Hereditary NET syndromes present in common patterns, where mainly two pathways are involved: the regulation of the cyclin-dependent cell cycle (especially in MEN1 and MEN4) and the involvement of the PI3K/mTOR pathway (especially in autosomal dominant syndrome caused by a mutation in the tumor suppressor gene on the 11q13 chromosome encoding the menin protein, characterized by primary hyperparathyroidism, duodenopancreatic neuroendocrine neoplasms (NETs) and anterior pituitary tumors [120,121]. Here, MEN1 is linked to primary hyperparathyroidism.