CAF-induced signaling pathways not discussed above, including Notch,303–305 Hedgehog,306–308 p53,309–312 Rho/Rock,313,314 HIF-1α,44,315–317 and peroxisome proliferator-activated receptor (PPAR)318–320 signaling cascades, have been widely studied to understand CAFs crosstalk with cancer cells. This evidence concerns the gene HIF1A and cancer.