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Recently, agonist antibodies to glucocorticoid-induced tumor necrosis factor receptor (GITR) (tumor necrosis factor receptor superfamily 18) have been shown to neutralize the suppressive activity of CD4+CD25+regulatory T cells. It was anticipated that this would be the role of the physiological ligand. We have identified and expressed the gene for mouse GITR ligand and have confirmed that its interaction with GITR reverses suppression by CD4+CD25+T cells. It also, however, provides a costimulatory signal for the antigen-driven proliferation of$na{\\ddot \\imath} ve$T cells and polarized T helper 1 and T helper 2 clones. RT-PCR and mAb staining revealed mouse GITR ligand expression in dendritic cells, macrophages, and B cells. Expression was controlled by the transcription factor NF-1 and potentially by alternative splicing of mRNA destabilization sequences.

Purpose Neuroendocrine neoplasms can occur as part of inherited disorders, usually in the form of well-differentiated, slow-growing tumors (NET). The main predisposing syndromes include: multiple endocrine neoplasias type 1 (MEN1), associated with a large spectrum of gastroenteropancreatic and thoracic NETs, and type 4 (MEN4), associated with a wide tumour spectrum similar to that of MEN1; von Hippel-Lindau syndrome (VHL), tuberous sclerosis (TSC), and neurofibromatosis 1 (NF-1), associated with pancreatic NETs. In the present review, we propose a reappraisal of the genetic basis and clinical features of gastroenteropancreatic and thoracic NETs in the setting of inherited syndromes with a special focus on molecularly targeted therapies for these lesions. Methods Literature search was systematically performed through online databases, including MEDLINE (via PubMed), and Scopus using multiple keywords’ combinations up to June 2022. Results Somatostatin analogues (SSAs) remain the mainstay of systemic treatment for NETs, and radiolabelled SSAs can be used for peptide-receptor radionuclide therapy for somatostatin receptor (SSTR)-positive NETs. Apart of these SSTR-targeted therapies, other targeted agents have been approved for NETs: the mTOR inhibitor everolimus for lung, gastroenteropatic and unknown origin NET, and sunitinib, an antiangiogenic tyrosine kinase inhibitor, for pancreatic NET. Novel targeted therapies with other antiangiogenic agents and immunotherapies have been also under evaluation. Conclusions Major advances in the understanding of genetic and epigenetic mechanisms of NET development in the context of inherited endocrine disorders have led to the recognition of molecular targetable alterations, providing a rationale for the implementation of treatments and development of novel targeted therapies.

Gastrointestinal stromal tumors (GISTs) are composed of various molecular subtypes, with differing prognostic and predictive relevance. Previously, tumors lacking mutations in the and genes have been designated as 'wild-type' GISTs; however, they represent a heterogeneous group currently undergoing further subclassification. Primary and secondary resistance to imatinib poses a significant clinical challenge, therefore ongoing research is trying to evaluate mechanisms to overcome resistance. Thorough understanding of the prognostic and predictive relevance of different genetic subtypes of GIST can guide clinical decision-making both in the adjuvant and the metastatic setting. Further work is required to identify tailored therapies for specific subgroups of GISTs wild-type for and mutations and to identify predictive factors of resistance to currently approved systemic therapies.

•Neurofibromatosis Type 1 (NF-1) is a genetic disorder caused by NF1 gene mutations, leading to neurofibromas.•Explored everolimus, an mTOR inhibitor, for its effect on NF-1 lesion size via meta-analysis.•Four phase II trials with 83 patients showed no significant effect of oral everolimus on lesion size reduction.•Safety discrepancies across studies raise concerns about everolimus' overall safety in NF-1 patients.•Emphasizes the necessity for more research, personalized treatments, and larger standardized trials in NF-1. This study addresses the effectiveness of oral everolimus in treating various malignancies associated with Neurofibromatosis Type 1 (NF1). The purpose is to determine whether everolimus reduces lesion size in NF1 patients, considering the controversial findings from previous clinical trials. The scientific hypotheses and questions involve evaluating the impact of everolimus on NF1-associated lesions and understanding the variability in treatment outcomes. A systematic review and meta-analysis were conducted following PRISMA and Cochrane Collaboration guidelines. The study included four-phase II, single-arm, nonrandomized trials investigating the effect of oral everolimus on NF1-associated lesion size. The search covered multiple databases, and data extraction involved evaluating studies for inclusion criteria and assessing quality using the Cochrane Collaboration's Risk of Bias in Nonrandomized Studies tool. Statistical analysis utilized Open Meta(Analyst). The search yielded 388 studies, with 10 selected for full-text review and four included in the final analysis. The quality of the studies ranged from low to moderate. The meta-analysis indicated no observed heterogeneity (I^2 = 0%), and the overall estimate suggested no significant reduction in NF1-associated lesion size with everolimus (P = 0.069). The findings reveal a varied and inconsistent picture of everolimus efficacy in NF1 treatment. The study highlights the need for personalized approaches, considering individual genetic and clinical differences. The limitations, including small sample sizes and nonrandomized trials, call for larger, more standardized research efforts. The study emphasizes ongoing trials and the importance of future research in understanding predictors of everolimus response and optimizing treatment strategies for NF1 patients. While everolimus shows promise in reducing lesion size in a subset of NF1 patients, the study cannot draw conclusive results due to limitations in the included studies. Ongoing, adequately powered trials are crucial for advancing the evidence base and informing the potential role of everolimus in NF1 treatment. There was no funding for this review and no conflicts of interest.

Neurofibromatosis (NF) presents a significant clinical challenge due to its complex genetic basis, diverse clinical manifestation, and substantial impact on a patient’s quality of life (QoL). This paper explores the multifaceted approach required to manage NF in Canada, emphasizing the integration of advanced diagnostic tools, targeted treatments, and comprehensive support systems. Healthcare providers, researchers, patient advocacy groups, and policymakers must collaborate to ensure NF patients receive the best possible care and support. This disease poses devastating consequences to families, and there has been a lack of awareness of this issue in Vancouver and, generally, in British Columbia. Currently, there is no clinic dedicated explicitly to NF in Metro Vancouver, and patients diagnosed with this disease must be flown to Toronto to get treated. The process is costly and inefficient, demanding changes. Some recent improvements in the field of NF have been noted, such as the use of gene therapy and MEK inhibitors. However, the long-term effect of this treatment is largely unknown and should be viewed with caution. This underscores the importance of enhancing psychological interventions to address the mental health challenges faced by NF patients. Specific gene sequences for different types of NF have also been mentioned in the article to offer insights on potential targets for gene-editing technology like CRISPR. Through ongoing advancements in medical science and a commitment to patient-centered care, this paper envisions significant improvements in the management and treatment of this complex condition.

A subset of GISTs lack mutations in the KIT/PDGFRA or RAS pathways and yet retain an intact succinate dehydrogensase (SDH) complex. We propose that these KIT/PDGFRA/SDH/RAS‐P WT GIST tumors be designated as quadruple wild‐type (WT) GIST. Further molecular and clinicophatological characterization of quadruple WT GIST will help to determine their prognosis as well as assist in the optimization of medical management, including clinical test of novel therapies. A subset of gastrointestinal stromal tumors (GISTs) lacks mutations in the KIT/platelet‐derived growth factor receptor alpha (PDGFRA) or RAS pathways and yet retains an intact succinate dehydrogensase (SDH) complex. We propose that these KIT/PDGFRA/SDH/RAS‐P WT GIST tumors be designated as the quadruple wild‐type (WT) GIST. Further, molecular and clinicopathological characterization of quadruple WT GIST will help determine their prognosis as well as assist in the optimization of medical management, including clinical test of novel therapies

The prevalence of concomitant myeloid neoplasms was recently reported to be unexpectedly high among adults without non-Langerhans cell histiocytosis (non-LCH); however, the coexistence of non-LCH with RUNX1 genetic aberration has not been reported previously. Herein, we report a 23-year-old woman with severe pancytopenia diagnosed with non-LCH following presentation with pancytopenia and marrow examination showing histiocytosis positive for CD45, CD68, CD136, and lysozyme but negative for CD1a, langerin, and S100. Whole-exome sequencing showed RUNX1 mutation and NF1 mutation. In the ensuing 6 months, she developed hepatosplenomegaly, and repeat bone marrow evaluation was diagnostic of acute myeloid leukemia (AML). Repeat mutational analysis showed again presence of RUNX1 mutation. She underwent induction therapy but died of septic shock. The demonstration of RUNX1 mutation in both non-LCH and AML bone marrow specimens at differing time points is suggestive of a biologic association of both distinct disease entities.

Serine and threonine kinases may contribute to insulin resistance and the development of type 2 diabetes. To test the potential for members of the mitogen-activated protein (MAP) kinase family to contribute to type 2 diabetes, we examined basal and insulin-stimulated Erk 1/2, JNK, and p38 phosphorylation in adipocytes isolated from healthy and type 2 diabetic individuals. Maximal insulin stimulation increased the phosphorylation of Erk 1/2 and JNK in healthy control subjects but not type 2 diabetic patients. Insulin stimulation did not increase p38 phosphorylation in either healthy control subjects or type 2 diabetic patients. In type 2 diabetic adipocytes, the basal phosphorylation status of these MAP kinases was significantly elevated and was associated with decreased IRS-1 and GLUT4 in these fat cells. To determine whether MAP kinases were involved in the downregulation of IRS-1 and GLUT4 protein levels, selective inhibitors were used to inhibit these MAP kinases in 3T3-L1 adipocytes treated chronically with insulin. Inhibition of Erk 1/2, JNK, or p38 had no effect on insulin-stimulated reduction of IRS-1 protein levels. However, inhibition of the p38 pathway prevented the insulin-stimulated decrease in GLUT4 protein levels. In summary, type 2 diabetes is associated with an increased basal activation of the MAP kinase family. Furthermore, upregulation of the p38 pathway might contribute to the loss of GLUT4 expression observed in adipose tissue from type 2 diabetic patients.

Dual inactivation of PTEN and INK4a/ARF tumor suppressor genes is a common feature observed in a broad spectrum of human cancer types. To validate functional collaboration between these genes in tumor suppression, we examined the biological consequences of Pten and/or Ink4a/Arf deficiency in cells and mice. Relative to single mutant controls, Ink4a/Arf-/-Pten+/- mouse embryonic fibroblast cultures exhibited faster rates of growth in reduced serum, grew to higher saturation densities, produced more colonies upon low density seeding, and showed increased susceptibility to transformation by oncogenic H-Ras. Ink4a/Arf deficiency reduced tumor-free survival and shortened the latency of neoplasias associated with Pten heterozygosity, specifically pheochromocytoma, prostatic intraepithelial neoplasia, and endometrial hyperplasia. Compound mutant mice also exhibited an expanded spectrum of tumor types including melanoma and squamous cell carcinoma. Functional synergy between Ink4a/Arf and Pten manifested most prominently in the development of pheochromocytoma, prompting an analysis of genes and loci implicated in this rare human neoplasm. The classical pheochromocytoma genes Ret, Vhl, and Nf-1 remained intact, a finding consistent with the intersection of these genes with pathways engaged by Pten and Ink4a/Arf. Notably, conventional and array-comparative genomic hybridization revealed frequent loss of distal mouse chromosome 4 in a region syntenic to human chromosome 1p that is implicated in human pheochromocytoma. This study provides genetic evidence of collaboration between Pten and Ink4a/Arf in constraining the growth and oncogenic transformation of cultured cells and in suppressing a wide spectrum of tumors in vivo.

Malignant triton tumor (MTT) is a malignant peripheral nerve sheath tumor (MPNST) with rhabdomyoblastic differentiation. This rare tumor, with fewer than 100 cases reported in the literature, generally affects adult patients with neurofibromatosis 1 (NF-1). We report such a case in a 34-year-old man with NF-1 who presented with a mass over the medial side of the arm. Histopathologically finding of rhabdomyoblasts among malignant Schwann cells in a tumor arising from a peripheral nerve supported by immunostaining with S-100 protein and myogenin confirmed the diagnosis. MTT has a poor prognosis owing to its aggressive biological behavior. The fact that this tumor is extremely rare has prompted us to report this case.