IL2 and neoplasm: Beyond the scope of PET imaging, also promising molecular structures can be targeted using SPECT-ligands; 99mTc-labeled interleukin-2 (99mTc-HYNIC-IL2) allowed the visualization and quantification of tumor infiltrating lymphocytes in the set of patients undergoing immunotherapy; here, 99mTc-HYNIC-IL2 SPECT could be used as a potential imaging approach, e.