Translocation Renal Cell Carcinoma: An Update on Clinicopathological and Molecular Features

Clinicopathologic and Molecular Characterization of Xanthomatous Giant Cell Renal Cell Carcinomas: Further Support for a Close Morphologic Spectrum to Eosinophilic Solid and Cystic Renal Cell Carcinomas

A recent study described a rare subtype of tuberous sclerosis complex ( TSC )-mutated renal cell carcinoma primarily characterized by Xanthomatous giant cell morphology. Only 2 cases in young individuals have been reported so far, making the correct diagnosis challenging from a pathological perspective. It remains unknown whether this tumor represents an independent subtype or belongs to other TSC -mutated tumors. We conducted a clinicopathologic evaluation and immunohistochemical profiling of 5 cases of Xanthomatous Giant Cell Renal Cell Carcinoma (XGC RCC) with confirmed TSC2 mutations through targeted DNA sequencing. In addition, we analyzed transcriptomic profiles using RNA-seq for the following samples: XGC RCC, Low-grade Oncocytic tumors (LOT), High-grade Oncocytic tumors/Eosinophilic Vacuolar Tumors (HOT/EVT), Eosinophilic Solid and Cystic Renal Cell Carcinomas (ESC RCC), Chromophobe cell Renal Cell Carcinomas (ChRCC), Renal Oncocytomas (RO), clear cell Renal Cell Carcinomas (ccRCC), and normal renal tissues. There were 2 female and 3 male patients, aged 22 to 58 years, who underwent radical nephrectomy for tumor removal. The tumor sizes ranged from 4.7 to 9.5 cm in diameter. These tumors exhibited ill-defined boundaries, showed an expansive growth pattern, and featured distinctive tumor giant cells with abundant eosinophilic to Xanthomatous cytoplasm and prominent nucleoli. All tumors had low Ki-67 proliferation indices (<1%) and demonstrated immune reactivity for CD10, PAX8, CK20, CathepsinK, and GPNMB. Next-generation sequencing confirmed TSC2 mutations in all cases. RNA sequencing-based clustering indicated a close similarity between the tumor and ESC RCC. One patient (1/5) died of an accident 63 months later, while the remaining patients (4/5) were alive without tumor recurrences or metastases at the time of analysis, with a mean follow-up duration of 43.4 months. Our research supports the concept that Xanthomatous giant cell renal cell carcinoma (XGC RCC) shares clinicopathological and molecular characteristics with ESC RCC and shows a relatively positive prognosis, providing further support for a close morphologic spectrum between the two. We propose considering XGC RCC as a distinct subtype of ESC RCC.

Primary retroperitoneal renal cell carcinoma associated with transcription EB gene fusion

BACKGROUND

Renal cell carcinoma (RCC) with the distinct type of t(6;11) (p21;q12) translocation (transcription factor EB, TFEB) is a rare neoplasm. It is even less when talks about primary retroperitoneal TFEB RCCs. To our knowledge, no previous literature has been reported about this kind of RCCs. In this article, we report a case of primary retroperitoneal renal cell carcinoma associated with transcription EB gene fusion.

METHODS

A 73-year-old male patient presented with a retroperitoneal mass for more than one month.

RESULTS

Pathologically, the mass was soft and colorful, tumor cells showed a biphasic morphology characterized by nests of larger epithelioid cells surrounding intraluminal collections of smaller cells clustered around basement membrane materia. These tumor cells were positive for Pax-8, EMA, TFEB, CK, P504S, Vimentin and CD10 on immunohistochemical stain, and positive for TFEB on fluorescence in situ hybridization assay.

CONCLUSIONS

We reported the first case of primary retroperitoneal renal cell carcinoma associated with transcription EB gene fusion. The pathological feature of the case we reported was very typical. The best treatment at presentation is the total resection. Long-term follow-up study is needed in order to acquire better diagonitic quality and fulfill diagnostic requirements.

Dissecting the multifaced function of transcription factor EB (TFEB) in human diseases: From molecular mechanism to pharmacological modulation

The transcription factor EB (TFEB) is a transcription factor of the MiT/TFE family that translocations from the cytoplasm to the nucleus in response to various stimuli, including lysosomal stress and nutrient starvation. By activating genes involved in lysosomal function, autophagy, and lipid metabolism, TFEB plays a crucial role in maintaining cellular homeostasis. Dysregulation of TFEB has been implicated in various diseases, including cancer, neurodegenerative diseases, metabolic diseases, cardiovascular diseases, infectious diseases, and inflammatory diseases. Therefore, modulating TFEB activity with agonists or inhibitors may have therapeutic potential. In this review, we reviewed the recently discovered regulatory mechanisms of TFEB and their impact on human diseases. Additionally, we also summarize the existing TFEB inhibitors and agonists (targeted and non-targeted) and discuss unresolved issues and future research directions in the field. In summary, this review sheds light on the crucial role of TFEB, which may pave the way for its translation from basic research to practical applications, bringing us closer to realizing the full potential of TFEB in various fields.

TFE3 gene rearrangement and protein expression contribute to a poor prognosis of renal cell carcinoma

Background

TFE3-rearranged renal cell carcinoma (TFE3-rearranged RCC) is a type of kidney cancer with a low incidence, with no consensus about whether it has a worse prognosis than clear cell renal cell carcinoma (ccRCC). This study attempted to elucidate the impact of TFE3-rearranged RCC by analyzing its clinical features and prognosis.

Methods

Patients treated in Sun Yat-sen Memorial Hospital (SYSMH) who were suspected to be diagnosed with TFE3-rearranged RCC were divided into two groups, TFE3-rearranged RCC and ccRCC with positive TFE3 protein expression on immunohistochemistry [TFE3(+) ccRCC], by dual-color, break-apart fluorescence in situ hybridization (FISH). After balancing the baseline characteristics with TFE3(+) ccRCC using the propensity score matching (PSM) method in a ratio of 2, we selected patients diagnosed with ccRCC with negative TFE3 protein expression on immunohistochemistry [TFE3(-) ccRCC]. The impact of TFE3 gene rearrangement and protein expression on renal cell carcinoma was determined by feature comparison with a nonparametric test and survival analysis with the Kaplan‒Meier method.

Results

Among 37 patients suspected of having TFE3-rearranged RCC, 13 patients were diagnosed with TFE3-rearranged RCC, and 24 patients had TFE3(+) ccRCC. The recurrence and new metastasis of TFE3-rearranged RCC was relatively common, even if the tumor stage was early at the first diagnosis. Through feature comparison and survival analysis, we found that TFE3-rearranged RCC was quite similar to TFE3(+) ccRCC. Compared with TFE3(-) ccRCC, TFE3(+) ccRCC tended to have a larger tumor diameter (P = 0.011), higher neutrophil/lymphocyte ratio (NLR) (P = 0.017) and metastatic potential (P = 0.022), and worse overall survival (OS) (P = 0.043) and PFS (P = 0.016). The survival analysis showed that TFE3-rearranged RCC had a worse PFS than ccRCC (P = 0.002), and TFE3(+) RCC had a worse PFS than TFE3(-) RCC (P = 0.001). According to the stratification system based on the combination of TFE3 and lymphovascular invasion (LVI), we further found that the prognosis from good to poor was TFE3(-) LVI(-), TFE3(+) LVI(-), TFE3(+) LVI(+) and TFE3(-) LVI(+), with statistically significant differences in both OS (P = 0.001) and PFS (P < 0.001). In addition, we also reported two cases with poor prognosis, of which one was TFE3-rearranged RCC and the other was TFE3(+) ccRCC.

Conclusions

This is a novel finding that both FISH confirmed TFE3 gene rearrangement-mediated TFE3-rearranged RCC and IHC confirmed positive TFE3 protein expression [TFE3(+)] contribute to a poor prognosis in RCC, suggesting more active treatment and careful follow-up for TFE3(+) RCC patients. The combination of TFE3 and LVI may be a new risk stratification system for RCC.

TFEB-associated renal cell carcinoma: A case report and literature review

RATIONALE

TFEB-associated renal cell carcinoma is very rare and belongs to the microphthalmia - associated transcription family translocation renal cell carcinoma.

PATIENT CONCERNS

Hospitalized for fever, a 29-year-old male patient had a left kidney lesion without any additional discomfort.

DIAGNOSES

Histopathological and immunohistochemical results were corresponding with TFEB renall cell carcinoma features.

INTERVENTIONS

Surgical resection of the tumor was performed.

OUTCOMES

After 8 months of follow-up, no tumor recurrence was observed.

LESSONS

TFEB-associated renal cell carcinoma is rare. The diagnosis is explicit. However, the optimal treatment needs to be further explored.

Chemotherapy, transarterial chemoembolization, and nephrectomy combined treated one giant renal cell carcinoma (T3aN1M1) associated with Xp11.2/TFE3: A case report

BACKGROUND

Renal cell carcinoma (RCC) with Xp11.2 translocation/TFE3 gene fusion is a rare and distinct subtype of RCC that is classified under tumors with translocation of the microphthalmia-associated transcriptional factor.

CASE SUMMARY

We report an adult case of Xp11.2 translocation advanced RCC with metastasis (T3aN1M1), after targeted treatment, alcohol ablation, and transarterial chemoembolization, who eventually underwent successful surgical excision. No recurrence or transfer was seen within one year, and the survival period was more than 3 years. A review of the relevant literature was conducted to improve our understanding of the pathogenesis, epidemiology, clinical manifestations, diagnosis, differential diagnosis, treatment, and other aspects of the disease.

CONCLUSION

Transarterial chemoembolization and ablation did not achieve the desired tumor reduction in this patient, but had a significant effect on reducing intraoperative bleeding and inhibiting tumor activity.

Glucose transporters as markers of diagnosis and prognosis in cancer diseases

The primary metabolic substrate for cells is glucose, which acts as both a source of energy and a substrate in several processes. However, being lipophilic, the cell membrane is impermeable to glucose and specific carrier proteins are needed to allow transport. In contrast to normal cells, cancer cells are more likely to generate energy by glycolysis; as this process generates fewer molecules of adenosine triphosphate (ATP) than complete oxidative breakdown, more glucose molecules are needed. The increased demand for glucose in cancer cells is satisfied by overexpression of a number of glucose transporters, and decreased levels of others. As specific correlations have been observed between the occurrence of cancer and the expression of glucose carrier proteins, the presence of changes in expression of glucose transporters may be treated as a marker of diagnosis and/or prognosis for cancer patients.

Case Report: TFE3 Positive Xp11.2 Translocation Renal Cell Carcinoma (TRCC) – A Case Study and Review of the Literature

Microphthalmia-associated transcription factor renal cell cancer, also known as translocation renal cell cancer, belongs to the group of extremely rare non-clear-cell kidney neoplasms. Their incidence is lower in adulthood than in childhood. The only known risk factor for the development of this tumor is prior chemotherapy. In the operable stage of the disease, the prognosis depends on the status of regional lymph nodes. Interestingly lymph node positivity worsens the prognosis only in the adult patient population. Radical surgical excision is the best therapy in the early stage. The optimal treatment strategy for locally advanced and metastatic disease has not been established, given the lack of evidence in such a rare disease. We present the case of a patient with an aggressive course of this neoplasm treated with temsirolimus, who achieved 10-month control of this neoplasm accompanied by a discussion on other therapeutic possibilities.

Histopathological spectrum of adult renal tumours: A Single center experience and review of literature

Background

Renal tumors constitute approximately 3% of all malignancies in adults. They form a heterogenous group with variable morphological, immunohistochemical, and molecular features.

Aim

The objective of this study was to analyze the spectrum of adult renal tumors at a tertiary care center and study the demographic and histomorphological features.

Materials and Methods

In this study, 55/87 nephrectomy specimens resected for adult renal tumors during a 1-year period were analyzed retrospectively.

Results

There were 4 benign (7.2%) and 51 (92.7%) malignant tumors. There was a male preponderance with a male: female ratio of 3.42:1. The tumors were seen to occur equally in both kidneys. The most common tumor was clear cell renal cell carcinoma (RCC), the conventional type accounting for 65.5% of our study group. There were one each of multilocular cystic renal neoplasm of low malignant potential, papillary RCC, chromophobe RCC, Mit family RCC, oncocytoma and angiomyolipoma and two clear cell papillary RCC during this 1-year period. Uncommon tumors included neuroendocrine carcinoma (1), epithelioid angiomyolipoma (1), mixed epithelial stromal tumor (1), Ewings sarcoma (2), and glomangioma (1). Five cases of urothelial carcinoma of renal pelvis/ureter also were present.

Conclusion

This article gives an overview of the spectrum of adult renal tumors at a tertiary care center with an in-depth literature review providing recent advances in each category of tumors.

The Role and Regulatory Mechanism of Transcription Factor EB in Health and Diseases

Transcription factor EB (TFEB) is a member of the microphthalmia-associated transcription factor/transcription factor E (MiTF/TFE) family and critically involved in the maintenance of structural integrity and functional balance of multiple cells. In this review, we described the effects of post-transcriptional modifications, including phosphorylation, acetylation, SUMOylation, and ubiquitination, on the subcellular localization and activation of TFEB. The activated TFEB enters into the nucleus and induces the expressions of targeted genes. We then presented the role of TFEB in the biosynthesis of multiple organelles, completion of lysosome-autophagy pathway, metabolism regulation, immune, and inflammatory responses. This review compiles existing knowledge in the understanding of TFEB regulation and function, covering its essential role in response to cellular stress. We further elaborated the involvement of TFEB dysregulation in the pathophysiological process of various diseases, such as the catabolic hyperactivity in tumors, the accumulation of abnormal aggregates in neurodegenerative diseases, and the aberrant host responses in inflammatory diseases. In this review, multiple drugs have also been introduced, which enable regulating the translocation and activation of TFEB, showing beneficial effects in mitigating various disease models. Therefore, TFEB might serve as a potential therapeutic target for human diseases. The limitation of this review is that the mechanism of TFEB-related human diseases mainly focuses on its association with lysosome and autophagy, which needs deep description of other mechanism in diseases progression after getting more advanced information.

Autophagy in Xp11 translocation renal cell carcinoma: from bench to bedside

Xp11 translocation renal cell carcinoma (tRCC) characterized by the rearrangement of the TFE3 is recently identified as a unique subtype of RCC that urgently requires effective prevention and treatment strategies. Therefore, determining suitable therapeutic targets and fully understanding the biological significance of tRCC is essential. The importance of autophagy is increasingly acknowledged because it shows carcinogenic activity or suppressor effect. Autophagy is a physiological cellular process critical to maintaining cell homeostasis, which is involved in the lysosomal degradation of cytoplasmic organelles and macromolecules via the lysosomal pathway, suggesting that targeting autophagy is a potential therapeutic approach for cancer therapies. However, the underlying mechanism of autophagy in tRCC is still ambiguous. In this review, we summarize the autophagy-related signaling pathways associated with tRCC. Moreover, we examine the roles of autophagy and the immune response in tumorigenesis and investigate how these factors interact to facilitate or prevent tumorigenesis. Besides, we review the findings regarding the treatment of tRCC via induction or inhibition of autophagy. Hopefully, this study will shed some light on the functions and implications of autophagy and emphasize its role as a potential molecular target for therapeutic intervention in tRCC.

Multidrug refractory aggressive metastatic TFE3 (+) renal cell carcinoma: A case report

BACKGROUND

Transcription factor E3 (TFE3) related renal cell carcinomas constitute a very small percent of all renal tumors in adults. Prognosis mainly depends on the stage of the disease at the time of diagnosis which is often poor. There is yet to be a standardized treatment protocol. Treatment options include agents identical to TFE3(-) cell renal carcinoma treatment. We present a case of a young woman with a rapidly progressing metastatic TFE3 (+) renal cell carcinoma.

CASE REPORT

A 31 year old female presented with abdominal mass, distension, nausea. Initial tests and tumor markers found to be normal. Abdominal CT scan revealed a left retroperitoneal mass along with three other neighboring masses in liver manifesting as metastases. Trucut biopsy and immunohistochemical staining confirmed the retroperitoneal mass as TFE3 (+) renal cell carcinoma.Management and outcome: Sunitinib, pazopanib, nivolumab, axitinib treatments are consecutively given after surgery. It is noteworthy that rapid progression was observed under nivolumab treatment.

DISCUSSION

During surveillance, rapid progression is noted under consecutive immunotherapy which was unexpected. Thus, there is a need for more standardized treatment protocols and invention of new agents for management of TFE3 (+) renal cell carcinoma.

Renal Cancer Without Primary Cancer in the Kidney: Extra-Renal TFE3 Translocation Associated Renal Cell Carcinoma

We report a case of an isolated para-aortic retroperitoneal renal cell carcinoma (RCC) in the absence of a primary cancer in the kidney. Single case reports in the literature have described extra-renal RCC in different locations with no evidence of primary renal tumor. We present the initial presentation, diagnostic imaging, surgical treatment, and pathologic evaluation. Immunohistochemistry demonstrated positivity for TFE3 and TFEB, both of which are Microphthalmia associated transcription factors (MiT) associated with translocation RCCs. We hypothesize these few cases of extra-renal RCC represent rare forms of translocation RCC.

6p.21 translocation renal cell carcinoma in the elderly: radiological findings mimicking fat poor angiomyolipoma or papillary renal cell carcinoma

6p21 translocation renal cell carcinoma (RCC) harboring TFEB gene fusion is a newly classified microphthalmia-associated transcription (MiT) factor-family translocation RCC with early onset. We present a case of 78-year-old man with a 6p21 translocation RCC that was diagnosed after partial nephrectomy for an incidental renal tumor on computed tomography (CT). Unenhanced CT showed a 20 mm, mildly low-density mass in the right kidney. Contrast-enhanced CT showed a heterogeneous and prolonged, mild enhancement in the tumor. On magnetic resonance imaging, the tumor showed iso-intensity within the renal parenchyma on T1-weighted-imaging (WI), low intensity on T2WI, and no restricted diffusion with low signal on diffusion-weighted imaging, with no clear tumor pseudocapsule. Fat poor angiomyolipoma and non-clear cell RCC were listed as differential diagnoses. Robot-assisted partial nephrectomy was successfully performed. Fluorescence in situ hybridization study of the resected tumor confirmed TFEB gene break, and the patient was diagnosed with a 6p21 translocation RCC. The patient is doing well without recurrence after 2.5 years of follow-up. Our patient is the oldest patient reported in previous literature.

A Tale of 2 Morphologies: Diagnostic Pitfalls in TFEB-Associated Renal Cell Carcinomas, Including a Novel NEAT1-TFEB Fusion

AIMS

Translocation-associated renal cell carcinomas (RCCs) have been extensively subcharacterized in recent years, such that each is largely recognized by the 2016 World Health Organization as categorical neoplastic entities in the genitourinary tract. Those belonging to the t(6;11) family of tumors classically have a fusion between TFEB and MALAT1/α, and display a particular histomorphology. Specifically, they show a biphasic population of both small and large epithelioid cells, the smaller component of which surrounds basement membrane-type material. Despite this apt description, the tumors have variable morphology and mimic other RCCs including those with TFE3 translocations. Therefore, a high degree of suspicion is required to make the correct diagnosis.

METHODS

The 2 cases described in this article were of strikingly different appearance, and initially considered consistent with other non-translocation-associated renal tumors. These included clear cell RCC (CCRCC), perivascular epithelioid cell tumor (PEComa), and other eosinophilic RCCs (mainly papillary RCC type 2).

RESULTS

Using RNA sequencing techniques, they were found to harbor distinct pathogenic rearrangements involving the TFEB gene, namely, fusions with CLTC and NEAT1 (the latter partnering heretofore never reported).

CONCLUSIONS

These alterations manifested in 2 notably dissimilar lesions, underscoring the importance of including this family of carcinomas in the differential of any renal neoplasm that does not display immunophenotypic characteristics consistent with its morphology.

Renal Cell Tumors: Molecular Findings Reshaping Clinico-pathological Practice

Over the past 20 years, the number of subtypes of renal epithelial cell neoplasia has grown. This growth has resulted from detailed histological and immunohistochemical characterization of these tumors and their correlation with clinical outcomes. Distinctive molecular phenotypes have validated the unique nature of many of these tumors. This growth of unique renal neoplasms has continued after the 2016 World Health Organization (WHO) Classification of Tumours. A consequence is that both the pathologists who diagnose the tumors and the clinicians who care for these patients are confronted with a bewildering array of renal cell carcinoma variants. Many of these variants have important clinical features, i.e. familial or syndromic associations, genomics alterations that can be targeted with systemic therapy, and benignancy of tumors previously classified as carcinomas. Our goal in the review is to provide a practical guide to help recognize these variants, based on small and distinct sets of histological features and limited numbers of immunohistochemical stains, supplemented, as necessary, with molecular features.

Immune Checkpoint Inhibitors in the Treatment of Renal Cancer: Current State and Future Perspective

Systemic treatment of renal cancer (RCC) has undergone remarkable changes over the past 20 years with the introduction of immunotherapeutic agents targeting programmed cell death (PD-1)/programmed death-ligand 1 (PD-L1) axis, as a single-agent or combined with anti-CTLA-4 monoclonal antibodies (MoAbs) or a multi-target vascular endothelial growth factor-(VEGF) tyrosine kinase inhibitor (TKI). In this paper, we review the main evidence on the use of Immune Checkpoint Inhibitors (ICIs) for RCC treatment from the first demonstration of activity of a nivolumab single agent in a phase I trial to the novel combination strategies (anti-PD-1 plus anti-CTLA4 or anti-PD-1 plus TKI). In addition, we discuss the use of anti-PD-1/PD-L1 agents in patients with non-clear cells and rare histological subtype RCC. Then, we critically examine the current findings in biomarkers that have been proposed to be prognostic or predictive to the response of immunotherapy including immune gene expression signature, B7-H1 expression, PBRM1 loss of function, PD-L1 expression, frame shift indel count, mutations in bromodomain-containing genes in patients with MiT family translocation RCC (tRCC), high expression of the T-effector gene signature, and a high myeloid inflammation gene expression pattern. To date, a single biomarker as a predictor of response has not been established. Since the dynamic behavior of the immune response and the different impact of ICI treatment on patients with specific RCC subtypes, the integration of multiple biomarkers and further validation in clinical trials are needed.

Elimination of dormant, autophagic ovarian cancer cells and xenografts through enhanced sensitivity to anaplastic lymphoma kinase inhibition

BACKGROUND

Poor outcomes for patients with ovarian cancer relate to dormant, drug-resistant cancer cells that survive after primary surgery and chemotherapy. Ovarian cancer (OvCa) cells persist in poorly vascularized scars on the peritoneal surface and depend on autophagy to survive nutrient deprivation. The authors have sought drugs that target autophagic cancer cells selectively to eliminate residual disease.

METHODS

By using unbiased small-interfering RNA (siRNA) screens, the authors observed that knockdown of anaplastic lymphoma kinase (ALK) reduced the survival of autophagic OvCa cells. Small-molecule ALK inhibitors were evaluated for their selective toxicity against autophagic OvCa cell lines and xenografts. Autophagy was induced by reexpression of GTP-binding protein Di-Ras3 (DIRAS3) or serum starvation and was evaluated with Western blot analysis, fluorescence imaging, and transmission electron microscopy. Signaling pathways required for crizotinib-induced apoptosis of autophagic cells were explored with flow cytometric analysis, Western blot analysis, short-hairpin RNA knockdown of autophagic proteins, and small-molecule inhibitors of STAT3 and BCL-2.

RESULTS

Induction of autophagy by reexpression of DIRAS3 or serum starvation in multiple OvCa cell lines significantly reduced the 50% inhibitory concentration of crizotinib and other ALK inhibitors. In 2 human OvCa xenograft models, the DIRAS3-expressing tumors treated with crizotinib had significantly decreased tumor burden and long-term survival in 67% to 79% of mice. Crizotinib treatment of autophagic cancer cells further enhanced autophagy and induced autophagy-mediated apoptosis by decreasing phosphorylated STAT3 and BCL-2 signaling.

CONCLUSIONS

Crizotinib may eliminate dormant, autophagic, drug-resistant OvCa cells that remain after conventional cytoreductive surgery and combination chemotherapy. A clinical trial of ALK inhibitors as maintenance therapy after second-look operations should be seriously considered.

Regulation of TFEB activity and its potential as a therapeutic target against kidney diseases

The transcription factor EB (TFEB) regulates the expression of target genes bearing the Coordinated Lysosomal Expression and Regulation (CLEAR) motif, thereby modulating autophagy and lysosomal biogenesis. Furthermore, TFEB can bind to the promoter of autophagy-associated genes and induce the formation of autophagosomes, autophagosome-lysosome fusion, and lysosomal cargo degradation. An increasing number of studies have shown that TFEB stimulates the intracellular clearance of pathogenic factors by enhancing autophagy and lysosomal function in multiple kidney diseases, such as cystinosis, acute kidney injury, and diabetic nephropathy. Taken together, this highlights the importance of developing novel therapeutic strategies against kidney diseases based on TFEB regulation. In this review, we present an overview of the current data on TFEB and its implication in kidney disease.

Clinicopathological characterisation of renal cell carcinoma in young adults: a contemporary update and review of literature

AIMS

Renal cell carcinomas are relatively rare in children and young adults. While well characterised in adults, the morphological and molecular characterisation of these tumours in young patients is relatively lacking. The objective of this study was to explore the spectrum of renal cell carcinoma (RCC) subtypes in children and young adults and to determine their clinico-pathological, immunohistochemical and molecular characteristics by evaluating a large retrospective cohort of renal cell carcinoma patients age 30 years or younger.

METHODS AND RESULTS

Sixty-eight cases with confirmed diagnosis of renal cell carcinoma at age 30 years or younger were identified at our institution. Clear cell carcinoma accounted for the most common subtype seen in this age group. Translocation renal cell carcinoma and rare familial syndrome subtypes such as succinate dehydrogenase deficient renal cell carcinoma and tuberous sclerosis complex-associated renal cell carcinoma were found relatively more frequently in this cohort. Despite applying the 2016 WHO classification criteria, a high proportion of the tumours in our series remained unclassified.

CONCLUSIONS

Our results suggest that renal cell carcinoma in children and young adults is a relatively rare disease that shares many histological similarities to renal cell carcinoma occurring in adults and yet demonstrate some unique clinical-pathological differences. Microphthalmia-associated transcription (MiT) family translocation RCC and rare familial syndrome subtypes are relatively more frequent in the paediatric and adolescent age groups than in adults. Clear cell RCC still accounted for the most common subtype seen in this age group. MiT family translocation RCC patients presented with advanced stage disease and had poor clinical outcomes. The large and heterogeneous subgroup of unclassified renal cell carcinoma contains phenotypically distinct tumours with further potential for future subcategories in the renal cell carcinoma classification.

Renal Tumors of Childhood-A Histopathologic Pattern-Based Diagnostic Approach

Renal tumors comprise approximately 7% of all malignant pediatric tumors. This is a highly heterogeneous group of tumors, each with its own therapeutic management, outcome, and association with germline predispositions. Histopathology is the key in establishing the correct diagnosis, and therefore pathologists with expertise in pediatric oncology are needed for dealing with these rare tumors. While each tumor shows different histologic features, they do have considerable overlap in cell type and histologic pattern, making the diagnosis difficult to establish, if based on routine histology alone. To this end, ancillary techniques, such as immunohistochemistry and molecular analysis, can be of great importance for the correct diagnosis, resulting in appropriate treatment. To use ancillary techniques cost-effectively, we propose a pattern-based approach and provide recommendations to aid in deciding which panel of antibodies, supplemented by molecular characterization of a subset of genes, are required.

Comprehensive Immunoprofiles of Renal Cell Carcinoma Subtypes

In recent years, renal epithelial tumors have been among the fastest reclassifying tumors, requiring updates to the tumor classification system. Nonetheless, immunohistochemistry (IHC) remains the most widely used tool for renal epithelial tumors. In this proposal, we aimed to create the most efficient IHC panel for categorizing the diverse subtypes of renal tumors, and to find out more specific immunohistochemical results in each subtype or each antibody. A total of 214 renal tumors were analyzed using 10 possible IHC markers to differentiate subtypes, including three major renal cell carcinoma (RCC) subtypes, clear-cell type (50 cases), papillary type (50 cases), and chromophobe type (20 cases), and minor subtypes (MiT RCC, 13 cases; collecting duct carcinoma, 5 cases; and oncocytoma, 10 cases). A triple immunomarker (cytokeratin 7 (CK7)-carbonic anhydrase IX (CAIX)- alpha-methylacyl-CoA racemase (AMACR)) panel is useful in particular high-grade clear-cell tumors. If IHC remains ambiguous, the use of an adjunctive panel can be suggested, including CD10, epithelial membrane antigen, cathepsin K, c-kit, hepatocyte nuclear factor 1-β, and E-cadherin. For an efficient immunohistochemical strategy for subtyping of RCC, we conclude that the CK7-CAIX-AMACR panel is the best primary choice for screening subtyping.

Expanding the morphologic spectrum of chromophobe renal cell carcinoma: A study of 8 cases with papillary architecture

Although typically arranged in solid alveolar fashion, chromophobe renal cell carcinoma (RCC) may also show several other architectural growth patterns. We include in this series 8 chromophobe RCC cases with prominent papillary growth, a pattern very rarely reported or only mentioned as a feature of chromophobe RCC, which is lacking wider recognition The differential diagnosis of such cases significantly varies from the typical chromophobe RCC with its usual morphology, particularly its distinction from papillary RCC and other relevant and clinically important entities. Of 972 chromophobe RCCs in our files, we identified 8 chromophobe RCCs with papillary growth. We performed immunohistochemistry and array Comparative Genomic Hybridisation (aCGH) to investigate for possible chromosomal aberrations. Patients were 3 males and 5 females with age ranging from 30 to 84 years (mean 57.5, median 60 years). Tumor size was variable and ranged from 2 to 14 cm (mean 7.5, median 6.6 cm). Follow-up was available for 7 of 8 patients, ranging from 1 to 61 months (mean 20.1, median 12 months). Six patients were alive with no signs of aggressive behavior, and one died of the disease. Histologically, all cases were composed of dual cell population consisting of variable proportions of leaf-like cells with pale cytoplasm and eosinophilic cells. The extent of papillary component ranged from 15 to 100% of the tumor volume (mean 51%, median 50%). Sarcomatoid differentiation was identified only in the case with fatal outcome. Immunohistochemically, all tumors were positive for CK7, CD117 and Hale's Colloidal Iron. PAX8 was positive in 5 of 8 cases, TFE3 was focally positive 3 of 8 tumors, and Cathepsin K was focally positive in 2 of 8 tumors. All cases were negative for vimentin, AMACR and HMB45. Fumarate hydratase staining was retained in all tested cases. The proliferative activity was low (up to 1% in 7, up to 5% in one case). Three cases were successfully analyzed by aCGH and all showed a variable copy number variation profile with multiple chromosomal gains and losses. CONCLUSIONS: Chromophobe RCC demonstrating papillary architecture is an exceptionally rare carcinoma. The diagnosis can be challenging, although the cytologic features are consistent with the classic chromophobe RCC. Given the prognostic and therapeutic implications of accurately diagnosis other RCCs with papillary architecture (i.e., Xp11.2 translocation RCC, FH-deficient RCC), it is crucial to differentiate these cases from chromophobe RCC with papillary architecture. Based on this limited series, the presence of papillary architecture does not appear to have negative prognostic impact. However, its wider recognition may allow in depth studies on additional examples of this rare morphologic variant.

Novel and established EWSR1 gene fusions and associations identified by next-generation sequencing and fluorescence in-situ hybridization

EWSR1 is a 'promiscuous' gene that can fuse with many different partner genes in phenotypically identical tumors or partner with the same genes in morphologically and behaviorally different neoplasms. Our study set out to examine the EWSR1 fusions identified at our institution over a 3-year period, using various methods, their association with specific entities and possible detection of novel partners and associations. Sixty-three consecutive cases investigated for EWSR1 gene fusions between 2015 and 2018 at our institution were included in this study. Fusions were identified by either break-apart fluorescence in-situ hybridization (FISH), our clinical RNA-based assay for fusion transcript detection or both. Twenty-eight cases were concurrently tested by FISH and NGS, 24 were tested by FISH alone and 11 by NGS alone. Of the 28 cases with dual testing, 24 were positive by both assays for an EWSR1 gene fusion, 3 cases were discordant with a positive FISH assay and a negative NGS assay, and 1 case was discordant with a negative FISH assay but a positive NGS assay. Three novel fusions were identified: a complex rearrangement involving three genes (EWSR1/RBFOX2/ERG) in Ewing sarcoma, a EWSR1/TCF7L2 fusion in a colon adenocarcinoma, and a EWSR1/TFEB fusion in a translocation-associated renal cell carcinoma. Both colonic adenocarcinoma and renal cell carcinoma had not been previously associated with EWSR1 rearrangements to our knowledge. In a subset of cases, detection of a specific partner had an impact on the histological diagnosis and patient management. In our experience, the use of a targeted NGS-based fusion assay is superior to EWSR1 break-apart FISH for the detection of known and novel EWSR1 rearrangements and fusion partners, particularly given the emerging understanding that distinct fusion partners result in different diseases with distinct prognostic and therapeutic implications.

MITF-the first 25 years

In this review, Goding and Arnheiter present the current understanding of MITF's role and regulation in development and disease and highlight key areas where our knowledge of MITF regulation and function is limited.

All transcription factors are equal, but some are more equal than others. In the 25 yr since the gene encoding the microphthalmia-associated transcription factor (MITF) was first isolated, MITF has emerged as a key coordinator of many aspects of melanocyte and melanoma biology. Like all transcription factors, MITF binds to specific DNA sequences and up-regulates or down-regulates its target genes. What marks MITF as being remarkable among its peers is the sheer range of biological processes that it appears to coordinate. These include cell survival, differentiation, proliferation, invasion, senescence, metabolism, and DNA damage repair. In this article we present our current understanding of MITF's role and regulation in development and disease, as well as those of the MITF-related factors TFEB and TFE3, and highlight key areas where our knowledge of MITF regulation and function is limited.

Microphthalmia family of transcription factors associated renal cell carcinoma

The microphthalmia (MiT) subfamily of transcription factors includes TFE3, TFEB, TFEC, and MITF. In the 2016 World Health Organization classification, MiT family translocation renal cell carcinoma (tRCC) including Xp11 tRCC and t(6;11) RCC, was newly defined as an RCC subtype. Xp11 and t(6;11) RCC are characterized by the rearrangement of the MiT transcription factors TFE3 and TFEB, respectively. Recent studies identified the fusion partner-dependent clinicopathological and immunohistochemical features in TFE3-rearranged RCC. Furthermore, RCC with TFEB amplification, melanotic MiT family translocation neoplasms, was identified may as a unique subtype of MiT family associated renal neoplasms, along with MITF associated RCC. In this review, we will collect available literature of these newly-described RCCs, analyze their clinicopathological and immunohistochemical features, and summarize their molecular and genetic evidences. We expect this review would be beneficial for the understanding of these rare subtypes of RCCs, and eventually promote clinical management strategies.

A Potential Prognostic Gene Signature for Predicting Survival for Glioblastoma Patients

OBJECTIVE

This study aimed to screen prognostic gene signature of glioblastoma (GBM) to construct prognostic model.

METHODS

Based on the GBM information in the Cancer Genome Atlas (TCGA, training set), prognostic genes (Set X) were screened by Cox regression. Then, the optimized prognostic gene signature (Set Y) was further screened by the Cox-Proportional Hazards (Cox-PH). Next, two prognostic models were constructed: model A was based on the Set Y; model B was based on part of the Set X. The samples were divided into low- and high-risk groups according to the median prognosis index (PI). GBM datasets in Gene Expression Ominous (GEO, GSE13041) and Chinese Glioma Genome Atlas (CGGA) were used as the testing datasets to confirm the prognostic models constructed based on TCGA.

RESULTS

We identified that the prognostic 14-gene signature was significantly associated with the overall survival (OS) in the TCGA. In model A, patients in high- and low-risk groups showed the significantly different OS (P = 7.47 × 10-9, area under curve (AUC) 0.995) and the prognostic ability were also confirmed in testing sets (P=0.0098 and 0.037). The model B in training set was significant but failed in testing sets.

CONCLUSION

The prognostic model which was constructed based on the prognostic 14-gene signature presented a high predictive ability for GBM. The 14-gene signature may have clinical implications in the subclassification of GBM.

Histological and molecular characterization of TFEB-rearranged renal cell carcinomas

The 2016 WHO Classification of Tumors of the Urinary System recognizes microphthalmia transcription factor (MiT) family translocation carcinomas as a separate entity among renal cell carcinomas. TFE3 and transcription factor EB (TFEB) are members of the MiT family for which chromosomal rearrangements have been associated with renal cell carcinoma formation. TFEB translocation renal cell carcinoma is a rare tumor harboring a t(6;11)(p21;q12) translocation. Recently, renal cell carcinomas with TFEB amplification have been identified. TFEB amplified renal cell carcinomas have to be distinguished from TFEB-translocated renal cancer, because they may demonstrate a more aggressive behavior. Herein, we present a TFEB-translocated and a TFEB-amplified carcinoma cases and describe their distinct histological, immunohistochemical, and molecular characteristics. In addition, we review conventional morphology, immunophenotype, genetic background, and clinical outcome of TFEB-rearranged RCCs in the literature, with a special emphasis on important differential diagnoses and the diagnostic approach.

Chromosomal aberrations in renal cell carcinoma: An overview with implications for clinical practice

Chromosomal instability and aberrations are known in many cancers including renal cell carcinoma. Detailed understanding of these changes has led to an improved drug discovery and continued developments in other therapeutic options. Chromosomal aberrations have a potential to be used to monitor disease including prognostication. There has been a growing experience in cytogenetic techniques and gap between clinic and laboratory has narrowed significantly in the recent past. Nevertheless, more work on validation of these techniques, establishing threshold and interobserver agreement needs to be carried out for these diagnostic/prognostic tests before utilizing them in clinics as a part of “personalized medicine” care. The review presented here is a summary of common genetic disorders in renal cancer and some of acquired genetic changes which can be used as biomarkers. The review also describes basics of commonly used genetic techniques for wider clinical community involved in the management of renal cancer.

The molecular characterization and therapeutic strategies of papillary renal cell carcinoma

Introduction: Papillary renal cell carcinoma (pRCC) is an important subtype of kidney cancer with a problematic pathological classification and highly variable clinical behavior. In this review, we summarize the current progression on pRCC in molecular level. Our findings highlight the need for molecular markers to accurately subtype pRCC and may lead to the development of more targeted agents and better patient stratification in clinical trials for pRCC. Areas covered: This review highlights the need for molecular markers to accurately subtype PRCC and may lead to the development of more targeted agents and better patient stratification in clinical trials for pRCC. Expert commentary: There are mainly two subtypes of pRCC based on histology. However, little is known about the genetic characterization of the sporadic forms of pRCC and there are currently no standard forms of therapy for patients with advanced disease. Both MET inhibitors and immunotherapy may be effective in advanced pRCC treatment. Therefore, understanding the molecular basis of pRCC and identifying the main goal of treatment is crucial for the selection of the best strategy.

Emerging roles and regulation of MiT/TFE transcriptional factors

The MiT/TFE transcription factors play a pivotal role in the regulation of autophagy and lysosomal biogenesis. The subcellular localization and activity of MiT/TFE proteins are primarily regulated through phosphorylation. And the phosphorylated protein is retained in the cytoplasm and subsequently translocates to the nucleus upon dephosphorylation, where it stimulates the expression of hundreds of genes, leading to lysosomal biogenesis and autophagy induction. The transcription factor-mediated lysosome-to-nucleus signaling can be directly controlled by several signaling molecules involved in the mTORC1, PKC, and AKT pathways. MiT/TFE family members have attracted much attention owing to their intracellular clearance of pathogenic factors in numerous diseases. Recently, multiple studies have also revealed the MiT/TFE proteins as master regulators of cellular metabolic reprogramming, converging on autophagic and lysosomal function and playing a critical role in cancer, suggesting that novel therapeutic strategies could be based on the modulation of MiT/TFE family member activity. Here, we present an overview of the latest research on MiT/TFE transcriptional factors and their potential mechanisms in cancer.

[TFEB-amplified renal cell carcinoma. A case report and review of the literature]

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.

Renal Cell Tumors: Understanding Their Molecular Pathological Epidemiology and the 2016 WHO Classification

Accumulating evidence suggests that renal cell tumors represent a group of histologically and molecularly heterogeneous diseases, even within the same histological subtype. In accordance with the increased understanding of the morphological, immunohistochemical, molecular, and epidemiological characteristics of renal cell tumors, the World Health Organization (WHO) classification of renal cell tumors has been modified. This review provides perspectives on both new and current subtypes of renal cell tumors, as well as on the emerging/provisional renal cell carcinomas in the new 2016 WHO classification, which focuses on features of their molecular pathological epidemiology. The WHO classification will require additional revisions to enable the classification of renal cell tumors as clinically meaningful subtypes and provide a better understanding of the unique characteristics of renal cell tumors.