POMC and neoplasm: ACTH-secreting tumor markedly express sst5 and D2R, and to a lesser extent sst1, 2 and 3 [160], but their pathobiology is more complex since, beside the corticotroph tumor, 70% of patients bear Cushing's disease showing circulating cortisol excess that can downregulate ACTH-cell sst2 expression leading to the lack of response to sst2 selective drugs, octreotide and lanreotide [74].