Searches of PubMed and Embase identified 133 eligible studies.<h4>Results</h4>Nine tracers have currently been evaluated in clinical trials, targeting the following biomarkers: carcinoembryonic antigen, vascular endothelial growth factor, epidermal growth factor receptor, folate receptor α and/or β, integrin αvβ3, 5-aminolevulinic acid and acidic tumour microenvironment. This evidence concerns the gene CEACAM5 and neoplasm.