Nevertheless, after analysis of other monoamine transporters that could potentially internalize mIBG on the basis of their affinity for catecholamine, we demonstrated that either their affinity for mIBG was too low (PMAT, OCT1–3), or their expression on tumor cells was insufficient (DAT) despite a capacity to internalize mIBG comparable to NET. The gene discussed is SLC6A3; the disease is neoplasm.