RATIONALE: Pituitary adenomas and paragangliomas are both rare endocrine diseases. Paragangliomas (PGL)/pheochromocytomas (PHEO) are part of an inherited syndrome in about 30% to 40% of cases. Among familial cases, mutations of the succinate dehydrogenase (SDH) subunit genes (succinate dehydrogenase subunit [SDH]B, SDHC, SDHD, succinate dehydrogenase subunit AF2 [SDHAF2] , and SDHA) are the most common cause.
PATIENT CONCERNS: We here report a 31-year-old patient with a known SDHD mutation whose disease has been revealed by a left PHEO during childhood and who presented at age 29 years a large paraganglioma of the right jugular foramen, a concomitant PHEO of the left adrenal and 2 retroperitoneal paragangliomas. A pituitary incidentaloma was found during investigations on a fluorodeoxyglucose (FDG)-positron emission tomography (PET) (FDG-PET).
DIAGNOSIS: A pituitary magnetic resonance imaging (MRI) confirmed the presence of a 14 mm pituitary macroadenoma. The pituitary function was normal except for hypogonadotropic hypogonadism. On examination of the fundus, a diagnosis of Pseudo Foster-Kennedy syndrome was made due to a venous compression of the right jugular vein caused by the paraganglioma (PGL). The pituitary adenoma was not compressive to the optic chiasm.
INTERVENTIONS: A treatment with acetazolamide was started in order to improve intracranial hypertension. The patient couldn't benefit of a surgical approach for the paraganglioma of the right jugular foramen; the patient has been treated with stereotactic radiosurgery (Gamma Knife).
OUTCOMES: The most recent MRI revealed that the right jugular foramen PGL is stable and the latest visual assessment demonstrated stability despite a recent reduction in acetazolamide dosage. A surveillance by MRI of the pituitary adenoma has been planned.
LESSONS: The association of a pituitary adenoma to paragangliomas within a same patient is very uncommon and raises the question of related physiopathological mechanisms.

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors that mainly occur in the gastrointestinal tract. The GISTs that are sporadically reported in extra-gastrointestinal regions are named as extra-gastrointestinal stromal tumors (EGISTs). However, the primary EGISTs that originate from the liver are rare.
PATIENT CONCERNS: A 64-year-old female presenting with right upper abdominal pain and thirsty for more than 20 days.
DIAGNOSIS: A diagnosis of a 15 × 14 × 7 cm liver mass located in the posterior right lobe of liver and spread to the right adrenal gland was confirmed. Pathological results showed that the tumor was mainly composed of epithelial cells and tested positive for CD117 and SDHB (succinate dehydrogenase complex iron sulfur subunit B). The gene mutational analyses for c-Kit and platelet-derived growth factor receptor alpha exons revealed negative results. Fluorescence in situ hybridization of murine double minute 2 produced negative fluorescence results which distinguished it from dedifferentiated liposarcomas. The postoperative gastroduodenal and colorectal endoscopy did not find any neoplastic lesions. To this end, the diagnosis of primary hepatic EGIST of wild type nature was confirmed.
INTERVENTIONS: The patient received right hepatectomy and adrenalectomy, no postoperative chemotherapy was administered.
OUTCOMES: The patient died 11 months after surgery due to tumor metastasis.
CONCLUSION: Primary hepatic EGIST is a rare and complicated disease of liver, a multidisciplinary team is necessary in diagnosis and treatment of primary hepatic EGIST.

The present research seeks to investigate the process of mixing targeted gene delivery and transcriptional targeting. We have conjugated Polyethylenimine polymers (PEI) and molecules of poly (ethylene glycol). The next step was covalent attachment of anti-HER2 variables domains of camelid heavy chains antibodies (VHHs) or nanobodies (Nbs) to the distal terminals of NHS-PEG3500 in PEI-PEG nanoparticles. The whole procedure yielded PEI-PEG-Nb immunoconjugates. Having determined the properties of polyplexes, steps were taken to investigate the most efficient ratio of PEI polymers to pDNA molecules (N/P) so that the greatest rate of transfection may be obtained. This immune targeted nano biopolymer could condense the gene constructs that coded a transcriptionally targeted truncated -Bid (tBid) killer gene which was controlled by the breast cancer-specific MUC1 promoter. The favourable physicochemical properties matching both the size and zeta potential were observed in engineered polyplexes. Elevated transfection efficiency in HER2 positive cell lines using Nb-modified polyplexes were shown by the results of flow cytometry as compared against non-modified particles. 1.6 and 4.8 fold higher transfection efficiencies were observed in in vitro gene expression researches which used PEI-PEG-Nb/pGL4.50 compared to the situation when native PEI polymers were utilized in both BT-474 and SK-BR-3, respectively. A 2.22 and 3.62 fold rise in the level of tBid gene expression in BT-474 and SK-BR-3 cell lines relative to unmodified PEI treated cells was the result of transfection with PEI-PEG-Nb/pMUC1-tBid, respectively. In those HER2-positive cells which were transfected by targeted polyplexes, higher levels of cell death were observed. This fact points not only to the effective targeted delivery, but it is also indicative of transcriptional targeting efficiency of tBid killer gene when its expression is controlled by MUC1 promoter.

BACKGROUND: Identification of genetic factors causing predisposition to renal cell carcinoma has helped improve screening, early detection, and patient survival.
METHODS: We report the characterization of a proband with renal and thyroid cancers and a family history of renal and other cancers by whole-exome sequencing (WES), coupled with WES analysis of germline DNA from additional affected and unaffected family members.
RESULTS: This work identified multiple predicted protein-damaging variants relevant to the pattern of inherited cancer risk. Among these, the proband and an affected brother each had a heterozygous Ala45Thr variant in SDHA, a component of the succinate dehydrogenase (SDH) complex. SDH defects are associated with mitochondrial disorders and risk for various cancers; immunochemical analysis indicated loss of SDHB protein expression in the patient's tumor, compatible with SDH deficiency. Integrated analysis of public databases and structural predictions indicated that the two affected individuals also had additional variants in genes including TGFB2, TRAP1, PARP1, and EGF, each potentially relevant to cancer risk alone or in conjunction with the SDHA variant. In addition, allelic imbalances of PARP1 and TGFB2 were detected in the tumor of the proband.
CONCLUSION: Together, these data suggest the possibility of risk associated with interaction of two or more variants.

BACKGROUND: Succinate dehydrogenase (SDH)-deficient gastrointestinal stromal tumors (GISTs) constitute a small KIT/PDGFRA-WT GIST subgroup featuring DNA methylation which, although pervasive, appears nevertheless not randomly distributed. Although often indolent, these tumors are mostly chemorefractory in aggressive cases. Promoter methylation-induced O
RESULTS: Nine GISTs of our series were SDH-deficient, revealing significantly enriched in MGMT-methylated cases (6/9-67%-, vs. 6/39-15%- of SDH-proficient GISTs; p = 0.004). The pathogenetically heterogeneous KIT/PDGFRA-WT GISTs were also significantly MGMT-methylated (11/24-46%-, vs. 1/24-4%- of KIT/PDGFRA-mutant cases, p = 0.002).
CONCLUSIONS: A subset of KIT/PDGFRA-WT GISTs, including their largest pathogenetically characterized subgroup (i.e., SDH-deficient ones), is preferentially MGMT-methylated. This finding could foster a reappraisal of alkylating agents for treating malignant cases occurring among these overall chemorefractory tumors.

OBJECTIVES: The goal of this study was to detect and explore the mechanisms of the succinate dehydrogenase (SDH) complex subunit-related gene mutations in cases of multiple paraganglioma (PGL) in the head and neck.
METHODS: In Beijing Tongren Hospital (Capital Medical University, Beijing, People's Republic of China) between January 2013 and February 2017, 23 cases of head and neck multiple PGL were evaluated by genetic sequencing. From these cases, four hereditary families and 10 cases with sporadic occurrences were found. Gene mutations, including SDHD, SDHB, SDHC, SDHAF2, VHL and RET in germ cells and somatic cells, were detected by gene capture and high throughput sequencing.
RESULTS: In family 1, 12 instances of SDHD gene mutation were detected, eight of which manifested as bilateral carotid body tumor (CBT) with one bilateral malignant CBT. In family 2, three cases of SDHD mutation were found with one case of bilateral CBT and two cases of unilateral CBT. In family 3, two cases of SDHD gene mutation were found, both characterized by vagus PGL and pheochromocytoma. Of the 10 patients with sporadic manifestations, five cases of SDHD gene mutation and one case of RET gene mutation were detected. Two novel gene mutations, c.387_393del7 mutation of SDHD gene and c.3247A>G mutation of RET gene, were also detected.
CONCLUSION: In patients with multiple PGL in the head and neck, these are accompanied by a genetic mutation of the germ cell. In this case study, this mutation was most commonly a mutation of the SDHD gene.
LEVEL OF EVIDENCE: 4 Laryngoscope, 129:E67-E71, 2019.

BACKGROUND: Succinate dehydrogenase (SDH)- deficient renal cell carcinoma (RCC) is a newly identified rare subtype of RCC, having only gained acceptance from the World Health Organization in 2016. To the best of our knowledge, there are only 55 reported cases worldwide. Here, we report a new case of SDH-deficient RCC.
CASE PRESENTATION: A 49-year-old male patient was incidentally found to have a large right renal mass. He had no personal or family history of paragangliomas (PGL), pheochromocytomas (PC), or gastrointestinal stromal tumors (GIST). The neoplasm was unilateral and unifocal. He underwent an open partial nephrectomy. Detailed pathological analysis was conducted to confirm the diagnosis. Genetic testing revealed a pathogenic mutation in the SDHB gene. He has been followed for 24 months now and has remained well without any evidence of local or distant recurrence. In this report we describe our experience with this diagnosis and review the relevant clinical, pathological, and genetic features.
CONCLUSIONS: Without the identification of SDHB deficiency, this patient's personal and familial predisposition to PC, PGL, GIST and metachronous RCCs may have gone undetected despite his RCC diagnosis. When faced with an eosinophilic RCC, pathologists should routinely search for vacuoles or flocculent cytoplasmic inclusions. When these are present, or in cases of difficult eosinophilic renal tumors, staining for SDHB is recommended. For tumours without adverse pathologic features (i.e. high nuclear grade, coagulative necrosis, or sarcomatoid differentiation) excision alone may be a reasonable option, with the addition of regular surveillance for PC and PGLs in those found to harbor germline SDH mutations.

The last 10 years have produced an amazing number of significant discoveries in the field of adrenal endocrinology. The development of the adrenal gland was linked to specific molecules. Cortisol-producing lesions were associated mostly with defects of the cyclic AMP (cAMP) signaling pathway, whereas aldosterone-producing lesions were found to be the result of defects in aldosterone biosynthesis or the potassium channel KCNJ5 and related molecules. Macronodular adrenal hyperplasia was linked to ARMC5 defects and new genes were found to be involved in adrenocortical cancer (ACC). The succinate dehydrogenase (SDH) enzyme was proven to be the most important molecular pathway involved in pheochromocytomas, along with several other genes. Adrenomedullary tumors are now largely molecularly elucidated. Unfortunately, most of these important discoveries have yet to produce new therapeutic tools for our patients with adrenal diseases: ACC in its advanced stages remains largely an untreatable disorder and malignant pheochromocytomas are equally hard to treat. Thus, the challenge for the next 10 years is to translate the important discoveries of the previous decade into substantial advances in the treatment of adrenal disorders and tumors.

Succinate dehydrogenase (SDH) is an enzyme complex, composed of four protein subunits, that plays a role in both the citric acid cycle and the electron transport chain. The genes for SDHA, SDHB, SDHC, and SDHD are located in the nuclear DNA, and mutations in these genes have initially been described in paragangliomas (PGL) and pheochromocytomas (PCC), which are relatively rare tumors derived from the autonomic nervous system and the adrenal medulla, respectively. Patients with SDH mutations, that are almost exclusively in the germline, are frequently affected by multiple PGL and/or PCC. In addition, other tumors have been associated with SDH mutations as well, including gastrointestinal stromal tumors, SDH-deficient renal cell carcinoma, and pituitary adenomas. Immunohistochemistry for SDHB and SDHA has been shown to be a valuable additional tool in the histopathological analysis of these tumors, and can be considered as a surrogate marker for molecular analysis. In addition, SDHB immunohistochemistry is relevant in the decision-making whether a genetic sequence variant represents a pathogenic mutation or not. In this review, we highlight the current knowledge of the physiologic and pathologic role of the SDH enzyme complex and its involvement in endocrine and non-endocrine tumors, with an emphasis on the applicability of immunohistochemistry.

Succinate dehydrogenase (SDH) is uniquely tasked with a dual role in the essential energy-producing processes of a cell. Although SDH subunits and assembly factors form part of the same enzyme complex, mutations in their respective genes lead to significantly different clinical phenotypes. Remarkable discoveries in the last 17 years have led to the delineation of the SDH complex deficiency syndrome and its multiple pathogenic branches. Here we provide an updated overview of SDH deficiency in order to raise awareness of its multiple connotations including nonneoplastic associations and pertinent features of the continually growing list of SDH-mutant tumors so as to better direct genetic counseling and predict prognosis.

Succinate dehydrogenase (SDH) is a mitochondrial enzyme complex composed of 4 protein subunits (SDHA, SDHB, SDHC, and SDHD). Germ line mutations of the genes encoding these SDH subunits result in hereditary syndromes harboring pheochromocytomas/paragangliomas, gastrointestinal stromal tumors, renal cell carcinomas, and pituitary adenomas. SDH-deficient renal cell carcinomas are rare, with a mean age of 38 to 40 years. Histologically, these tumors show a characteristic appearance that includes a solid, nested, or tubular architecture with variable cysts. Cells are typically cuboidal, have indistinct cell borders and eosinophilic cytoplasm, and show flocculent intracytoplasmic inclusions. Loss of immunohistochemical staining for SDHB is the hallmark of these tumors. Although most SDH-deficient renal cell carcinomas are clinically indolent, some tumors may behave aggressively, particularly those with a high nuclear grade, tumor necrosis, or sarcomatoid differentiation. Accurate classification of these tumors is important for clinical follow-up, screening, and genetic evaluation of the patients and other family members for this hereditary tumor syndrome.

The spectrum of the renal oncocytic tumors has been expanded in recent years to include several novel and emerging entities. We describe a cohort of novel, hitherto unrecognized and morphologically distinct high-grade oncocytic tumors (HOT), currently diagnosed as "unclassified" in the WHO classification. We identified 14 HOT by searching multiple institutional archives. Morphologic, immunohistochemical (IHC), molecular genetic, and molecular karyotyping studies were performed to investigate these tumors. The patients included 3 men and 11 women, with age range from 25 to 73 years (median 50, mean 49 years). Tumor size ranged from 1.5 to 7.0 cm in the greatest dimension (median 3, mean 3.4 cm). The tumors were all pT1 stage. Microscopically, they showed nested to solid growth, and focal tubulocystic architecture. The neoplastic cells were uniform with voluminous oncocytic cytoplasm. Prominent intracytoplasmic vacuoles were frequently seen, but no irregular (raisinoid) nuclei or perinuclear halos were present. All tumors demonstrated prominent nucleoli (WHO/ISUP grade 3 equivalent). Nine of 14 cases were positive for CD117 and cytokeratin (CK) 7 was either negative or only focally positive in of 6/14 cases. All tumors were positive for AE1-AE3, CK18, PAX 8, antimitochondrial antigen, and SDHB. Cathepsin K was positive in 13/14 cases and CD10 was positive in 12/13 cases. All cases were negative for TFE3, HMB45, Melan-A. No TFEB and TFE3 genes rearrangement was found in analyzable cases. By array CGH, complete chromosomal losses or gains were not found in any of the cases, and 3/9 cases showed absence of any abnormalities. Chromosomal losses were detected on chromosome 19 (4/9), 3 with losses of the short arm (p) and 1 with losses of both arms (p and q). Loss of chromosome 1 was found in 3/9 cases; gain of 5q was found in 1/9 cases. On molecular karyotyping, 3/3 evaluated cases showed loss of heterozygosity (LOH) on 16p11.2-11.1 and 2/3 cases showed LOH at 7q31.31. Copy number (CN) losses were found at 7q11.21 (3/3), Xp11.21 (3/3), Xp11.22-11.21 (3/3), and Xq24-25 (2/3). CN gains were found at 13q34 (2/3). Ten patients with available follow up information were alive and without disease progression, after a mean follow-up of 28 months (1 to 112 months). HOT is a tumor with unique morphology and its IHC profile appears mostly consistent. HOT should be considered as an emerging renal entity because it does not meet the diagnostic criteria for other recognized eosinophilic renal tumors, such as oncocytoma, chromophobe renal cell carcinoma (RCC), TFE3 and TFEB RCC, SDH-deficient RCC, and eosinophilic solid and cystic RCC.

Pheochromocytomas and paragangliomas (PGLs) due to mutations of succinate dehydrogenase (SDH) B, a subunit of the SDH complex with a role in the Krebs cycle and the respiratory chain, tend to be larger at diagnosis and more prone to metastatic disease than other tumors. This presentation contrasts with the behavior of some cell line models of SDHB impairment, which show reduced growth compared to wild type. We hypothesize that reduced growth of SDHB-impaired monolayer culture models might reflect lack of support from sources within the tumor microenvironment. The present study therefore investigates how the microenvironment, modeled here by fibroblast co-culture, modulates cell metabolism, growth and invasion in an Sdhb-impaired mouse pheochromocytoma cell line. We employed two different constructs of short hairpin RNA to knockdown Sdhb and compared growth in a monolayer with and without fibroblast co-culture. Sdhb-silenced cells showed functional impairment of SDH with elevated succinate to fumarate ratio and decreased oxidative capacity. Cell growth was delayed with an increase in doubling time of 2 h or 20 h. Clonogenic cell survival and viability, on the other hand, were either unchanged or increased compared to control. In standard monolayer culture, no differences in pro-metastatic features were present. Co-culture with primary mouse fibroblast reversed the difference of proliferation between control and Sdhb knockdown but was unable to significantly influence invasiveness under these culture conditions. Metabolic studies identified that lactate secreted by fibroblasts was taken up preferentially by Sdhb-silenced cells. In summary, the present study identified a potential role for the tumor microenvironment in influencing phenotypic features of SDHB-mutated PGLs, providing a basis for the use of therapies targeted towards the tumor microenvironment.

BACKGROUND: Pituitary adenomas and paragangliomas/pheocromocytomas are rare endocrine tumours, which can be sporadic or familial. During many years their coexistence in the same individual was considered a coincidental finding. However, an association between these two entities was recently demonstrated, with the possible involvement of SDHx genes.
CASE REPORT: We describe a 57-year-old female patient, who was under surveillance since 1997 for a malignant paraganglioma with vertebral bone metastasis, and harboured a germline frameshift mutation in exon 6 of SDHB gene [c.587-591DelC]. Seventeen years later, she was diagnosed with acromegaly and underwent transesphenoidal endoscopic resection of a somatotropinoma. Three months after surgery she started treatment with lanreotide for residual disease. Despite initial good response, she developed resistance to first generation of somatostatin analogues and treatment had to be switched to pegvisomant. In the immunohistochemical staining, the pituitary adenoma was positive for SDHA expression, while SDHB showed an heterogeneous staining pattern, with areas markedly positive and others with positive and negative cells.
CONCLUSIONS: Our findings provide useful data for understanding the link between paragangliomas/pheocromocytomas and somatotropinomas. While we confirm the well-established link between SDHB mutations and paragangliomas/pheocromocytomas, particularly with malignant paragangliomas, the preservation-at least partially-of SDHB expression in the somatotropinoma tissue does not allow drawing definite conclusions about the involvement of the SDHB mutation in pituitary adenoma.

AIM: The aim of the present study was to confirm therapeutic efficacy and find probable mechanism of action of amentoflavone in hepatocellular carcinoma (HCC) in vivo.
MATERIALS AND METHODS: Luciferase reporter vector pGL4.50_transfected SK-Hep1 (SK-Hep1/luc2) tumor-bearing mice were treated with vehicle or amentoflavone (100 mg/kg/day by gavage) for 14 days. Tumor growth, amentoflavone toxicity, and extracellular signal-regulated kinase (ERK)/nuclear factor-kappaB (NF-ĸB) signaling in tumor progression were evaluated with digital caliper, bioluminescence imaging, computed tomography, body weight, pathological examination of liver, and immunohistochemistry staining.
RESULTS: Amentoflavone significantly inhibited tumor growth, ERK/NF-ĸB activation, and expression of tumor progression-associated proteins as compared to vehicle-treated group. In addition, body weight and liver morphology of mice were not influenced by amentoflavone treatment.
CONCLUSION: These results suggest that amentoflavone inhibits HCC progression through suppression of ERK/NF-ĸB signaling.

OBJECTIVE: To analyze the germline variations of genes RET, VHL, SDHD and SDHB in patients with pheochromocytoma and/or paraganglioma and to evaluate variations of these genes in Chinese patients.
METHODS: Patients who were treated in Peking University First Hospital from September 2012 to March 2014 and diagnosed with pheochromocytoma and/or paraganglioma by pathologists were included in this study. Twelve patients were included in total, of whom 11 had pheochromocytoma, and 1 had paraganglioma. Deoxyribonucleic acid (DNA) was extracted from the leukocytes of peripheral blood of the patients. The exons 10, 11, 13-16 of the RET gene, and all exons of VHL, SDHB and SDHD genes and their nearby introns (±20 bp) were amplified with polymerase chain reactions, and the products were sent to a biotechnology company for sequencing. The sequencing results were compared with wildtype sequences of these genes to identify variations. One of the patients was diagnosed with multiple endocrine neoplasia type 2A. A family analysis was performed in his kindred, and his family members received genetic tests for the related variations.
RESULTS: Three patients were found to have germline gene variations. A c.136C>T (p.R46X) variation of the SDHB gene was found in a patient with malignant pheochromocytoma. A c.1901G>A (C634Y) variation, as well as c.2071G>A (p.G691S) and c.2712C>G (p.S904S) variations of the RET gene were found in a patient with multiple endocrine neoplasia type 2A. After a family analysis, five family members of this patient were found to have the same variations. c.2071G>A (p.G691S) and c.2712C>G (p.S904S) variations of the RET gene were also found in a clinical sporadic patient without evidence of malignancy. A patient with congenital single ventricle malformation and pheochromocytoma was included in this study, and no variation with clinical significance was found in the four genes of this patient.
CONCLUSION: 25% (3/12) patients with pheochromocytoma or paraganglioma were found to have missense or nonsense germline gene variations in this study, including the c.136C>T (p.R46X) variation of the SDHB gene, the c.1901G>A (C634Y) variation of the RET gene, and c.2071G>A (p.G691S) and c.2712C>G (p.S904S) variations of the RET gene. The former two variations have already been confirmed to be pathogenic. The existence of these variations in Chinese patients with pheochromocytoma and/or paraganglioma was validated in this study, which supports the conclusion that genetic testing is necessary to be generally performed in patients with pheochromocytoma and/or paraganglioma.

Inactivating mutations of the succinate dehydrogenase subunit B (

BACKGROUND: We present a series of papillary renal cell carcinomas (PRCC) reminiscent of so-called "oncocytic variant of papillary renal cell carcinoma" (OPRCC), included in the 2016 WHO classification as a potential type 3 PRCC. OPRCC is a poorly understood entity, cytologically characterized by oncocytic cells with non-overlapping low grade nuclei. OPRCC is not genotypically distinct and the studies concerning this variant have shown an inconsistent genetic profile. The tumors presented herein demonstrated predominantly papillary/tubulopapillary architecture and differed from OPRCC by pseudostratification and grade 2-3 nuclei (Fuhrman/ISUP). Because there is a morphologic overlap between renal oncocytoma (RO) and PRCC in the cases included in this study, the most frequently affected chromosomes in RO and PRCC were analyzed.
MATERIALS AND METHODS: 147 PRCC composed of oncocytic cells were retrieved from our registry in order to select a group of morphologically uniform tumors. 10 cases with predominantly papillary, tubulopapillary or solid architectural patterns were identified. For immunohistochemical analysis, the following antibodies were used: vimentin, antimitochondrial antigene (MIA), AMACR, PAX8, CK7, CK20, AE1-3, CAM5.2, OSCAR, Cathepsin K, HMB45, SDHB, CD10, and CD117. Enumeration changes of locus 1p36, chromosomes 7, 14, 17, X, Y and rearrangement of CCND1 were examined by FISH. For further study, only tumors showing karyotype similar to that of RO were selected. The tumors exhibiting either trisomy of chromosomes 7, 17 or gain of Y, thus abnormalities characteristic for PRCC, were excluded.
RESULTS: There were 5 males and 5 females, with patient age ranging from 56 to 79 years (mean 66.8 years). The tumor size ranged from 2 to 10 cm (mean 5.1 cm). Follow-up was available for 8/10 patients (mean 5.2 years); one patient died of the disease, while 7 of 8 are alive and well. Immunohistochemically, all cases were reactive for AMACR, vimentin, PAX8, OSCAR, CAM5.2, and MIA. SDHB was retained in all cases. 9/10 cases were positive for CD10, 7/10 cases reacted with CK7, 4/10 with Cathepsin K, and 2/10 with AE1-3. None of the cases were positive for CD117, HMB45 and CK20. All 10 cases were analyzable by FISH and showed chromosomal abnormalities similar to that usually seen in RO (i.e. loss of 1p36 gene loci, loss of chromosome Y, rearrangement of CCND1 and numerical changes of chromosome 14).
CONCLUSIONS: We analyzed a series of renal tumors combining the features of PRCC/OPRCC and RO, that included pseudostratification and mostly high grade oncocytic cells lining papillary/tubulopapillary structures, karyotype characterized by loss of 1p36, loss of chromosome Y, rearrangement of CCND1 gene and numerical changes of chromosome 14. Despite the chromosomal numerical abnormalities typical of RO, we classified these tumors as part of the spectrum of PRCC because of their predominant papillary/tubulopapillary architecture, immunoprofile that included reactivity for AMACR, vimentin and lack of reactivity for CD117, all of which is incompatible with the diagnosis of RO. This study expands the morphological spectrum of PRCC by adding a cohort of diagnostically challenging cases, which may be potentially aggressive.

PURPOSE: Metabolic aberrations have been described in neoplasms with pathogenic variants (PV) in the Krebs cycle genes encoding succinate dehydrogenase (SDH), fumarate hydratase (FH) and isocitrate dehydrogenase (IDH). In turn, accumulation of oncometabolites succinate, fumarate, and 2-hydroxyglutarate can be employed to identify tumors with those PV . Additionally, such metabolic readouts may aid in genetic variant interpretation and improve diagnostics.
METHODS: Using liquid chromatography-mass spectrometry, 395 pheochromocytomas and paragangliomas (PPGLs) from 391 patients were screened for metabolites to indicate Krebs cycle aberrations. Multigene panel sequencing was applied to detect driver PV in cases with indicative metabolite profiles but undetermined genetic drivers.
RESULTS: Aberrant Krebs cycle metabolomes identified rare cases of PPGLs with germline PV in FH and somatic PV in IDHx and SDHx, including the first case of a somatic IDH2 PV in PPGL. Metabolomics also reliably identified PPGLs with SDHx loss-of-function (LOF) PV. Therefore we utilized tumor metabolite profiles to further classify variants of unknown significance in SDHx, thereby enabling missense variants associated with SDHx LOF to be distinguished from benign variants.
CONCLUSION: We propose incorporation of metabolome data into the diagnostics algorithm in PPGLs to guide genetic testing and variant interpretation and to help identify rare cases with PV in FH and IDHx.

INTRODUCTION: Paraganglioma (PGL) is a rare neuroendocrine tumor. Currently, the malignancy is defined as the presence of metastatic spread at presentation or during follow-up. Several gene mutations are listed in the pathogenesis of PGL, among which succinate dehydrogenase (SDHX), particularly the SDHB isoform, is the main gene involved in malignancy. A 55-year-old male without evidence of catecholamine secretion had surgery for PGL of the urinary bladder. After 1 year, he showed a relapse of disease and demonstrated malignant PGL without evidence of catecholamine secretion with a germline heterozygous mutation of succinate dehydrogenase B (SDHB). After failure of a second surgery for relapse, he started medical treatment with sunitinib daily but discontinued due to serious side effects. Cyclophosphamide, vincristine, and dacarbazine (CVD) chemotherapeutic regimen stopped the disease progression for 7 months.
CONCLUSION: Malignant PGL is a very rare tumor, and SDHB mutations must be always considered in molecular diagnosis because they represent a critical event in the progression of the oncological disease. Currently, there are few therapeutic protocols, and it is often difficult, as this case demonstrates, to decide on a treatment option according to a reasoned set of choices.

High lactate production in cells during growth under oxygen-rich conditions (aerobic glycolysis) is a hallmark of tumor cells, indicating the role of mitochondrial function in tumorigenesis. In fact, enhanced mitochondrial biogenesis and impaired quality control are frequently observed in cancer cells. Mitochondrial DNA (mtDNA) encodes 13 subunits of oxidative phosphorylation (OXPHOS), is present in thousands of copies per cell, and has a very high mutation rate. Mutations in mtDNA and nuclear DNA (nDNA) genes encoding proteins that are important players in mitochondrial biogenesis and function are involved in oncogenic processes. A wide range of germline mtDNA polymorphisms, as well as tumor mtDNA somatic mutations have been identified in diverse cancer types. Approximately 72% of supposed tumor-specific somatic mtDNA mutations reported, have also been found as polymorphisms in the general population. The ATPase 6 and NADH dehydrogenase subunit genes of mtDNA are the most commonly mutated genes in breast cancer (BC). Furthermore, nuclear genes playing a role in mitochondrial biogenesis and function, such as peroxisome proliferators-activated receptor gamma coactivator-1 (PGC-1), fumarate hydratase (FH) and succinate dehydrogenase (SDH) are frequently mutated in cancer. In this review, we provide an overview of the mitochondrial germline variants and mutations in cancer, with particular focus on those found in BC.

The hereditary cancer syndromes hereditary leiomyomatosis and renal cell cancer (HLRCC) and succinate dehydrogenase-related hereditary paraganglioma and pheochromocytoma (SDH PGL/PCC) are linked to germline loss-of-function mutations in genes encoding the Krebs cycle enzymes fumarate hydratase and succinate dehydrogenase, thus leading to elevated levels of fumarate and succinate, respectively

BACKGROUND: 18F-FDOPA positron emission tomography/computed tomography (PET/CT) is a sensitive nuclear imaging technology for the diagnosis of pheochromocytomas (PHEO). However, its utility in determining predictive factors for the secretion of catecholamines remains poorly studied.
METHODS: Thirty-nine histologically confirmed PHEO were included in this retrospective single-center study. Patients underwent 18F-FDOPA PET/CT before surgery, with an evaluation of several uptake parameters (standardized uptake values [SUVmax and SUVmean] and the metabolic burden [MB] calculated as follows: MB = SUVmean × tumor volume) and measurement of plasma and/or urinary metanephrine (MN), normetanephrine (NM), and chromogranin A. Thirty-five patients were screened for germline mutations in the RET, SDHx, and VHL genes. Once resected, primary cultures of 5 PHEO were used for real-time measurement of catecholamine release by carbon fiber amperometry.
RESULTS: The MB of the PHEO positively correlated with 24-h urinary excretion of NM (r = 0.64, p < 0.0001), MN (r = 0.49, p = 0.002), combined MN and NM (r = 0.75, p < 0.0001), and eventually plasma free levels of NM (r = 0.55, p = 0.006). In the mutated patients (3 SDHD, 2 SDHB, 3 NF1, 1 VHL, and 3 RET), a similar correlation was observed between MB and 24-h urinary combined MN and NM (r = 0.86, p = 0.0012). For the first time, we demonstrate a positive correlation between the PHEO-to-liver SUVmax ratio and the mean number of secretory granule fusion events of the corresponding PHEO cells revealed by amperometric spikes (p = 0.01).
CONCLUSION: While the 18F-FDOPA PET/CT MB of PHEO strongly correlates with the concentration of MN, amperometric recordings suggest that 18F-FDOPA uptake could be enhanced by overactivity of catecholamine exocytosis.

Pheochromocytomas and paragangliomas are neuroendocrine tumors which arise from adrenal medulla, and sympathetic or parasympathetic nerves, respectively. Hereditary cases afflicted by both or either pheochromocytomas and paragangliomas have been reported: these are called hereditary pheochromocytoma/paraganglioma syndromes (HPPS). Many cases of HPPS are caused by mutations of one of the succinate dehydrogenase (SDH) genes; mainly SDHB and SDHD that encode subunits for the mitochondrial respiratory chain complex II. 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). Results showed that all of these pedigrees harbor germline mutations in one of the SDH genes. In two pedigrees, a novel IVS2-2A>C mutation in SDHB, at the acceptor-site in intron 2, was found, and the tumor RNA of the patient clearly showed frameshift caused by exon skipping. Each of the remaining two pedigrees harbors a reported missense mutation, R242H in SDHB or G106D in SDHD. Importantly, all these mutations are heterozygous in constitutional DNAs, and two-hit mutations were evident in tumor DNAs. We thus conclude that the newly identified IVS2-2A>C mutation in SDHB is responsible for HPPS. The novel mutation revealed by our study may contribute to improvement of clinical management for patients with HPPS.

Oligodendrogliomas are primary human brain tumors with a characteristic 1p/19q co-deletion of important prognostic relevance, but little is known about the pathology of this chromosomal mutation. We developed a network-based approach to identify novel cancer gene candidates in the region of the 1p/19q co-deletion. Gene regulatory networks were learned from gene expression and copy number data of 178 oligodendrogliomas and further used to quantify putative impacts of differentially expressed genes of the 1p/19q region on cancer-relevant pathways. We predicted 8 genes with strong impact on signaling pathways and 14 genes with strong impact on metabolic pathways widespread across the region of the 1p/19 co-deletion. Many of these candidates (e.g. ELTD1, SDHB, SEPW1, SLC17A7, SZRD1, THAP3, ZBTB17) are likely to push, whereas others (e.g. CAP1, HBXIP, KLK6, PARK7, PTAFR) might counteract oligodendroglioma development. For example, ELTD1, a functionally validated glioblastoma oncogene located on 1p, was overexpressed. Further, the known glioblastoma tumor suppressor SLC17A7 located on 19q was underexpressed. Moreover, known epigenetic alterations triggered by mutated SDHB in paragangliomas suggest that underexpressed SDHB in oligodendrogliomas may support and possibly enhance the epigenetic reprogramming induced by the IDH-mutation. We further analyzed rarely observed deletions and duplications of chromosomal arms within oligodendroglioma subcohorts identifying putative oncogenes and tumor suppressors that possibly influence the development of oligodendroglioma subgroups. Our in-depth computational study contributes to a better understanding of the pathology of the 1p/19q co-deletion and other chromosomal arm mutations. This might open opportunities for functional validations and new therapeutic strategies.

Cell growth and survival depend on a delicate balance between energy production and synthesis of metabolites. Here, we provide evidence that an alternative mitochondrial complex II (CII) assembly, designated as CII

Context: Mutations in genes encoding for the succinate dehydrogenase (SDH) complex are linked to hereditary paraganglioma syndromes. Paraganglioma syndrome 3 is associated with mutations in SDHC and typically manifests as benign, nonfunctional head and neck paragangliomas.
Design: We describe a case of a 51-year-old woman who initially presented with diarrhea and hypertension and was found to have a retroperitoneal mass, which was resected with a pathology consistent with paraganglioma. Five years later, her symptoms recurred, and she was found to have new retroperitoneal lymphadenopathy and lytic lesions in the first lumbar vertebral body and the right iliac crest, which were visualized on CT scan and octreoscan but not on iodine-123-meta-iodobenzylguanidine (123I-MIBG) and bone scans. She had significantly elevated 24-hour urine norepinephrine and dopamine. The patient received external beam radiation and a series of different antineoplastic agents. Her disease progressed, and she eventually expired within 2 years. Genetic testing revealed a heterozygous SDHC c.43C>T, p.Arg15X mutation, which was also detected in her daughter and her grandson, both of whom have no biochemical or imaging evidence of paraganglioma syndrome yet.
Conclusion: We report a unique case of functional, metastatic abdominal paraganglioma associated with SDHC germline mutation. Our case exemplifies that SDHC germline mutation has variable penetrance, which may manifest with an aggressive biology that could be missed by a 123I-MIBG scan.

BACKGROUND: Pheochromocytoma (Ph) is a rare catecholamine-secreting neuroendocrine tumour that arises from the chromaffin cells of the adrenal medulla. Ph usually presents with symptoms including paroxysmal headache, sweating, palpitations, and hypertension.
CLINICAL CASE: During a computed tomography (CT) scan in a normotensive 49-year-old man, an incidentaloma of 4.5 cm was detected. Hypercortisolism was excluded after the dexamethasone suppression test, levels of DHEAS all falling within the normal range. After a 24-h urine collection, normal urinary metanephrines and a 4-fold higher level compared to the normal range of urinary normetanephrines were observed. Cortisoluria levels were within the normal range. Multiple endocrine neoplasia type 2 (MEN 2) was also excluded. Before the adrenalectomy,
CONCLUSIONS: This is a case report in which, in a normotensive patient with Ph, both MIBG and FDG PET-CT were negative, as were also genetic exams, including VHL, this underlining the difficulties in diagnosing this condition; furthermore, a rare case of ED occurred after surgery.

Pheochromocytoma (PCC) is a tumor derived from adrenomedullary chromaffin cells. Prognosis of malignant PCC is generally poor due to local recurrence or metastasis. We aim to report a case of malignant PCC with 18-year survival and discuss which factors may be related to mortality and long-term survival in malignant pheochromocytoma. The patient, a 45-year-old man, reported sustained arterial hypertension with paroxysmal episodes of tachycardia, associated with head and neck burning sensation, and hand and foot tremors. Diagnosis of PCC was established biochemically and a tumor with infiltration of renal parenchyma was resected. No genetic mutation or copy number variations were identified in SDHB, SDHD, SDHC, MAX and VHL. Over 18 years, tumor progression was managed with 131I-MIBG (iodine-metaiodobenzylguanidine) and 177Lutetium-octreotate therapy. Currently, the patient is asymptomatic and presents sustained stable disease, despite the presence of lung, para-aortic lymph nodes and femoral metastases. Adequate response to treatment with control of tumor progression, absence of significant cardiovascular events and other neoplasms, and lack of mutations in the main predisposing genes reported so far may be factors possibly associated with the prolonged survival in this case. Early diagnosis and life-long follow-up in patients with malignant pheochromocytoma are known to be crucial in improving survival.