Succinate Dehydrogenase (SDH) D Subunit (SDHD) Inactivation in a Growth-Hormone-Producing Pituitary Tumor: A New Association for SDH?
Section on Endocrinology and Genetics, Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Building 10, CRC, Room 1-3330, 10 Center Drive, MSC1103, Bethesda, Maryland 20892, USA. The Journal of Clinical Endocrinology and Metabolism
(Impact Factor: 6.21).
12/2011; 97(3):E357-66. DOI: 10.1210/jc.2011-1179
Mutations in the subunits B, C, and D of succinate dehydrogenase (SDH) mitochondrial complex II have been associated with the development of paragangliomas (PGL), gastrointestinal stromal tumors, papillary thyroid and renal carcinoma (SDHB), and testicular seminoma (SDHD).
Our aim was to examine the possible causative link between SDHD inactivation and somatotropinoma.
A 37-yr-old male presented with acromegaly and hypertension. Other family members were found with PGL. Elevated plasma and urinary levels of catecholamines led to the identification of multiple PGL in the proband in the neck, thorax, and abdomen. Adrenalectomy was performed for bilateral pheochromocytomas (PHEO). A GH-secreting macroadenoma was also found and partially removed via transsphenoidal surgery (TTS). Genetic analysis revealed a novel SDHD mutation (c.298_301delACTC), leading to a frame shift and a premature stop codon at position 133 of the protein. Loss of heterozygosity for the SDHD genetic locus was shown in the GH-secreting adenoma. Down-regulation of SDHD protein in the GH-secreting adenoma by immunoblotting and immunohistochemistry was found. A literature search identified other cases of multiple PGL and/or PHEO in association with pituitary tumors.
We describe the first kindred with a germline SDHD pathogenic mutation, inherited PGL, and acromegaly due to a GH-producing pituitary adenoma. SDHD loss of heterozygosity, down-regulation of protein in the GH-secreting adenoma, and decreased SDH enzymatic activity supports SDHD's involvement in the pituitary tumor formation in this patient. Older cases of multiple PGL and PHEO and pituitary tumors in the literature support a possible association between SDH defects and pituitary tumorigenesis.
Available from: David A Cano
- "Around 15–40% of FIPA patients harbor germline mutations in the aryl hydrocarbon receptor interacting protein gene (AIP) gene. More recently, it has been suggested that mutations in succinate dehydrogenase genes can predispose to pituitary tumors although the evidence is limited to a single kindred of patients (46). "
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ABSTRACT: Animal models constitute valuable tools for investigating the pathogenesis of cancer as well as for preclinical testing of novel therapeutics approaches. However, the pathogenic mechanisms of pituitary-tumor formation remain poorly understood, particularly in sporadic adenomas, thus, making it a challenge to model pituitary tumors in mice. Nevertheless, genetically engineered mouse models (GEMMs) of pituitary tumors have provided important insight into pituitary tumor biology. In this paper, we review various GEMMs of pituitary tumors, highlighting their contributions and limitations, and discuss opportunities for research in the field.
Available from: Kimberly J Bussey
- "For example, BRAF mutations are highly prevalent in thyroid cancer and other cancers, and are associated with more aggressive disease in thyroid cancer , . SDHB mutations were initially identified in familial paraganglioma, but were later found to be prevalent in kidney cancers and gastrointestinal stromal tumors, and recently pituitary tumors , , . Thus, discovering the molecular changes associated with endocrine cancer initiation and/or progression is likely to play an important role in a broad group of human malignancies. "
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Several members of the zinc finger protein family have been recently shown to have a role in cancer initiation and progression. Zinc finger protein 367 (ZNF367) is a member of the zinc finger protein family and is expressed in embryonic or fetal erythroid tissue but is absent in normal adult tissue.
We show that ZNF367 is overexpressed in adrenocortical carcinoma, malignant pheochromocytoma/paraganglioma and thyroid cancer as compared to normal tissue and benign tumors. Using both functional knockdown and ectopic overexpression in multiple cell lines, we show that ZNF367 inhibits cellular proliferation, invasion, migration, and adhesion to extracellular proteins in vitro and in vivo. Integrated gene and microRNA expression analyses showed an inverse correlation between ZNF367 and miR-195 expression. Luciferase assays demonstrated that miR-195 directly regulates ZNF367 expression and that miR-195 regulates cellular invasion. Moreover, integrin alpha 3 (ITGA3) expression was regulated by ZNF367.
Our findings taken together suggest that ZNF367 regulates cancer progression.
Available from: Anthony J Gill
- "Including this case, of the 9 pituitary adenomas reported in association with confirmed SDH mutation, the mean age has been 45 years (range, 30 to 62 y), and 6 have occurred in men. Seven have had hormone production documented clinically or by IHC, of which 6 have been prolactin-producing macroadenomas21,24,26 and 1 a growth hormone–secreting macroadenoma.25 In addition, the clinically nonfunctioning pituitary macroadenoma arising in the setting of germline SDHA mutation, which we recently described,23 also demonstrated positive IHC staining for prolactin (previously unreported data). "
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ABSTRACT: Germline mutations in the succinate dehydrogenase genes (SDHA, SDHB, SDHC, and SDHD) are established as causes of pheochromocytoma/paraganglioma, renal carcinoma, and gastrointestinal stromal tumor. It has recently been suggested that pituitary adenomas may also be a component of this syndrome. We sought to determine the incidence of SDH mutation in pituitary adenomas. We performed screening immunohistochemistry for SDHB and SDHA on all available pituitary adenomas resected at our institution from 1998 to 2012. In those patients with an abnormal pattern of staining, we then performed SDH mutation analysis on DNA extracted from paraffin-embedded tissue, fresh frozen tissue, and peripheral blood. One of 309 adenomas (0.3%) demonstrated an abnormal pattern of staining, a 30 mm prolactin-producing tumor from a 62-year-old man showing loss of staining for both SDHA and SDHB. Examination of paraffin-embedded and frozen tissues confirmed double-hit inactivating somatic SDHA mutations (c.725_736del and c.989_990insTA). Neither of these mutations was present in the germline. We conclude that, although pathogenic SDH mutation may occur in pituitary adenomas and can be identified by immunohistochemistry, it appears to be a very rare event and can occur in the absence of germline mutation. SDH-deficient pituitary adenomas may be larger and more likely to produce prolactin than other pituitary adenomas. Unless suggested by family history and physical examination, it is difficult to justify screening for SDH mutations in pituitary adenomas. Surveillance programs for patients with SDH mutation may be tailored to include the possibility of pituitary neoplasia; however, this is likely to be a low-yield strategy.
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