CXCR4 and neoplasm: Although such information is not available in the context of CXCR4-targeted endoradiotherapy, future studies investigating a tumor sink effect on [68Ga]Ga-PentixaFor PET should also consider potential receptor fluctuations prior to CXCR4-directed therapies, e.g., due to interaction of CXCR4 with other chemokine receptors on a subcellular level.