroblasts into BALB/c mice noted a decline in the proportion of Pdpn-positive CAFs and a rise in S100A4-positive CAFs in a time-dependent manner [47].