LAT1-specific PET radiotracers: Development and clinical experiences of a new class of cancer-specific radiopharmaceuticals.

Abstract

The quest for a cancer-specific positron emission tomography (PET) tracer has been ongoing for decades. Current evidence shows that targeting amino acid metabolism dysregulation is a valid alternative cancer detection method and can complement the conventional approach, which relies on targeting increased glucose metabolism. The rate of amino acid metabolism in all major organs is mostly equally low and does not change in any physiological dynamics. The amino acid metabolism rate only spikes in malignant tissues. PET imaging targeting LAT1 (L-type amino acid transporter 1) demonstrated accurate cancer imaging of various cancer types with nearly negligible background uptake. LAT1 is a pan-cancer biomarker of amino acid metabolism dysregulation. The upregulated LAT1 expression in cancer cells depicts their dynamic behavior and aggressiveness. This review discussed PET radiotracers developed as a LAT1-specific agent and how this new class of cancer-specific radiopharmaceuticals could deliver PET images with clinical properties we yearn for, such as high specificity toward various malignancies, robust non-cancer exclusion (mainly inflammatory reactions), accurate malignant lesion delineation, representative therapeutic monitoring, and long-term prognostication.