Fumarate Hydratase Expression Research Articles

Abstract B006: Rescuing expression of a tumor suppressor gene – restoring FH in Hereditary leiomyomatosis and renal cell carcinoma

Abstract Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is a disorder characterized by the loss of fumarate hydratase (FH) activity, leading to the development of cutaneous leiomyomas, uterine leiomyomas, and aggressive early-onset type 2 papillary renal cell carcinoma. In HLRCC, the disease is driven by the somatic loss of the remaining functional FH allele in individuals carrying a germline pathogenic variant in one copy of the FH gene. The complete loss of FH activity disrupts the tricarboxylic acid (TCA) cycle, resulting in the accumulation of fumarate, which disrupts signaling pathways and contributes to the oncogenic phenotype. We recently identified a single nucleotide polymorphism (SNP) in an intronic region of the fumarate hydratase (FH) gene that leads to the loss of FH activity (Crooks et al., 2023). This SNP introduces a novel splice-acceptor site, resulting in the inclusion of an aberrant exon between wild-type exons 9 and 10. This ‘poison-like’ exon encodes a premature STOP codon, producing a nonfunctional truncated FH protein. Previous studies have shown that restoring FH activity can abrogate pathogenic behavior in patient-derived cells, highlighting the potential for therapeutic interventions targeting FH activity restoration. Our goal is to restore FH enzymatic activity by preventing the inclusion of this cryptic exon in carriers of this variant. To achieve this, we are exploring strategies to restore functional FH production by interfering with the inclusion of the pathogenic intron during splicing by removing the splice acceptor using CRISPR-Cas9 or base editing technologies. We tested these approaches by generating a reporter cell line that recapitulates the splicing pattern observed in patients, where expression of GFP depends on correct splicing between exon 9 and 10. We successfully identified antisense oligonucleotide (ASO) and single-guide RNA (sgRNA) sequences that restore GFP expression in our reporter cell lines. We are now evaluating the efficacy of these reagents in patient-derived cells. An alternative approach involves using synthetic RNA to restore FH expression. The expression of proteins from synthetic RNAs is a promising strategy for treating cancer and infectious diseases. We are currently investigating the efficiency of restoring FH activity through in-vitro transcribed (IVT) mRNA. This approach has the advantage of enabling FH function restoration in cells with mutations that are not amenable to antisense oligonucleotide (ASO) or gene editing techniques. This work serves as an avenue to investigate the application of nucleic acid therapies to restoring activity tumor suppressor genes in kidney cancer. Citation Format: Siddhardha S. Maligireddy, Mariana D. Mandler, Jodie C. Lunger, Christina M. Fitzsimmons, Daniel R. Crooks, Geetha M. Cawthon, Christopher J. Ricketts, Cathy D. Vocke, W. Marson Linehan, Pedro J. Batista. Rescuing expression of a tumor suppressor gene – restoring FH in Hereditary leiomyomatosis and renal cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B006.

Pitfalls in Urine Cytology: A Case of Fumarate Hydratase-Deficient Renal Cell Carcinoma Initially Diagnosed as High-Grade Urothelial Carcinoma.

Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is a rare, aggressive, hereditary subtype of renal cancer that requires careful diagnostic considerations. We report a case of a 33-year-old Asian woman who presented with a 20-day history of hematuria. Imaging studies revealed a solid tumor in the lower pole of the right kidney with lymph node metastases. Urinary cytology revealed benign squamous cells, inflammatory cells, and atypical epithelial cells, suggestive of high-grade urothelial carcinoma. Following a right nephrectomy, the tumor displayed papillary structures composed of cells exhibiting atypical, elongated nuclei with eosinophilic nucleoli and peripheral halos. Immunohistochemical staining demonstrated negative FH expression. Genetic analysis identified a somatic missense mutation in the FH gene, confirming the diagnosis of FH-deficient RCC. This case highlights the importance of integrating cytological, histological, and genetic analyses for accurate diagnosis of FH-deficient RCC.

Fumarate Hydratase-Deficient Renal Cell Carcinoma—A Clinicopathological Study of a Series of 11 Cases

Abstract Introduction Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is a rare, molecularly defined renal tumor with aggressive behavior. The diagnosis of these tumors is challenging because of varied morphology and limited access to molecular testing and immunohistochemistry (IHC) for FH and 2-succinocysteine. We aim to elucidate the histomorphology, clinical presentation, and follow-up of this tumor in this first series of cases of FH-deficient RCCs from India. Objectives This article aims to understand and elucidate the clinical presentation, pathologic findings, treatment options, and outcomes of FH-deficient RCC. Materials and Methods Diagnosed cases of FH-deficient RCC between January 2021 and January 2023 including clinical details were retrieved from the electronic medical record database. Histopathological and immunohistochemical slides were reviewed. Results Out of 11 cases of FH-deficient RCC, 36% had been referred with a diagnosis of type 2 papillary RCC. One patient presented with metastatic disease. All had mixed histologic patterns with the predominant pattern being papillary and showed FH loss on IHC. The classically described inclusion like nucleoli was present only focally in most cases. A subset of tumors had low-grade solid-nested morphology and these patients presented at an earlier stage (T2a). Two patients on multikinase inhibitors are alive with disease at 14 months' follow-up. Conclusion FH-deficient RCCs can have varied histologic patterns within the same tumor and show loss of FH expression by IHC. A subset has low grade morphology and tends to have a more indolent course. It is important to have a high index of suspicion for this diagnosis due to its varied histological appearance and aggressive behavior.

Fumarate Hydratase-Deficient Renal Cell Carcinoma With Predominant Tubulocystic Features Mimics Tubulocystic Renal Cell Carcinoma.

Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) rarely exhibits a predominant tubulocystic architecture with few other components. RCC with pure tubules and cysts lined by eosinophilic tumor cells with prominent nucleoli would raise the diagnosis of tubulocystic RCC. It is important to differentiate the 2 entities because they lead to different outcomes. To address the concern, a multicenter study was implemented to explore useful clinicopathologic features in differentiation between tubulocystic FH-deficient RCC and tubulocystic RCC. Clinical factors included age, sex, tumor size, and outcome. Morphologic factors included cell morphology, presence or absence of a nontubulocystic component, and stromal findings. Immunohistochemistry, fluorescence in situ hybridization, and next-generation sequencing were performed to explore the protein expression and molecular profiles of the 2 entities. We evaluated 6 patients with tubulocystic RCC and 10 patients with tubulocystic FH-deficient RCC. Tubulocystic RCC exhibited a small size (<4.0 cm, pT1a), low Ki-67 index (<5%), retained FH, and negative 2SC expression. Tubulocystic FH-deficient RCC had a relatively large size and a high Ki-67 index. Perinucleolar haloes, loss of FH, and 2SC positivity were always observed. Pure tubulocystic architecture was not observed in FH-deficient RCC, because focal nontubulocystic components can always be seen. We emphasized multiple sectioning to identify a nontubulocystic architecture to exclude tubulocystic RCC. Moreover, tumor size, FH/2SC staining, and the Ki-67 index can differentiate tubulocystic FH-deficient RCC from tubulocystic RCC. The diagnosis of tubulocystic RCC was not recommended in renal mass biopsy because of the limited tissues sampled.

Expression of programmed cell death ligand 1 and clinicopathological and immunological characteristics in fumarate hydratase-deficient renal cell carcinoma

Objective: To investigate the expression of programmed cell death ligand 1 (PD-L1), clinicopathologic features, immunohistochemical expression and molecular characteristics in fumarate hydratase (FH)-deficient renal cell carcinoma and to explore the potential application of immunotherapy in the patients. Methods: There were six patients with FH-deficient renal cell carcinoma treated at the First Affiliated Hospital of Fujian Medical University between January 2020 and October 2022. The clinical data, histological morphology, immunophenotype, PD-L1 expression and next-generation sequencing results were tabulated and analyzed. Results: There were 6 patients, all male, age ranged from 37 to 72 years (mean 45.7 years). Four cases were high-grade (WHO/ISUP grade3-4) with 2 or more histologic patterns, including papillary (most common), glandular, tubular, vesicular, ethmoid, nest-like, cystic and solid structures. Two cases were low-grade which showed nest-like, glandular, or tubular arrangement with eosinophilic flocculent cytoplasm and small intracellular vacuoles. Immunohistochemical analysis revealed strong expression of 2SC in all 6 cases, negative expression of FH in 5 cases, and positive expression of GATA3 in 5 cases. In high-grade cases, the mean values of CD4 and CD8 positive T-lymphocytes in advanced tumor invasion were 180.3/mm2 and 130.5/mm2, respectively. PD-L1 combined positive scores (CPS) were 20, 50, 5 and 30, respectively. The Ki-67 proliferative index were 20%, 20%, 10% and 30%, respectively. In low-grade cases, the mean values of CD4 and CD8 positive T-lymphocytes were 123.0/mm2 and 100.5/mm2, respectively. The PD-L1 CPS score was 1, and the Ki-67 proliferation index was 3%. High-throughput sequencing showed FH gene somatic mutation in 3 cases, FH gene germline mutation in 2 cases, and FH gene mutation was not detected in one case. Conclusion: FH-deficient renal cell carcinoma is more commonly high-grade than low grade. FH and 2SC are immunohistochemical markers used in the diagnosis of FH-deficient renal cell carcinoma, and GATA3 positivity is supportive of the diagnosis. The tumor infiltration of high-grade FH-deficient renal cell carcinoma shows an increase in CD4 and CD8 positive T-lymphocytes, and high expression of PD-L1; thus, anti-PD-L1 immunotherapy can be used as a treatment option.

Fumarate Hydratase Enhances the Therapeutic Effect of PD-1 Antibody in Colorectal Cancer by Regulating PCSK9.

Despite the notable achievements of programmed death 1 (PD-1) antibodies in treating various cancers, the overall efficacy remains limited in the majority of colorectal cancer (CRC) cases. Metabolism reprogramming of tumors inhibits the tricarboxylic acid (TCA) cycle, leading to down-regulation of fumarate hydratase (FH), which is related to poor prognosis in CRC patients. By establishing a tumor-bearing mouse model of CRC with Fh1 expression deficiency, we confirmed that the therapeutic effect of PD-1 antibodies alone was suboptimal in mice with low Fh1 expression, which was improved by combination with a protein invertase subtilisin/kexin 9 (PCSK9) inhibitor. Mechanistically, FH binds to Ras-related nucleoprotein (RAN), which inhibits the nuclear import of the PCSK9 transcription factor SREBF1/2, thus reducing the expression of PCSK9. This leads to increased clonal expansion of CD8+ T cells while the number of Tregs remains unchanged, and the expression of PD-L1 does not change significantly, thus enhancing the immunotherapy response. On the contrary, the expression of PCSK9 increased in CRC cells with low FH expression, which antagonized the effects of immunotherapy. Overall, CRC patients with low FH expression may benefit from combinatorial therapy with PD-1 antibodies and PCSK9 inhibitors to enhance the curative effect.

The Role of Morphology in Predicting Fumarate Hydratase-deficient Uterine Leiomyomas in Young Women.

Hereditary leiomyomatosis and renal cell carcinoma is caused by germline mutations in the fumarate hydratase (FH) gene and is associated with an increased incidence of leiomyomas and a potentially aggressive variant of renal cell carcinoma. Pathologic evaluation of uterine leiomyoma can provide an opportunity for early recognition of the syndrome. We reviewed all archived slides of the cases to identify the characteristic morphologic features described for FH-deficient leiomyomas. We performed immunohistochemistry on whole sections of patients with uterine leiomyoma to evaluate for both FH and 2-succinocysteine (2SC) expression. Of the 106 cases, 19 showed the characteristic eosinophilic nucleoli with perinuclear halos, and 24 revealed a characteristic eosinophilic cytoplasmic inclusion consisting of pink globules present within the cytoplasm. Both of these morphologic findings were present together in 15 cases, and hemangiopericytomatous vessels were detected in 23 cases. The loss of FH protein expression was detected in 14 out of 106 cases (13%), and 13 out of 106 cases (12%) were positive for 2SC. We detected 10 cases with both 2SC-positive and FH expression loss. The presence of eosinophilic nucleoli with perinuclear halos and eosinophilic cytoplasmic inclusion was associated with both loss of FH protein expression and 2SC positivity ( P < 0.001). These findings underscore the importance of hematoxylin and eosin-based predictive morphology in FH-deficient uterine leiomyomas. Therefore, morphologic assessment of uterine leiomyomas for features of FH deficiency can serve as a screening tool for hereditary leiomyomatosis and renal cell carcinoma syndrome, allowing patients to be divided according to their hereditary risk assessment.

Cancer-cell-derived fumarate suppresses the anti-tumor capacity of CD8+ T cells in the tumor microenvironment

Metabolic alterations in the microenvironment significantly modulate tumor immunosensitivity, but the underlying mechanisms remain obscure. Here, we report that tumors depleted of fumarate hydratase (FH) exhibit inhibition of functional CD8+ Tcell activation, expansion, and efficacy, with enhanced malignant proliferative capacity. Mechanistically, FH depletion in tumor cells accumulates fumarate in the tumor interstitial fluid, and increased fumarate can directly succinate ZAP70 at C96 and C102 and abrogate its activity in infiltrating CD8+ Tcells, resulting in suppressed CD8+ Tcell activation and anti-tumor immune responses invitro and invivo. Additionally, fumarate depletion by increasing FH expression strongly enhances the anti-tumor efficacy of anti-CD19 CAR Tcells. Thus, these findings demonstrate a role for fumarate in controlling TCR signaling and suggest that fumarate accumulation in the tumor microenvironment (TME) is a metabolic barrier to CD8+ Tcell anti-tumor function. And potentially, fumarate depletion could be an important strategy for tumor immunotherapy.

Characterization of Protein (2SC) Succination as a Biomarker for Fumarate Hydratase-deficient Renal Cell Carcinoma.

Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is an aggressive, rare genetic disease affecting the kidney and other organ systems. We constructed a specialized multi-institutional cohort of 20 primary FH-deficient RCC cases with aims of characterizing a new commercially available antibody, S-(2-succino)-cysteine (2SC). Herein, we present our findings on the biomarker characterization and performance of 2SC expression by immunohistochemistry (IHC) in FH-deficient RCC, and other common and rare RCC subtypes. Morphological assessment revealed characteristic cytomorphologic features and a majority (55%) of FH-deficient RCC had mixed architectural growth patterns. We observed predominantly diffuse and strong cytoplasmic staining with limited nuclear positivity for 2SC staining on IHC. Receiver operating characteristic curves (ROC) for 2SC identified the threshold IHC score (cut-off) as 90; with the sensitivity and specificity being 100% and 91% respectively. The findings of the present study along with the prior evidence in literature encourages utilization of 2SC as a positive marker along with the loss of fumarate hydratase (FH) expression by anti-FH IHC staining as a negative marker, in clinical and/or pathologic scenarios when considering FH-deficient RCC in the differential diagnosis. FH-/2SC+ may serve as a comprehensive IHC panel in identifying such cases and excluding morphologically similar entities.

A Clinicopathologic and Molecular Analysis of Fumarate Hydratase-deficient Pheochromocytoma and Paraganglioma.

Up to 40% of pheochromocytomas (PCCs) and paragangliomas (PGLs) are hereditary. Germline mutations/deletions in fumarate hydratase ( FH ) cause hereditary leiomyomatosis and renal cell carcinoma syndrome which manifests predominantly with FH-deficient uterine/cutaneous leiomyomas and renal cell carcinomas (RCCs)-tumors characterized by loss of immunohistochemical (IHC) expression of FH and/or positive staining for S-(2-succino)-cysteine. Occasional patients develop PCC/PGL. We investigated the incidence, morphologic, and clinical features of FH-deficient PCC/PGL. We identified 589 patients with PCC/PGLs that underwent IHC screening for FH and/or S-(2-succino)-cysteine. Eight (1.4%) PCC/PGLs were FH deficient (1.1% in an unselected population). The median age for FH-deficient cases was 55 (range: 30 to 77y) with 50% arising in the adrenal. All 4 with biochemical data were noradrenergic. Two (25%) metastasized, 1 dying of disease after 174 months. Germline testing was performed on 7 patients, 6 of whom had FH missense mutations. None were known to have a significant family history before presentation or developed cutaneous leiomyomas, or FH-deficient RCC at extended follow-up. The patient wild-type for FH on germline testing was demonstrated to have somatic FH mutation and loss of heterozygosity corresponding to areas of subclonal FH deficiency in her tumor. One patient did not undergo germline testing, but FH mutation was demonstrated in his tumor. We conclude that FH-deficient PCC/PGL are underrecognized but can be identified by IHC. FH-deficient PCC/PGL are strongly associated with germline missense mutations but are infrequently associated with leiomyoma or RCC, suggesting there may be a genotype-phenotype correlation. FH-deficient PCC/PGL may have a higher metastatic risk.

A Clinicopathological and Molecular Analysis of Fumarate Hydratase (FH)-deficient Renal Cell Carcinomas with Heterogeneous Loss of FH Expression

Aims. Fumarate hydratase (FH)-deficient renal cell carcinoma (RCC) is a rare aggressive renal malignancy associated with hereditary leiomyomatosis and RCC syndrome (HLRCC). Tumors exhibiting heterogeneous (ie, patchy) FH loss by immunohistochemistry have rarely been described, may be diagnostically challenging, and have never been the focus of a study. We aimed to investigate the FH mutational status of FH-deficient RCC with heterogeneous versus complete FH loss, to characterize additional genetic drivers, and to evaluate 2SC immunohistochemistry in this setting. Methods and Results. We studied FH-deficient RCC with heterogeneous (n = 3) and complete (n = 4) FH loss. Targeted next-generation sequencing (NGS) was performed on all tumors. No patients had a known history of HLRCC. All tumors had histological features within the morphologic spectrum described for FH-deficient RCC. All 7 tumors were immunoreactive for 2SC. Molecularly, all 7 tumors revealed multiple hits involving the FH locus resulting in complete loss of wild-type alleles. All tumors with heterogeneous FH loss harbored FH missense variants within domain 2 of the protein, and each had concomitant copy neutral loss of heterozygosity (CN-LOH). In complete FH loss tumors, FH alterations included splice variants with concomitant loss of heterozygosity (n = 2) and homozygous gene deletions (n = 2). Other non-recurrent alterations included biallelic alterations of TP53, NF2, SMAD4 and activation of PIK3CA. Conclusions. Our series highlights how heterogeneous FH loss (patchy positive staining) is an important staining pattern to recognize since it is compatible with a diagnosis of FH-deficient RCC and should prompt additional ancillary studies (confirmatory 2SC immunohistochemistry and/or molecular testing) and genetic evaluation.

Pan-Cancer Analysis Reveals FH as a Potential Prognostic and Immunological Biomarker in Lung Adenocarcinoma.

Fumarate hydratase (FH) is an important enzymatic component in the tricarboxylic acid cycle. Studies have reported that FH plays an important role in hereditary leiomyomatosis and renal cell cancer (HLRCC). However, the role of FH in human different cancers remains unknown. This study is aimed at analyzing the prognostic value of FH and demonstrating the correlation between FH expression and tumor immunity. Results showed that FH was mutated or copy number varied in 27 types of cancer. FH mRNA was abnormally upregulated across various cancers. Survival analysis suggested high expression of FH was associated with poor prognosis in many cancer types, including lung adenocarcinoma (LUAD). Additionally, FH expression was associated with immune infiltration, including B cells, CD4+ T cells, CD8+ T cells, neutrophils, macrophages, and dendritic cells, especially in liver hepatocellular carcinoma (LIHC), LUAD, and lung squamous cell carcinoma (LUSC). Moreover, FH expression showed a strong correlation with immune checkpoint markers in LUAD and testicular germ cell tumors (TGCT). These results indicate that FH is an immunotherapeutic target and a potential prognostic biomarker in LUAD.

Identification of Two Novel CIL-102 Upregulations of ERP29 and FUMH to Inhibit the Migration and Invasiveness of Colorectal Cancer Cells by Using the Proteomic Approach.

CIL-102 (1-[4-(furo[2,3-b]quinolin-4-ylamino) phenyl]ethanone) is a major active agent of Camptotheca acuminata’s alkaloid derivative, and its anti-tumorigenic activity, a valuable biological property of the agent, has been reported in many types of cancer. In this study, we researched the novel CIL-102-induced protein for either the induction of cell apoptosis or the inhibition of cell migration/invasiveness in colorectal cancer cells (CRC) and their molecular mechanism. Firstly, our data showed that CIL-102 treatment not only increased the cytotoxicity of cells and the production of Reactive Oxygen Species (ROS), but it also decreased cell migration and invasiveness in DLD-1 cells. In addition, many cellular death-related proteins (cleavage caspase 9, cleavage caspase 3, Bcl-2, and TNFR1 and TRAIL) and JNK MAPK/p300 pathways were increased in a time-dependent manner. Using the proteomic approach with a MALDI-TOF-TOF analysis, CIL-102-regulated differentially expressed proteins were identified, including eight downregulated and 11 upregulated proteins. Among them, upregulated Endoplasmic Reticulum resident Protein 29 (ERP29) and Fumarate Hydratase (FUMH) by CIL-102 were blocked by the inhibition of ROS production, JNK activity, and p300/CBP (CREB binding protein) signaling pathways. Importantly, the knockdown of ERP29 and FUMH expression by shRNA abolished the inhibition of cell migration and invasion by CIL-102 in DLD-1 cells. Together, our findings demonstrate that ERP29 and FUMH were upregulated by CIL102 via ROS production, JNK activity, and p300/CBP pathways, and that they were involved in the inhibition of the aggressive status of colorectal cancer cells.

FH-deficient renal cell carcinoma expands the spectrum of renal papillary tumors

Das Fumarat-Hydratase(FH)-defiziente Nierenzellkarzinom (NZK) ist eine distinkte Entität, welche eine biallelische Inaktivierung des FH-Gens zeigt, die konsekutiv mit einem Expressions- bzw. Funktionsverlust des FH-Proteins einhergeht. Diese Alteration führt zu einer Akkumulation des Onkometaboliten Fumarat im Citratzyklus und vielfältigen Störungen des Zellhaushaltes und der DNA-Prozessierung. Das FH-defiziente NZK zeigt häufig ein morphologisch überlappendes Spektrum mit papillären NZK (Typ 2), wobei typischerweise ein Wechsel verschiedener Wachstumsmuster inkl. tubulozystischer, kribriformer und/oder solider Differenzierung zu beobachten ist. Eine typische, jedoch nicht spezifische morphologische Eigenschaft sind die prominenten eosinophilen, Viruseinschlußkörperchen-artigen Nukleolen mit perinukleolärem Halo. Der immunhistochemische Verlust der FH-Expression untermauert die Diagnose, kann in seltenen Fällen jedoch erhalten sein. Zumeist zeigen FH-defiziente NZK ein sehr aggressives biologisches Verhalten mit oftmalig primärer Metastasierung bei Diagnosestellung. Die initiale Beschreibung erfolgte als NZK in Assoziation mit dem Hereditären-Leiomyomatose-und-Nierenzellkarzinom(HLRCC)-Syndrom, welches zusätzlich kutane und uterine Leiomyome umfasst. Aktuelle Daten zeigen jedoch auch einen steigenden Anteil an sporadischen Fällen, sodass eine Unterscheidung (hereditär vs. sporadisch) angemessen erscheint. Bisher sind wenige, aber vielversprechende Daten bezüglich wirksamer systemischer therapeutischer Optionen beschrieben. Zusammenfassend ist eine korrekte Diagnose aufgrund des typischerweise biologisch aggressiven Verhaltens, gegebenenfalls vom Standard abweichender therapeutischer Optionen und möglichem Indikator einer hereditären Erkrankung von großer Bedeutung.

Immunoexpression of SDHB, FH, and CK20 among eosinophilic renal tumors: A tissue microarray study

BackgroundDifferential diagnosis can be a challenge for eosinophilic subtypes of renal cell tumors due to their overlapping histomorphological and immunohistochemical features. We aimed to investigate the frequency of rare variants of renal cell carcinomas (RCCs) such as succinate dehydrogenase-deficient RCC (SDDRCC), hereditary leiomyomatosis and RCC (HLRCC)-associated RCC, and eosinophilic, solid, and cystic RCC (ESCRCC) in our population. Materials and methodsRenal tumors which could be considered in the eosinophilic tumor category were included: 91 conventional clear cell RCCs with eosinophilic cytoplasm, 72 papillary RCCs, 74 chromophobe RCCs, 88 oncocytomas, and 37 other rare subtypes. Using the tissue microarray method, succinate dehydrogenase B (SDHB), fumarate hydratase (FH), and cytokeratin 20 (CK20) antibodies were performed by immunohistochemistry. Immunohistochemistry was repeated on whole block sections for selected cases. The utility of these antibodies in the differential diagnosis was also investigated. ResultsLoss of SDHB expression was detected in three tumors, two of which showed typical morphology for SDDRCC. In additional two tumors, SDHB showed weak cytoplasmic expression without a mitochondrial pattern (possible-SDHB deficient). None of the tumors showed loss of FH expression. Heterogeneous reactions were observed with SDHB and FH antibodies. Only one ESCRCC was detected with diffuse CK20 positivity. ConclusionSDDRCCs, HLRCC-associated RCCs, and ESCRCCs are very rare tumors depending on the population. Possible weak staining and focal loss of SDHB and FH expression should be kept in mind and genetic testing must be included for equivocal results.

Perinatal undernourishment provokes long-lasting alterations of clusterin and fumarate hydratase expression in the rat nucleus accumbens

ABSTRACT Background Background: Perinatal malnutrition seems to provoke important neurochemical alterations in the brain that lead to higher vulnerability to develop neuropsychiatric disorders in the adulthood. Objectives We have examined the persistence and reversibility of the changes induced by perinatal undernourishment on the expression of fumarate hydratase in the rat nucleus accumbens, bearing in mind that this expression has been previously linked with addictive disorders. Clusterin, a multifunctional protein known to be neuroprotective and possibly related to addiction in humans, was studied in parallel. Methods Female Wistar rats underwent a severe restriction of food during gestation and lactation. Upon weaning, a subgroup of undernourished animals was switched to normal chow and another one continued under food restriction. Control rats and their mothers were fed on chow along the experiment. Fumarate hydratase and clusterin were quantified by western blot after five months of postnatal life in the three experimental groups. Results Food restriction along the whole experimental period provoked a marked upregulation of both clusterin and fumarate hydratase in the mitochondrial fraction of the nucleus accumbens. In the case of clusterin, this upregulation was also observed in the cytosolic fraction of the nucleus accumbens. When undernourishment was limited to gestation and lactation the two proteins appeared downregulated with respect to controls. Conclusion The results are consistent with the idea that perinatal malnutrition provokes marked changes in brain neurochemistry that are not fully corrected by the rehabilitation of normal feeding and could be linked to behavioural disturbances in the adulthood, that is, increased vulnerability to addiction.

Novel morphological and genetic features of fumarate hydratase deficient renal cell carcinoma in HLRCC syndrome patients with a tailored therapeutic approach

The hereditary leiomyomatosis and renal cell carcinoma syndrome (HLRCC) is defined by germline mutations in the fumarate hydratase (FH) gene and associated with leiomyomas and aggressive renal cell carcinomas with FH deficiency. Here, we comprehensively characterize two new patients with HLRCC syndrome on a morphological, immunohistochemical and genetic level. The patients developed aggressive HLRCC syndrome-associated RCCs, uterine leiomyomas and dermal leiomyomas. One HLRCC syndrome-associated RCC exhibited an unusual morphology with accumulation of "colloid-like" cytoplasmic inclusions, which might serve as a novel sentinel feature to trigger further testing. This case showed partially retained FH expression, initially hampering correct diagnosis. Comprehensive next-generation sequencing analyses of HLRCC syndrome-associated RCC and leiomyomas in our patients revealed divergent genetic changes in the FH gene in different tumors from the same patient. While all leiomyomas (uterine and cutaneous) showed a FH loss of heterozygosity (LOH) as a wildtype allele inactivating event, one HLRCC-RCC showed a second, undescribed NM_000143.3; c.947C>T; p.Ala316Val FH mutation accompanying the preexisting splice site mutation c.378+2T>C. In the other HLRCC syndrome-associated RCC, the FH mutation (NM_000143.3; c.462T>G; p.Asn154Lys with a somatic LOH) represents another variant of unknown significance that we link to HLRCC - and thus classify as likely pathogenic. Due to the specific diagnosis of metastatic HLRCC syndrome-associated RCC, both cases were treated in first line with bevacizumab/erlotinib and showed remarkable and long lasting responses. These findings allow new morphological and molecular insights into the biology of the HLRCC syndrome, corroborate the "second hit" hypothesis of tumor formation in HLRCC patients and may promote a distinct therapeutic approach.

Multiple Bioinformatics Analyses of Integrated Gene Expression Profiling Data and Verification of Hub Genes Associated with Diabetic Retinopathy.

BackgroundDiabetic retinopathy (DR) is a serious complication of diabetes that can lead to blindness. This study aimed to identify the core genes and molecular functions involved in DR through multiple bioinformatics analyses.Material/MethodsThe mRNA gene profiles of human DR tissues from the GSE60436 and GSE53257 datasets were assessed with R software and integrated to identify the co-expressed differentially expressed genes (DEGs). Multiple bioinformatics analyses were used: Gene Ontology (GO) analysis, signaling pathway analysis, and hub gene prediction. Quantitative reverse transcription-PCR (qRT-PCR) was used to verify the hub genes.ResultsThe Database for Annotation, Visualization and Integrated Discovery (DAVID) online tool suggested that the biological processes of the DEGs focused on mitochondrial transport, the cellular components focused on mitochondria, and molecular functions focused on catalytic activity. The results provided by DAVID were consistent with those provided by STRING and the GeneMANIA online database. All the DEGs function in metabolic pathways, consistent with the g: Profiler online analysis results. The protein-protein interaction (PPI) networks forecasted by STRING and GeneMANIA were entered into Cytoscape for cytoHubba degree analysis. The hub genes predicted by cytoHubba suggested that fumarate hydratase (FH) might be relevant to DR. qRT-PCR suggested that the expression of FH was higher in DR retinal tissues than in normal control tissues.ConclusionsMultiple bioinformatics analyses verified that FH could be used as a potential diagnostic marker and new therapeutic target of DR.

Prevalence of somatic and germline mutations of Fumarate hydratase in uterine leiomyomas from young patients.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome is caused by germline mutations in the Fumarate hydratase (FH) gene. In young women, the syndrome often presents with symptomatic uterine leiomyomas, leading to myomectomy or hysterectomy. In this study, we aimed to investigate the incidence and mutational profiles of FH-negative leiomyomas from young patients, thus allowing for early identification and triage of syndromic patients for surveillance. We evaluated 153 cases of uterine leiomyomas from women aged up to 30years for loss of FH expression by tissue microarray (TMA)-based immunohistochemical staining. Mutational analysis of tumours with loss of FH was carried out by polymerase chain reaction (PCR) amplification of 10 exons within the FH gene and subsequent Sanger sequencing. The status of promoter methylation was assessed by bisulphite sequencing. Loss of FH protein expression was detected in seven (4.6%) of 153 tested uterine leiomyomas from young patients. All FH-negative leiomyomas displayed staghorn vasculature and fibrillary/neurophil-like cytoplasm. We found that six (86%) of seven FH-negative tumours detected by immunohistochemistry harboured FH mutations, 50% of which contained germline mutations. In particular, the germline mutational rate in FH gene was 2.0% (three of 153 cases). Bisulphite sequencing analysis failed to detect promoter methylation in any of the seven tumours. Our study showed a relatively high rate of FH germline mutation in FH-negative uterine leiomyomas from patients aged up to 30years. While genetic mutations confer protein expression loss, epigenetic regulation of the FH gene appears to be unrelated to this phenotype.

Leiomyoma with Bizarre Nuclei: a Study of 108 Cases Focusing on Clinicopathological Features, Morphology, and Fumarate Hydratase Alterations.

Leiomyoma with bizarre nuclei (LBN) is an uncommon variant of uterine smooth muscle neoplasm. Involvement of fumarate hydratase (FH) has been suggested in the pathogenesis of a subset of LBN. The goal of our study is to assess the clinicopathological, morphological, immunohistochemical and molecular findings focusing on FH in LBNs (n = 108) and compare it with the findings in usual leiomyomas (UL; n = 50) and leiomyosarcomas (LMS; n = 42). Immunohistochemically, loss of FH expression was found in 67/108 of LBN, 1/50 of UL and in no LMS. Class 4/5 FH mutations were detected in 15/53 LBN with sufficient DNA quality for molecular analysis. Pathogenic variants of the FH gene were detected in neither UL nor LMS. Local recurrence after surgery was present in 18/92 of LBN patients, 7 of which were histologically verified and 2 of which were found to be LBN. Our results confirmed that LBN behave in a benign fashion, although they may relapse. FH gene mutations were a common finding only in LBN, but not in UL and LMS. Immunohistochemistry with an antibody against FH seems to have a good sensitivity (87%) and moderate specificity (58%) with regard to predicting FH gene mutations and could be used as a screening method in tumors with features suggestive of FH alterations to identify patients who are at risk for the FH aberrations.