While it is conceivable that SST may indirectly regulate effector T-cell responses by enhancing regulatory T-cell function, recent research implies that SST analogs, such as octreotide, may impede regulatory T-cell function in patients with neuroendocrine tumors by downregulating the expression of immune regulatory molecules, such as PD1 and CTLA4) (34). Here, CTLA4 is linked to neuroendocrine neoplasm.