Question: Tumors of which three organs are classically associated with the multiple endocrine neoplasia type 1 syndrome?

Context:
Multiple endocrine neoplasia type 1 (MEN1; formerly known as Wermer syndrome) is a rare disorder characterized by the combined occurrence of two or more tumors involving parathyroid, pancreatic islets and anterior pituitary glands; some other tumors have also been described.
 Hyperparathyroidism is the most common feature of MEN1 (95% of patients), pancreatic islet tumors or pancreatic NET (neuroendocrine tumor) occur in 40-70% and pituitary tumors in 30-40% of MEN 1 patients
 In addition, other tumors, such as adrenal cortical tumors, carcinoid tumors, lipomas, angiofibromas, colagenomas and meningiomas may be present. 
the most important causes malignant pancreatic neuroendocrine tumors (NET) and thymic carcinoids. 
Multiple endocrine neoplasia type 1 (MEN1) is inherited in an autosomal dominant fashion and predisposes to the development of hyperplastic or neoplastic changes in the parathyroid and pituitary glands and the endocrine pancreas, along with numerous other characteristic tumors and features. 
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid and adrenocortical tumors, and neuroendocrine tumors (NETs) of the pancreas and pituitary. 
The pancreatic NETs are predominantly gastrinomas and insulinomas, and the pituitary NETs are mostly prolactinomas and somatotrophinomas. 
We address the potential role of miRNAs in the endocrine pancreas, the pituitary gland, and the parathyroid glands-areas where MEN 1 shows high penetrance. 
Moreover, studies have provided evidence that dysregulation of miRNAs was responsible for endocrine carcinogenesis, including pancreatic, pituitary, and parathyroid tumors.
MEN1 and MEN2 are rare inherited cancer syndromes which express a variety of endocrine and nonendocrine tumors.
Multiple endocrine neoplasia Type 1 (MEN1) is a rare hereditary tumor syndrome predisposing to tumor development in several endocrine organs.
 Its major manifestations include hyperparathyroidism, tumors of endocrine pancreas and pituitary. 
eside these three, several other endocrine (adrenocortical, foregut carcinoid) and nonendocrine (lipoma, angiofibroma, collagenoma, ependymoma, meningioma) tumors have been described to be associated with this syndrome
Both familial and sporadic forms of the disease are known. The diagnosis of MEN1 can be established if two of the three major manifestations are found in the same patient, whereas the diagnosis of familial MEN1 requires one MEN1 patient and a first degree relative with at least one MEN1 manifestation. 
Both benign (parathyroid, anterior pituitary) and malignant (gastrinoma, glucagonoma) lesions may develop in MEN1 patients
Multiple endocrine neoplasia type 1 (MEN1) is a classic hereditary tumor syndrome characterized by a genetic predisposition to develop a variety of neuroendocrine neoplasias and hormone excess syndromes.
Multiple endocrine neoplasia type 1 (MEN 1) is a familial syndrome characterized by parathyroid, enteropancreatic and pituitary tumors. 
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited tumor syndrome characterized by the development of multiple endocrine tumors
Multiple facial angiofibromas were observed in 28 (88%) of the patients with MEN1, with 16 patients (50%) having 5 or more. Angiofibromas were clinically and histologically identical to those in individuals with tuberous sclerosis. Collagenomas were observed in 23 patients (72%). Also observed were cafe au lait macules in 12 patients (38%), lipomas in 11 patients (34%), confetti-like hypopigmented macules in 2 patients (6%), and multiple gingival papules in 2 patients (6%)
Multiple angiofibromas, collagenomas, lipomas, confetti-like hypopigmented macules and multiple gingival papules are cutaneous manifestations of MEN1 and should be looked for in both family members of patients with MEN1 and individuals with hyperparathyroidism of other MEN1-associated tumors. 
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder characterized by nodular proliferation of the parathyroid glands and tumors of the anterior pituitary gland, the endocrine pancreas, and the neuroendocrine cell system of the gut.
We report here a genetic study of a female MEN1 patient with the association of nodular hyperplasia of two parathyroid glands, an insulinoma, multiple duodenal gastrinomas, a prolactinoma, and a gastric carcinoid.
Multiple endocrine neoplasia type 1 (MEN1) is defined clinically by the combined occurrence of multiple tumors, typically of the parathyroid glands, pancreatic islet cells, and anterior pituitary gland.
In support of previous findings in islet tumors, we found down-regulation of the cell-cycle regulator, p18, in both the pancreatic islet and pituitary adenomas, suggesting that reduced p18 levels may be important for Men1-related tumorigenesis in multiple tissues. Surprisingly, we identified increased p16 transcript in pancreatic islet and pituitary tumors. 
 The patient was studied and diagnosed with a multiple endocrine neoplasia type I (MEN I), familiar (mother with MEN I). A scintigraphic study with 99mTc-MIBI was performed in order to localize hyperfunctioning parathyroid glands because of biochemical diagnosis of primary hyperparathyroidism. 
The tumor was removed and histologically confirmed as a carcinoid within a thymus in a MEN type I syndrome. 
MEN I patients can benefit from the examination with this agent which can potentially localize not only parathyroid endocrine pathology but also unknown associated tumors.
Pancreatic endocrine tumors occur sporadically and as part of the multiple endocrine neoplasia type 1 (MEN 1) and von Hippel-Lindau (VHL) syndromes. 
We have analyzed 22 nonfamilial and 16 MEN 1-associated pancreatic endocrine tumors for loss of heterozygosity (LOH) at 3p, 11q13, and 18q. LOH at 3p was revealed in 45% and 36% of tumors from 31 patients with nonfamilial and MEN 1-associated disease, respectively.
The data indicate involvement of tumor suppressor genes on 3p and 18q, in addition to the MEN1 gene at 11q13, in the tumorigenesis of both nonfamilial and MEN 1-associated pancreatic endocrine tumors.
Multiple endocrine neoplasia type 1 (MEN1) is characterized by the development of endocrine tumors of the parathyroid and pituitary glands, pancreas, and duodenum. Less frequently occurring tumors associated with MEN1 include non-endocrine tumors such as lipomas and angiofibromas. 
An increased incidence of thyroid neoplasms, leiomyomas, adrenal cortical hyperplasia, hepatic focal nodular hyperplasia, and renal angiomyolipoma has been noted in the MEN1 population. 
A germline mutation of the MEN1 gene was detected, and deletions of the MEN1 gene were consistently detected in multiple neuroendocrine tumors involving the parathyroid glands and the pancreas and a hepatic neuroendocrine tumor metastasis, as predicted by Knudson's "two hit" hypothesis.
Two hits of the MEN1 gene were also detected in esophageal leiomyoma tissue, suggesting that tumorigenesis was directly related to the patient's underlying MEN1.
 In contrast, follicular thyroid adenoma, papillary thyroid carcinoma, hepatic focal nodular hyperplasia, and adrenal cortical hyperplasia consistently showed retained heterozygosity of the MEN1 gene with flanking markers and an intragenic marker. Therefore, these tumors appear to develop along pathogenetic pathways that are different from classical MEN1-associated tumors.
Twelve unrelated (German MEN1 families and their associated tumors (5 parathyroid tumors, 1 vipoma, 1 gastrinoma, 1 insulinoma) were characterized for MEN1 gene mutations by single-strand conformational variant (SSCV) analysis and DNA sequence analysis as well as for loss of heterozygosity on chromosome 11q13. 
Multiple endocrine neoplasia type 1 (MEN1) consists of benign, and sometimes malignant, tumors (often multiple in a tissue) of the parathyroids, enteropancreatic neuroendocrine system, anterior pituitary, and other tissues. Skin angiofibromas and skin collagenomas are common. 

Answer: Multiple endocrine neoplasia type 1 syndrome is an inherited cancer syndrome defined by occurrence of multiple neuro-endocrine tumors and is classically associated with the combined occurrence of two or more tumors involving parathyroid gland, pancreas and pituitary gland. Other tumors, including but not limited to adrenal cortical tumor, carcinoid tumors lipoma, leiomyoma, duodenal gastrinoma, hepatic focal nodular hyperplasia, and renal angiomyolipoma, angiofibroma, colagenoma, thyroid tumor and meningioma, may also be present.
Exact answer: parathyroid gland, pancreas, pituitary gland