SLC18A2 and neoplasm: They observed a lower accumulation of [18F]-FDA compared to [18F]-DOPA in large liver lesions, presumably due to a decrease in NET expression following tumor dedifferentiation. Interestingly, when MPC cells were injected subcutaneously, only [18F]-DOPA PET, but not [18F]-FDA could detect the tumors and this may reflect the expression of VMAT 1 and VMAT2 in the tumor cells (Fig. 1) [42].