Furthermore, although the majority of NETs are sporadic tumors, a proportion of them (10–15%) are attributable to familial cancer syndrome, like Multiple Endocrine Neoplasia (MEN) 1 and 2, von-Hippler-Lindau Syndrome and Tuberous Sclerosis Complex 1 (TSC-1) and Tuberous Sclerosis Complex 2 (TSC-2) [24]. This evidence concerns the gene TSC2 and multiple endocrine neoplasia type 1.