FAP and metastatic colorectal cancer: Preclinical studies targeting FAPα+ fibroblasts with either a DNA vaccine against FAPα, an FAPα enzymatic inhibitor, an FAPα antibody, or chimeric antigen receptor T-cells targeting FAPα, also provided promising preclinical results in mice [243], but failed in clinical trials (phase II in metastatic colorectal cancer using a humanized anti-FAPα antibody or the inhibitor PT-100) [243,244].