The major milestones towards the clinical translation of nanobody-based PET probes are currently the phase II study of a 68Ga-NOTA-labeled anti-HER2 nanobody in HER2-positive breast cancer patients (40) and the phase I/II study of a [68Ga]Ga-NOTA-anti-MMR (Macrophage Mannose Receptor) for the detection of tumor-associated macrophages (TAM) (41). This evidence concerns the gene MRC1 and breast cancer.