In vivo fluorescence imaging in mouse models of metastatic pheochromocytomas and paragangliomas

Pheochromocytomas (PHEOs) and extra-adrenal paragangliomas (PGLs) are rare adrenaline-producing tumors. The two tumor types are closely related and are distinguished primarily by their location: pheochromocytomas occur in the center of the adrenal glands while extra-adrenal paragangliomas originate in the paraganglia of the sympathetic nervous system (most commonly in the abdomen). Extra-adrenal paragangliomas are less common, but more likely to be malignant, than pheochromocytomas.
Diagnosis of metastatic PHEOs/PGLs is difficult and tends to rely on identification of adrenaline/noradrenaline production in areas where adrenaline/noradrenaline is not normally produced. Furthermore, such metastases are notoriously difficult to treat. A variety of chemotherapy combinations and radiotherapy are used as palliative treatment, but complete remission is rare.
Consequently, the mouse pheochromocytoma mCherry tumor allograft model was developed, which is functionally similar to human PHEO/PGLs. This mouse model has recently been used to assess the value of the [177Lu]Lu-DOTA-(Tyr3)octreotate (DOTATATE), a labeled somatostatin receptor analog, as a targeted therapy for metastatic PHEO/PGLs in man. And this study confirms that the mCherry model is a uniquely powerful tool for evaluating therapeutic or diagnostic agents that specifically target the somatostatin-2 receptor.

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