ACTA1 and neoplasm: Vimentin is regarded as the bottommost marker of fibroblasts, and alpha-smooth muscle actin (α-SMA) is usually used to identify activated fibroblasts (myofibroblasts) which are also usually regarded as cancer-associated fibroblasts (CAFs) in the tumor microenvironment.25 Indeed, the reduced fibroblasts and myofibroblasts in the ageing intestinal microenvironment at A+D-d21 were observed (Fig. 3d).