Recently, the analysis of six fibroblast markers: fibroblast activated protein (FAP), integrin β1/CD29, αsmooth muscle actin (αSMA), fibroblast surface protein (FSP1), platelet derived growth factor receptor β (PDGFRβ), and caveolin 1 (CAV1) has allowed the identification of four BrCa CAFs’ subsets that accumulate differentially in normal tissue and in BrCa subtypes, exerting different roles in tumor immunobiology and metastasis [11]. The gene discussed is ACTA1; the disease is neoplasm.