SPARC and cancer: These data demonstrate that CAFs adopt a myofibroblastic phenotype in co-culture with cancer cells in vitro and that this process can be inhibited by treatment with PDE5i, despite the presence of cancer cells, resulting in down-regulation of myofibroblast genes such as ACTA2 (α-SMA), myosin light-chain kappa (MYLK), osteonectin (SPARC), and transgelin (TAGLN) (Figure 5D).