SMO and cancer: Indeed, recent strategies to target CAFs include the use of the kinase inhibitor, imatinib to block stromal PDGF receptors [23], antibodies to block vascular endothelial growth factor (VEGF) derived from both cancer cells and CAFs to inhibit tumor angiogenesis [24] and the use of smoothened (Smo) inhibitors to block tumor-stromal Hedgehog signaling and deplete stromal fibroblasts that overexpress the hedgehog (Hh) receptor Smo [25], [26], [27], [28].