PYGM

Gene Summary

Gene:PYGM; glycogen phosphorylase, muscle associated
Location:11q13.1
Summary:This gene encodes a muscle enzyme involved in glycogenolysis. Highly similar enzymes encoded by different genes are found in liver and brain. Mutations in this gene are associated with McArdle disease (myophosphorylase deficiency), a glycogen storage disease of muscle. Alternative splicing results in multiple transcript variants.[provided by RefSeq, Sep 2009]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:glycogen phosphorylase, muscle form
Source:NCBIAccessed: 09 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 10 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 09 March, 2017 using data from PubMed, MeSH and CancerIndex

Latest Publications: PYGM (cancer-related)

Dieci MV, Smutná V, Scott V, et al.
Whole exome sequencing of rare aggressive breast cancer histologies.
Breast Cancer Res Treat. 2016; 156(1):21-32 [PubMed] Related Publications
Little is known about mutational landscape of rare breast cancer (BC) subtypes. The aim of the study was to apply next generation sequencing to three different subtypes of rare BCs in order to identify new genes related to cancer progression. We performed whole exome and targeted sequencing of 29 micropapillary, 23 metaplastic, and 27 pleomorphic lobular BCs. Micropapillary BCs exhibit a profile comparable to common BCs: PIK3CA, TP53, GATA3, and MAP2K4 were the most frequently mutated genes. Metaplastic BCs presented a high frequency of TP53 (78 %) and PIK3CA (48 %) mutations and were recurrently mutated on KDM6A (13 %), a gene involved in histone demethylation. Pleomorphic lobular carcinoma exhibited high mutation rate of PIK3CA (30 %), TP53 (22 %), and CDH1 (41 %) and also presented mutations in PYGM, a gene involved in glycogen metabolism, in 8 out of 27 samples (30 %). Further analyses of publicly available datasets showed that PYGM is dramatically underexpressed in common cancers as compared to normal tissues and that low expression in tumors is correlated with poor relapse-free survival. Immunohistochemical staining on formalin-fixed paraffin-embedded tissues available in our cohort of patients confirmed higher PYGM expression in normal breast tissue compared to equivalent tumoral zone. Next generation sequencing methods applied on rare cancer subtypes can serve as a useful tool in order to uncover new potential therapeutic targets. Sequencing of pleomorphic lobular carcinoma identified a high rate of alterations in PYGM. These findings emphasize the role of glycogen metabolism in cancer progression.

Iida Y, Aoki K, Asakura T, et al.
Hypoxia promotes glycogen synthesis and accumulation in human ovarian clear cell carcinoma.
Int J Oncol. 2012; 40(6):2122-30 [PubMed] Related Publications
Ovarian clear cell carcinoma (OCCC) has several significant characteristics based on molecular features that are distinct from those of ovarian high-grade serous carcinoma. Cellular glycogen accumulation is the most conspicuous feature of OCCC and in the present study its metabolic mechanism was investigated. The amount of glycogen in cells cultured under hypoxia increased significantly and approximately doubled after 48 h (P<0.01) compared to that under normoxic conditions. Periodic acid-Schiff positive staining also demonstrated intracellular glycogen storage. Western blot analysis revealed that HIF1α, which was overexpressed and stabilized under hypoxic conditions, led to an increase in the levels of cellular glycogen synthase 1, muscle type (GYS1), and conversely to a decrease in inactive phosphorylated GYS1 at serine (Ser) 641. Additional increases were observed in both protein phosphatase 1, which dephosphorylates and thereby induces GYS1 enzyme activity, and glycogen synthase kinase 3 beta (GSK3β) phosphorylated at Ser9, which is inactive on phosphorylation of GYS1 and subsequently induces its enzyme activity. By contrast, the level of PYGM-b decreased. These results indicated that the glycogen accumulation under a hypoxic environment resulted in the promotion of glycogen synthesis, but did not lead to inhibition of glycogen degradation and/or consumption. Under hypoxic conditions, HAC2 cells showed activation of the PI3K/AKT pathway caused by a mutation in exon 20 of PIK3CA, encoding the catalytic subunit p110α of PI3K. The resulting activation of AKT (phosphoSer473) also plays a role as a central enhancer in glycogen synthesis through suppression of GSK3β via phosphorylation at Ser9. Hypoxia decreased the cytocidal activity of cisplatin and doxorubicin to various degrees. In conclusion, the hypoxic conditions together with HIF1 expression and stabilization increased the intracellular glycogen contents and resistance to the anticancer drugs.

Marini F, Carbonell Sala S, Falchetti A, et al.
The genetic ascertainment of multiple endocrine neoplasia type 1 syndrome by ancient DNA analysis.
J Endocrinol Invest. 2008; 31(10):905-9 [PubMed] Related Publications
Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant inherited endocrine cancer syndrome characterised by parathyroid, pancreas, and anterior pituitary tumors. The disease responsible gene, MEN1, was identified in 1997 and localizes to chromosome 11q13 in a minimal 600 kb interval between PYGM and D11S449 loci. About 10-20% of MEN1 patients do not have any mutation in the coding region and/or in the exon-intron junctions of the MEN1 gene. In this case, familial haplotype analysis of the 11q13 region, in at least two generations of affected members, is the only possible genetic ascertainment of the disease. We performed a microsatellite haplotype analysis at 11q13 region in 8 living and 1 deceased member of a MEN1 Italian family without any detected germline mutation of the MEN1 gene. The application of forensic techniques for ancient DNA analysis made it possible to identify the familial disease-associated haplotype and demonstrated that MEN1 disease haplotype family history can be reconstructed even when one or more family members are deceased. Identification of MEN1 disease haplotype is helpful in the clinical management of patients and relatives in families without any mutation of the MEN1 gene. Genetic screening allows the identification of individuals who are at risk before the development of clinical symptoms, limiting invasive annual cancer surveillance only to genetically positive individuals and making it possible to avoid further clinical screenings in non-carriers.

Vageli D, Daniil Z, Dahabreh J, et al.
Microsatellite instability and loss of heterozygosity at the MEN1 locus in lung carcinoid tumors: a novel approach using real-time PCR with melting curve analysis in histopathologic material.
Oncol Rep. 2006; 15(3):557-64 [PubMed] Related Publications
The possible causes and genetic mechanisms of pulmonary carcinoid tumor development are unclear. In this study, we examined genetic alterations at the MEN1 locus in archival material from 15 pulmonary carcinoids. We employed, for the first time in this setting, real-time PCR with melting curve analysis in order to identify loss of heterozygosity (LOH) or microsatellite instability (MI) in two polymorphic markers (PYGM, D11S449) at the MEN1 locus and one additional marker (D11S906) of a putative oncosuppressive region distal to the MEN1 gene. Sequencing data were available in a selected subset of tumors in order to verify the reliability of real-time PCR analysis. We observed LOH at PYGM in 38% of the cases and MI in 13.3% of the cases. Our data indicate that real-time PCR with melting curve analysis is a reliable technique for LOH and MI detection and indicate that genetic errors at the MEN1 locus but also distal to it may be involved in the development of sporadic pulmonary carcinoid tumors.

Maire G, Forus A, Foa C, et al.
11q13 alterations in two cases of hibernoma: large heterozygous deletions and rearrangement breakpoints near GARP in 11q13.5.
Genes Chromosomes Cancer. 2003; 37(4):389-95 [PubMed] Related Publications
Hibernomas are rare, benign tumors with a histological appearance resembling that of brown adipose tissue. The diagnosis of hibernomas may be difficult because some of them contain only a small number of the characteristic multivacuolated fat cells and can be mistakenly classified as well-differentiated liposarcomas. Cytogenetic information has been reported for 10 cases, showing that these tumors are characterized by structural rearrangements involving 11q13. Previous fluorescence in situ hybridization (FISH) studies revealed consistent and sometimes cryptic losses of the MEN1 region in 11q13.1. Here, we describe the molecular cytogenetic analysis of two new hibernoma cases. Both tumors showed complex rearrangements, simultaneously including translocations, inversions, and deletions affecting the pair of chromosomes 11. The translocation partners were chromosome 5 in one case and chromosomes 16 and 22 in the other case. The 11q13 region was concomitantly rearranged on both chromosomes 11. FISH studies revealed large heterozygous deletions within the 11q13 band, from 11q13.1 to 11q13.5. Genes such as PYGM, MEN1, CCND1, FGF3, ARIX, and GARP were deleted, showing that the size of the 11q13 altered region was larger than previously reported. Furthermore, both tumors had breakpoints in 11q13.5, one of them in the immediate proximity of the GARP gene. Our results suggest that rearrangements of GARP or a neighboring gene may be important for the pathogenesis of hibernomas.

Cetani F, Pardi E, Giovannetti A, et al.
Genetic analysis of the MEN1 gene and HPRT2 locus in two Italian kindreds with familial isolated hyperparathyroidism.
Clin Endocrinol (Oxf). 2002; 56(4):457-64 [PubMed] Related Publications
OBJECTIVES: Familial hyperparathyroidism may occur as part of hereditary syndromes, including multiple endocrine neoplasia types 1 and 2 (MEN1 and MEN2A), hyperparathyroidism-jaw tumour (HPT-JT) syndrome and familial isolated hyperparathyroidism (FIHP). It is unclear whether the latter is a distinct genetic entity or a variant of MEN1 or HPT-JT, where, because of reduced penetrance, only primary hyperparathyroidism (PHPT) is present. In the present study, we describe two unrelated Italian kindreds with FIHP, in which the clinical, histopathological and genetic analyses of the MEN1 gene and HPRT2 locus at 1q21-32 suggest that both might be a variant of MEN1 and HPT-JT syndromes.
PATIENTS AND DESIGN: We studied 16 members, aged 14-50 years, of two unrelated kindreds with FIHP. Genomic DNA was isolated from peripheral blood leucocytes in all family members, and from parathyroid tissue in those who underwent parathyroidectomy.
MEASUREMENTS: Ionized calcium and PTH were measured in all family members. The nine coding exons and 16 splice junctions of the MEN1 gene from constitutional DNA were amplified by the polymerase chain reaction (PCR) and sequenced. Parathyroid glands were obtained from five subjects. Allelic deletions (loss of heterozygosity, LOH) of chromosomes 11q13 and 1q21-q32 were assessed using PYGM and D11S449, and D1S215, D1S222, D1S428, D1S412, D1S413 and D1S477, respectively. Forward primers were conjugated with 5' fluorescent dye. PCR products were analysed using an ABI PRISM 310 sequencer.
RESULTS: Five members of family 1 and three of family 2 had PHPT. A heterozygous deletion of 1 bp of the MEN1 gene in exon 10 (1785delA) was found in affected members of family 1. No MEN1 gene mutation was found in any member of family 2. LOH at 11q13 was observed in family 1 tumours, but not in those from family 2. Studies at 1q21-32 showed LOH in two family 2 tumours, whereas a retained heterozygosity was found in the remaining member. No LOH at 1q21-32 was found in family 1 tumours. The pathology of family 1 showed chief cell hyperplasia with a diffuse-nodular pattern of growth. Cut surface showed no cystic structures. Typical parathyroid adenoma was diagnosed in one member of family 2 and atypical adenoma in the remaining two. These tumours showed cystic structures.
CONCLUSIONS: In conclusion, we describe two unrelated kindreds with FIHP which, on the basis of histopathological and genetic studies, could be labelled as variants of the MEN1 and HPT-JT syndromes, respectively. Therefore, an extensive analysis of the genes involved in these diseases should be performed in families with familial isolated hyperparathyroidism to identify the subset linked to the MEN1 gene or to the HPRT2 locus.

Asteria C, Anagni M, Persani L, Beck-Peccoz P
Loss of heterozygosity of the MEN1 gene in a large series of TSH-secreting pituitary adenomas.
J Endocrinol Invest. 2001; 24(10):796-801 [PubMed] Related Publications
Thyrotropin-secreting pituitary adenomas (TSH-omas) are rare tumors (0.5% of all pituitary adenomas) showing an invasive behavior and usually sporadic, although a few cases are associated with multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant inherited syndrome. This disorder is linked to loss of heterozygosity (LOH) on 11q13 and inactivating mutations of MEN1 gene, which is located in the same chromosomal region. As other types of anterior pituitary adenomas, TSH-omas are the result of a monoclonal outgrowth where the intrinsic genetic defects involving oncogenes or tumor suppressor genes occur in a progenitor cell. However, so far no activating mutations of particular oncogenes or inactivating mutations of tumor suppressor genes have been identified. Starting from the observation that 3-30% of sporadic pituitary adenomas show LOH on 11q13, and that allelic losses on the long arms of chromosome 11, beside 10 and 13, are significantly associated with the transition from the non-invasive to the invasive phenotype, we decided to investigate LOH on 11q13 and mutations of menin in a large series of TSH-omas. Thirteen tumors were evaluated. DNA was extracted from tumors by standard methods and genomic DNA from peripheral blood leukocytes was used as control. LOH was screened by using 3 polymorphic markers on 11q13: D11S956, PYGM, INT-2. In 3 out of 15 cases we could demonstrate LOH on 11q13, but none of the tumors showed menin mutation after sequence analysis. These data strongly suggest that menin does not play a causative role in the development of TSH-omas, and are in agreement with other studies demonstrating a limited role of menin in pituitary sporadic tumorigenesis.

Pannett AA, Thakker RV
Somatic mutations in MEN type 1 tumors, consistent with the Knudson "two-hit" hypothesis.
J Clin Endocrinol Metab. 2001; 86(9):4371-4 [PubMed] Related Publications
MEN type 1 is an autosomal dominant disorder characterized by the combined occurrence of tumors of the parathyroids, anterior pituitary, and pancreatic islet cells. The MEN1 gene, which is located on chromosome 11q13, consists of 10 exons and encodes a 610-amino acid protein named MENIN. The observation of LOH involving 11q13 in MEN type 1 tumors and the inactivating germline mutations found in patients suggest that the MEN1 gene acts as a tumor suppressor, in keeping with the "two-hit" model of hereditary cancer. The second hit in MEN type 1 tumors typically involves large chromosomal deletions that include 11q13. However, this only represents one mechanism by which the second hit may occur, and the other mechanisms, such as intragenic deletions or point mutations that inactivate the gene, have not been reported in MEN type 1 tumors. We have therefore undertaken studies to search for such mutations in six MEN type 1 tumors (four parathyroid tumors, one insulinoma, and one lipoma) that did not have LOH at 11q13 as assessed using the flanking markers D11S480, D11S1883 and PYGM centromerically and D11S449 and D11S913 telomerically. This revealed four somatic mutations, which consisted of two missense mutations and two frameshift mutations in two parathyroid tumors, one insulinoma, and one lipoma. Thus, our results, which represent the first small intragenic somatic mutations reported in MEN type 1 tumors, provide further evidence that the role of the MEN1 gene is consistent with that of a tumor suppressor gene, as postulated by Knudson's "two-hit" hypothesis.

McKeeby JL, Li X, Zhuang Z, et al.
Multiple leiomyomas of the esophagus, lung, and uterus in multiple endocrine neoplasia type 1.
Am J Pathol. 2001; 159(3):1121-7 [PubMed] Free Access to Full Article Related Publications
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant hereditary disorder characterized by multiple parathyroid, pancreatic, duodenal, and pituitary neuroendocrine tumors. Nonendocrine mesenchymal tumors, such as lipomas, collagenomas, and angiofibromas have also been reported. MEN1-associated neuroendocrine and some mesenchymal tumors have documented MEN1 gene alterations on chromosome 11q13. To test whether the MEN1 gene is involved in the pathogenesis of multiple smooth muscle tumors, we examined the 11q13 loss of heterozygosity (LOH) and clonality patterns in 15 leiomyomata of the esophagus, lung, and uterus from five patients with MEN1. Forty sporadic uterine leiomyomata were also studied for 11q13 LOH. LOH analysis was performed using four polymorphic DNA markers at the MEN1 gene locus; D11S480, PYGM, D11S449, and INT-2. 11q13 LOH was detected in 10 of 12 (83%) MEN1-associated esophageal and uterine smooth muscle tumors. In contrast, LOH at the MEN1 gene locus was demonstrated only in 2 of 40 (5%) sporadic uterine tumors. LOH at 11q13 was not documented in three lung smooth muscle tumors from a single patient with MEN1. Ten tumors from two female patients were additionally assessed for clonality by X-chromosome inactivation analysis. The results demonstrated different clonality patterns in multiple tumors in the same organ in each individual patient. The data indicate that leiomyomata of the esophagus and uterus in MEN1 patients arise as independent clones, develop through MEN1 gene alterations, and are an integral part of MEN1. However, the MEN1 gene is not a significant contributor to the tumorigenesis of sporadic uterine leiomyomata.

Petzmann S, Ullmann R, Klemen H, et al.
Loss of heterozygosity on chromosome arm 11q in lung carcinoids.
Hum Pathol. 2001; 32(3):333-8 [PubMed] Related Publications
Neuroendocrine lung tumors such as typical carcinoid, atypical carcinoid, small-cell lung carcinoma, and large-cell neuroendocrine carcinoma represent a variable group with different biologic characteristics and unclear genetical relationships. We investigated the pattern of allelic loss on chromosome arm 11q in 20 sporadic carcinoid tumors of the lung using 10 microsatellite markers. Loss of heterozygosity was found in 13 of 20 tumors. In 5 of 9 typical carcinoids, 3 distinct regions of allelic loss were identified: 11q13.1 (D11S1883), 11q14.3-11q21 (D11S906), and 11q25 (D11S910). Atypical carcinoids showed loss of heterozygosity at 4 different regions: the first, most proximal region at 11q13 between markers PYGM and D11S937; the second at 11q14.3-11q21 (D11S906); and the third and fourth defined by markers D11S939 (11q23.2-23.3) and D11S910 (11q25). However, the region 11q13 harboring the MEN1 gene was more frequently affected in atypical carcinoids (7 of 11) than in typical carcinoids (2 of 9). The high rate of allelic losses within chromosomal region 11q13 in atypical carcinoids emphasizes the importance of this region for tumor development. We also recognized that more aggressive atypical carcinoids defined by high mitotic counts, vascular invasion, and/or organ metastasis are combined with increased allelic losses. HUM PATHOL 32:333-338.

Papillon E, Rolachon A, Calender A, et al.
A malignant gastrointestinal stromal tumour in a patient with multiple endocrine neoplasia type 1.
Eur J Gastroenterol Hepatol. 2001; 13(2):207-11 [PubMed] Related Publications
Loss of heterozygosity for polymorphic markers flanking the multiple endocrine neoplasia type 1 (MEN-1) gene in parathyroid and pancreatic islet tumours from subjects with MEN-1 has been well documented and has led to the hypothesis that the MEN-1 gene functions as a recessive tumour suppressor gene. We report a case of MEN-1 with duodeno-pancreatic gastrinoma, parathyroid hyperplasia, pituitary adenoma, adrenal adenoma, and lipomas, whose rare association with a malignant gastrointestinal stromal tumour (GIST) represents an undescribed combination. MEN-1 mutation in this family was shown as a frameshift (1607delA) in exon 10. To assess the role of the MEN-1 gene in the pathogenesis of tumours less commonly associated with MEN-1, we studied GIST DNA for loss of the unaffected MEN-1 gene allele. Stromal tumour and peripheral leucocyte DNAs from our patient were examined for loss of heterozygosity using the PYGM microsatellite polymorphism and an intragenic polymorphism (D418D in exon 9) in the MEN-1 gene. We showed no evidence for loss of the wild-type MEN-1 allele in GIST. The MEN-1 germline inactivating mutation 1607delA-ter558 in exon 10 was detected in the stromal tumour DNA, but no somatic mutation in the wild-type MEN-1 allele in GIST DNA was detected. Occurrence of GIST could be consistent with the possibility that this MEN-1-related uncommon neoplasm arose independently by a mechanism unrelated to the MEN-1 gene.

Schulte KM, Heinze M, Mengel M, et al.
Complete sequencing and mRNA expression analysis of the MEN-I gene in adrenal myelolipoma.
Horm Metab Res. 2000; 32(5):169-73 [PubMed] Related Publications
The molecular pathogenesis of adrenal myelolipoma is unclear. Endocrine activity of these tumors and association with other endocrine tumors have stimulated the hypothesis that it may belong to the group of sporadic tumors caused by defects of the gene responsible for multiple endocrine neoplasia type I (MEN-I). DNA of blood and tumoral sections from two patients with adrenal myelolipoma were analyzed by examination of variable number of tandem repeats (VNTR) loci PYGM, D11S987, D11S480, and D11S449 on chromosome 11q13 and by complete direct DNA sequencing of all coding exons and splice junctions of the MEN-I gene. Menin expression was examined by RT-PCR. RT-PCR did not detect menin expression in one adrenal myelolipoma. No loss of heterozygozity on chromosome 11q13 was identified. Intragenic heterozygozity was retained in codon 418 of the menin gene in both patients. No mutation was identified in the coding exons of the menin gene. Complete DNA sequencing yielded no hint that defects of the MEN-I gene are responsible for the formation of adrenal myelolipomas. Adrenal myelolipomas do not share the loss of heterozygozity on chromosome 11q13 observed in some benign adenomatous and many malignant adrenocortical tumors.

Zwermann O, Beuschlein F, Mora P, et al.
Multiple endocrine neoplasia type 1 gene expression is normal in sporadic adrenocortical tumors.
Eur J Endocrinol. 2000; 142(6):689-95 [PubMed] Related Publications
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder with neoplasia of the anterior pituitary, the parathyroid, the endocrine pancreas and other endocrine tissues including the adrenal cortex. The tumor-suppressor gene causing this disease was identified at the gene locus 11q13. We recently reported that adrenocortical carcinomas frequently show loss of heterozygosity (LOH) of 11q13, but do not contain point mutations within the MEN1-coding region. To investigate whether reduced gene expression (for example by mutations within the MEN1 promoter) may contribute to the tumorigenesis of sporadic adrenocortical tumors, 24 adrenocortical specimen were studied by Northern blot analysis. This series included six adrenocortical carcinomas, four cortisol-producing adenomas, six aldosterone-producing adenomas, three endocrine-inactive adenomas and six normal adrenal glands. The presence of LOH of 11q13 was investigated using five polymorphic microsatellite markers (D11S956, PYGM, D11S4939, D11S4946 and D11S987) close to the MEN1 gene. Poly-A mRNA was hybridized with a PCR-generated cDNA probe of the MEN1 gene, a cDNA of the former MEN1 candidate gene phospholipase (PLC) beta3 and a mouse beta-actin cDNA for normalization. LOH of 11q13 was detected in five out of six carcinomas and two inactive adenomas, but in none of the hormone-producing adenomas. Compared with normal adrenals (100+/-6. 5%, mean+/-s.e.m.) MEN1 mRNA in adrenocortical tumors was expressed in similar amounts (carcinomas 109+/-11%, cortisol-producing adenomas 131+/-10%, aldosterone-producing adenomas 113+/-13%, endocrine-inactive adenomas 111+/-2%) with the exception of one adrenocortical carcinoma with low MEN1 mRNA expression (66%). PLCbeta3 mRNA expression showed a variable pattern without reaching significant differences between the groups. We conclude that since mRNA levels were unaltered in the majority of tumors, mutations of the MEN1 gene causing altered gene transcription is unlikely to be a major pathogenic factor of sporadic adrenocortical tumors.

Schulte KM, Heinze M, Mengel M, et al.
MEN I gene mutations in sporadic adrenal adenomas.
Hum Genet. 1999; 105(6):603-10 [PubMed] Related Publications
Loss of heterozygosity (LOH) on chromosome 11q13 occurs in about 20% of sporadic adrenal neoplasms. Adrenal lesions, mostly benign, occur in up to 40% of patients from MEN I kindreds. The MEN I gene, positioned on 11q13, has been considered a primary candidate gene in these lesions. We studied a group of 15 patients with sporadic adrenal adenoma, and 1 patient with multinodular hyperplasia. Of the 16 patients, 4 had incidentally discovered masses, 5 had Conn's syndrome, 6 suffered from Cushing's syndrome, and 9 had high sex hormone production. Studies with the markers D11S480, PYGM, D11S449, and D11S987 in 13 patients (12 of whom were from our group of 16) revealed 4 losses of heterozygosity on D11 S480 on 11q13, but the deletion did not affect the MEN I gene in any case. We present complete direct DNA sequencing data of the menin gene in 14 sporadic adrenal adenomas and one with adrenal hyperplasia. We identified one heterozygous missense mutation, T552S, in a hormonally inactive adrenal adenoma. One base exchange was identified close to the intron-exon boundary in intron 9 of a nodular adrenal hyperplasia. mRNA expression studies found that MEN I was transcribed in all 13 samples analyzed. In summary, our study identified the second patient with sporadic benign adrenal tumor presenting a menin gene mutation. Our complete direct sequencing approach adds evidence that menin gene mutations may account only for a minority of benign adrenal tumors if at all. Another tumor-suppressor gene inactivated in sporadic adrenal neoplasms may be located on chromosome 11q13.

Lininger RA, Zhuang Z, Man Y, et al.
Loss of heterozygosity is detected at chromosomes 1p35-36 (NB), 3p25 (VHL), 16p13 (TSC2/PKD1), and 17p13 (TP53) in microdissected apocrine carcinomas of the breast.
Mod Pathol. 1999; 12(12):1083-9 [PubMed] Related Publications
INTRODUCTION: Apocrine carcinomas of the breast are an unusual special category of predominantly AR+, ER-, and PR- breast cancer, characterized by cells with abundant, eosinophilic cytoplasm and nuclei with often prominent nucleoli. To further investigate these lesions, loss of heterozygosity (LOH) was evaluated at multiple chromosomal loci, including loci frequently mutated in breast cancer.
MATERIALS AND METHODS: Twenty-five intraductal apocrine carcinomas, 11 invasive apocrine carcinomas, and six apocrine hyperplasias were retrieved from the files of the Armed Forces Institute of Pathology (Washington, DC) and Fairfax Hospital (Fairfax, VA). Cells from lesional as well as normal tissues were microdissected. LOH was performed at a number of chromosomal loci, including loci commonly altered in breast cancer: 1p35-36 (NB), 3p25.5 (VHL), 8p12 (D8S136), 9p21 (p16), 11p13 (D11S904), 11q13 (INT-2 and PYGM), 16p13.3 (TSC2/PKD1 gene region), 17p13 (TP53), 17q13 (NM23), and 22q12 (D22S683).
RESULTS: Among informative in situ and invasive apocrine carcinomas, LOH was present in 33% of 15 cases for 17p13 (TP53), as well as 36% of 14 cases for 3p25 (VHL), 30% of 10 cases for 1p35-36 (NB), and 27% of 11 cases for 16p13.3 (TSC2/PKD1). A higher frequency of LOH was noted among invasive apocrine carcinomas (30 to 50%) compared with in situ apocrine carcinomas (23 to 33%) at these loci. LOH was present simultaneously for TP53 and either VHL or NB in five cases. Infrequent (< or =12%) or absent LOH was detected at the remaining loci, including several loci commonly mutated in breast cancer (i.e., INT2, PYGM, and NM23). LOH was not detected in any of the six apocrine hyperplasias.
CONCLUSION: An intermediate frequency of allelic loss was detected at multiple tumor suppressor gene loci, including 17p13 (TP53), as well as 1p35-336 (NB), 3p25 (VHL), and 16p13 (PKD1/ TSC2), in apocrine carcinomas of the breast, with a higher overall frequency of LOH noted among invasive tumors compared with in situ tumors. Aside from LOH at p53, LOH was infrequent or absent at several other loci commonly mutated in breast cancer. This preliminary molecular evidence supports immunohistochemical data that apocrine carcinomas of the breast may possess unique mechanisms of carcinogenesis, compared with ordinary ductal carcinomas. However, further study is needed to support this assertion and to determine if the LOH detected is truly etiologic or if it is the result of genetic progression.

Sanz-Ortega J, Bryant B, Sanz-Esponera J, et al.
LOH at the APC/MCC gene (5Q21) is frequent in early stages of non-small cell lung cancer.
Pathol Res Pract. 1999; 195(10):677-80 [PubMed] Related Publications
Lung cancer is the leading cause of death in both women and men in the United States and many European countries. Molecular cytogenetic and LOH analyses of non-small cell lung cancer have shown somatic genetic alterations in a variety of chromosomes, such as 1p, 3p, 5q, 8p, 9p, 11p, 11q and 17p. Allelic deletions of the known tumor suppressor gene APC at 5q21 are frequently observed in advanced stages of lung cancer and have been correlated with poor prognosis in previous reports. We investigated 33 cases of NSCL for LOH at 5q21: 22 squamous cell and 11 adenocarcinomas. Normal and tumor cells were microdissected from paraffin embedded tissues and PCR amplification was performed utilising the specific markers D5S299 and D5S346 at 5q21 and PYGM at 11q13, respectively. Clinicopathological data, survival and recurrence rates were obtained in all cases. We detected LOH at 5q21 in 4/9 (44%) informative adenocarcinomas and in 13/16 (81%) informative SCC. LOH was frequent in early stages (12/15 stage I cases) and did not correlate with recurrence or poor survival. Our results show that LOH at 5q21 is more frequent in squamous cell carcinomas than in adenocarcinomas, is frequent in early stages of the disease, and does not have prognostic significance.

Böni R, Vortmeyer AO, Huang S, et al.
Mutation analysis of the MEN1 tumour suppressor gene in malignant melanoma.
Melanoma Res. 1999; 9(3):249-52 [PubMed] Related Publications
During the initiation and progression of malignant melanoma a series of genetic events accumulate, including alterations of chromosome 11q. Recently, an important tumour suppressor gene, the multiple endocrine neoplasia type 1 (MEN1) gene, has been mapped on 11q13 and has been cloned. To assess whether the MEN1 region is involved in tumour initiation and progression, we analysed 23 primary cutaneous melanomas and 17 metastases for loss of heterozygosity (LOH) using two informative polymorphic markers closely linked to the MEN1 gene (PYGM and D11S449). To search for mutations within the gene, single-strand conformation polymorphism (SSCP) analysis was performed using 13 primer sets with designed intronic sequences to amplify the MEN1 coding sequence exons 2 to 10. None of the cases showed LOH at the MEN1 gene locus. By SSCP analysis, no aberrant bands were identified on exons 3 to 10. Analysis of exon 2 revealed the presence of aberrant bands in two of the analysed melanomas. Sequencing analysis revealed a genetic polymorphism at S145S (AGC-->ACT) in both sections. None of the cases analysed showed MEN1 gene mutations. This study represents the first genetic analysis of the MEN1 gene in sporadic melanomas. Our data demonstrate no evidence of deletion or mutation of the MEN1 gene in primary or metastatic melanoma. Therefore, MEN1 gene alterations appear not to be associated with tumorigenesis of malignant melanoma. The MEN1 gene appears to be a highly specific tumour suppressor gene only involving tumours within the spectrum of MEN1 disease.

Watanabe T, Tsukamoto F, Shimizu T, et al.
Familial isolated hyperparathyroidism caused by single adenoma: a distinct entity different from multiple endocrine neoplasia.
Endocr J. 1998; 45(5):637-46 [PubMed] Related Publications
Familial hyperparathyroidism (FHPT) is a hereditary disease where hyperparathyroidism (HPT) is transmitted in an autosomal dominant fashion. FHPT consists of a variety of diseases such as multiple endocrine neoplasia type1 (MEN 1) and type2 (MEN 2), familial isolated hyperparathyroidism (FIHPT) with single adenoma and with multiple adenomas (or hyperplasia), and FHPT with jaw-tumor (FHPT-JT). Isolation of the genes responsible for MEN1, and 2, i.e. MEN1 and RET, respectively, makes it possible to examine the relations among disorders constituting FHPT. We studied germ-line mutations in these 2 genes in a family of FHPT with single parathyroid adenoma. The disorder in this family was proved to be an entity different from MEN1 because no germ-line mutations in MEN1 gene were found in the affected members. The loss of heterozygosity (LOH) at MEN1 gene and PYGM were not found in the abnormal parathyroid in this family, supporting the above conclusion. No mutations in exons 10, and 11 of RET proto-oncogene was found in germ-line DNA of the affected member of the family, suggesting no relation to MEN2A. Linkage study excluded the possibility of FHPT-JT syndrome. PRAD1 was not overexpressed in the parathyroid tumors in this family. The relation of this disorder to FIHPT with multiple enlarged parathyroid glands remains to be clarified. A search for the gene(s) predisposing to FIHPT is needed.

Farrell WE, Simpson DJ, Bicknell J, et al.
Sequence analysis and transcript expression of the MEN1 gene in sporadic pituitary tumours.
Br J Cancer. 1999; 80(1-2):44-50 [PubMed] Free Access to Full Article Related Publications
The majority of pituitary tumours are monoclonal in origin and arise sporadically or occasionally as part of multiple endocrine neoplasia type 1 (MEN1). Whilst a multi-step aetiology involving both oncogenes and tumour suppressor genes has been proposed for their development, the target(s) of these changes are less clearly defined. Both familial and sporadic pituitary tumours have been shown to harbour allelic deletion on 11q13, which is the location of the recently cloned MEN1 gene. We investigated 23 sporadic pituitary tumours previously shown to harbour allelic deletion on 11q13 with the marker PYGM centromeric and within 50 kb of the MEN1 locus. In addition, the use of intragenic polymorphisms in exon 9 and at D11S4946, and of telomeric loci at D11S4940 and D11S4936, revealed that five of 20 tumours had loss of heterozygosity (LOH) telomeric to the menin gene. However, the overall pattern of loss in informative cases was indicative of non-contiguous deletion that brackets the menin gene. Sequence analysis of all MEN1 coding exons and flanking intronic sequence, in tumours and matched patient leucocyte DNA, did not reveal mutation(s) in any of the 23 tumours studied. A benign polymorphism in exon 9 was encountered at the expected frequency, and in seven patients heterozygous for the polymorphism the tumour showed retention of both copies of the menin gene. Reverse transcription polymerase chain reaction analysis of ten evaluable tumours and four normal pituitaries revealed the presence of the menin transcript. Whilst these findings suggest that gene silencing is unlikely to be mechanistic in sporadic pituitary tumorigenesis, they do not exclude changes in the level or stability of the transcript or translation to mature protein. Our study would support and extend very recent reports of a limited role for mutations in the MEN1 gene in sporadic pituitary tumours. Alternatively, these findings may point to an, as yet, unidentified tumour suppressor gene in this region.

D'Adda T, Keller G, Bordi C, Höfler H
Loss of heterozygosity in 11q13-14 regions in gastric neuroendocrine tumors not associated with multiple endocrine neoplasia type 1 syndrome.
Lab Invest. 1999; 79(6):671-7 [PubMed] Related Publications
Loss of heterozygosity (LOH) at the MEN1 gene locus at 11q13 is commonly found in type II gastric carcinoid tumors, which are associated with multiple endocrine neoplasia type 1 (MEN-1). In contrast, information is scanty or absent for other types of gastric neuroendocrine tumors, represented by type I carcinoids (associated with chronic atrophic gastritis), type III (sporadic) carcinoids, and neuroendocrine carcinomas. Moreover, LOH analysis of the allelic region distal to the MEN1 gene, which is postulated to contain an additional tumor suppressor gene effective in MEN-1-associated and sporadic endocrine tumors, has never been performed. To clarify these issues, DNA extracted from archival tissue from 25 type I carcinoids, 4 type III carcinoids, and 2 neuroendocrine carcinomas was amplified by PCR, using primers for six polymorphic markers located on chromosome 11q13 (PYGM, D11S4946, and D11S913) and 11q14 (D11S916, D11S901, and D11S1365), for analysis of LOH. Allelic losses in the 11q13-14 region with at least two polymorphic markers were found in 12 of 25 (48%) type I carcinoids. When LOH was found in the 11q13 region, it was large and continuous and extended to the most telomeric marker investigated. In one tumor, retention of heterozygosity for markers in the MEN1 region and LOH for distal markers were observed. No LOH was found in three of four type III carcinoids. Large deletions in both the 11q13 and 11q14 regions were observed in both neuroendocrine carcinomas investigated. In conclusion, LOH in the 11q13-14 regions is frequently found in type I carcinoids and neuroendocrine carcinomas of the stomach, suggesting the involvement of the MEN1 gene and/or a more telomeric tumor suppressor gene in the pathogenesis of these non-MEN-1-associated neuroendocrine tumors. The low rate of LOH at 11q13-14 suggests the predominance of different genetic mechanisms in type III carcinoids, which also differ from other types of gastric carcinoids in the lack of a promoter role for gastrin.

Kjellman M, Roshani L, Teh BT, et al.
Genotyping of adrenocortical tumors: very frequent deletions of the MEN1 locus in 11q13 and of a 1-centimorgan region in 2p16.
J Clin Endocrinol Metab. 1999; 84(2):730-5 [PubMed] Related Publications
To identify chromosomal regions that may contain loci for tumor suppressor genes involved in adrenocortical tumor development, a panel of 60 tumors (39 carcinomas and 21 adenomas) were screened for loss of heterozygosity. Although the vast majority of loss of heterozygosity (LOH) were detected in the carcinomas and involved chromosomes 2, 4, 11, and 18, only few were found in the adenomas. Therefore, 2 loci that harbor the familial cancer syndromes Carney complex in 2p16 and the multiple endocrine neoplasia type 1 gene in 11q13 were further studied in 27 (13 carcinomas and 14 adenomas) of the 60 tumors. Detailed analysis of the 2p16 region mapped a minimal area of overlapping deletions to a 1-centimorgan region, which is separate from the Carney complex locus. LOH for a microsatellite marker (PYGM), very close to the MEN1 gene, was detected in all 8 informative carcinomas (100%) and in 2 of 14 adenomas. Of the 27 cases analyzed in detail, 13 cases (11 carcinomas and 2 adenomas) showed LOH on chromosome 11 and was therefore selected for MEN1 gene mutation analysis. In 6 cases a common polymorphism (Asp418Asp) was found, but no mutation was detected. In conclusion, our data indicate the existence of tumor suppressor genes at multiple chromosomal locations, whose inactivations are involved in the development of adrenocortical carcinomas. Loss of genetic material from 2p16 was strongly associated with the malignant phenotype, as it was seen in almost all carcinomas but not in any of the adenomas. LOH in 11q13 also occurred frequently in the carcinomas, but was not associated with a MEN1 mutation, suggesting the involvement of a different tumor suppressor gene on this chromosome.

Görtz B, Roth J, Speel EJ, et al.
MEN1 gene mutation analysis of sporadic adrenocortical lesions.
Int J Cancer. 1999; 80(3):373-9 [PubMed] Related Publications
To clarify the role of the MEN1 gene in the tumorigenesis of sporadic adrenocortical tumors, we performed a molecular study on 35 adrenocortical lesions including 6 hyperplasias, 19 adenomas and 10 carcinomas. Loss of heterozygosity (LOH) of the MEN1 gene was assessed by PCR using an intragenic (D11S4946) and 2 flanking microsatellite markers (D11S4936, PYGM) and/or fluorescence in situ hybridization (FISH) with a 40-kb cosmid probe containing the MEN1 gene. The complete coding sequence of the MEN1 gene was screened for mutations using non-radioactive, PCR-based single-strand conformation polymorphism (SSCP) analysis and MDE heteroduplex gel electrophoresis. PCR-LOH and FISH analyses performed in 29 tumors (PCR-LOH in 4, FISH in 17 and both in 8 tumors) revealed allelic deletion of the MEN1 locus in 8 (27.5%) and at 11q13 in 9 (31%) tumors. Furthermore, the frequency of LOH at 11q13 was significantly higher in adrenocortical carcinomas (60%) than in benign lesions (11%). Mutation analysis of tumor samples revealed 9 polymorphisms in 7 tumors (S145S, R171Q, R171Q together with L432L) but no mutations, with the exception of one adrenocortical adenoma. The latter tumor contained a somatic E109X stop codon mutation in exon 2 and a 5178-9G-->A splice mutation in intron 4, which was also detectable in various nontumorous tissues and blood indicative of a germ-line mutation. The patient, who had no clinical signs or family history of MEN1, later also developed a neuroendocrine carcinoma (atypical carcinoid) of the lung. Our findings indicate that inactivating mutations of the MEN1 tumor-suppressor gene appear not to play a prominent role in the development of sporadic hyperplastic or neoplastic lesions of the adrenal cortex and that the newly reported 5178-9G-->A splice mutation in intron 4 might cause a variant of the MEN1 phenotype.

Gadelha MR, Prezant TR, Une KN, et al.
Loss of heterozygosity on chromosome 11q13 in two families with acromegaly/gigantism is independent of mutations of the multiple endocrine neoplasia type I gene.
J Clin Endocrinol Metab. 1999; 84(1):249-56 [PubMed] Related Publications
Familial acromegaly/gigantism occurring in the absence of multiple endocrine neoplasia type I (MEN-1) or the Carney complex has been reported in 18 families since the biochemical diagnosis of GH excess became available, and the genetic defect is unknown. In the present study we examined 2 unrelated families with isolated acromegaly/gigantism. In family A, 3 of 4 siblings were affected, with ages at diagnosis of 19, 21, and 23 yr. In family B, 5 of 13 siblings exhibited the phenotype and were diagnosed at 13, 15, 17, 17, and 24 yr of age. All 8 affected patients had elevated basal GH levels associated with high insulin-like growth factor I levels and/or nonsuppressible serum GH levels during an oral glucose tolerance test. GHRH levels were normal in affected members of family A. An invasive macroadenoma was found in 6 subjects, and a microadenoma was found in 1 subject from family B. The sequence of the GHRH receptor complementary DNA in 1 tumor from family A was normal. There was no history of consanguinity in either family, and the past medical history and laboratory results excluded MEN-1 and the Carney complex in all affected and unaffected screened subjects. Five of 8 subjects have undergone pituitary surgery to date, and paraffin-embedded pituitary blocks were available for analysis. Loss of heterozygosity on chromosome 11q13 was studied by comparing microsatellite polymorphisms of leukocyte and tumor DNA using PYGM (centromeric) and D11S527 (telomeric), markers closely linked to the MEN-1 tumor suppressor gene. All tumors exhibited a loss of heterozygosity at both markers. Sequencing of the MEN-1 gene revealed no germline mutations in either family, nor was a somatic mutation found in tumor DNA from one subject in family A. The integrity of the MEN-1 gene in this subject was further supported by demonstration of the presence of MEN-1 messenger ribonucleic acid, as assessed by RT-PCR. These data indicate that loss of heterozygosity in these affected family members appears independent of MEN-1 gene changes and suggest that a novel (tissue-specific?) tumor suppressor gene(s) linked to the PYGM marker and expressed in the pituitary is essential for regulation of somatotrope proliferation.


The search for the MEN1 gene. The European Consortium on MEN-1.
J Intern Med. 1998; 243(6):441-6 [PubMed] Related Publications
The search for the gene whose mutations predispose individuals to multiple endocrine neoplasia type 1 (MEN-1) started in 1988 when the MEN1 locus was assigned to 11q13, close to PYGM. It came to an end with the recent identification of a gene expressed ubiquitously which harbours inactivating mutations associated with MEN-1. During these nine years, the genetic linkage interval had been slowly reduced, and losses of heterozygosity (LOH) in MEN-1 tumours had given strong indications that MEN1 was a tumour suppressor gene. It is ironic that MEN1 was finally found to be located less than 100 kb telomeric to PYGM. From the beginning, this gene was the most tightly linked genetically to MEN-1. In addition, LOH had already shown (in 1990) that it was the most likely centromeric boundary of the MEN1 minimal region. We recently narrowed the critical region to 900 kb through meiotic mapping, and established a 1200-kb sequence-ready contig consisting of cosmids, bacterial artificial chromosomes (BACs) and P1-derived artificial chromosomes (PACs), including three gene clusters (19 genes and 3 expressed sequence tags). Taking LOH results into account, the gene was likely to be present in the 300-kb area telomeric to PYGM that we had covered with BACs. One of the novel genes that we have identified by cDNA selection in this region, SCG2 (Suppressor Candidate Gene 2), proved to be identical to the recently published MEN1 gene. Mutation analysis of SCG2 in 11 unrelated MEN-1 families identified one nucleotide sequence polymorphism and 10 different mutations that segregated with the disease.

Chakrabarti R, Srivatsan ES, Wood TF, et al.
Deletion mapping of endocrine tumors localizes a second tumor suppressor gene on chromosome band 11q13.
Genes Chromosomes Cancer. 1998; 22(2):130-7 [PubMed] Related Publications
Multiple endocrine neoplasia type 1 syndrome (MEN1, MIM 131100), an autosomal dominant disease, is characterized by parathyroid hyperplasia, pancreatic endocrine tumors, and pituitary adenomas. These tumors also occur sporadically. Both the familial (MEN1) and the sporadic tumors reveal loss of heterozygosity (LOH) for chromosome band 11q13 sequences. Based on prior linkage and LOH analyses, the MEN1 gene was localized between PYGM and D11S460. Recently, the MEN1 gene (menin) has been cloned from sequences 30-kb distal to PYGM. We performed deletion mapping on 25 endocrine tumors (5 MEN1 and 20 sporadic) by using 21 polymorphic markers on chromosome band 11q13. Of these, two (137C7A, 137C7B) were derived from PYGM-containing BAC (bacterial artificial chromosome-137C7) sequences, one from INT2-containing cosmid sequences and the marker D11S4748, a (CA)20 repeat marker that was developed by us. The LOH analysis shows that the markers close to the MEN1 (menin) gene were not deleted in three of the tumors. These tumors, however, showed LOH for distal markers. Thus, the data suggest the existence of a second tumor suppressor gene on chromosome band 11q13.

Emmert-Buck MR, Debelenko LV, Agarwal S, et al.
11q13 allelotype analysis in 27 northern American MEN1 kindreds identifies two distinct founder chromosomes.
Mol Genet Metab. 1998; 63(2):151-5 [PubMed] Related Publications
We analyzed constitutional and tumor DNA from 27 MEN1 kindreds not known to be related to each other. Disease allele haplotypes were constructed for each pedigree based on shared alleles from two or more affected members and from determination of allelic loss patterns in their tumors. Analysis of disease allele haplotypes showed unexpected linkage disequilibrium at marker PYGM. Further haplotype analysis indicated this could be explained by the presence of two founder chromosomes, one in four families, the other in three. A shared disease haplotype was not observed among two MEN1 kindreds with the prolactinoma phenotype of MEN1.

Manickam P, Guru SC, Debelenko LV, et al.
Eighteen new polymorphic markers in the multiple endocrine neoplasia type 1 (MEN1) region.
Hum Genet. 1997; 101(1):102-8 [PubMed] Related Publications
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder in which affected individuals develop tumors primarily in the parathyroids, anterior pituitary, endocrine pancreas, and duodenum. The locus for MEN1 is tightly linked to the marker PYGM on chromosome 11q13, and linkage analysis has previously placed the MEN1 gene within a 2-Mb interval flanked by markers D11S1883 and D11S449. Loss of heterozygosity (LOH) studies in MEN1 and sporadic tumors have helped narrow the location of the gene to a 600-kb interval between PYGM and D11S449. Eighteen new polymerase chain reaction (PCR)-based polymorphic markers were generated for the MEN1 region, with ten mapping to the PYGM-D11S449 interval. These new markers, along with 14 previously known polymorphic markers, were precisely mapped on a 2.8-Mb (D11S480-D11S913) high-density clone contig-based, physical map generated for the MEN1 region.

Kedra D, Seroussi E, Fransson I, et al.
The germinal center kinase gene and a novel CDC25-like gene are located in the vicinity of the PYGM gene on 11q13.
Hum Genet. 1997; 100(5-6):611-9 [PubMed] Related Publications
Multiple endocrine neoplasia type 1 (MEN1) is tightly linked to the muscle-type glycogen phosphorylase (PYGM) gene in 11q13. This region of the human genome contains additional disease-related loci implicated in the development of insulin-dependent diabetes mellitus, familial paraganglioma type 2, spinocerebellar ataxia type 5, Bardet-Biedl syndrome and translocation t(11;17) described in B-cell non-Hodgkin's lymphoma. We approached cloning of candidate disease genes from 11q13 by large-scale genomic sequencing. We obtained > 106 kb of sequence around the PYGM gene and established a transcriptional map that includes: (i) two genes previously localized to 11q13, PYGM and a zinc-finger protein (ZFM1) gene; (ii) the germinal center kinase (GCK, human B-lymphocyte serine/threonine protein kinase) gene; (iii) a novel human CDC25-like (HCDC25L) gene; (iv) a dystrophia myotonica protein kinase-like (DMPKL) gene; and (v) a novel ubiquitously expressed gene of unknown function (germinal center kinase- neighboring gene, GCKNG).

Forbes SA, Pannett AA, Bassett JH, et al.
Mapping of the gene encoding the B56 beta subunit of protein phosphatase 2A (PPP2R5B) to a 0.5-Mb region of chromosome 11q13 and its exclusion as a candidate gene for multiple endocrine neoplasia type 1 (MEN1).
Hum Genet. 1997; 100(3-4):481-5 [PubMed] Related Publications
The multiple endocrine neoplasia type 1 (MEN1) locus has been previously localised to 11q13 by combined tumour deletion mapping and recombination studies, and a 0.5-Mb region, flanked by PYGM and D11S449, has been defined. In the course of constructing a conting, we have identified the location of the gene encoding the B56 beta subunit of protein phosphatase 2A (PP2A), which is involved in cell signal transduction pathways and thus represents a candidate gene for MEN1. We have searched for mutations in the PP2A-B56 beta coding region, together with the 5' and 3' untranslated regions in six MEN1 patients. DNA sequence abnormalities were not identified and thus the PP2A-B56 beta gene is excluded as the candidate gene for MEN1. However, our precise localisation of PP2A-B56 beta to this region of 11q13 may help in elucidating the basis for other disease genes mapping to this generich region.

Lemmens I, Merregaert J, Van de Ven WJ, et al.
Construction of a 1.2-Mb sequence-ready contig of chromosome 11q13 encompassing the multiple endocrine neoplasia type 1 (MEN1) gene. The European Consortium on MEN1.
Genomics. 1997; 44(1):94-100 [PubMed] Related Publications
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant familial cancer syndrome characterized by parathyroid, pancreatic, and anterior pituitary tumors. The MEN1 locus has been previously localized to chromosome 11q13, and a 2-Mb gene-rich region flanked by D11S1883 and D11S449 has been defined. We have pursued studies to facilitate identification of the MEN1 gene by narrowing this critical region to a 900-kb interval between the VRF and D11S1783 loci through melotic mapping. This was achieved by investigating 17 cosmids for microsatellite polymorphisms, which defined two novel polymorphisms at the VRF and A0138 loci, and utilizing these to characterize recombinants in MEN1 families. In addition, we have established a 1200-kb sequence-ready contig consisting of 26 cosmids, eight BACs, and eight PACs that encompass this region. The precise locations for 19 genes and three ESTs within this contig have been determined, and three gene clusters consisting of a centromeric group (VRF, FKBP2, PNG, and PLCB3), a middle group (PYGM, ZFM1, SCG1, SCG2 (which proved to be the MEN1 gene), and PPP2R5B), and a telomeric group (H4B, ANG3, ANG2, ANG1, FON, FAU, NOF, NON, and D11S2196E) were observed. These results represent a valuable transcriptional map of chromosome 11q13 that will help in the search for disease genes in this region.

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