Efficacy of Immunohistochemistry for SDHB in the Screening of Hereditary Pheochromocytoma-Paraganglioma.
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SUBMITTER: Choi HR
PROVIDER: S-EPMC8301322 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:IntroductionPheochromocytomas and paragangliomas (PCC/PGL) are rare neuroendocrine tumors and can secrete catecholamine. Previous studies have found that SDHB immunohistochemistry (IHC) can predict SDHB germline gene mutation, and SDHB mutation is closely associated with tumor progression and metastasis. This study aimed to clarify the potential effect of SDHB IHC as a predictive marker for tumor progression in PCC/PGL patients.MethodsWe included PCC/PGL patients diagnosed in Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from 2002 to 2014 for retrospective analysis and discovered that SDHB (-) staining patients had poorer prognoses. Then we examined SDHB protein expression by IHC on all tumors in the prospective series, which was composed of patients from 2015 to 2020 in our center.ResultsIn the retrospective series, the median follow-up was 167 months, and during follow-up, 14.4% (38/264) patients developed metastasis or recurrence, and 8.0% (22/274) patients died. Retrospective analysis revealed that 66.7% (6/9) of participants in the SDHB (-) group and 15.7% (40/255) of those in the SDHB (+) group developed progressive tumors (OR: 10.75, 95% CI: 2.72-52.60, P=0.001), and SDHB (-) was independently associated with poor outcomes after adjusting by other clinicopathological parameters (OR: 11.68, 95% CI: 2.58-64.45, P=0.002). SDHB (-) patients had shorter disease-free survival (DFS) and overall survival (OS) (P<0.001) and SDHB (-) was significantly associated with shorter median DFS (HR: 6.89, 95% CI: 2.41-19.70, P<0.001) in multivariate cox proportional hazard analysis. In the prospective series, the median follow-up was 28 months, 4.7% (10/213) patients developed metastasis or recurrence, and 0.5% (1/217) patient died. For the prospective analysis, 18.8% (3/16) of participants in the SDHB (-) group had progressive tumors compared with 3.6% (7/197) in the SDHB (+) group (RR: 5.28, 95% CI: 1.51-18.47, P=0.009), statistical significance remained (RR: 3.35, 95% CI: 1.20-9.38, P=0.021) after adjusting for other clinicopathological factors.ConclusionsOur findings demonstrated patients with SDHB (-) tumors had a higher possibility of poor outcomes, and SDHB IHC can be regarded as an independent biomarker of prognosis in PCC/PGL.
| S-EPMC10061060 | biostudies-literature
Project description:BackgroundGermline mutations of the tumor suppressor genes SDHB, SDHC and SDHD play a major role in hereditary paraganglioma and pheochromocytoma. These three genes encode subunits of succinate dehydrogenase (SDH), the mitochondrial tricarboxylic acid cycle enzyme and complex II component of the electron transport chain. The majority of variants of the SDH genes are missense and nonsense mutations. To date few large deletions of the SDH genes have been described.MethodsWe carried out gene deletion scanning using MLPA in 126 patients negative for point mutations in the SDH genes. We then proceeded to the molecular characterization of deletions, mapping breakpoints in each patient and used haplotype analysis to determine whether the deletions are due to a mutation hotspot or if a common haplotype indicated a single founder mutation.ResultsA novel deletion of exon 3 of the SDHB gene was identified in nine apparently unrelated Dutch patients. An identical 7905 bp deletion, c.201-4429_287-933del, was found in all patients, resulting in a frameshift and a predicted truncated protein, p.Cys68HisfsX21. Haplotype analysis demonstrated a common haplotype at the SDHB locus. Index patients presented with pheochromocytoma, extra-adrenal PGL and HN-PGL. A lack of family history was seen in seven of the nine cases.ConclusionThe identical exon 3 deletions and common haplotype in nine patients indicates that this mutation is the first Dutch SDHB founder mutation. The predominantly non-familial presentation of these patients strongly suggests reduced penetrance. In this small series HN-PGL occurs as frequently as pheochromocytoma and extra-adrenal PGL.
| S-EPMC2670821 | biostudies-literature
Project description:Pheochromocytoma and paragangliomas (PCC/PGL) are neuroendocrine tumors that arise from chromaffin cells of the adrenal medulla and sympathetic/parasympathetic ganglia, respectively. Of clinical relevance regarding diagnosis is the highly variable presentation of symptoms in PCC/PGL patients. To date, the clear-cut correlations between the genotypes and phenotypes of PCC/PGL have not been entirely established. In this study, we reviewed the medical records of PCC/PGL patients with pertinent clinical, laboratory and genetic information. Next-generation sequencing (NGS) performed on patient samples revealed specific germline mutations in the SDHB (succinate dehydrogenase complex iron-sulfur subunit B) and SDHD (succinate dehydrogenase complex subunit D) genes and these mutations were validated by Sanger sequencing. Of the 119 patients, two were identified with SDHB mutation and one with SDHD mutation. Immunohistochemical (IHC) staining was used to analyze the expression of these mutated genes. The germline mutations identified in the SDH genes were c343C>T and c.541-542A>G in the SDHB gene and c.334-337delACTG in the SDHD gene. IHC staining of tumors from the c.343C>T and c.541-2A>G carriers showed positive expression of SDHB. Tumors from the c.334-337delACTG carrier showed no expression of SDHD and a weak diffused staining pattern for SDHB. We strongly recommend genetic testing for suspected PCC/PGL patients with a positive family history, early onset of age, erratic hypertension, recurrence or multiple tumor sites and loss of SDHB and/or SDHD expression. Tailored personal management should be conducted once a patient is confirmed as an SDHB and/or SDHD mutation carrier or diagnosed with PCC/PGL.
| S-EPMC6240141 | biostudies-other
Project description:Succinate dehydrogenase subunit B (SDHB) deficiency frequently occurs in cluster I pheochromocytomas and paragangliomas (PCPGs). SDHB-mutated PCPGs are characterized by alterations in the electron transport chain, metabolic reprogramming of the tricarboxylic cycle, and elevated levels of reactive oxygen species (ROS). We discovered that SDHB-deficient PCPG cells exhibit increased oxidative stress burden, which leads to elevated demands for glutathione metabolism. Mechanistically, nuclear factor erythroid 2-related factor 2 (NRF2)-guided glutathione de novo synthesis plays a key role in supporting cellular survival and the proliferation of SDHB-knockdown (SDHBKD) cells. NRF2 blockade not only disrupted ROS homeostasis in SDHB-deficient cells but also caused severe cytotoxicity by the accumulation of DNA oxidative damage. Brusatol, a potent NRF2 inhibitor, showed a promising effect in suppressing SDHBKD metastatic lesions in vivo, with prolonged overall survival in mice bearing PCPG allografts. Our findings highlight a novel therapeutic strategy of targeting the NRF2-driven glutathione metabolic pathway against SDHB-mutated PCPG.
| S-EPMC7072390 | biostudies-literature
Project description:Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors arising from the adrenal medulla and extra-adrenal ganglia, respectively. Approximately 15-25% of PCC/PGL can become metastatic. Up to 30-40% of patients with PCC/PGL have a germline pathogenic variant in a known susceptibility gene for PCC/PGL; therefore, all patients with PCC/PGL should undergo clinical genetic testing. Most of the susceptibility genes are associated with variable penetrance for PCC/PGL and are associated with different syndromes, which include susceptibility for other tumors and conditions. The objective of this review is to provide an overview of the germline susceptibility genes for PCC/PGL, the associated clinical syndromes, and recommended surveillance.
| S-EPMC10259326 | biostudies-literature
Project description:PurposeMinimal data exist regarding the efficacy of screening protocols for individuals with SDHx germline pathogenic variants with hereditary paraganglioma-pheochromocytoma syndrome. This study aimed to evaluate the SDHx-related tumor detection rate in individuals undergoing clinical screening protocols.MethodsA multicenter retrospective longitudinal observational study was conducted. Individuals with germline SDHx pathogenic variants underwent clinical whole-body imaging and biochemical testing.ResultsTwo hundred sixty-three individuals with SDHx germline pathogenic variants completed 491 imaging screens. Individuals with SDHB germline pathogenic variants were most common (n = 188/263, 72%), followed by SDHD (n = 35/263, 13%) and SDHC (n = 28/263, 11%). SDHx-related tumors were found in 17% (n = 45/263) of the cohort. Most SDHx-related tumors were identified on baseline imaging screen (n = 39/46, 85%). Individuals with SDHD pathogenic variants had the highest tumor detection rate (n = 14/35, 40%). Of imaging screens identifying SDHx-related paraganglioma/pheochromocytoma, 29% (n = 12/41) had negative biochemical testing. Secondary actionable findings were identified in 15% (n = 75/491) of imaging screens.ConclusionCurrent SDHx screening protocols are effective at identifying SDHx-related tumors. Tumor detection rates vary by SDHx gene and screening has the potential to uncover actionable secondary findings. Imaging is an essential part of the screening process as biochemical testing alone does not detect all disease.
| S-EPMC7710583 | biostudies-literature
Project description:Abstract Background: SDHB immunostaining can be used to functionally characterize SDH status in PCC and PGL. Assessing SDHB expression on tumors is inexpensive and can be used as an alternative to genetic testing. More importantly, assessment of SDHB expression can be of value in interpreting Variant of Unknown Significance (VUS) in SDH related genes. Objective: To investigate the effectiveness of SDHB immunostaining as an initial screening tool in identifying germline SDH mutations and the value of SDHB assessment in the clinical characterization of our patient cohort. Design: Prospective and retrospective analysis of 57 randomly selected patients with PCC and PGL from the year 1997 to 2018. Setting: In our institution on patients referred from London and South East England including Kent, Surrey and Sussex. Patients: Predominant Caucasian Population with diverse ethnicities. 57 patients - 34 patients (14M & 20F) with PGL and 25 with PCC (15M &10F). Age (mean: 41years at diagnosis with range 9-80 years). 2 patients had both PCC & PGL and multifocal PGLs were identified in few patients with SDHD and SDHB mutation. There were 65 tumors in total included in this study. Intervention: Resected tumor SDHB immunostaining with Sigma prestige antibodies (HPA002868 100UL - Anti-SDHB Rabbit monoclonal antibody) at a dilution of 1:1000. Genetic testing performed on predominant candidate genes. Main outcome measures: Concordance of SDHB loss of expression with presence of pathogenic mutation in candidate SDH genes. Secondarily, to explore SDHB immunostaining in our patient cohort with VUS in candidate genes. Results: SDHB immunostaining was negative in 22/23 tumors in patients with confirmed SDH mutation (false negative = 1 SDHB PCC where it was weak (+)). The staining was positive in 23/24 sporadic tumors, 10/11 VUS (in SDH, MAX and TMEM genes - both PCCs & PGLs), 2/2 PCCs in MEN-2, 2/2 PCCs in NF-1 and 2/3 PCCs in VHL. The negative immunostaining in 1 PGL with VUS in SDHB may imply lack of SDH enzyme activity and hence suggestive of a pathological mutation. The sensitivity is 96% and the specificity approaches 93% if the weak positive SDHB immunostaining with SDHD and VHL tumors were to be considered concordant. The concordance was 95% in the PGL group alone. Conclusions: SDHB immunostaining is a cost effective addition to PGL and PCC tumor characterization and performs with high sensitivity and specificity. SDH functional characterization has an important role in the management of patients who do not satisfy the current criteria for genetic testing (UK genetics testing directory for PCC/PGL). 18% of patients had VUS in a SDH related gene and we have found that SDHB immunostaining provided helpful information to inform follow-up and cascade screening decisions in this group.
| S-EPMC6552923 | biostudies-literature
Project description:PurposePheochromocytomas and paragangliomas (PCPG) are usually benign neuroendocrine tumors. However, PCPGs with mutations in the succinate dehydrogenase B subunit (SDHB) have a poor prognosis and frequently develop metastatic lesions. SDHB-mutated PCPGs exhibit dysregulation in oxygen metabolic pathways, including pseudohypoxia and formation of reactive oxygen species, suggesting that targeting the redox balance pathway could be a potential therapeutic approach.Experimental designWe studied the genetic alterations of cluster I PCPGs compared with cluster II PCPGs, which usually present as benign tumors. By targeting the signature molecular pathway, we investigated the therapeutic effect of ascorbic acid on PCPGs using in vitro and in vivo models.ResultsBy investigating PCPG cells with low SDHB levels, we show that pseudohypoxia resulted in elevated expression of iron transport proteins, including transferrin (TF), transferrin receptor 2 (TFR2), and the divalent metal transporter 1 (SLC11A2; DMT1), leading to iron accumulation. This iron overload contributed to elevated oxidative stress. Ascorbic acid at pharmacologic concentrations disrupted redox homeostasis, inducing DNA oxidative damage and cell apoptosis in PCPG cells with low SDHB levels. Moreover, through a preclinical animal model with PCPG allografts, we demonstrated that pharmacologic ascorbic acid suppressed SDHB-low metastatic lesions and prolonged overall survival.ConclusionsThe data here demonstrate that targeting redox homeostasis as a cancer vulnerability with pharmacologic ascorbic acid is a promising therapeutic strategy for SDHB-mutated PCPGs.
| S-EPMC7443979 | biostudies-literature
Project description:BackgroundGermline mutations in the succinate dehydrogenase complex genes SDHB, SDHC, and SDHD predispose to pheochromocytomas and paragangliomas. Here, we examine the SDHB, SDHC, and SDHD mutation spectrum in the Danish population by screening of 143 Danish pheochromocytoma and paraganglioma patients.MethodsMutational screening was performed by Sanger sequencing or next-generation sequencing. The frequencies of variants of unknown clinical significance, e.g. intronic, missense, and synonymous variants, were determined using the Exome Aggregation Consortium database, while the significance of missense mutations was predicted by in silico and loss of heterozygosity analysis when possible.ResultsWe report 18 germline variants; nine in SDHB, six in SDHC, and three in SDHD. Of these 18 variants, eight are novel. We classify 12 variants as likely pathogenic/pathogenic, one as likely benign, and five as variants of unknown clinical significance.ConclusionsIdentifying and classifying SDHB, SDHC, and SDHD variants present in the Danish population will augment the growing knowledge on variants in these genes and may support future clinical risk assessments.
| S-EPMC4898401 | biostudies-literature
Project description:Pheochromocytoma/paraganglioma (PPGL) is an endocrine tumor of the chromaffin cells in the adrenal medulla or the paraganglia. Currently, about 70% of PPGLs can be explained by germline or somatic mutations in several broadly expressed susceptibility genes including RET, VHL, and SDHB, while for the remaining, mainly sporadic cases, the pathogenesis is still unclear. Even for known susceptible genes, how mutations in these mostly ubiquitous genes result in tissue-specific pathogenesis remains unanswered, and why RET-mutated tumors almost always occur in the adrenal while SDHB-mutated tumors mostly occur extra-adrenal remains a mystery. By analyzing 22 sporadic PPGLs using SNP 6.0 genotyping arrays combined with expression profiling of 4 normal and 4 tumor tissues, we identified GIPC2, a gene located at 1p31.1 with preferential expression in adrenal and inducible by adrenal glucocorticoid, as a novel putative tumor suppressor gene for PPGLs. Copy number deletion and GIPC2 promoter hypermethylation but not GIPC2 mutation, accompanied with reduced GIPC2 expression, were observed in 39 of 55 PPGLs in our cohort. Examination of a published expression database consisting of 188 PPGLs found little GIPC2 expression in Cluster 1A (SDHx-associated) and Cluster 2A (NF1/RET-associated) tumors, but less pronounced reduction of GIPC2 expression in Cluster 1B (VHL-associated) and Cluster 2B/2C tumors. GIPC2 induced p27, suppressed MAPK/ERK and HIF-1ɑ pathways as well as cancer cell proliferation. Overexpressing GIPC2 in PC12 cells inhibited tumor growth in nude mice. We found GIPC2 interacted with the nucleoprotein NONO and both proteins regulated p27 transcription through the same GGCC box on p27 promoter. Significantly, low expression of both GIPC2 and p27 was associated with shorter disease-free survival time of PPGLs patients in the TCGA database. We found that PPGL-causing mutations in RET and in SDHB could lead to primary rat adrenal chromaffin cell proliferation, ERK activation, and p27 downregulation, all requiring downregulating GIPC2. Notably, the RET-mutant effect required the presence of dexamethasone while the SDHB-mutant effect required its absence, providing a plausible explanation for the tumor location preference. In contrast, the PPGL-predisposing VHL mutations had no effect on proliferation and GIPC2 expression but caused p53 downregulation and reduced apoptosis in chromaffin cells compared with wild-type VHL. Thus, our study raises the importance of cortical hormone in PPGL development, and GIPC2 as a novel tumor suppressor provides a unified molecular mechanism for the tumorigenesis of both sporadic and hereditary tumors of Clusters 1A and 2A concerning SDHB and RET, but not tumors of Cluster 1B concerning VHL and other clusters.
| S-EPMC8096975 | biostudies-literature