Another study developed a novel radiolabeled FAP inhibitor probe [18F]AlF-FAPI-74 for non-invasive monitoring of the effects of anti-FAP CAR T-cell therapy in solid tumors, demonstrating its potential for detecting changes in FAP expression in the tumor microenvironment and serving as a biomarker for predicting and monitoring response to FAP-targeted therapy [203]. Here, FAP is linked to neoplasm.