Indeed, several CAF populations have been identified in different cancer types by combining the study of several CAF markers, such as Fibroblast Activation Protein (FAP), Smooth Muscle-α Actin (SMA) and Regulator of G protein signaling 5 (RGS5)10–24, later confirmed with the development of single cell RNA sequencing (scRNAseq)14,17,20,21,25–33. Here, RGS5 is linked to cancer.