IL2 and cancer: IL2 has been recently labelled with 18F by conjugation with succinimidyl 4-18F-fluorobenzoate (18F-SFB) for in vivo imaging of tumour-infiltrating CD25+ activated T lymphocytes and for CXCR4 antagonist therapy monitoring, obtaining promising results that suggest 18F-FB-IL2 as a clinical non-invasive tool for cancer imaging and driving immunotherapy choice [150].