Comprehensive study of 9 novel cases of TFEB-amplified renal cell carcinoma: an aggressive tumor with frequent PDL1 expression

A clinicopathological and molecular series of five TFEB-altered renal cell carcinoma (RCC) cases: highlighting an aggressive subset of TFEB-rearranged RCC concomitant with TFEB amplification/gene copy number gains

The classification of TFEB-altered renal cell carcinoma (RCC) has been revised to include TFEB-rearranged RCC and TFEB-amplified RCC in the 2022 World Health Organization (WHO) Classification of Tumors of the Urinary System. Given the wide spectrum of TFEB-altered RCC in terms of morphology and clinical behavior, an accurate diagnosis is challenging yet crucial, particularly in aggressive cases. Moreover, the concurrence of TFEB gene rearrangement and amplification/gene copy number (GCN) gains was also observed, but there was limited knowledge of these cases. We presented three TFEB-rearranged RCC cases, one TFEB-amplified RCC case, and one case of concomitant TFEB-rearranged and -amplified RCC, comparing the similarities and differences among these three subgroups. Furthermore, we summarized the clinicopathological and molecular features of TFEB-rearranged RCC concomitant with TFEB amplification/GCN gains from the literature and the present study. TFEB-altered RCCs exhibit significant heterogeneity in morphology and clinical behavior while displaying similar immunohistochemical profiles, including positive staining for Melan-A, PAX8, and CD117, and negative staining for CK7. A typical biphasic "rosette-like" morphology has been observed in a proportion of TFEB-rearranged RCC concomitant with TFEB amplification/GCN gains, which has been noted in TFEB-rearranged RCC, but not in cases with only TFEB amplification. Notably, TFEB-rearranged RCCs concomitant with TFEB amplification/GCN gains tend to be aggressive, in contrast to the often indolent nature of TFEB-rearranged cases, irrespective of the extent of TFEB gene copy increase. Therefore, a TFEB FISH assay is essential for unclassified RCC cases that exhibit melanocytic marker expression, and fluorescent signals should be counted and interpreted acurrately.

Comparison of Primary and Metastatic Fumarate Hydratase-Deficient Renal Cell Carcinomas Documents Morphologic Divergence and Potential Diagnostic Pitfall With Peritoneal Mesothelioma

Fumarate hydratase (FH)-deficient renal cell carcinomas are rare neoplasms characterized by wide morphologic heterogeneity and pathogenetic mutations in the FH gene. They often show aggressive behavior with rapid diffusion to distant organs, so novel therapeutic scenarios have been explored, including EGFR inhibitors and PD-L1 expression for targeted immunotherapy. Herein, we investigated a series of 11 primary FH-deficient renal cell carcinomas and 7 distant metastases to evaluate tumor heterogeneity even in metastatic sites and estimate the specific spread rates to various organs. Furthermore, the tumors were tested for immunohistochemical PD-L1 expression and EGFR mutations. Most metastatic cases involved the abdominal lymph nodes (4/7; 57%), followed by the peritoneum (3/7; 42%), the liver (2/7; 29%), and the lungs (1/7; 14%). Six metastatic localizations were histologically documented, revealing a morphologic heterogeneous architecture often differing from that of the corresponding primary renal tumor. Peritoneal involvement morphologically resembled a benign reactive mesothelial process or primary peritoneal mesothelioma, thus advocating to perform an accurate immunohistochemical panel, including PAX8 and FH, to reach a proper diagnosis. A pure low-grade succinate dehydrogenase-looking primary FH-deficient renal cell carcinoma was also recorded. As for therapy, significant PD-L1 labeling was found in 60% of primary renal tumors, whereas none of them carried pathogenetic EGFR mutations. Our data show that FH-deficient renal cell carcinoma may be morphologically heterogeneous in metastases as well, which involve the lymph nodes, the liver, and the peritoneum more frequently than other renal tumors. Due to the high frequency of this latter (42%), pathologists should always be concerned about ruling out mesothelial-derived mimickers, and the occurrence of rarer, primary, low-grade-looking types. Finally, contrary to EGFR mutations, PD-L1 expression could be a possible predictive biomarker for the therapy of these tumors.

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.

A TFEB-Amplified Renal Cell Carcinoma with Long-Term, Complete Immunotherapy Response: Retrospective Support for the Value of Molecular Classification

Recent years have seen the recognition and establishment of numerous subtypes of renal cell carcinoma (RCC), including adoption of an entire category of "molecularly defined renal carcinomas" in the fifth Edition of World Health Organization Classification. To add value, new diagnostic entities should be clinicopathologically distinct, or better, imply specific management and treatment angles, especially if adjunctive testing is needed for diagnosis. One such promising future treatment angle for a molecularly defined subtype, TFEB-amplified RCC, is immunotherapy, for which recent scholarship has demonstrated frequent expression of PD-L1. Herein, we report a case of metastatic TFEB-amplified RCC, where the patient experienced a long-term, complete response to PDL1-directed therapy, which had been serendipitously used years ago under a renal tumor subtype-agnostic indication. This promising experience suggests formal exploration of immunotherapy for these tumors.

Metastatic Translocated Renal Cell Carcinoma in a Kidney Transplant Patient - a Case Report and Review of the Literature

TFEB-altered renal cell carcinomas are rare tumours. Here, we report the exceptional case of such a tumour in the setting of solid organ transplantation and with already metastatic disease at the time of diagnosis. The primary tumour occurred in the native kidney and only focally showed biphasic morphology whereas the metastasis, among others to the transplant kidney, showed nonspecific, albeit different morphology, but both had consistent TFEB translocation. Treatment with the immune checkpoint inhibitor pembrolizumab together with the multi-kinase inhibitor lenvatinib achieved partial response 14 months after diagnosis.

Prognosis and Clinicopathological Characters of Adult TFEB-Altered Renal Cell Carcinoma: A Single Center Experience of 18 Cases

INTRODUCTION

TFEB-altered renal cell carcinoma (RCC) is a rare entity characterized by the rearrangement of the TFEB gene or TFEB amplified. The therapeutic implications and long-term survival of TFEB-altered RCC remain unclear, especially for metastatic cases.

MATERIALS AND METHODS

The current study initially enrolled 7604 consecutive RCC patients at our center and a total of 248 patients were selected for FISH and immunohistochemistry (IHC) analysis. Eventually, eighteen TFEB-altered RCC patients were identified. We then reported the clinical, morphological, IHC, and radiological features of these cases.

RESULTS

The median age at initial diagnosis was 45 years, ranging from 18 years to 66 years. The majority of the TFEB-altered RCC patients were male (61.1%), with localized disease (T1-2N0M0, 77.8%). The median split TFEB fluorescent signal was 24%, ranging from 15%-80%. The morphological characteristics of TFEB-altered RCC were variable, with acinar, papillary, solid, or nest patterns. IHC and magnetic resonance imaging features of TFEB-altered RCC were nonspecific. Nine patients with localized disease received partial nephrectomy and five patients with localized disease received radical nephrectomy. During the median follow-up of 67 months, no signs of recurrence or metastasis were found in these patients. Two patients had distant metastasis and received axitinib plus PD-1 immunotherapy. One of them died at 40-month follow-up and another still alive at 88-month follow-up.

CONCLUSION

TFEB-altered RCC is an extremely rare variant, exhibited mixed morphological characteristics. The radiological feature lack specificity, resembling clear cell RCC or papillary RCC. Genetic analyses including FISH analysis is crucial in the diagnosis of TFEB-altered RCC. For localized TFEB-altered RCC, both radical nephrectomy and partial nephrectomy conferred satisfactory prognosis. For metastatic TFEB-altered RCC, immunotherapy-based drug combinations could be a promising treatment strategy.

Papillary Renal Cell Carcinoma: A Review of Prospective Clinical Trials

OPINION STATEMENT

PRCC is a unique histologic entity compared to other forms of renal cell carcinoma, harboring distinct molecular drivers. The WHO 2022 classification is further emphasizing the molecular biology by making molecular classifications of PRCC subclassifications and discontinuing the morphologic type 1 and type 2 classification system. We agree with this functional classification system and encourage all future clinical trials to only include patients with similar diagnosis instead of conducting basket trials (including all nccRCC together) which limits the scientific value of those conclusions. Based on recent disease-specific clinical trial (S1500, PAPMET), the current standard of care for patients with treatment naïve PRCC is cabozantinib. Prospective clinical trials clearly establish that immune checkpoint inhibitor therapy has meaningful activity in PRCC. The data to date include only single-arm clinical trials of combination immune therapy. Despite the positive and encouraging results, we need validation through randomized studies because of the overestimation of effect size seen in single-arm trials. These randomized trials are currently underway and enrolling. We strongly encourage all physicians to support these studies and enroll patients with PRCC to these trials in order to continue improving the standard of care.

A new glance at autophagolysosomal-dependent or -independent function of transcriptional factor EB in human cancer

Autophagy-lysosome system plays a variety of roles in human cancers. In addition to being implicated in metabolism, it is also involved in tumor immunity, remodeling the tumor microenvironment, vascular proliferation, and promoting tumor progression and metastasis. Transcriptional factor EB (TFEB) is a major regulator of the autophagy-lysosomal system. With the in-depth studies on TFEB, researchers have found that it promotes various cancer phenotypes by regulating the autophagolysosomal system, and even in an autophagy-independent way. In this review, we summarize the recent findings about TFEB in various types of cancer (melanoma, pancreatic ductal adenocarcinoma, renal cell carcinoma, colorectal cancer, breast cancer, prostate cancer, ovarian cancer and lung cancer), and shed some light on the mechanisms by which it may serve as a potential target for cancer treatment.

Exploration of clinicopathological features of rearranged renal cell carcinoma and TFE3, TFEB, and ALK staining performance in renal entities

Rearranged renal cell carcinomas (RCC) are rare types of kidney cancer. The clinicopathological features of rearranged RCC require further validation. The pathological diagnosis usually depends on immunohistochemistry and molecular analysis. This study aimed to explore the expression features of anti-TFE3, TFEB, and ALK in different renal entities. In addition, we collected thirty-six TFE3-rearranged RCC, two TFEB-altered RCC, and one ALK-rearranged RCC to explore their clinicopathological features. We observed that TFE3 can sometimes be weakly expressed in non-TFE3-rearranged RCC. TFE3-rearranged RCC usually exhibited strong TFE3 expression. However, clear cell RCC and FH-deficient RCC also displayed strong TFE3 expression. TFEB also can be weakly expressed in clear cell RCC. However, ALK IHC showed a relatively high specificity and was negative for all non-ALK-rearranged RCC. The ALK-rearranged RCC was analyzed using next generation sequencing to explore gene alterations, and we identified a novel gene partner, SLIT1. ALK-rearranged RCC appears to have eosinophilic cytoplasm. Tumor cells with clear cytoplasm may exclude this diagnosis. Psammomatous bodies (22/38) and pattern multiplicity (35/38) were observed in more than half of the patients. In conclusion, weak TFE3 expression did not indicate TFE3 rearrangement. Strong TFE3 expression had a higher value for indicating TFE3-rearranged RCC, although other entities can also exhibit a strong pattern. Young age combined with morphological features (psammomatous calcification and pattern multiplicity) may indicate the diagnosis of rearranged RCC.

TFEB ‐translocated and ‐amplified renal cell carcinoma with VEGFA co‐amplification: A case of long‐term control by multimodal therapy including a vascular endothelial growth factor‐receptor inhibitor

Introduction

Renal cell carcinoma with TFEB amplification is rare and reportedly aggressive. We herein report a case of renal cell carcinoma with TFEB translocation and amplification in which long-term control was achieved by multimodal therapy including a vascular endothelial growth factor -receptor inhibitor.

Case presentation

A 70-year-old man was referred to our institution for the treatment of renal cell carcinoma with multinodal metastases. Open nephrectomy and lymph node dissection were performed. Immunohistochemistry for transcription factor EB was positive, and fluorescent in situ hybridization revealed TFEB rearrangement and amplification. The diagnosis was TFEB-translocated and -amplified renal cell carcinoma. VEGFA amplification was also demonstrated by fluorescent in situ hybridization. The residual and recurrent tumors were treated and controlled for 52 months by vascular endothelial growth factor-receptor target therapy, radiation therapy, and additional surgery.

Conclusion

A good long-term response to anti-vascular endothelial growth factor drug therapy may be due to VEGFA amplification and subsequent vascular endothelial growth factor overexpression.

TFE3 and TFEB-rearranged renal cell carcinomas: an immunohistochemical panel to differentiate from common renal cell neoplasms

TFE3/TFEB-rearranged renal cell carcinomas are characterized by translocations involving TFE3 and TFEB genes. Despite the initial description of typical morphology, their histological spectrum is wide, mimicking common subtypes of renal cell tumors. Thus, the diagnosis is challenging requiring the demonstration of the gene rearrangement, usually by FISH. However, this technique is limited in most laboratories and immunohistochemical TFE3/TFEB analysis is inconsistent. We sought to identify a useful immunohistochemical panel using the most common available markers to recognize those tumors. We performed an immunohistochemical panel comparing 27 TFE3-rearranged and 10 TFEB-rearranged renal cell carcinomas to the most common renal cell tumors (150 clear cell, 100 papillary, 50 chromophobe renal cell carcinomas, 18 clear cell papillary renal cell tumors, and 50 oncocytomas). When dealing with neoplasms characterized by cells with clear cytoplasm, CA9 is a helpful marker to exclude clear cell renal cell carcinoma. GATA3, AMACR, and CK7 are useful to rule out clear cell papillary renal cell tumor. CK7 is negative in TFE3/TFEB-rearranged renal cell carcinoma and positive in papillary renal cell carcinoma, being therefore useful in this setting. Parvalbumin and CK7/S100A1 respectively are of paramount importance when TFE3/TFEB-rearranged renal cell carcinoma resembles oncocytoma and chromophobe renal cell carcinoma. Moreover, in TFEB-rearranged renal cell carcinoma, cathepsin K and melanogenesis markers are constantly positive, whereas TFE3-rearranged renal cell carcinoma stains for cathepsin K in roughly half of the cases, HMB45 in 8% and Melan-A in 22%. In conclusion, since TFE3/TFEB-rearranged renal cell carcinoma may mimic several histotypes, an immunohistochemical panel to differentiate them from common renal cell tumors should include cathepsin K, CA9, CK7, and parvalbumin.