The Clinicopathological Characteristics and Prognosis of 55 Patients With TFE3-Rearranged Renal Cell Carcinomas.

OBJECTIVE: To explore the clinicopathological features and prognosis of TFE3-rearranged renal cell carcinomas (TFE3-rRCC). METHODS: In this retrospective observational study, the data of patients with TFE3-rRCC admitted to Xijing Hospital from January 2010 to October 2023 were collected, encompassing the general information, pathological diagnosis, immunohistochemistry, and the results of FISH detection. The treatment information and survival data of the patients were recorded during the follow-up. RESULTS: A total of 55 patients with TFE3-rRCC were enrolled, among whom 25 were males and 30 were females. TFE3 FISH assay suggested the disruption of the TFE3 gene. Fifty-four patients underwent surgical resection of kidney lesions, while 1 patient did not. By the end of follow-up in December 2023, 3 patients were lost to follow-up, 28 patients remained alive, and 24 patients had died. Among the 52 patients followed up, 31 developed metastases, involving lymph nodes, liver, bone, lung, peritoneum, pleura, adrenal gland, and brain. The 1-year and 5-year survival rates of the patients were 84.6% and 50.6%, respectively. In this study, there were 31 patients with TFE3-rRCC recurrence or metastasis. Median PFS was 7 and 13 months in the VEGFR-TKI and VEGFR-TKI+ ICI groups, respectively. The median OS was 12 months in the VEGFR-TKI treatment group. The median OS data of VEGFR-TKI+ ICI group has not been reached. The ORR and DCR was 25%, 66.7% in the VEGFR-TKI group. The ORR and DCR was 33.3%, 77.8% in the VEGFR-TKI+ ICI group. CONCLUSION: TFE3-rRCC is a rare subtype of malignant renal tumor. The diagnosis mainly relies on pathological morphology, immunohistochemistry, and the detection of TFE3 gene disruption by FISH. In terms of treatment, surgery is the primary approach, and lymph nodes, liver, and bone are the main metastatic sites. VEGFR-TKI+ICI treatment might be an option of recurrent or metastatic TFE3-rRCC.

TFE Terpolymers: Once Promising - Are There Still Perspectives in the 21st Century: Synthesis, Characterization, and Properties-Part I.

Polytetrafluoroethylene (PTFE) exhibits outstanding properties such as high-temperature stability, low surface tension, and chemical resistance against most solvents, strong acids, and bases. However, these traits make it challenging to subject PTFE to standard polymer processing procedures, such as thermoforming and hot incremental forming. While polymer processing at temperatures above the melting point of PTFE is already demanding, the typically large molar mass of PTFE results in extremely high melt viscosities, complicating the processing of PTFE. Also, PTFE tends to decompose at temperatures close to its melting point. Therefore, fluoropolymers obtained by copolymerizing tetrafluoroethylene (TFE) with various co-monomers are studied as alternatives to PTFE (e.g., fluorinated ethylene-propylene (FEP)), combining its advantages with better processability. TFE terpolymers have emerged as desirable PTFE alternatives. This review provides an overview of the synthesis with various comonomers and microstructural analysis of PTFE terpolymers and the relationships between the microstructures of TFE terpolymers and their properties.

A genetic basis for sex differences in Xp11 translocation renal cell carcinoma.

Xp11 translocation renal cell carcinoma (tRCC) is a rare, female-predominant cancer driven by a fusion between the transcription factor binding to IGHM enhancer 3 (TFE3) gene on chromosome Xp11.2 and a partner gene on either chromosome X (chrX) or an autosome. It remains unknown what types of rearrangements underlie TFE3 fusions, whether fusions can arise from both the active (chrXa) and inactive X (chrXi) chromosomes, and whether TFE3 fusions from chrXi translocations account for the female predominance of tRCC. To address these questions, we performed haplotype-specific analyses of chrX rearrangements in tRCC whole genomes. We show that TFE3 fusions universally arise as reciprocal translocations and that oncogenic TFE3 fusions can arise from chrXi:autosomal translocations. Female-specific chrXi:autosomal translocations result in a 2:1 female-to-male ratio of TFE3 fusions involving autosomal partner genes and account for the female predominance of tRCC. Our results highlight how X chromosome genetics constrains somatic chrX alterations and underlies cancer sex differences.

Four years of natural progressive course: A rare case report of juvenile Xp11.2 translocations renal cell carcinoma with TFE3 gene fusion.

Background: Renal cell carcinoma (RCC) with TFE3 gene fusion caused by Xp11.2 translocations is a rare RCC subtype. This tumor is typically seen in children, comprising 20‒40% of overall RCC cases compared to 1‒1.6% observed in adults. Xp11.2 RCC is associated with a poor prognosis due to both the progression of local lesions and early distant and lymphatic metastasis. Case presentation: A case of RCC with Xp11.2 RCC translocations and TFE3 gene fusion was found in a pediatric patient, illustrating the catastrophic effects of ignoring the condition. The tumor developed from a local lesion to lymph metastasis (3.2-12 cm) within 4 years. Despite ongoing controversy, surgical resection remains the most common and productive approach. In this patient, renal retroperitoneal lymph node dissection and radical nephrectomy of the left kidney were performed via laparoscopic surgery. The RCC-associated Xp11.2 translocation/TFE3 gene fusions were identified by postoperative pathology. Microscopic analysis showed the presence of intravascular cancer thrombus, renal sinus invasion, and cancer necrosis. The pathological stages were confirmed as PT3aN1M0 with a negative margin. Follow-up at 5 months showed that the patient recovered without the use of any adjuvant treatments. Conclusion: Our study highlights the natural course, diagnosis, and treatment of RCC-associated Xp11.2 translocation/TFE3 gene fusions, especially the necessity of early surgery. This case may be a helpful reference for urologists in the treatment of similar cases. It also serves as a precautionary signal for patients who neglect the renal neoplasm.

The Spectrum of "TFEopathies" - Flipping the mTOR Switch in Renal Tumorigenesis.

The Mammalian Target of Rapamycin Complex 1 (mTORC1) is a serine threonine kinase that couples nutrient and growth factor signaling to the cellular control of metabolism and plays a fundamental role in aberrant proliferation in cancer. mTORC1 has previously been considered an "on/off" switch, capable of phosphorylating the entire pool of its substrates when activated. However recent studies have indicated that mTORC1 may be active towards its canonical substrates, 4EBP1 and S6K, involved in mRNA translation and protein synthesis, and inactive towards TFEB and TFE3, transcription factors involved in the regulation of lysosome biogenesis, in several pathological contexts. Among these conditions are Birt Hogg Dube (BHD) and recently, Tuberous Sclerosis Complex (TSC). Furthermore, TFEB and TFE3 hyperactivation in these syndromes, and in translocation Renal Cell Carcinomas (tRCC), drives mTORC1 activity towards the canonical substrates, through the transcriptional activation of the Rag GTPases, thereby positioning TFEB and TFE3 upstream of mTORC1 activity towards 4EBP1 and S6K. The expanding importance of TFEB and TFE3 in the pathogenesis of these renal diseases warrants a novel clinical grouping that we term "TFEopathies". Currently, there no therapeutic options directly targeting TFEB and TFE3, which represents a challenging and critically required avenue for cancer research.

Coxiella burnetii inhibits nuclear translocation of TFEB, the master transcription factor for lysosomal biogenesis.

Coxiella burnetii is a highly infectious, Gram-negative, obligate intracellular bacterium and the causative agent of human Q fever. The Coxiella Containing Vacuole (CCV) is a modified phagolysosome that forms through fusion with host endosomes and lysosomes. While an initial acidic pH < 4.7 is essential to activate Coxiella metabolism, the mature, growth-permissive CCV has a luminal pH of ~5.2 that remains stable throughout infection. Inducing CCV acidification to a lysosomal pH (~4.7) causes Coxiella degradation, suggesting that Coxiella regulates CCV pH. Supporting this hypothesis, Coxiella blocks host lysosomal biogenesis, leading to fewer host lysosomes available to fuse with the CCV. Host cell lysosome biogenesis is primarily controlled by the transcription factor EB (TFEB), which binds Coordinated Lysosomal Expression And Regulation (CLEAR) motifs upstream of genes involved in lysosomal biogenesis and function. TFEB is a member of the microphthalmia/transcription factor E (MiT/TFE) protein family, which also includes MITF, TFE3, and TFEC. This study examines the roles of MiT/TFE proteins during Coxiella infection. We found that in cells lacking TFEB, both Coxiella growth and CCV size increase. Conversely, TFEB overexpression or expression in the absence of other family members leads to significantly less bacterial growth and smaller CCVs. TFE3 and MITF do not appear to play a significant role during Coxiella infection. Surprisingly, we found that Coxiella actively blocks TFEB nuclear translocation in a Type IV Secretion System-dependent manner, thus decreasing lysosomal biogenesis. Together, these results suggest that Coxiella inhibits TFEB nuclear translocation to limit lysosomal biogenesis, thus avoiding further CCV acidification through CCV-lysosomal fusion. IMPORTANCE: The obligate intracellular bacterial pathogen Coxiella burnetii causes the zoonotic disease Q fever, which is characterized by a debilitating flu-like illness in acute cases and life-threatening endocarditis in patients with chronic disease. While Coxiella survives in a unique lysosome-like vacuole called the Coxiella Containing Vacuole (CCV), the bacterium inhibits lysosome biogenesis as a mechanism to avoid increased CCV acidification. Our results establish that transcription factor EB (TFEB), a member of the microphthalmia/transcription factor E (MiT/TFE) family of transcription factors that regulate lysosomal gene expression, restricts Coxiella infection. Surprisingly, Coxiella blocks TFEB translocation from the cytoplasm to the nucleus, thus downregulating the expression of lysosomal genes. These findings reveal a novel bacterial mechanism to regulate lysosomal biogenesis.

An orbital perivascular epithelioid cell tumor (PEComa) in a 9-year-old boy: Case report and review of the literature.

Perivascular epithelioid cell tumors (PEComas) are a family of benign neoplasms characterized by smooth muscle and melanocytic differentiation. Orbital cases are rare. A 9-year-old male presented with a slowly growing orbital mass. Magnetic resonance imaging (MRI) revealed a well-defined orbital mass without intracranial extension. The microscopic appearance of the complete resection specimen showed large nests of epithelioid cells with wide cytoplasm containing melanin pigment and round to oval nuclei with mild cytonuclear atypia and low mitotic activity. Immunohistochemistry was positive for HMB45 and negative for melanA, smooth muscle actin, desmin and S-100 protein. Pangenomic RNA-sequencing identified an in-frame NONO-TFE3 rearrangement, and clustering data showed that the tumor's gene expression profile was grouped with other previously studied PEComas. A diagnosis of orbital pigmented PEComa with uncertain malignant potential associated with a NONO-TFE3 rearrangement was made. There was no recurrence after 1 year of follow-up.

RIT2 regulates autophagy lysosomal pathway induction and protects against α-synuclein pathology in a cellular model of Parkinson's disease.

Substantial work has been devoted to better understand the contribution of the myriad of genes that may underly the development of Parkinson's disease (PD) and their role in disease etiology. The small GTPase Ras-like without CAAX2 (RIT2) is one such genetic risk factor, with one single nucleotide polymorphism in the RIT2 locus, rs12456492, having been associated with PD risk in multiple populations. While RIT2 has previously been shown to influence signaling pathways, dopamine transporter trafficking, and LRRK2 activity, its cellular function remains unclear. In the current study, we have situated RIT2 to be upstream of various diverse processes associated with PD. In cellular models, we have shown that RIT2 is necessary for activity-dependent changes in the expression of genes related to the autophagy-lysosomal pathway (ALP) by regulating the nuclear translocation of MiT/TFE3-family transcription factors. RIT2 is also associated with lysosomes and can regulate autophagic flux and clearance by regulating lysosomal hydrolase expression and activity. Interestingly, upregulation of RIT2 can augment ALP flux and protect against α-synuclein aggregation in cortical neurons. Taken together, the present study suggests that RIT2 can regulates gene expression upstream of ALP function and that enhancing RIT2 activity may provide therapeutic benefit in PD.

Patients with ASPSCR1-TFE3 fusion achieve better response to ICI based combination therapy among TFE3-rearranged renal cell carcinoma.

BACKGROUND: TFE3-rearranged renal cell carcinoma (TFE3-rRCC) is a rare but highly heterogeneous renal cell carcinoma (RCC) entity, of which the clinical treatment landscape is largely undefined. This study aims to evaluate and compare the efficacy of different systemic treatments and further explore the molecular correlates. METHODS: Thirty-eight patients with metastatic TFE3-rRCC were enrolled. Main outcomes included progression-free survival (PFS), overall survival, objective response rate (ORR) and disease control rate. RNA sequencing was performed on 32 tumors. RESULTS: Patients receiving first-line immune checkpoint inhibitor (ICI) based combination therapy achieved longer PFS than those treated without ICI (median PFS: 11.5 vs. 5.1 months, P = 0.098). After stratification of fusion partners, the superior efficacy of first-line ICI based combination therapy was predominantly observed in ASPSCR1-TFE3 rRCC (median PFS: not reached vs. 6.5 months, P = 0.01; ORR: 67.5% vs. 10.0%, P = 0.019), but almost not in non-ASPSCR1-TFE3 rRCC. Transcriptomic data revealed enrichment of ECM and collagen-related signaling in ASPSCR1-TFE3 rRCC, which might interfere with the potential efficacy of anti-angiogenic monotherapy. Whereas angiogenesis and immune activities were exclusively enriched in ASPSCR1-TFE3 rRCC and promised the better clinical outcomes with ICI plus tyrosine kinase inhibitor combination therapy. CONCLUSIONS: The current study represents the largest cohort comparing treatment outcomes and investigating molecular correlates of metastatic TFE3-rRCC based on fusion partner stratification. ICI based combination therapy could serve as an effective first-line treatment option for metastatic ASPSCR1-TFE3 rRCC patients. Regarding with other fusion subtypes, further investigations should be performed to explore the molecular mechanisms to propose pointed therapeutic strategy accordingly.

[2022 WHO classification of renal cell carcinomas: Focus on papillary renal cell carcinoma]. / Classification OMS 2022 des cancers du rein : focus sur le carcinome rénal papillaire.

Renal cell carcinomas (RCC) represent a group of heterogeneous tumors whose classification has greatly evolved since 1981. The latest update in 2022 classifies all renal cell carcinomas into six categories according to their morphology or the detection of specific molecular alterations. Molecular disassembly of renal cell carcinomas with papillary features has enabled the identification of new entities characterized by a specific molecular alteration, such as Fumarate Hydratase (FH) deficient RCC, TFE3-rearranged RCC or TFEB-altered RCC. This new classification allows for a more accurate diagnosis but requires a thorough knowledge of the genomic alterations to search for with immunohistochemical or molecular biology techniques. According to the new WHO 2022 classification, papillary renal cell carcinoma (PRC) type 1 or type 2 classification is no longer recommended. A classification based on nucleolar ISUP grade must be preferred: low-grade PRC (ISUP 1-2) or high-grade PRC (ISUP 3-4). The other prognostic factors remain the same: the pTNM stage, lymphovascular invasion, and the presence or absence of dedifferentiated areas referring to sarcomatoid or rhabdoid features. Of note, the presence of necrosis is not currently recognized as a poor prognostic element for this type of carcinoma. The diagnosis of high-grade PRC is from now on a diagnosis of exclusion. It can only be sustained after having ruled out TFE3-rearranged RCC, TFEB-altered RCC, and FH-deficient RCC. For clinicians, the diagnosis of PRC implies suggesting an oncogenetic consultation to screen for an associated genetic tumor syndrome regardless of the patient's age.

Exploring G-quadruplex structure in PRCC-TFE3 fusion oncogene: Plausible use as anti cancer therapy for translocation Renal cell carcinoma (tRCC).

The TFE3 fusion gene, byproduct of Xp11.2 translocation, is the diagnostic marker for translocation renal cell carcinoma (tRCC). Absence of any clinically recognized therapy for tRCC, pressing a need to create novel and efficient therapeutic approaches. Previous studies shown that stabilization of the G-quadruplex structure in oncogenes suppresses their expression machinery. To combat the oncogenesis caused by fusion genes, our objective is to locate and stabilize the G-quadruplex structure within the PRCC-TFE3 fusion gene. Using the Quadruplex-forming G Rich Sequences (QGRS) mapper and the Non-B DNA motif search tool (nBMST) online server, we found putative G-quadruplex forming sequences (PQS) in the PRCC-TFE3 fusion gene. Circular dichroism demonstrating a parallel G-quadruplex in the targeted sequence. Fluorescence and UV-vis spectroscopy results suggest that pyridostatin binds to this newly discovered G-quadruplex. The PCR stop assay, as well as transcriptional or translational inhibition using real time PCR and Dual luciferase assay, revealed that stable G-quadruplex formation affects biological processes. Confocal microscopy of HEK293T cells transfected with the fusion transcript confirmed G-quadruplexes formation in cell. This investigation may shed light on G-quadruplex's functions in fusion genes and may help in the development of therapies specifically targeted against fusion oncogenes, which would enhance the capability of current tRCC therapy approach.

The WHO 2022 Classification of Renal Neoplasms (5th Edition): Salient Updates.

The first categorization for renal tumours was made by the WHO in 1981 and included only renal cell carcinoma (RCC). After that, classification was continuously altered over five decades. The WHO 2022 Classification of Urinary and Male Genital Tumours 2022 (5th edition) is molecular-driven and contains major revisions compared to the earlier classification from 2016. This revised edition divided renal tumours into four major broad categories: clear cell renal tumours, papillary renal cell tumours, oncocytic and chromophobe renal tumours, and collecting duct tumours. 'Other renal tumours' and 'molecularly defined renal carcinomas' are two other categories that were also included. Transcription factor binding to IGHM enhancer 3 (TFE3)-rearranged, TFEB-altered, elongin C (ELOC)-mutated (formerly TCEB1)-mutated, fumarate hydratase (FH)-deficient, succinate dehydrogenase (SDH)-deficient, anaplastic lymphoma kinase (ALK)-rearranged, and SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1)-deficient renal cell carcinomas are molecularly defined entities. Eosinophilic vacuolated tumours and low-grade oncocytic tumours are classified as emerging entities. Molecularly characterized renal tumours include those with SMARCB1 deficiencies, TFE3 rearrangements, TFEB alterations, ALK rearrangements, ELOC mutations, etc. Thyroid-like follicular carcinoma, eosinophilic vacuolated tumour, and low-grade oncocytic tumour are a few emerging entities of renal tumours. Improved therapy targets for each kidney tumour can be achieved using immunohistochemistry (IHC) and molecular definition updates. This study aims to highlight new developments in the WHO 2022 categorization of renal tumours with regard to diagnostic, morphological, molecular, IHC, clinical, and prognostic updates.

d-mannose targets PD-1 to lysosomal degradation and enhances T cell-mediated anti-tumor immunity.

High expression of programmed cell death protein 1 (PD-1), a typical immune checkpoint, results in dysfunction of T cells in tumor microenvironment. Antibodies and inhibitors against PD-1 or its ligand (PD-L1) have been widely used in various malignant tumors. However, the mechanisms by which PD-1 is regulated are not fully understood. Here, we report a mechanism of PD-1 degradation triggered by d-mannose and the universality of this mechanism in anti-tumor immunity. We show that d-mannose inactivates GSK3ß via promoting phosphorylation of GSK3ß at Ser9, thereby leading to TFE3 translocation to nucleus and subsequent PD-1 proteolysis induced by enhanced lysosome biogenesis. Notably, combination of d-mannose and PD-1 blockade exhibits remarkable tumor growth suppression attributed to elevated cytotoxicity activity of T cells in vivo. Furthermore, d-mannose treatment dramatically improves the therapeutic efficacy of MEK inhibitor (MEKi) trametinib in vivo. Our findings unveil a universally unrecognized anti-tumor mechanism of d-mannose by destabilizing PD-1 and provide strategies to enhance the efficacy of both immune checkpoint blockade (ICB) and MEKi -based therapies.

Treatment of metastatic TFE3 microphthalmia transcription factor translocation renal cell carcinoma: a case report.

Background: Microphthalmia-associated transcription factor/transcription factor E (MiTF/TFE) translocation renal cell carcinoma (RCC) is a rare type of non-clear cell RCC (nccRCC), which is more common in females. Currently, there is no standardized treatment for advanced metastatic microphthalmia translocation RCC (MiT-RCC). The main treatment modalities include surgery, chemotherapy, immunotherapy, anti-vascular endothelial growth factor or vascular endothelial growth factor receptor (VEGFR) inhibitors, mammalian target of rapamycin (mTOR) inhibitors, and targeted therapy against the mesenchymal-epithelial transition (MET) factor signaling pathway. Case Description: We present the case of an 8-year-old male patient with hematuria and paroxysmal urinary pain. Based on tumor genetic testing results and targeted drug matching analysis, the patient underwent tumor biopsy, tumor radical surgery with vascular osteotomy, and cervicothoracic lymph node dissection. The patient was then treated with a combination of immunotherapy [sintilimab, a drug directed against programmed cell death receptor-1 (PD-1)] and VEGFR tyrosine kinase inhibitor (TKI) (from pazopanib to sunitinib). Throughout the 10 cycles of conventional chemotherapy (seven courses of sintilimab since the start of the third chemotherapy treatment), the patient's condition remained stable, with no tumor recurrence at the primary site. However, in the later stages, the patient developed a large amount of ascites, and the family requested discontinuation of treatment, ultimately leading to the patient's death. Conclusions: In this case report, we summarize the therapeutic strategy of a young patient with metastatic transcription factor E3 (TFE3) MiT-RCC. For this disease, early immunotherapy and the use of precision-targeted drugs may have a favorable impact on the survival prognosis of the patient but may still be of less benefit in children with advanced multiple metastases. Therefore, further research on tumor driver genes, among other treatment components, is urgently needed to improve precision therapy.

An unusual case of primary splenic soft part alveolar sarcoma: case report and review of the literature with emphasis on the spectrum of TFE3-associated neoplasms.

BACKGROUND: Alveolar soft part sarcoma is a rare tumour of soft tissues, mostly localized in muscles or deep soft tissues of the extremities. In rare occasions, this tumour develops in deep tissues of the abdomen or pelvis. CASE PRESENTATION: In this case report, we described the case of a 46 year old man who developed a primary splenic alveolar soft part sarcoma. The tumour displayed typical morphological alveolar aspect, as well as immunohistochemical profile notably TFE3 nuclear staining. Detection of ASPSCR1 Exon 7::TFE3 Exon 6 fusion transcript in molecular biology and TFE3 rearrangement in FISH confirmed the diagnosis. CONCLUSION: We described the first case of primary splenic alveolar soft part sarcoma, which questions once again the cell of origin of this rare tumour.

The New WHO Category of "Molecularly Defined Renal Carcinomas": Clinical and Diagnostic Features and Management Implications.

The evolution of classification of renal tumors has been impacted since the turn of the millennium by rapid progress in histopathology, immunohistochemistry, and molecular genetics. Together, these features have enabled firm recognition of specific, classic types of renal cell carcinomas, such as clear cell renal cell carcinoma, that in current practice trigger histologic-type specific management and treatment protocols. Now, the fifth Edition World Health Classification's new category of "Molecularly defined renal carcinomas" changes the paradigm, defining a total of seven entities based specifically on their fundamental molecular underpinnings. These tumors, which include TFE3-rearranged, TFEB-altered, ELOC-mutated, fumarate hydratase-deficient, succinate dehydrogenase-deficient, ALK-rearranged, and SMARCB1-deficient renal medullary carcinoma, encompass a wide clinical and histopathologic phenotypic spectrum of tumors. Already, important management aspects are apparent for several of these entities, while emerging therapeutic angles are coming into view. A brief, clinically-oriented introduction of the entities in this new category, focusing on relevant diagnostic, molecular, and management aspects, is the subject of this review.

Epithelioid hemangioendothelioma-its history, clinical features, molecular biology and current therapy.

Epithelioid hemangioendothelioma (EHE) is a remarkably rare tumor arising from endothelial cells that is classified as a vascular tumor in the WHO classification. The tumor is predominantly characterized by the presence of fusion genes, such as WWTR1-CAMTA1 or YAP1-TFE3, with a minority of cases exhibiting other rare fusion genes. EHE exhibits a broad age of onset, typically presenting at ~50 years, but it is not uncommon in pediatric populations. It manifests in a variety of organs, including the liver, lung, soft tissue and bone. Initial multiple-organ involvement is also observed. The tumor's biological behavior and prognosis vary substantially based on the primary site of manifestation. From a therapeutic perspective, initial active surveillance might be considered in selected cases, although surgical intervention remains the mainstay of treatment, especially for localized single-organ involvement. Chemotherapy is administered to patients with progressive unresectable tumors. Recent advances in the biological analysis of EHE fusion genes have elucidated their diverse functions. Additionally, next-generation sequencing has facilitated the identification of other mutations beyond the fusion genes. These continuous efforts to understand the biology of the fusion genes themselves and/or the dysregulated signaling by fusion genes are expected to lead to the development of novel therapeutic strategies for EHE. This article aims to provide a comprehensive review of EHE, encompassing its historical context, clinical manifestations, molecular biology and the current state of treatment.

Design and validation of a reporter mouse to study the dynamic regulation of TFEB and TFE3 activity through in vivo imaging techniques.

TFEB and TFE3 belong to the MiT/TFE family of transcription factors that bind identical DNA responsive elements in the regulatory regions of target genes. They are involved in regulating lysosomal biogenesis, function, exocytosis, autophagy, and lipid catabolism. Precise control of TFEB and TFE3 activity is crucial for processes such as senescence, stress response, energy metabolism, and cellular catabolism. Dysregulation of these factors is implicated in various diseases, thus researchers have explored pharmacological approaches to modulate MiT/TFE activity, considering these transcription factors as potential therapeutic targets. However, the physiological complexity of their functions and the lack of suitable in vivo tools have limited the development of selective MiT/TFE modulating agents. Here, we have created a reporter-based biosensor, named CLEARoptimized, facilitating the pharmacological profiling of TFEB- and TFE3-mediated transcription. This innovative tool enables the measurement of TFEB and TFE3 activity in living cells and mice through imaging and biochemical techniques. CLEARoptimized consists of a promoter with six coordinated lysosomal expression and regulation motifs identified through an in-depth bioinformatic analysis of the promoters of 128 TFEB-target genes. The biosensor drives the expression of luciferase and tdTomato reporter genes, allowing the quantification of TFEB and TFE3 activity in cells and in animals through optical imaging and biochemical assays. The biosensor's validity was confirmed by modulating MiT/TFE activity in both cell culture and reporter mice using physiological and pharmacological stimuli. Overall, this study introduces an innovative tool for studying autophagy and lysosomal pathway modulation at various biological levels, from individual cells to the entire organism.Abbreviations: CLEAR: coordinated lysosomal expression and regulation; MAR: matrix attachment regions; MiT: microphthalmia-associated transcription factor; ROI: region of interest; TBS: tris-buffered saline; TF: transcription factor; TFE3: transcription factor binding to IGHM enhancer 3; TFEB: transcription factor EB; TH: tyrosine hydroxylase; TK: thymidine kinase; TSS: transcription start site.