Neurofibromin Research Articles

Challenges in the management of metastatic gastrointestinal stromal tumor in a patient with neurofibromatosis type 1: a case report

BackgroundNeurofibromatosis type 1 is an inherited cancer predisposition syndrome that is caused by a mutation in the NF1 gene that encodes neurofibromin. Patients with neurofibromatosis type 1 have a higher risk of gastrointestinal stromal tumor. This study reports the case of a patient with gastrointestinal stromal tumor who was later diagnosed to have neurofibromatosis type 1 and, unlike usual features, had some uncommon features such as occurrence at an early age and unusual site of origin.CaseWe report the case of a 29-year-old Indian female diagnosed to have gastrointestinal stromal tumor originating from the greater curvature of the stomach. Gastrointestinal stromal tumor was wild type, negative for c-kit and platelet-derived growth factor receptor, and had an aggressive clinical course not responding to oral tyrosine kinase inhibitors. On later evaluation, we found that the patient had germline mutation in NF1. This case has some unusual features compared with gastrointestinal stromal tumor cases reported in neurofibromatosis type 1. Firstly, the age of onset for gastrointestinal stromal tumor in neurofibromatosis type 1 is earlier in our case compared with previous cases reported in literature. Secondly, the site of occurrence is in the stomach, without involving other parts of the intestine. Gastrointestinal stromal tumor in neurofibromatosis type 1 is usually multifocal, and small intestine is the common site of occurrence. When occurring in the stomach, it is usually associated with other lesions in the small intestine. Lastly, the clinical course is aggressive compared with previous case reports and series.ConclusionOur patient had germline NF1 mutation and cutaneous stigmata of neurofibromatosis. Our patient had unicentric gastrointestinal stromal tumor occurring at younger age and involving greater curvature of the stomach, with spindle cell type histology and high-risk features. If gastrointestinal stromal tumor occurs at young age, we should look into neurocutaneous markers.

Woman With Left Pulsatile Exophthalmos

Neurofibromatosis is rarely seen in emergency departments unless it becomes symptomatic. There are 3 types of neurofibromatosis. Neurofibromatosis type 1 (NF-1; von Recklinghausen disease) is the most common of the 3 types of neurofibromatosis disease. In the disease, there are skin, peripheral and central nervous system, bone, and soft tissue involvements, and there is an increase in the susceptibility to cancer. 1 Hirbe A.C. Gutmann D.H. Neurofibromatosis type 1: a multidisciplinary approach to care. Lancet Neurol. 2014; 13: 834-843https://doi.org/10.1016/S1474-4422(14)70063-8 Abstract Full Text Full Text PDF PubMed Scopus (261) Google Scholar NF-1 is seen once in 3000 births, showing autosomal dominant inheritance and affecting many systems simultaneously. 2 Ghalayani P. Saberi Z. Sardari F. Neurofibromatosis type I (von Recklinghausen’s disease): a family case report and literature review. Dent Res J (Isfahan). 2012; 9 (PMC3491339): 483-488 Google Scholar The NF-1 gene is located on chromosome 17 and encodes a type of tumor suppressor protein called neurofibromin. As a result of incomplete or incorrect folding of this protein, benign and rarely malignant nerve tumors are seen from the early stages of life. Because the disease affects many systems at the same time, the diagnostic criteria have been shaped in this direction. Diagnostic criteria include café au lait spots, neurofibromas, axillary and/or inguinal freckles, optic glioma, Lisch nodules (iris hamartomas), typical bone lesions, and NF-1 disease in first-degree relatives. 3 Ferner R.E. Huson S.M. Thomas N. et al. Guidelines for the diagnosis and management of individuals with neurofibromatosis 1. J Med Genet. 2007; 44: 81-88https://doi.org/10.1136/jmg.2006.045906 Crossref PubMed Scopus (645) Google Scholar In uncertain cases, genetic testing may be requested to confirm the diagnosis. Metin Yadigaroglu is Assistant Professor, Faculty of Medicine, Department of Emergency Medicine, Samsun University, Samsun, Turkey. Twitter: @mtnydgrdr. Melih Imamoglu is Assistant Professor, Faculty of Medicine, Department of Emergency Medicine, Karadeniz Technical University, Trabzon, Turkey. Twitter: @melihimam. Muhammet Fatih Beser is Emergency Specialist, Faculty of Medicine, Department of Emergency Medicine, Karadeniz Technical University, Trabzon, Turkey. Twitter: @drfatih. Sinan Pasli is Assistant Professor, Faculty of Medicine, Department of Emergency Medicine, Karadeniz Technical University, Trabzon, Turkey.

Abstract #1165370: Unique Case of an Adult Patient with Neurofibromatosis Type 1 with Noonan Syndrome (NFNS) Features and Idiopathic Hypoparathyroidism Complicated by Recurrent Episodes of Hypo- and Hypercalcemia

NFNS is a rare RASopathy consisting of phenotypic features of neurofibromatosis type I (NF-1) and Noonan syndrome (NS) features. Endocrine disorders in this syndrome can commonly involve growth hormone related disorders. Here, we present the management of an adult patient with a unique case of NFNS with idiopathic hypoparathyroidism. A 22-year-old male with NFNS diagnosed in early childhood presented to our facility. NF1-like features included multiple café-au-lait spots, Lisch nodules, and basal ganglia hamartomas. NS-like features included webbed neck, bilateral ptosis, low posteriorly set ears, short stature, and intellectual delay. Patient’s family history was significant for NF-1 in a brother and father, and a maternal grandmother with hypocalcemia throughout her childhood. Genetic testing was significant for a positive NF-1 gene panel and a negative NS gene panel, consistent with NFNS. It should be noted that at age 15, he presented with pre-B acute lymphoid lymphoma (ALL) and hypocalcemia. At the time, his ionized calcium level (iCa) was 0.57 mg/dL (n = 4.5-5.6 mg/dL) and total calcium was 4.2 mg/dL (n = 8.8-10.3 mg/dL). He had hyperphosphatemia of 9.2 mg/dL (n = 3.0-4.5 mg/dL) with a low PTH of 3.7 pg/mL (n = 10-65pg/mL) and hypomagnesemia of 1.4 mg/dL (n = 1.7-2.2 mg/dL). The patient was treated with calcitriol, calcium carbonate, vitamin D and magnesium gluconate. Since his hypoparathyroidism diagnosis, the patient has multiple readmissions for recurrent episodes of hypocalcemia and hypercalcemia. During his first hypercalcemic episode, the patient also had acute pancreatitis associated with a chemotherapy agent. He required treatment with aggressive fluids, subcutaneous calcitonin, furosemide, and termination of home calcium and calcitriol supplementation. Following these initial episodes, the patient has continued to have recurrent episodes of hypocalcemia and hypercalcemia that were not associated with any other etiology such as acute pancreatitis, chronic immobilization, or chemotherapy regimens. While there have been a few previous reports of hypoparathyroidism in NS [1, 2], none were noted in association with NFNS. In our extensive literature review, we have not been able to find another case report of idiopathic hypoparathyroidism in NFNS. We feel that the uniqueness of the case coupled with the challenges associated with the adulthood management of recurrent hypercalcemia and hypocalcemia in this patient makes this a very interesting case to present.

Altered Expressions of NF1 and NF1-Related microRNAs as Biomarkers in the Diagnosis of Undifferentiated Pleomorphic Sarcoma.

Objective: Undifferentiated pleomorphic sarcoma (UPS) is a highly malignant, aggressive, and pleomorphic subtype of soft tissue sarcoma in adults. However, UPS is difficult to be diagnosed due to the lack of specific morphological and immunophenotypic features. Here, we aimed to identify new biomarkers for the diagnosis of UPS. Methods: The mRNA and protein expression of neurofibromin 1 (NF1) in 68 pairs of UPS and adjacent normal tissues were detected by qRT-PCR and immunohistochemistry, and the correlation between the NF1 protein expression and clinicopathological characteristics was analyzed. Then, differentially expressed microRNAs (DE miRNAs) were identified between the UPS tumor tissue and matched adjacent normal tissue using Hisep sequencing, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG). The DE miRNAs of the regulating NF1 gene were also identified using the TargetScan and miRanda databases and validated by qRT-PCR. Results: Compared with the adjacent normal tissue, both mRNA and protein expressions of NF1 in the UPS tumor tissue were significantly decreased, and the positive rate of NF1 protein was associated with the tumor size, metastasis, and recurrence. A total of 125 known DE miRNAs were identified from the screened miRNAs based on | log2(Fold Change) ≥5 and p-value < 0.05 (A total of 82 upregulated and 43 downregulated DE miRNAs in the UPS tissue). Target genes regulated by the DE miRNAs were enriched in pathways of metabolisms, RNA degradation, PI3K-Akt, and Rap1 pathway. In total, 11 miRNAs which were predicted to regulate the NF1 gene were screened. After verification, the relative expressions of hsa-miR-199a-3p and hsa-miR-34a-5p were increased and decreased in the UPS tumor tissue compared with those in the adjacent normal tissue, respectively. Conclusion: NF1 and NF1-related microRNAs including hsa-miR-199a-3p and hsa-miR-34a-5p may be novel biomarkers in the diagnosis of undifferentiated pleomorphic sarcoma (UPS).

Von Recklinghausen disease revealed by breast node: Case report

Neurofibromatosis causes various types of benign or malignant tumors of the central or peripheral nerves and often causes pigmented macules of the skin and sometimes other manifestations. We present a case of 29 years old patient diagnosed by neurofibromatosis manifested by breast lesion, at the beginning, the diagnosis was not clear, but after the anatomopalogist report von Recklinghausen disease was suspected and the patient was having all the criteria to confirm that. Recent scientific data support a possible association between breast cancer and NF1. It has been suggested that there may be genes that could interact with the NF1 gene, particularly in relation to the BRCA1 subset. They could share a common gene location (both NF1 and BRCA1 are on human chromosome 17q). Multiple cutaneous lesions in NF-1 may obscure breast lumps leading to delayed detection of cancer. Early onset, aggressive behavior and different natural history of these tumors require a specific approach to their detection and management.

CENTRAL ODONTOGENIC FIBROMA IN ASSOCIATION WITH BROWN TUMOR OF HYPERPARATHYROIDISM IN A PATIENT WITH NF1 AND RENAL FAILURE

<h3>Objective</h3> Neurofibromatosis type 1 is an autosomal dominant disorder caused by mutations in the NF1 gene at chromosomal location 17q11.2. We present a patient with bone abnormalities and a myriad of lesions secondary to his redeveloping renal failure and NF1. <h3>Clinical Presentation</h3> A 21-year-old male renal transplant recipient with NF1 presented with painless masses and large, irregular radiolucent lesions in the maxilla and mandible. The bone was generally "moth-eaten" with a sparse trabeculation pattern. <h3>Intervention and Diagnosis</h3> Histologic examination of an incisional biopsy of the left mandibular lesion revealed two types of tissue with distinct histologic features. Approximately 3/4ths of the specimen was made up of variably cellular dense fibrous connective tissue interspersed with numerous inactive islands and cords of odontogenic epithelium. The remaining specimen consisted of abundant multinucleated giant cells embedded within a highly cellular stroma containing extravasated erythrocytes and hemosiderin. Throughout the specimen, seams of lace-like osteoid and irregular trabeculae of woven bone were noted. The lesion was diagnosed as a central odontogenic fibroma (COdF) in association with a central giant cell lesion, most consistent with brown tumor of hyperparathyroidism. The bone changes were interpreted to be highly suggestive of renal osteodystrophy. <h3>Conclusion</h3> Around 30 cases of hybrid central giant cell granuloma-like lesion in association with central odontogenic fibroma have been reported. This, to the best of our knowledge, is the first reported case of brown tumor in association with COdF. It has been proposed that a primary COdF induces a reactive giant cell response, however, this is unlikely here, given that the primary tumor was probably a ‘brown tumor'. Our case illustrates the point that the giant cell component may be the initiating entity in these hybrid lesions.

Re-evaluation of missense variant classifications in NF2.

Missense variants in the NF2 gene result in variable NF2 disease presentation. Clinical classification of missense variants often represents a challenge, due to lack of evidence for pathogenicity and function. This study provides a summary of NF2 missense variants, with variant classifications based on currently available evidence. NF2 missense variants were collated from pathology‐associated databases and existing literature. Association for Clinical Genomic Sciences Best Practice Guidelines (2020) were followed in the application of evidence for variant interpretation and classification. The majority of NF2 missense variants remain classified as variants of uncertain significance. However, NF2 missense variants identified in gnomAD occurred at a consistent rate across the gene, while variants compiled from pathology‐associated databases displayed differing rates of variation by exon of NF2. The highest rate of NF2 disease‐associated variants was observed in exon 7, while lower rates were observed toward the C‐terminus of the NF2 protein, merlin. Further phenotypic information associated with variants, alongside variant‐specific functional analysis, is necessary for more definitive variant interpretation. Our data identified differences in frequency of NF2 missense variants by exon between gnomAD population data and NF2 disease‐associated variants, suggesting a potential genotype‐phenotype correlation; further work is necessary to substantiate this.

Pediatric High Grade Glioma Classification Criteria and Molecular Features of a Case Series.

Pediatric high-grade gliomas (pHGGs) encompass a heterogeneous group of tumors. Three main molecular types (H3.3 mutant, IDH mutant, and H3.3/IDH wild-type) and a number of subtypes have been identified. We provide an overview of pHGGs and present a mono-institutional series. We studied eleven non-related pHGG samples through a combined approach of routine diagnostic tools and a gene panel. TP53 and H3F3A were the most mutated genes (six patients each, 54%). The third most mutated gene was EGFR (three patients, 27%), followed by PDGFRA and PTEN (two patients each, 18%). Variants in the EZHIP, MSH2, IDH1, IDH2, TERT, HRAS, NF1, BRAF, ATRX, and PIK3CA genes were relatively infrequent (one patient each, 9%). In one case, gene panel analysis documented the presence of a pathogenic IDH2 variant (c.419G>A, p.Arg140Gln) never described in gliomas. More than one-third of patients carry a variant in a gene associated with tumor-predisposing syndromes. The absence of constitutional DNA did not allow us to identify their constitutional origin.

Structural basis of activation of the tumor suppressor protein neurofibromin

Mutations in the NF1 gene cause the familial genetic disease neurofibromatosis type I, as well as predisposition to cancer. The NF1 gene product, neurofibromin, is a GTPase-activating protein and acts as a tumor suppressor by negatively regulating the small GTPase, Ras. However, structural insights into neurofibromin activation remain incompletely defined. Here, we provide cryoelectron microscopy (cryo-EM) structures that reveal an extended neurofibromin homodimer in two functional states: an auto-inhibited state with occluded Ras-binding site and an asymmetric open state with an exposed Ras-binding site. Mechanistically, the transition to the active conformation is stimulated by nucleotide binding, which releases a lock that tethers the catalytic domain to an extended helical repeat scaffold in the occluded state. Structure-guided mutational analysis supports functional relevance of allosteric control. Disease-causing mutations are mapped and primarily impact neurofibromin stability. Our findings suggest a role for nucleotides in neurofibromin regulation and may lead to therapeutic modulation of Ras signaling.

A case report and review of the literature on Von Recklinghausen’s disease complicated with cervicofacial plexiform neurofibromas

Neurofibromatosis type I, also known as Von Recklinghausen disease, is an autosomal dominant genodermatosis caused by a mutation in the NF1 gene on chromosome 17q11.2. It is characterized by a wide range of clinical signs and symptoms comprising macules of café-au-lait and tumours of the nerve sheath [1]. Neurofibromas make up 90% of all instances and plexiform tumors are less common [2]. Plexiform neurofibromas are largely pathognomonic for NF1, appearing as a “bag of worms” with diffuse involvement along a nerve segment and its branches [3]. The eyelids, trunk, and limbs are the most common sites for plexiform neurofibromas. It’s unusual to find localization in the cervico-facial region [4]. We present the case of a 20-year-old female patient who had been followed for von Recklinghausen’s disease from childhood and complained of a growing cervicofacial lump.

Clinical Masks of Neurofibromatosis Type 1

Neurofibromatosis type 1 is the most common autosomal dominant tumor syndrome. The prevalence of the disease is 1 in 3000 people. Neurofibromatosis type 1 is characterized by the gradual appearance of signs of the disease and pronounced clinical polymorphism from erased and atypical forms to severe classical manifestations. The review is devoted to the consideration of diseases, the manifestations of which are significantly similar to neurofibromatosis type 1, and therefore, molecular diagnosis of the disease is an important method for differential diagnosis. To make a diagnosis of neurofibromatosis type 1, it is necessary to find mutations in the NF1 gene using sequencing. In 10% of cases, neurofibromatosis type 1 is caused by large deletions of the 17q11.2 locus, therefore, multiplex ligation-dependent probe amplification is also necessary. Typically, the initial manifestations of neurofibromatosis type 1 are multiple café-au-lait spots, which may be the only external signs of the disease for many years. Therefore, patients with neurofibromatosis type 1 may be mistakenly diagnosed with diseases for which these pigmentary changes are characteristic: Bloom, LEOPARD, Carney, Costello, Cowden, Legius, Nijmegen, Noonan, Peitz-Jägers, Silver-Russell, cardio-facio-cutaneous syndromes. The detection of subcutaneous tumors can become the basis for an incorrect diagnosis of the clinically similar Legius syndrome and multiple endocrine neoplasia. In addition, multiple lipomas are specific manifestations of Madelung or Dercum lipomatosis, familial angiolipomatosis, the etiology of which is considered unknown. Therefore, I assume that these diseases are atypical forms of neurofibromatosis type 1, since a number of authors have described the identification of mutations in NF1 gene in patients with multiple lipomatosis. Therefore, it is important to widely introduce into clinical practice the possibility of molecular genetic identification of the disease in order to identify cases of neurofibromatosis type 1 that do not meet the diagnostic criteria adopted by the NIH. It is promising to create a panel for the study of all genes, mutations in which can cause manifestations similar to neurofibromatosis. Early diagnosis of the disease is necessary for timely initiation of treatment and prevention of severe manifestations, since effective methods of antitumor therapy of neurofibromatosis type 1, such as inhibitors of mitogen-activated kinase, are being introduced into clinical practice.

SDHB knockout and succinate accumulation are insufficient for tumorigenesis but dual SDHB/NF1 loss yields SDHx-like pheochromocytomas.

SUMMARYInherited pathogenic succinate dehydrogenase (SDHx) gene mutations cause the hereditary pheochromocytoma and paraganglioma tumor syndrome. Syndromic tumors exhibit elevated succinate, an oncometabolite that is proposed to drive tumorigenesis via DNA and histone hypermethylation, mitochondrial expansion, and pseudohypoxia-related gene expression. To interrogate this prevailing model, we disrupt mouse adrenal medulla SDHB expression, which recapitulates several key molecular features of human SDHx tumors, including succinate accumulation but not 5hmC loss, HIF accumulation, or tumorigenesis. By contrast, concomitant SDHB and the neurofibromin 1 tumor suppressor disruption yields SDHx-like pheochromocytomas. Unexpectedly, in vivo depletion of the 2-oxoglutarate (2-OG) dioxygenase cofactor ascorbate reduces SDHB-deficient cell survival, indicating that SDHx loss may be better tolerated by tissues with high antioxidant capacity. Contrary to the prevailing oncometabolite model, succinate accumulation and 2-OG-dependent dioxygenase inhibition are insufficient for mouse pheochromocytoma tumorigenesis, which requires additional growth-regulatory pathway activation.

Abstract 48: A typical neurofibromatosis type 1 presenting as overgrowth syndrome

A 6 years old boy presented to the endocrinology department as unilateral left leg overgrowth since birth. Limb discrepancy had been negligible at birth but became evident as the child gained height and further he developed a limping gait by 2 years of age. On examination, he had multiple café au lait spots of > 5 mm over the body and hyperpigmentation on anterolateral aspect of left leg which turned out to be a venous malformation on color Doppler and MRI of the leg. There was no other neuro cutaneous marker and no family history of similar illness or any other neuro cutaneous lesions or any abdominal malignancy. A probable diagnosis of segmental overgrowth syndrome was made with associated café au laits. We wanted to rule out syndromic cause for the same, so patient was advised clinical whole exome sequencing. Genetic result revealed atypical NF1 with heterogenous 3’ splice site variation in intron 36 of the NF1 gene. We hereby report rare presentation of neurofibromatosis as segmental overgrowth syndrome.

Selected Articles from This Issue

Despite previous assumptions that constitutively high Wnt signaling promotes colorectal cancer in each stage of disease, recent studies have demonstrated that reduced Wnt signaling is associated with colorectal cancer invasiveness and poor prognoses. However, little work has been done to elucidate how diminished Wnt signaling underlies aggressive colorectal cancer phenotypes. Chen and colleagues used genetic manipulation strategies and orthotopic mouse models to show that abrogating Wnt signaling increases colorectal cancer invasiveness and decreases immune responsiveness in vivo. Disrupting Wnt signaling by targeting Wnt coreceptor LDL receptor-related protein 6 (LRP6) with CRISPR/Cas9 or transducing a dominant negative version of Wnt transcriptional effector lymphoid enhancer binding factor 1 (LEF1) increases tumor submucosal invasion and dissemination in mice. Using RNA-Seq, the authors revealed that reducing Wnt signaling elevates expression of markers associated with stemness and a mesenchymal phenotype, while repressing expression of immune-stimulatory molecules and collagens. The authors used TCGA data to demonstrate that the low Wnt signaling expression profile corresponds with poor survival in colorectal cancer patients, underscoring the potential clinical relevance of dampened Wnt signaling in colorectal cancer progression.Cholangiocarcinoma (CCA) is an aggressive biliary tract cancer for which effective therapeutics are lacking. Prostaglandin E2 (PGE2)-mediated inflammation is a critical component of CCA carcinogenesis and progression. 15-hydroxyprostaglandin dehydrogenase (15-PGDH) chemically modifies and inactivates PGE2, but its expression is often diminished in CCA. In their work, Zhang and colleagues leveraged public data to show that expression of histone methyltransferase G9a negatively correlates with 15-PGDH expression. The authors validated the G9a-15-PGDH relationship in a mouse model of CCA in which the Notch intracellular domain and constitutively active Akt are expressed via hydrodynamic injection of sleeping beauty transposase-based plasmids. shRNA-mediated G9a silencing increases 15-PGDH expression in CCA cell lines, limiting cell proliferation in vitro and tumor growth in vivo. ChIP assays demonstrated that G9a is recruited to the 15-PGDH promoter by the Myc/Max/E-box complex, which prevents signal transducer and activator of transcription 4 (STAT4) from binding the promoter and inducing 15-PGDH expression. The work presented elucidates a previously unknown mechanism underlying CCA development and progression and reveals a novel potential target for CCA therapeutic strategies.Neurofibromatosis type 2 is characterized by growth of benign nervous system tumors, such as schwannomas, which can lead to deafness, brain stem compression, and death. Neurofibromatosis type 2 is caused by mutations in tumor suppressor gene NF2. Previously, Cho and colleagues demonstrated that NF2 loss promotes elevated TβR1 signaling, resulting in phosphorylation and degradation of tumor suppressor Raf kinase inhibitor protein (RKIP). While TGF-β inhibitors halt schwannoma growth, they are not ideal therapeutics given schwannomas occur around adolescence and TGF-β is required for development. Here, Cho and colleagues developed a novel TβR1 inhibitor, Nf18001, that abrogates TβR1-mediated RKIP degradation while maintaining canonical TGF-β signaling. The authors used human and mouse schwannoma cell lines to demonstrate that Nf18001 disrupts TβR1-RKIP interactions to sustain RKIP expression and lower NF2-mutant cell viability while not influencing normal fibroblast survival. Nf18001 arrests cell cycle progression in schwannoma cells, and augments Schwann cell differentiation marker expression while diminishing expression of markers associated with cell stemness. Nf18001 also displayed efficacy in a schwannoma allograft mouse model, where treatment slowed tumor growth.The pro-tumorigenic role of signal transducer and activator of transcription 3 (STAT3) in multiple myeloma has been established, but therapeutically targeting STAT3 has proven challenging. Similarly, given its canonical role in DNA damage repair, checkpoint kinase 1 (Chk1) inhibition has been tested in anti-cancer therapeutic regimens, but with ambiguous results. In their study, Zhou and colleagues employed a gene expression array to demonstrate that Chk1 inhibition diminishes expression of oncogenic STAT3 target genes in multiple myeloma cells, suggesting Chk1 inhibition may also effectively inhibit STAT3 activity. Subsequent work showed that Chk1 directly binds to STAT3 and phosphorylates it at tyrosine 705, enabling STAT3 dimerization and DNA binding. Chk1 inhibition — pharmacologically and via shRNA silencing — diminishes STAT3 tyrosine 705 phosphorylation and inhibits STAT3 DNA binding, reducing expression of STAT3 transcriptional targets. Chk1 inhibition abrogates STAT3 tyrosine 705 phosphorylation in IL-6–dependent, -independent, and bortezomib-resistant cells, as well as in patient primary myeloma mononuclear cells and multiple myeloma cells implanted into mice, suggesting Chk1 inhibition may provide therapeutic efficacy against multiple myeloma through a STAT3-related mechanism.

Clinicopathological and molecular characterization of biphasic hyalinizing psammomatous renal cell carcinoma: further support for the newly proposed entity

The classification of renal neoplasms continues to evolve with novel, emerging, and provisional entities being described constantly. Biphasic hyalinizing psammomatous renal cell carcinoma (BHP RCC) associated with somatic NF2 mutations is one such new renal entity and is considered as a provisional category of RCC due to its very limited data. To provide further support for the newly proposed entity, we identified three additional cases of BHP RCC, with clinicopathological, immunohistochemical, and various molecular analyses. There were 2 males and 1 female, aged 65, 56, and 69 years, respectively. The neoplasms were unencapsulated, and all had a characteristic biphasic appearance of smaller cells clustering around basement membrane material within larger acini, forming pseudorosettes or a glomeruloid pattern. Hyalinized sclerotic stroma and psammoma bodies were abundant in two cases and focally present in one case. Focal areas of a less distinctive appearance were also noted; one additionally had an elongated tubular pattern in the myxoid stroma that is reminiscent of mucinous tubular and spindle cell carcinoma; one consisted solid alveolar architectures of epithelioid clear cells, bearing some resemblance to clear cell RCC. The neoplasms did not have a distinctive immunohistochemistry (IHC) profile, though all labeled for vimentin and CK7. Targeted DNA sequencing revealed that one case harbored a pathogenic somatic frameshift mutation in the NF2 gene, which was further confirmed by Sanger sequencing. The other two cases lacked NF2 mutations and instead demonstrated NF2 promoter methylation by methylation-specific polymerase chain reaction. Subsequent IHC assessment showed loss of expression of NF2 in all 3 cases, which evaluated NF2 status at the protein level. According to RNA sequencing-based clustering analysis, the 3 cases formed a distinct group with a shared specific transcriptional profile different from that of other established renal tumor types. In addition, phosphate inositide 3-kinase (PI3K)/AKT pathway was enriched significantly and on the top of all enriched pathways. Clinically, one patient developed bone metastases and died of disease two years after diagnosis. The other two patients had no evidence of recurrence or metastases, at 4- and 5-yearfollow-up. These findings not only validate previously described clinicopathological featuresbut also expand the potentially genetic alterations and available clinical outcome data.

A family case report of Neurofibromatosis

Neurofibromatosis is a genetic disease inherited in an autosomal, dominant manner. The course of von Recklinghausen’s disease varies from patient to patient. Most cases are mild and uncomplicated. The diagnosis of NF1 is based on the criteria of the National Institutes of Health (NIH). Type 2 neurofibromatosis is inherited, in most cases autosomal dominantly. The abnormal allele can be inherited from either parent, with the risk of passing the gene on to the offspring from the parent, being 50%. This article describes the familial form of neurofibromatosis. In the case in question, all three sisters were found to be mutated in the NF1 gene by genetic testing. In the same family, the clinical manifestation of the disease may be different for sisters and children. Due to compliance with medical recommendations, the disease does not significantly affect the quality of life of the families affected.

Identification of Subtypes and a Delayed Graft Function Predictive Signature Based on Ferroptosis in Renal Ischemia-Reperfusion Injury.

Renal ischemia-reperfusion injury (IRI) is an inevitable process in kidney transplantation, leading to acute kidney injury, delayed graft function (DGF), and even graft loss. Ferroptosis is an iron-dependent regulated cell death in various diseases including IRI. We aimed to identify subtypes of renal IRI and construct a robust DGF predictive signature based on ferroptosis-related genes (FRGs). A consensus clustering analysis was applied to identify ferroptosis-associated subtypes of 203 renal IRI samples in the GSE43974 dataset. The FRG-associated DGF predictive signature was constructed using the Least Absolute Shrinkage and Selection Operator (LASSO), and its robustness was further verified in the validation set GSE37838. The present study revealed two ferroptosis-related patient clusters (pBECN1 and pNF2 cluster) in renal IRI samples based on distinct expression patterns of BECN1 and NF2 gene clusters. Cluster pBECN1 was metabolically active and closely correlated with less DGF, while pNF2 was regarded as the metabolic exhausted subtype with higher incidence of DGF. Additionally, a six-gene (ATF3, SLC2A3, CXCL2, DDIT3, and ZFP36) ferroptosis-associated signature was constructed to predict occurrence of DGF in renal IRI patients and exhibited robust efficacy in both the training and validation sets. High-risk patients tended to have more infiltration of dendritic cells, macrophages, and T cells, and they had significantly enriched chemokine-related pathway, WNT/β-catenin signaling pathway, and allograft rejection. Patients with low risks of DGF were associated with ferroptosis-related pathways such as glutathione and fatty acid metabolism pathways. In conclusion, patient stratification with distinct metabolic activities based on ferroptosis may help distinguish patients who may respond to metabolic therapeutics. Moreover, the DGF predictive signature based on FRGs may guide advanced strategies toward prevention of DGF in the early stage.

Targeting HNRNPU to overcome cisplatin resistance in bladder cancer

PurposeThe overall response of cisplatin-based chemotherapy in bladder urothelial carcinoma (BUC) remains unsatisfactory due to the complex pathological subtypes, genomic difference, and drug resistance. The genes that associated with cisplatin resistance remain unclear. Herein, we aimed to identify the cisplatin resistance associated genes in BUC.Experimental designThe cytotoxicity of cisplatin was evaluated in six bladder cancer cell lines to compare their responses to cisplatin. The T24 cancer cells exhibited the lowest sensitivity to cisplatin and was therefore selected to explore the mechanisms of drug resistance. We performed genome-wide CRISPR screening in T24 cancer cells in vitro, and identified that the gene heterogeneous nuclear ribonucleoprotein U (HNRNPU) was the top candidate gene related to cisplatin resistance. Epigenetic and transcriptional profiles of HNRNPU-depleted cells after cisplatin treatment were analyzed to investigate the relationship between HNRNPU and cisplatin resistance. In vivo experiments were also performed to demonstrate the function of HNRNPU depletion in cisplatin sensitivity.ResultsSignificant correlation was found between HNRNPU expression level and sensitivity to cisplatin in bladder cancer cell lines. In the high HNRNPU expressing T24 cancer cells, knockout of HNRNPU inhibited cell proliferation, invasion, and migration. In addition, loss of HNRNPU promoted apoptosis and S-phase arrest in the T24 cells treated with cisplatin. Data from The Cancer Genome Atlas (TCGA) demonstrated that HNRNPU expression was significantly higher in tumor tissues than in normal tissues. High HNRNPU level was negatively correlated with patient survival. Transcriptomic profiling analysis showed that knockout of HNRNPU enhanced cisplatin sensitivity by regulating DNA damage repair genes. Furthermore, it was found that HNRNPU regulates chemosensitivity by affecting the expression of neurofibromin 1 (NF1).ConclusionsOur study demonstrated that HNRNPU expression is associated with cisplatin sensitivity in bladder urothelial carcinoma cells. Inhibition of HNRNPU could be a potential therapy for cisplatin-resistant bladder cancer.

RAS and beyond: the many faces of the neurofibromatosis type 1 protein.

ABSTRACTNeurofibromatosis type 1 is a rare neurogenetic syndrome, characterized by pigmentary abnormalities, learning and social deficits, and a predisposition for benign and malignant tumor formation caused by germline mutations in the NF1 gene. With the cloning of the NF1 gene and the recognition that the encoded protein, neurofibromin, largely functions as a negative regulator of RAS activity, attention has mainly focused on RAS and canonical RAS effector pathway signaling relevant to disease pathogenesis and treatment. However, as neurofibromin is a large cytoplasmic protein the RAS regulatory domain of which occupies only 10% of its entire coding sequence, both canonical and non-canonical RAS pathway modulation, as well as the existence of potential non-RAS functions, are becoming apparent. In this Special article, we discuss our current understanding of neurofibromin function.

Neural Differentiation of Human Dental Mesenchymal Stem Cells Induced by ATRA and UDP-4: A Comparative Study.

Human mesenchymal stem cells (MSC) are multipotent stem cells, which are isolated from various sources. Currently, there is a worldwide interest for dental MSC to be used against neurodegenerative diseases, since they derive from the neural crest and express embryonic stem cell markers. This fact prompted us to explore their potential for neural trans-differentiation in culture. We employed all-trans-retinoic acid (ATRA) and 2-(3-ethylureido)-6-methylpyridine (UDP-4) to induce neural differentiation of human MSC from the dental apical papilla (SCAP). The SCAP were exposed to either agent separately and assessed for proliferation, viability, morphology, and gene expression of the following neural-specific markers: neuron-specific enolase (ENO2), neurofibromin 1 (NF1), choline acetyltransferase (CHAT), tyrosine hydroxylase (TH), and the vesicular GABA transporter (SLC32A1). They were also assessed for the expression of glial fibrillary acidic protein (GFAP) and neuronal nuclear antigen (NeuN) by immunofluorescence. ATRA or UDP-4 treatment inhibited the cell growth and promoted limited cell death, but to a different extent. The addition of the neuroprotective agent recombinant human erythropoietin-alpha (rhEPO-α) enhanced the UDP-4-inducing capacity for more than three weeks. ATRA or UDP-4 treatment significantly upregulated ENO2 and NF1 expression, indicating neuronal differentiation. Moreover, the ATRA treatment significantly induced the upregulation of the GABAergic-specific SLC32A1, while the UDP-4 treatment led to the significant upregulation of the adrenergic-specific TH. The UDP-4 treatment induced the expression of NeuN and GFAP after four and three weeks, respectively, while the ATRA-treatment did not. Our findings indicate that SCAP can be differentiated into neural-like cells after treatment with ATRA or UDP-4 by exhibiting a disparate pattern of differentiation. Therefore, UDP-4 is suggested here as a new potent neural-differentiation-inducing compound, which, when combined with rhEPO-α, could lay the foundation for robust stem-cell-based therapies of neurodegeneration.