The succinate dehydrogenase (SDH) enzyme was proven to be the most important molecular pathway involved in pheochromocytomas, along with several other genes.
In this study, we investigated mutations of SDH genes in six HPPS patients from four Japanese pedigrees using peripheral blood lymphocytes (from one patient with pheochromocytoma and five patients with neck paraganglioma) and tumor tissues (from two patients with paraganglioma).
Clinical, biochemical, pathological attributes, and outcomes in the MEN-PCC group were correlated with the genotype, and further compared with non-MEN, apparently sporadic adrenal-PCCs (n = 132, excluding 37 extra-adrenal and 15 VHL/NF1/SDH-associated PCC).
Transcriptional profiling analysis classified the tumor within cluster 2 of PCCs/PGLs (without SDH gene mutations) and identified downregulation of genes involved in neuronal development and homeostasis (NLGN4, CD99 and CSF2RA) as well as upregulation of Drosha, an important gene involved in miRNA and rRNA processing.
Metabolome profiling by HRMAS NMR spectroscopy of pheochromocytomas and paragangliomas detects SDH deficiency: clinical and pathophysiological implications.
The aim of this study was to investigate interobserver variability among seven expert endocrine pathologists using a web-based virtual microscopy approach in a large multicenter pheochromocytoma/paraganglioma cohort (n=351): (1) 73 SDH mutated, (2) 105 non-SDH mutated, (3) 128 samples without identified SDH-x mutations, and (4) 45 with incomplete SDH molecular genetic analysis.
Mutations of the SDH gene are associated with many tumors, such as renal cell carcinoma, wild type gastrointestinal stromal tumors (WT GISTs) and hereditary paragangliomas/pheochromocytomas.
IDH1 and IDH2 mutations are found in many neoplasms, and germline alterations in SDH genes and FH predispose to pheochromocytoma/paraganglioma and other cancers.
Patients with germline mutations in one of the SDH genes are at substantially increased risk of developing paragangliomas, pheochromocytomas (pheos), and other tumors (all combined referred to as SDH-related tumors).
Using the yeast model, here, we report functional investigations on several missense SDH mutations found in patients affected by pheochromocytomas or paragangliomas.
The dysfunction of genes involved in the cellular response to hypoxia, such as VHL, EGL nine homolog 1, and the succinate dehydrogenase (SDH) genes, leads to a direct abrogation of hypoxia inducible factor (HIF) degradation, resulting in a pseudo-hypoxic state implicated in PCC/PGL development.
Genetic analysis for PHEO/paraganglioma genes (SDH A-D, SDHAF2, RET, VHL, TMEM127, and MAX), and pituitary-related genes (AIP, MEN1, and p27) were negative.
It is now recognized that all of the SDH genes are involved in the tumorigenesis of not only paragangliomas/pheochromocytomas, but also other tumor types, most notably gastrointestinal stromal tumors.
The differing effect of the SDHD p.Pro81Leu on HNPGL and pheochromocytoma risks suggests differing mechanisms of tumorigenesis in SDH-associated HNPGL and pheochromocytoma.
As SDH mutations are virtually always germline, we conclude that approximately 15% of all pheochromocytomas or paragangliomas are associated with germline SDH mutation and that immunohistochemistry can be used to triage genetic testing.
The paraganglioma-pheochromocytoma syndrome is caused by germline-inactivating mutations in the mitochondrial succinate dehydrogenase (SDH) genes SDHB, SDHC, SDHD, or SDHAF2, and VHL is the result of inactivating VHL gene mutations.
Recent studies indicate that succinate dehydrogenase (SDH) genes B, C, or D are, at least partly, involved in the pathogenesis of pheochromocytoma or paraganglioma.
Germline mutations in SDH genes are responsible for 6% and 9% of sporadic paragangliomas and phaeochromocytomas, respectively, 29% of paediatric cases, 38% of malignant tumours and more than 80% of familial aggregations of paraganglioma and phaeochromocytoma.
Mutations in genes encoding succinate dehydrogenase and its anchoring subunits (SDH genes) are at the origin of hereditary head and neck paraganglioma (PGL) and a subset of apparently sporadic pheochromocytoma.