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PubMed1999

Somatic MEN1 gene mutation does not contribute significantly to sporadic pituitary tumorigenesis.

Pituitary adenomas are a common manifestation of multiple endocrine neoplasia type 1 (MEN1) but most of them occur sporadically. There are only a few well defined genetic abnormalities known to occur in these sporadic tumours. The MEN1 gene located on 11q13 has recently been cloned and allelic deletion and mutation analysis studies have implicated the MEN1 gene in a significant fraction of the sporadic counterparts of typical MEN1 neoplasms (parathyroid tumours, insulinomas and gastrinomas). To determine if MEN1 gene inactivation is also involved in the development of sporadic pituitary adenomas, allelic deletions of chromosome 11q13 and MEN1 gene mutations and polymorphisms were assessed in 35 sporadic tumours of the anterior pituitary (9 prolactin-secreting, 8 GH-secreting, 3 TSH-secreting, 2 TSH/GH-secreting, 4 Cushing, 9 silent). Thirty-one tumours were found to be heterozygous for at least one MEN1 intragenic polymorphism (25 cases) or for a flanking gene polymorphism (6 cases). The remaining tumours were not informative. No mutations were found in any tumour except in one prolactinoma which was homozygous or hemizygous for a mutation (1-117 C-->T) in a region close to the promoter. Unfortunately, blood or normal tissue was not available in this case. Our data show that somatic MEN1 mutations do not contribute significantly to tumorigenesis of sporadic pituitary adenomas and suggest that mutation of other genes are likely to contribute to the pathogenesis of these tumours.

Adenoma↗
PubMed1976

Multiple forms of corticotropin (adrenocorticotropic hormone, ACTH) and their significance.

Big corticotropin (adrenocroticotropic hormone, ACTH), an immunoreactive form of ACTH with low biological activity and which elutes in the void volume on Sephadex G-50 gel filtration, is found in plasma and extracts of human pituitary and tumour. Controlled tryptic digestion of big ACTH releases a product with full corticotropic activity which is indistinguishable from the (1-39) ACTH with respect to size, charge and susceptibility to tryptic digestion. Immunoreactive ACTH, predominantly in the big form, is found in virtually all tissue extracts of carcinoma primary to or metastatic from the lung, but not of carcinoma metastatic to the lung, and even in precancerous lung lesions. The absence of clinical Cushing syndrome in patients with carcinoma of the lung and moderate elevation of plasma concentrations of ACTH is due to the low biological activity of big ACTH. Prolonged survival (for more than two years) of patients with lung carcinoma has been observed only in those whose plasma ACTH is low before therapy or after resection of the lung tumour. Rabbit, rat and mouse pituitaries contain an intermediate sized ACTH but the usual 1-39 peptide predominates in the pituitaries of monkey, sheep, dog, cat and guinea pig, as well as man. The hormonal form of ACTH appears to be an important factor regulating the cortisol/corticosterone ratio in mammalian adrenal corticoid secretion because administration of porcine ACTH to rabbits alters the adrenal secretory pattern so as to decrease corticosterone production and increase cortisol production.

Addison Disease↗
PubMed1990

Multiple endocrine neoplasia: how many syndromes?

The phrase multiple endocrine neoplasia (MEN) generally denotes an association of tumors so specific as to constitute a syndrome. Three well-recognized such syndromes exist. All are autosomal dominant traits and all have been tentatively mapped to specific chromosomes. Other purported endocrine tumor syndromes have been suggested either as new entities or as subtypes of the existing MEN syndromes. The evidence in favor of these contentions is examined critically. Only one "new" association, that of pheochromocytomas and islet cell tumors, seems reasonable, and even in this setting, some relatives have had manifestations of von Hippel-Lindau syndrome. There is no compelling reason why such conditions as von Hippel-Lindau syndrome, peripheral neurofibromatosis, McCune-Albright syndrome, and others should be reclassified as MEN syndromes, although awareness of their collective endocrine abnormalities is clinically important.

Adenoma, Islet Cell↗
PubMed1989

Co-existence of two aneuploid stemlines in benign adenomas. A report of three cases with stemline heterogeneity.

The co-existence of 2 or more aneuploid stemlines (DNA multiploidy) has been described in malignant human neoplasms and such cancers have often been found to be associated with a poor prognosis. Here 3 benign human adenomas with 2 co-existing aneuploid stemlines are described. Despite DNA stemline heterogeneity and large DNA indices up to 2.8 none of the adenomas recurred or gave rise to metastases after a simple excision during the follow-up of 8, 10 and 11 years. Two adenomas were hormonally active. Marked cellular atypia and frequent mitoses were seen in 1 of the adenomas but the other 2 tumours had little atypia. The present cases indicate that DNA stemline heterogeneity may occur in benign adenomas, and not even the presence of 2 aneuploid stemlines with greatly increased nuclear DNA content can be regarded as a conclusive sign of malignancy.

Adenoma↗
PubMed1996

Genetic mapping studies of 40 loci and 23 cosmids in chromosome 11p13-11q13, and exclusion of mu-calpain as the multiple endocrine neoplasia type 1 gene.

Forty loci (16 polymorphic and 24 non-polymorphic) together with 23 cosmids isolated from a chromosome 11-specific library were used to construct a detailed genetic map of 11p13-11q13. The map was constructed by using a panel of 13 somatic cell hybrids that sub-divided this region into 19 intervals, a meiotic mapping panel of 33 multiple endocrine neoplasia type 1 (MEN1) families (134 affected and 269 unaffected members) and a mitotic mapping panel that was used to identify loss of heterozygosity in 38 MEN1-associated tumours. The results defined the most likely order of the 16 loci as being: 11pter-D11S871-(D11S288, D11S149)-11cen-CNTF-PGA-ROM1-D11S480-PYGM- SEA-D11S913-D11S970-D11S97- D11S146-INT2-D11S971-D11S533-11qter. The meiotic mapping studies indicated that the most likely location of the MEN1 gene was in the interval flanked by PYGM and D11S97, and the results of mitotic mapping suggested a possible location of the MEN1 gene telomeric to SEA. Mapping studies of the gene encoding mu-calpain (CAPN1) located CAPN1 to 11q13 and in the vicinity of the MEN1 locus. However, mutational analysis studies did not detect any germ-line CAPN1 DNA sequence abnormalities in 47 unrelated MEN1 patients and the results therefore exclude CAPN1 as the MEN1 gene. The detailed genetic map that has been constructed of the 11p13-11q13 region should facilitate the construction of a physical map and the identification of candidate genes for disease loci mapped to this region.

Animals↗
PubMed1983

Malignancies of the endocrine glands.

Patients with malignant tumors of the endocrine system can be effectively treated by surgery, the 5 year survival rate varying between 30-90 per cent, depending on organ involvement. In the Federal Republic of Germany, 1 out every 5 persons dies as a result of malignancy. Less than 1 per cent of the total annual rate of such deaths relates to malignancies originating in the endocrine glands.

Adolescent↗
PubMed2002

Multiple endocrine neoplasia type I.

Multiple endocrine neoplasia type I is a rare autosomal dominant disorder with many endocrine and nonendocrine manifestations. Hyperparathyroidism, islet cell tumors, and pituitary tumors are diagnosed most commonly in these patients. There is controversy regarding treatment of the different manifestations and screening modalities of this disorder because no large series has determined the best therapeutic approach. Our institution advocates early screening with biochemical and radiographic testing in patients with a definite predilection for this disorder. Patients with hyperparathyroidism should undergo early surgical intervention of at least three and a half glands combined with bilateral upper thymectomy through a cervical incision. Although the recurrence rate is high, disease-free survival can be for as long as 30 years. Pituitary tumors are predominantly prolactinomas and growth hormone-releasing tumors. Prolactinomas usually require pharmacologic therapy, whereas growth hormone-releasing tumors are treated surgically. Enteropancreatic tumors should be treated surgically or medically, depending on the hormone secreted. Insulinomas respond well to distal pancreatectomy, with enucleation of the tumor from the head and uncinate process of the pancreas. However, there is controversy regarding the surgical treatment of gastrinomas. Carcinoid tumors should be treated with early surgical intervention. Adrenal lesions are thought to occur in association with pancreatic lesions and commonly have an indolent course. Adrenocortical cancers are uncommon in patients with multiple endocrine neoplasia type I. Skin lesions can be excised when cosmetically unappealing.

Adult↗