Clinical Translation of [Ga]Ga-NOTA-anti-MMR-sdAb for PET/CT Imaging of Protumorigenic Macrophages.

Purpose: Macrophage mannose receptor (MMR, CD206) expressing tumor-associated macrophages (TAM) are protumorigenic and was reported to negatively impact therapy responsiveness and is associated with higher chances of tumor relapse following multiple treatment regimens in preclinical tumor models. Since the distribution of immune cells within the tumor is often heterogeneous, sampling "errors" using tissue biopsies will occur. In order to overcome this limitation, we propose positron emission tomography (PET)/X-ray computed tomography (CT) imaging using Ga-labeled anti-MMR single-domain antibody fragment (sdAb) to assess the presence of these protumorigenic TAM.