Fibroblast activation protein is not expressed in normal cardiac fibroblasts16; nevertheless, cardiac FAP activation has been reported under various pathologic conditions in animal models.5,17 The possibility of detecting fibroblast activity by FAPI PET/CT after MI has already been shown in a murine model.10 In our present in-human experience on cardiac FAPI tracer accumulation we could demonstrate that in an unselected cohort of individuals with malignancy about 20% of subjects showed distinct cardiac tracer accumulation. This evidence concerns the gene FAP and cancer.