We performed a cytofluorimetric analysis aimed to evaluate the parallel expression of IFN-γ, TNFα, IL-10, IL-6, IL-4, IL-2 in the serum of 10 patients (8 males and 2 females, mean age: 67.4 ± 3.7, median age: 68) with intestinal (6 patients), bronchial (typical carcinoid, 2 patients), and breast NETs (2 patients) receiving treatment with lanreotide. Here, IL4 is linked to breast neuroendocrine neoplasm.