A primary rectal neoplasm with novel DDX5-TFEB fusion.

We report a case of primary rectal neoplasm with a novel DDX5-TFEB fusion in a 14-year-old boy. Histologically, the neoplasm was composed of epithelioid tumor cells with abundant clear to eosinophilic cytoplasm, arranged in nests with rich stromal capillary vasculature. Immunohistochemically, the tumor cells were positive for transcription factor EB (TFEB) and negative for PAX8, TFE3, HMB45, and PCK. TFEB gene rearrangement and low-level amplification were identified using break-apart fluorescence in situ hybridization. Next-generation sequencing identified a heretofore unreported DDX5-TFEB gene fusion, which was confirmed by using reverse transcription-polymerase chain reaction and Sanger sequencing. The major morphological differential diagnoses include perivascular epithelioid cell tumor, microphthalmia-associated transcriptional factor family translocation renal cell carcinoma, and alveolar soft part sarcoma. The morphological, immumophenotypical, and genetic characteristics of this tumor did not fit well with current classification, but it may represent an unusual PEComa-like tumor with a novel DDX5-TFEB fusion.

Long Non-Coding RNA H19 Expression Correlates with Autophagy Process in Adrenocortical Carcinoma.

Adrenocortical carcinoma (ACC) is characterized by poor prognosis and high mortality. The suppression of the long-non-coding RNA H19, counterbalanced by IGF2 over-expression, leads to down-regulation of the autophagy markers, high proliferation rate and metastatic potential in patients affected by ACC. The administration of the deacetylase inhibitors (DACi) panobinostat, trichostatin A (TSA) and SAHA affected the cell viability of H295R monolayer and spheroids and induced the over-expression of H19 and autophagy transcripts. H19 knock down in H295R cells was not able to modulate the expression level of autophagy transcripts. Instead, H19 knock down was able to impede the ability of DACi to modulate the protein level of the autophagy markers. Furthermore, the administration of higher concentration of DACi was able to down-regulate the protein level of Beclin1 and p62 and to induce the conversion of LC3B-I into the active LC3B-II form, thus confirming an active autophagic process. Neither the active protein level nor the activity of caspases 8 and 3 was prompted by the DACi, thus excluding the involvement of the executioners of apoptosis in H295R decay. The DACi restore H19, the autophagy markers and trigger cell death in ACC cells. The re-activation of autophagy would represent a novel strategy for the treatment of patients affected by this severe malignancy.

YAP1-TFE3-fused hemangioendothelioma: a multi-institutional clinicopathologic study of 24 genetically-confirmed cases.

YAP1-TFE3-fused hemangioendothelioma is an extremely rare malignant vascular tumor. We present the largest multi-institutional clinicopathologic study of YAP1-TFE3-fused hemangioendothelioma to date. The 24 cases of YAP1-TFE3-fused hemangioendothelioma showed a female predominance (17 female, 7 male) across a wide age range (20-78 years old, median 44). Tumors were most commonly located in soft tissue (50%), followed by bone (29%), lung (13%), and liver (8%), ranging from 3 to 115 mm in size (median 40 mm). About two-thirds presented with multifocal disease, including 7 cases with distant organ metastasis. Histopathologically, we describe three dominant architectural patterns: solid sheets of coalescing nests, pseudoalveolar and (pseudo)vasoformative pattern, and discohesive strands and clusters of cells set in a myxoid to myxohyaline stroma. These patterns were present in variable proportions across different tumors and often coexisted within the same tumor. The dominant cytomorphology (88%) was large epithelioid cells with abundant, glassy eosinophilic to vacuolated cytoplasm, prominent nucleoli and well-demarcated cell borders. Multinucleated or binucleated cells, prominent admixed erythrocytic and lymphocytic infiltrates, and intratumoral fat were frequently present. Immunohistochemically, ERG, CD31, and TFE3 were consistently expressed, while expression of CD34 (83%) and cytokeratin AE1/AE3 (20%) was variable. CAMTA1 was negative in all but one case. All cases were confirmed by molecular testing to harbor YAP1-TFE3 gene fusions: majority with YAP1 exon 1 fused to TFE3 exon 4 (88%), or less commonly, TFE3 exon 6 (12%). Most patients (88%) were treated with primary surgical resection. Over a follow-up period of 4-360 months (median 36 months) in 17 cases, 35% of patients remained alive without disease, and 47% survived many years with stable, albeit multifocal and/or metastatic disease. Five-year progression-free survival probability was 88%. We propose categorizing YAP1-TFE3-fused hemangioendothelioma as a distinct disease entity given its unique clinical and histopathologic characteristics in comparison to conventional epithelioid hemangioendothelioma.

Hibernoma-like Changes and TFE3 Expression in Mesothelioma Mimicking TFE3-Translocation Renal Cell Carcinoma: A Diagnostic Pitfall.

The long delay between asbestos exposure and the development of mesothelioma will likely result in an increased incidence of mesothelioma in our industrialized societies. Radiation therapy is another factor known to induce these tumors. We describe a rare case of foamy looking mesothelioma in a 63-year-old patient with a long oncology history of a supposed peritoneal carcinomatosis. The pathologist was faced with a diagnostic pitfall as this peritoneal clear cell tumor expressed transcription factor binding to immunoglobulin heavy constant mu enhancer 3 (TFE3) at the nuclear level. Fortunately, the pathologist performed an extensive panel of immunomarkers, leading to a final diagnosis of epithelioid mesothelioma. Thus, we describe the first case of mesothelioma expressing TFE3. Note that there was no rearrangement of TFE3 in fluorescence in situ hybridization.

ALK rearrangement in TFE3-positive renal cell carcinoma: Alternative diagnostic option to exclude Xp11.2 translocation carcinoma.

Anaplastic lymphoma kinase (ALK)-rearranged renal cell carcinoma (RCC) is a rare subtype of RCC with gene fusion involving ALK at 2p23. It was first included in the renal tumor classification system by WorldHealth organization (WHO) as a distinct emerging/provisional renal entity in 2016. To date, only a few cases of ALK-RCC have been reported. Here, we report an exceptional case of ALK-RCC in a 15-year-old girl and review the literature. The patient presented with gross hematuria and a tumor measured 7 cm × 6 cm was found in the left kidney by imaging examination. Then a laparoscopic radical nephrectomy combined with local lymph node dissection was performed. The pathologic stage of the tumor was pT1bN1Mx and postoperative pathology showed that the tumor corresponded to WHO/ISUP grade 3-4. Immunohistochemistry (IHC) demonstrated moderate nuclear expression of TFE3 protein. Interestingly, ALK gene rearrangement rather than TFE3 gene rearrangement was observed by fluorescence in situ hybridization (FISH). Now the girl is still alive without evidence of recurrence for 10 months follow-up. In conclusion, the positive expression of nuclear TFE3 in immunohistochemistry may be deceptive, the detection of ALK could be a diagnostic option if TFE3 was negative in FISH study. Large-scale and long-term studies are still needed to explore the biological behavior and molecular characteristic of ALK-RCC.

SmbHLH53 is relevant to jasmonate signaling and plays dual roles in regulating the genes for enzymes in the pathway for salvianolic acid B biosynthesis in Salvia miltiorrhiza.

Basic helix-loop-helix (bHLH) transcription factors play essential roles in myriad regulatory processes, including secondary metabolism. In this study with Salvia miltiorrhiza, we isolated and characterized SmbHLH53, which encodes a bHLH family member. Expression of this gene was significantly induced by wounding and multiple hormones, including methyl jasmonic acid; transcript levels were highest in the leaves and roots. Phylogenetic analysis indicated that SmbHLH53 clusters withAtbHLH17 and AtbHLH13, two negative regulators of jasmonate (JA) responses, and is localized in the nucleus and cell membrane. Yeast two-hybrid and bimolecular fluorescent complementation assays indicated that SmbHLH53 forms a homodimer as well as a heterodimer with SmbHLH37. It also interacts with both SmJAZs1/3/8 and SmMYC2, the core members of the JA signal pathway. Unexpectedly, we noted that overexpression of SmbHLH53 did not significantly influence the concentrations of rosmarinic acid and salvianolic acid B in transgenic plants. Results from yeast one-hybrid assays showed that SmbHLH53 binds to the promoters of SmTAT1, SmPAL1, and Sm4CL9, the key genes for enzymes in the pathway for phenolic acid synthesis. Assays of transient transcriptional activity demonstrated that SmbHLH53 represses the promoter of SmTAT1 while activating the promoter of Sm4CL9. Thus, the present work revealed that SmbHLH53 may play dual roles in regulating the genes for enzymes in the pathway for Sal B biosynthesis.

Clinicopathologic and Molecular Analysis of the TFEB Fusion Variant Reveals New Members of TFEB Translocation Renal Cell Carcinomas (RCCs): Expanding the Genomic Spectrum.

Xp11 renal cell carcinoma (RCC) with different gene fusions may have different clinicopathologic features. We sought to identify variant fusions in TFEB translocation RCC. A total of 31 cases of TFEB RCCs were selected for the current study; MALAT1-TFEB fusion was identified in 25 cases (81%, 25/31) using fusion probes. The remaining 6 cases (19%, 6/31) were further analyzed by RNA sequencing and 5 of them were detected with TFEB-associated gene fusions, including 2 ACTB-TFEB, 1 EWSR1-TFEB, 1 CLTC-TFEB, and 1 potential PPP1R10-TFEB (a paracentric inversion of the TFEB gene, consistent with "negative" TFEB split FISH result, and advising a potential diagnostic pitfall in detecting TFEB gene rearrangement). Four of the 5 fusion transcripts were successfully validated by reverse transcription-polymerase chain reaction and Sanger sequencing. Morphologically, approximately one third (29%, 9/31) of TFEB RCCs showed typical biphasic morphology. The remaining two thirds of the cases (71%, 22/31) exhibited nonspecific morphology, with nested, sheet-like, or papillary architecture, resembling other types of renal neoplasms, such as clear cell RCC, Xp11 RCC, perivascular epithelioid cell tumor (PEComa), or papillary RCC. Although cases bearing a MALAT1-TFEB fusion demonstrated variable morphologies, all 9 cases featuring typical biphasic morphology were associated with MALAT1-TFEB genotype. Accordingly, typical biphasic morphology suggests MALAT1-TFEB fusion, whereas atypical morphology did not suggest the specific type of fusion. Isolated or clustered eosinophilic cells were a common feature in TFEB RCCs, which may be a useful morphology diagnostic clue for TFEB RCCs. Clinicopathologic variables assessment showed that necrosis was the only morphologic feature that correlated with the aggressive behavior of TFEB RCC (P=0.004). In summary, our study expands the genomic spectrum and the clinicopathologic features of TFEB RCCs, and highlights the challenges of diagnosis and the importance of subtyping of this tumor by combining morphology and multiple molecular techniques.

A novel partner of TFE3 in the Xp11 translocation renal cell carcinoma: clinicopathological analyses and detection of EWSR1-TFE3 fusion.

The renal cell carcinomas associated with Xp11 translocations (Xp11 translocation RCCs) harbor gene fusions involving TFE3, a member of the microphthalmia-associated transcription factor (MiTF) family. In the present study, we identified a novel partner of TFE3, Ewing sarcoma breakpoint region 1 (EWSR1), in an Xp11 translocation RCC. A 57-year-old Japanese woman without special disease history was referred to us for treatment of an RCC. The resected tumor displayed an alveolar growth pattern with high-grade nuclei. The tumor was diffusely positive for TFE3 and cathepsin K. Anchored multiplex PCR revealed a novel fusion, EWSR1-TFE3. Fluorescent in situ hybridization analysis demonstrated the rearrangements of EWSR1 and TFE3. RT-PCR analysis confirmed the chimeric transcript. No neoplasm with EWSR1-TFE3 has been reported so far, in any organ. The results will expand the genomic spectrums of Xp11 translocation RCCs and contribute to better understanding of the roles of the MiTF family in the oncogenic process.

[The histopathology and immunohistochemistry of granular cell tumour. A study of 12 cases with a brief historical note]. / Análisis histopatológico e inmunohistoquímico del tumor de células granulares. Estudios de 12 casos con una breve nota histórica.

INTRODUCTION AND OBJECTIVE: Granular cell tumour (GCT) is a benign neoplasm of neural/schwannian origin, usually presenting as a single asymptomatic lesion, mainly located in the dermis and subcutaneous tissue or submucosa, although multiple tumours may occur. Microscopically, GCTs are composed of large cells with abundant eosinophilic, granular cytoplasm arranged in sheets, nests, cords or trabeculae. Based on the cytological characteristics and the presence of necrosis, three types are recognized: benign, atypical and malignant. We aim to present the cytological and immunohistochemical characteristics of 12 granular cell tumours. MATERIALS AND METHODS: 12 cases of GCT were selected from the consultation files of one of the authors (COH) The paraffin embedded tissue was processed for immunostaining with S-100 protein, calretinin, CD68, α-inhibin, PGP9.5, CD57 (Leu7), CD63 (NKI / C3), Gap43 (growth-associated protein-43), SOX10, TFE-3 and Ki-67. RESULTS AND CONCLUSIONS: 6 male and 6 female patients, with an average age of 40, made up the study group. The most frequent location for the tumours was in the subcutaneous soft tissues of the arms. There were no malignant cases. All tumours were positive for S-100, CD57, SOX10, calretinin, CD68, PGP9.5, α-inhibin and TFE-3, with a low Ki-67 (1-5%). Additionally, we reported, for the first time, the positive immunoreaction to Gap43 (growth-associated protein-43) in GCT.

[TFEB-amplified renal cell carcinoma. A case report and review of the literature]. / Carcinoma de células renales asociado a amplificación del gen TFEB. Presentación de un caso y revisión de la literatura.

Renal carcinomas associated with translocation of transcription factors of the MiT/TFE family include, according to the latest World Health Organization classification, carcinomas with Xp11 translocation that involve the TFE3 gene and those with translocation t(6;11)(p21;q12) that affect the TFEB gene. Each one of these sub-types have well-defined clinicopathological and molecular characteristics. Currently, progress in molecular techniques has led to the description of neoplasms with molecular changes in these same genes but with alterations different to translocation. Thus, recently, cases have been published of TFEB-amplified renal carcinomas with prognoses that vary from cases associated with translocation and could therefore represent a new entity. We present a case of TFEB-amplified renal carcinoma with a full description of the clinicopathological characteristics and an updated revision of these neoplasms.

Melanotic Xp11 translocation renal cancer: a report of a distinctive case and a review of the literature.

BACKGROUND: Melanotic Xp11 translocation renal cancer (TRC) is a newly described exceedingly rare tumor, and its characterization remains controversial. This study aimed to describe a case of distinctive melanotic Xp11 TRC and to elucidate its clinicopathological and molecular genetic features. CASE PRESENTATION: A 44-year-old Chinese female presented with a left renal mass. Abdominal ultrasonography and computed tomography (CT) scans revealed a 4.5 cm × 4.0 cm mass in the left kidney. Grossly, the well-demarcated mass was black with moderately firm consistency. Microscopic examination indicated that the tumor was characterized by the presence of nests and cords of polygonal cells with clear and granular eosinophilic cytoplasm, central round to oval nuclei and occasional nucleoli. Intracytoplasmic melanin was observed in approximately 45% of tumor cells. Uniquely, the tumor presented with intranuclear eosinophilic pseudoinclusions and thick-walled stromal blood vessels. IHC showed that tumor cells were diffusely positive for TFE3 and exhibited patchy and weak HMB45 staining. FISH confirmed the presence of TFE3 rearrangement. CONCLUSION: This case is the twentieth published case of melanotic Xp11 TRC. Moreover, the present patient had a favorable prognosis given that she was disease free at her 113-month postoperative follow-up. Our case adds to the small body of literature on these exceptionally rare tumors and widens their clinicopathological spectrum.

TFE3 is a diagnostic marker for solid pseudopapillary neoplasms of the pancreas.

Aberrant Wnt signaling is a hallmark of solid pseudopapillary neoplasms (SPNs) of the pancreas. Transcription factor E3 (TFE3) plays a critical role in activation and regulation of the Wnt pathway and is predicted to be a candidate gene implicated in SPN by gene regulatory network analysis. The aim of this study was to evaluate TFE3 as a marker for SPN. Paraffin-embedded tissues of SPN (n = 75) and other primary pancreatic tumors were analyzed, including pancreatic neuroendocrine tumors (n = 17), pancreatic ductal adenocarcinomas (n = 14), pancreatic neuroendocrine carcinomas (n = 4), and acinar cell carcinomas (n = 3). The clinicopathological features were summarized as well. Differentiation of specific pancreatic duct or acinus was not found in any SPN tissue. Morphologic and immunohistochemical results indicated that SPN displays certain characteristics of neuroendocrine cells. Overall, 71 (94.67%) cases of SPN showed nuclear accumulation for TFE3, most of which displayed moderate to intense expression. The TFE3 positive rates in pancreatic neuroendocrine tumor, pancreatic ductal adenocarcinoma, and pancreatic neuroendocrine carcinoma were 23.53%, 14.29%, and 25%, respectively. All 3 cases of acinar cell carcinoma were negative for TFE3. We conclude that SPN may originate from primordial pancreatic cells and is accompanied by some characteristics of neuroendocrine tumors. TFE3, besides ß-catenin, can be an additional diagnostic marker of SPN in differential diagnosis.

Insulin suppresses the AMPK signaling pathway to regulate lipid metabolism in primary cultured hepatocytes of dairy cows.

Dairy cows with type II ketosis display hepatic fat accumulation and hyperinsulinemia, but the underlying mechanism is not completely clear. This study aimed to clarify the regulation of lipid metabolism by insulin in cow hepatocytes. In vitro, cow hepatocytes were treated with 0, 1, 10, or 100 nm insulin in the presence or absence of AICAR (an AMP-activated protein kinase alpha (AMPKα) activator). The results showed that insulin decreased AMPKα phosphorylation. This inactivation of AMPKα increased the gene and protein expression levels of carbohydrate responsive element-binding protein (ChREBP) and sterol regulatory element-binding protein-1c (SREBP-1c), which downregulated the expression of lipogenic genes, thereby decreasing lipid biosynthesis. Furthermore, AMPKα inactivation decreased the gene and protein expression levels of peroxisome proliferator-activated receptor-α (PPARα), which upregulated the expression of lipid oxidation genes, thereby increasing lipid oxidation. In addition, insulin decreased the very low density lipoprotein (VLDL) assembly. Consequently, triglyceride content was significantly increased in insulin treated hepatocytes. Activation of AMPKα induced by AICAR could reverse the effect of insulin on PPARα, SREBP-1c, and ChREBP, thereby decreasing triglyceride content. These results indicate that insulin inhibits the AMPKα signaling pathway to increase lipid synthesis and decrease lipid oxidation and VLDL assembly in cow hepatocytes, thereby inducing TG accumulation. This mechanism could partly explain the causal relationship between hepatic fat accumulation and hyperinsulinemia in dairy cows with type II ketosis.

Malignant perivascular epithelioid cell tumor of the oropharynx with strong TFE3 expression mimicking alveolar soft part sarcoma: a case report and review of the literature.

Perivascular epithelioid cell tumors (PEComas) in the head and neck region are rare, with 26 cases described in literature. These distinct mesenchymal tumors normally express both myoid and melanocytic markers. We here report an interesting and challenging case of malignant PEComa that showed transcription factor E3 (TFE3) protein expression and rearrangement, paucity of muscle and melanocytic marker expression, and morphologically mimicked alveolar soft part sarcoma. Awareness of this morphologic pitfall and recognition of TFE3 gene-rearranged PEComa, as a distinct subtype of PEComa, is essential to avoid misdiagnosis.

Clinicopathological Characteristics of Ovarian Sclerosing Stromal Tumor with an Emphasis on TFE3 Overexpression.

A sclerosing stromal tumor is a very rare benign sex cord-stromal tumor of the ovary. Because its clinical presentation and imaging findings are similar to those of borderline or malignant epithelial tumors and other sex cord-stromal tumors, accurate preoperative clinical diagnosis can be difficult. The aim of this study was to analyze the clinicopathological characteristics of SSTs and examine the immunohistochemical expression TFE3, which has not been studied in SSTs. Our study cohort consisted of 9 patients diagnosed as having SST; the median age was 36 years. Radiologically, SSTs presented as multiseptated cystic masses, mixed echoic masses, pseudolobular masses, solid pelvic masses, or uterine subserosal nodules. In 4 of the 9 cases, the preoperative clinical impression was a borderline or malignant ovarian tumor. SSTs displayed the following histopathological features: 1) relatively well-circumscribed cellular nodules that were randomly distributed in the fibrous or edematous stroma; 2) a characteristic alternating pattern of hypercellular and hypocellular areas; 3) a hemangiopericytoma-like vascular growth pattern in the cellular nodules; 4) bland-looking spindle-shaped cells and round or polygonal cells densely clustered around blood vessels; and 5) red blood cell-containing intracytoplasmic vacuole-like spaces in the tumor cell cytoplasm, possibly indicating epithelioid hemangioendothelioma. Immunohistochemically, the tumor cells exhibited diffuse and moderate-to-strong TFE3 expression in 7 of the 9 SSTs. TFE3 was strongly expressed in the nuclei of round or polygonal cells and lutein cells. In contrast, neither luteinized thecomas nor fibromas appreciably expressed TFE3. In summary, our study describes characteristic histopathological features that may be useful for differentiating SSTs from other sex-cord stromal tumors and demonstrates for the first time that SSTs show strong TFE3 expression. Further investigations are necessary to clarify the role of TFE3 in the development of SSTs.

Immunocytochemistry for SOX-11 and TFE3 as diagnostic markers for solid pseudopapillary neoplasms of the pancreas in FNA biopsies.

BACKGROUND: Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare malignant tumors that can be sampled via endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Although diagnosing SPNs can be straightforward in cases with a classic morphology and a typical immunoprofile, challenges can occur with morphologic variants or limited specimens. Recently, 2 immunohistochemical stains, SRY-related high-mobility group box 11 (SOX-11) and transcription factor E3 (TFE3), have been demonstrated to be highly sensitive and specific for SPNs in pancreatic resection specimens. The current study evaluates the diagnostic utility of these stains with EUS-FNA. METHODS: Thirteen EUS-FNA specimens from SPNs with sufficient material for immunocytochemistry were identified from 2000 to 2016. These cases were compared with 13 EUS-FNA specimens of non-SPN pancreatic neoplasms. Immunocytochemistry for SOX-11, TFE3, and ß-catenin was performed on all cell blocks and then was scored independently by 2 pathologists in a masked manner. RESULTS: Nuclear reactivity for SOX-11 was detected in 13 of 13 SPNs and in 0 of 13 non-SPNs; this resulted in sensitivity and specificity values of 100%, a positive predictive value (PPV) of 1, and a negative predictive value (NPV) of 1. Nuclear reactivity for TFE3 was detected in 9 of 13 SPNs and in 0 of 13 non-SPNs; this resulted in a sensitivity of 69.2%, a specificity of 100%, a PPV of 1, and an NPV of 0.765. Nuclear reactivity for ß-catenin was detected in 13 of 13 SPNs and in 1 of 13 non-SPNs; this resulted in a sensitivity of 100%, a specificity of 92.3%, a PPV of 0.929, and an NPV of 1. CONCLUSIONS: SOX-11 is a sensitive and specific immunocytochemical stain for SPNs in EUS-FNA specimens, and it may be useful as a diagnostic marker for distinguishing SPNs from its cytologic mimics. Cancer Cytopathol 2017;125:831-7. © 2017 American Cancer Society.

Melanotic Translocation Renal Cell Carcinoma With a Novel ARID1B-TFE3 Gene Fusion.

A 36-year-old male was found to have a 7.0 cm left upper pole renal mass on renal ultrasound. Following nephrectomy, the mass was grossly ill-demarcated, friable and red-brown, invading renal parenchyma, hilar fat and the renal vein. Microscopically, the tumor had a nested and papillary architecture. The cells demonstrated abundant clear and eosinophilic cytoplasm and focal intracytoplasmic melanin pigment. Nucleoli were prominent. By immunohistochemistry, the tumor was positive for TFE3; HMB-45 stained approximately 5% of tumor cells corresponding to the histologic melanin pigment, which was confirmed with Fontana-Masson stain with bleach. Immunostains for PAX8, CD10, MiTF, and CAIX were negative; keratins Cam 5.2 and AE1/AE3 were focally positive. Targeted next-generation sequencing revealed an ARID1B-TFE3 gene fusion. Melanotic Xp11 renal cell carcinoma is a rare, pigment containing translocation variant demonstrating overlapping features with melanoma and is usually associated with an SFPQ-TFE3 gene fusion. The patient is alive and without evidence of disease 7 years after his diagnosis. The combination of high grade histopathology, the presence of melanin, absent PAX8, keratin positivity, and relatively indolent clinical behavior with a unique translocation may warrant recognition as a distinct renal cell carcinoma translocation subtype.

Transcription factor EB is involved in autophagy-mediated chemoresistance to doxorubicin in human cancer cells.

Transcription factor EB (TFEB) is a master regulator of autophagy activity and lysosomal biogenesis, but its role in autophagy-mediated cell survival and chemotherapy resistance is not completely understood. In this study, we explored whether TFEB played an important role in autophagy-mediated chemotherapy resistance in human cancer LoVo and HeLa cells in vitro. Treatment of human colon cancer LoVo cells with doxorubicin (0.5 µmol/L) induced autophagy activation and nuclear translocation of TFEB, which resulted from inactivation of the mTOR pathway. In both LoVo and HeLa cells, overexpression of TFEB enhanced doxorubicin-induced autophagy activation and significantly decreased doxorubicin-induced cell death, whereas knockdown of TFEB with small interfering RNA blocked doxorubicin-induced autophagy and significantly enhanced the cytotoxicity of doxorubicin. In LoVo cells, autophagy inhibition by 3-methyladenine (3-MA) or knockdown of autophagy-related gene Atg5 increased cell death in response to doxorubicin, and abolished TFEB overexpression-induced chemotherapy resistance, suggesting that the inhibition of autophagy made cancer cells more sensitive to doxorubicin. The results demonstrate that TFEB-mediated autophagy activation decreases the sensitivity of cancer cells to doxorubicin.

Tfe3 and Tfeb Transcriptionally Regulate Peroxisome Proliferator-Activated Receptor γ2 Expression in Adipocytes and Mediate Adiponectin and Glucose Levels in Mice.

Members of the MiT transcription factor family are pivotal regulators of several lineage-selective differentiation programs. We show that two of these, Tfeb and Tfe3, control the regulator of adipogenesis, peroxisome proliferator-activated receptor γ2 (Pparγ2). Knockdown of Tfeb or Tfe3 expression during in vitro adipogenesis causes dramatic downregulation of Pparγ2 expression as well as adipogenesis. Additionally, we found that these factors regulate Pparγ2 in mature adipocytes. Next, we demonstrated that Tfeb and Tfe3 act directly by binding to consensus E-boxes within the Pparγ transcriptional regulatory region. This transcriptional control also exists in vivo, as we discovered that wild-type mice in the fed state increased their expression of Tfe3, Tf3b, and Pparγ in white adipose tissue. Furthermore, Tfe3 knockout (Tfe3KO) mice in the fed state failed to upregulate Pparγ and the adiponectin gene, a Pparγ-dependent gene, confirming the in vivo role for Tfe3. Lastly, we found that blood glucose is elevated and serum adiponectin levels are suppressed in the Tfe3KO mice, indicating that the Tfe3/Tfeb/Pparγ2 axis may contribute to whole-body energy balance. Thus, we offer new insights into the upstream regulation of Pparγ by Tfe3/Tf3b and propose that targeting these transcription factors may offer opportunities to complement existing approaches for the treatment of diseases that have dysregulated energy metabolism.

RBM10-TFE3 Renal Cell Carcinoma: A Potential Diagnostic Pitfall Due to Cryptic Intrachromosomal Xp11.2 Inversion Resulting in False-negative TFE3 FISH.

Xp11 translocation renal cell carcinoma (RCC) are defined by chromosome translocations involving the Xp11 breakpoint which results in one of a variety of TFE3 gene fusions. TFE3 break-apart florescence in situ hybridization (FISH) assays are generally preferred to TFE3 immunohistochemistry (IHC) as a means of confirming the diagnosis in archival material, as FISH is less sensitive to the variable fixation which can result in false positive or false negative IHC. Prompted by a case report in the cytogenetics literature, we identify 3 cases of Xp11 translocation RCC characterized by a subtle chromosomal inversion involving the short arm of the X chromosome, resulting in an RBM10-TFE3 gene fusion. TFE3 rearrangement was not detected by conventional TFE3 break-apart FISH, but was suggested by strong diffuse TFE3 immunoreactivity in a clean background. We then developed novel fosmid probes to detect the RBM10-TFE3 gene fusion in archival material. These cases validate RBM10-TFE3 as a recurrent gene fusion in Xp11 translocation RCC, illustrate a source of false-negative TFE3 break-apart FISH, and highlight the complementary role of TFE3 IHC and TFE3 FISH.