The control group consisted of 58 unrelated adult patients (patients of our center, their families and friends, as well as staff and students) with no history of NET in the themselves and their families, as well as other syndromes that may be part of the MEN1 syndrome: hyperparathyroidism, pituitary tumor, adrenal gland tumor; or in the composition of VHL: kidney cancer, phaeochromocytoma, or cerebral hemangiomas. Here, VHL is linked to hyperparathyroidism.