Genomic Characterization of Renal Cell Carcinoma with Sarcomatoid Dedifferentiation Pinpoints Recurrent Genomic Alterations

Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

Epigenomic signatures of sarcomatoid differentiation to guide the treatment of renal cell carcinoma

Renal cell carcinoma with sarcomatoid differentiation (sRCC) is associated with poor survival and a heightened response to immune checkpoint inhibitors (ICIs). Two major barriers to improving outcomes for sRCC are the limited understanding of its gene regulatory programs and the low diagnostic yield of tumor biopsies due to spatial heterogeneity. Herein, we characterized the epigenomic landscape of sRCC by profiling 107 epigenomic libraries from tissue and plasma samples from 50 patients with RCC and healthy volunteers. By profiling histone modifications and DNA methylation, we identified highly recurrent epigenomic reprogramming enriched in sRCC. Furthermore, CRISPRa experiments implicated the transcription factor FOSL1 in activating sRCC-associated gene regulatory programs, and FOSL1 expression was associated with the response to ICIs in RCC in two randomized clinical trials. Finally, we established a blood-based diagnostic approach using detectable sRCC epigenomic signatures in patient plasma, providing a framework for discovering epigenomic correlates of tumor histology via liquid biopsy.

Renal Cell Carcinoma of Variant Histology: New Biologic Understanding Leads to Therapeutic Advances

Renal cell carcinoma (RCC) is one of the 10 most commonly diagnosed solid tumors. Most RCCs are histologically defined as clear cell, comprising approximately 75% of diagnoses. However, the remaining RCC cases are composed of a heterogeneous combination of diverse histopathologic subtypes, each with unique pathogeneses and clinical features. Although the therapeutic approach to both localized and metastatic RCCs has dramatically changed, first with the advent of antiangiogenic targeted therapies and more recently with the approval of immune checkpoint inhibitor (ICI)-based combinations, these advances have primarily benefited the clear cell RCC patient population. As such, there remains critical gaps in the optimization of treatment regimens for patients with non-clear cell, or variant, RCC histologies. Herein, we detail recent advances in understanding the biology of RCC with variant histology and how such findings have guided novel clinical studies investigating precision oncology approaches for these rare subtypes. Among the most common variant histology RCCs are papillary RCC, comprising approximately 15%-20% of all diagnoses. Although a histopathologically diverse subset of tumors, papillary RCC is canonically associated with amplification of the MET protooncogene; recently completed and ongoing trials have investigated MET-directed therapies for this patient population. Finally, we discuss the unique biology of RCC with sarcomatoid dedifferentiation and the recent clinical findings detailing its paradoxical sensitivity to ICIs.

A Novel Irreversible TEAD Inhibitor, SWTX-143, Blocks Hippo Pathway Transcriptional Output and Causes Tumor Regression in Preclinical Mesothelioma Models

The Hippo pathway and its downstream effectors, the YAP and TAZ transcriptional coactivators, are deregulated in multiple different types of human cancer and are required for cancer cell phenotypes in vitro and in vivo, while largely dispensable for tissue homeostasis in adult mice. YAP/TAZ and their main partner transcription factors, the TEAD1-4 factors, are therefore promising anticancer targets. Because of frequent YAP/TAZ hyperactivation caused by mutations in the Hippo pathway components NF2 and LATS2, mesothelioma is one of the prime cancer types predicted to be responsive to YAP/TAZ-TEAD inhibitor treatment. Mesothelioma is a devastating disease for which currently no effective treatment options exist. Here, we describe a novel covalent YAP/TAZ-TEAD inhibitor, SWTX-143, that binds to the palmitoylation pocket of all four TEAD isoforms. SWTX-143 caused irreversible and specific inhibition of the transcriptional activity of YAP/TAZ-TEAD in Hippo-mutant tumor cell lines. More importantly, YAP/TAZ-TEAD inhibitor treatment caused strong mesothelioma regression in subcutaneous xenograft models with human cells and in an orthotopic mesothelioma mouse model. Finally, SWTX-143 also selectively impaired the growth of NF2-mutant kidney cancer cell lines, suggesting that the sensitivity of mesothelioma models to these YAP/TAZ-TEAD inhibitors can be extended to other tumor types with aberrations in Hippo signaling. In brief, we describe a novel and specific YAP/TAZ-TEAD inhibitor that has potential to treat multiple Hippo-mutant solid tumor types.

The incidence, pathogenesis, and management of non-clear cell renal cell carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer and is divided into two distinct subtypes, clear cell renal cell carcinoma (ccRCC) and non-clear cell renal cell carcinoma (nccRCC). Although many treatments exist for RCC, these are largely based on clinical trials performed in ccRCC and there are limited studies on the management of nccRCC. Non-clear cell RCC consists of multiple histological subtypes: papillary, chromophobe, translocation, medullary, collecting duct, unclassified, and other rare histologies. Due to variations in pathogenesis and therapeutic response, therapy should be tailored to specific variant histologies. For patients with localized nccRCC, surgical resection remains the gold standard. In the metastatic setting, the standard of care has yet to be clearly defined, and most guidelines recommend clinical trial participation. General therapeutic options include immunotherapy, either as monotherapy or in combination, targeted therapies such as vascular endothelial growth factor tyrosine kinase inhibitors and MET inhibitors, and chemotherapy in certain subtypes. Here we present a review of the incidence and pathogenesis of the various subtypes, as well as available clinical data to support therapeutic recommendations for these subtypes. We also highlight currently available clinical trials in nccRCC and future directions in investigating novel treatment modalities tailored to patients with variant histology.

Silencing of genes by promoter hypermethylation shapes tumor microenvironment and resistance to immunotherapy in clear-cell renal cell carcinomas

The efficacy of immune checkpoint inhibitors varies in clear-cell renal cell carcinoma (ccRCC), with notable primary resistance among patients. Here, we integrate epigenetic (DNA methylation) and transcriptome data to identify a ccRCC subtype characterized by cancer-specific promoter hypermethylation and epigenetic silencing of Polycomb targets. We develop and validate an index of methylation-based epigenetic silencing (iMES) that predicts primary resistance to immune checkpoint inhibition (ICI) in the BIONIKK trial. High iMES is associated with VEGF pathway silencing, endothelial cell depletion, immune activation/suppression, EZH2 activation, BAP1/SETD2 deficiency, and resistance to ICI. Combination therapy with hypomethylating agents or tyrosine kinase inhibitors may benefit patients with high iMES. Intriguingly, tumors with low iMES exhibit increased endothelial cells and improved ICI response, suggesting the importance of angiogenesis in ICI treatment. We also develop a transcriptome-based analogous system for extended applicability of iMES. Our study underscores the interplay between epigenetic alterations and tumor microenvironment in determining immunotherapy response.

Müllerian-Type Clear Cell Carcinoma of Donor Origin in a Male Patient with a Kidney Transplant: Ascertained by Molecular Testing

Clear cell carcinomas of Müllerian origin have a strong female predominance and only extremely rarely will arise within the kidney, presumably due to ectopic Müllerian embryogenesis. Herein, we report a unique case of metastatic Müllerian type clear cell carcinoma in a 37-year-old patient who had previously received a transplanted kidney from his father at age 11 (due to severe bilateral vesicoureteral reflux) and remained on chronic immunosuppression. The tumor was highly aggressive and demonstrated somatic mutations in NF2 and SETD2. Imaging of the transplanted kidney did not reveal any clear evidence of malignancy. However, targeted multigene sequencing and short tandem repeat testing revealed that the cancer was of donor origin, presumably from ectopic Müllerian tissue transplanted to the patient along with the kidney graft. The tumor was resistant to first-line therapy with a triple combination of carboplatin plus paclitaxel plus bevacizumab, as well as to second-line immunotherapy with nivolumab plus ipilimumab after tapering down the patient's immunosuppression. Despite the tumor being genetically distinct from the host, the use of immune checkpoint therapy with nivolumab plus ipilimumab did not yield a response. This unique case showcases the value of molecular testing in determining the tumor origin in patients with solid organ transplants who present with cancers of unknown primary. This can prompt the potential investigation of other recipients from the same donor.

Interferon signaling promotes tolerance to chromosomal instability during metastatic evolution in renal cancer

Molecular routes to metastatic dissemination are critical determinants of aggressive cancers. Through in vivo CRISPR-Cas9 genome editing, we generated somatic mosaic genetically engineered models that faithfully recapitulate metastatic renal tumors. Disruption of 9p21 locus is an evolutionary driver to systemic disease through the rapid acquisition of complex karyotypes in cancer cells. Cross-species analysis revealed that recurrent patterns of copy number variations, including 21q loss and dysregulation of the interferon pathway, are major drivers of metastatic potential. In vitro and in vivo genomic engineering, leveraging loss-of-function studies, along with a model of partial trisomy of chromosome 21q, demonstrated a dosage-dependent effect of the interferon receptor genes cluster as an adaptive mechanism to deleterious chromosomal instability in metastatic progression. This work provides critical knowledge on drivers of renal cell carcinoma progression and defines the primary role of interferon signaling in constraining the propagation of aneuploid clones in cancer evolution.

The role of immunotherapy in non-clear cell renal cell carcinoma

The category of non-clear cell renal cell carcinoma (nccRCC) includes several clinically, histologically, and molecularly diverse entities. Traditionally, they comprise type 1 and type 2 papillary, chromophobe, unclassified, and other histologies (medullary, collecting duct carcinoma, and translocation-associated). Molecular knowledge has allowed the identification of some other specific subtypes, such as fumarate hydratase-deficient renal cell carcinoma (RCC) or succinate dehydrogenase-associated RCC. In addition, it has recognized some alterations with a possible predictive role, e.g., MET proto-oncogene receptor tyrosine kinase (MET) alterations in papillary tumors. Standard therapies for the management of advanced clear cell RCC (ccRCC), i.e., vascular endothelial growth factor receptor (VEGFR) pathway inhibitors and mammalian target of rapamycin inhibitors, have shown poorer results in nccRCC patients. Therefore, there is a need to improve the efficacy of the treatment for advanced nccRCC. Immunotherapy, especially immune checkpoint inhibitors (ICIs) targeting programmed death 1/programmed death ligand 1 and cytotoxic T-lymphocyte associated protein 4 (CTLA-4), has demonstrated a significant survival benefit in several malignant neoplasias, including ccRCC, with a proportion of patients achieving long survival. The combinations of ICI or ICI + VEGFR tyrosine kinase inhibitors (TKIs) are the standard of care in advanced ccRCC. Unfortunately, major pivotal trials did not include specific nccRCC populations. In recent years, several studies have retrospectively or prospectively evaluated ICIs alone or in combination with another ICI or with TKIs in nccRCC patients. In this article, we review data from available trials in order to elucidate clinical and molecular profiles that could benefit from immunotherapy approaches.

Hot topics in renal cancer pathology: implications for clinical management

INTRODUCTION

The updated European Association of Urology (EAU) Guidelines issued a weak recommendation for adjuvant pembrolizumab for patients with high-risk operable clear cell Renal Cell Carcinoma (ccRCC). High risk of recurrence was defined, as per protocol-criteria, as T2 with nuclear grade 4 or sarcomatoid differentiation, T3 or higher, regional lymph node metastasis, or stage M1 with no evidence of disease. Considering the heterogeneous population included in the recommendation, it has been questioned if adjuvant pembrolizumab may lead to overtreatment of some patients as well as undertreatment of patients with worse prognosis.

AREAS COVERED

In this review, we discuss the issues related to the assessment of pathological features required to identify those patients harboring a high-risk tumor, highlighting the issue related to interobserver variability and discuss the currently available prognostic scoring systems in ccRCC.

EXPERT OPINION

PPathologist assessment of prognostic features suffers from interobserver variability which may depend on gross sampling and the pathologist's expertise. The presence of clear cell feature is not sufficient criteria by itself to define ccRCC since clear cell can be also found in other histotypes. Application of molecular biomarkers may be useful tools in the near future to help clinicians identify patients harboring tumors with worse prognosis.

The significance of sarcomatoid and rhabdoid dedifferentiation in renal cell carcinoma

Dedifferentiation in renal cell carcinoma (RCC), either sarcomatoid or rhabdoid, is an infrequent event that may occur heterogeneously in the setting of any RCC histology and is associated with poor outcomes. Sarcomatoid dedifferentiation is associated with inferior survival with angiogenesis targeted therapy and infrequent responses to cytotoxic chemotherapy. However, immune checkpoint therapy has significantly improved outcomes for patients with sarcomatoid dedifferentiation. Biologically, sarcomatoid dedifferentiation has increased programmed death-ligand 1 (PD-L1) expression and an inflamed tumor microenvironment, in addition to other distinct molecular alterations. Less is known about rhabdoid dedifferentiation from either a clinical, biological, or therapeutic perspective. In this focused review, we will discuss the prognostic implications, outcomes with systemic therapy, and underlying biology in RCC with either sarcomatoid or rhabdoid dedifferentiation present.

Novel Driver Strength Index highlights important cancer genes in TCGA PanCanAtlas patients

Background

Cancer driver genes are usually ranked by mutation frequency, which does not necessarily reflect their driver strength. We hypothesize that driver strength is higher for genes preferentially mutated in patients with few driver mutations overall, because these few mutations should be strong enough to initiate cancer.

Methods

We propose formulas for the Driver Strength Index (DSI) and the Normalized Driver Strength Index (NDSI), the latter independent of gene mutation frequency. We validate them using TCGA PanCanAtlas datasets, established driver prediction algorithms and custom computational pipelines integrating SNA, CNA and aneuploidy driver contributions at the patient-level resolution.

Results

DSI and especially NDSI provide substantially different gene rankings compared to the frequency approach. E.g., NDSI prioritized members of specific protein families, including G proteins GNAQ, GNA11 and GNAS, isocitrate dehydrogenases IDH1 and IDH2, and fibroblast growth factor receptors FGFR2 and FGFR3. KEGG analysis shows that top NDSI-ranked genes comprise EGFR/FGFR2/GNAQ/GNA11-NRAS/HRAS/KRAS-BRAF pathway, AKT1-MTOR pathway, and TCEB1-VHL-HIF1A pathway.

Conclusion

Our indices are able to select for driver gene attributes not selected by frequency sorting, potentially for driver strength. Genes and pathways prioritized are likely the strongest contributors to cancer initiation and progression and should become future therapeutic targets.

The Role of Cytoreductive Nephrectomy in Renal Cell Carcinoma with Sarcomatoid Histology: A Case Series and Review of the Literature

Background: Renal cell carcinoma with sarcomatoid dedifferentiation represents a rare histological entity characterized by aggressive behavior, limited efficacy of tyrosine kinase inhibitors or mTOR inhibitors, and poor outcome. The immune checkpoint inhibitor therapy regimen combining ipilimumab with nivolumab represents a new standard of care for this patient population due to a hitherto unprecedented response rate and overall survival. On the other hand, the role of cytoreductive nephrectomy in metastatic renal cell carcinoma, in particular, with sarcomatoid histology, remains controversial. Patient and Methods: In the present case series, we report six patients with locally advanced or synchronous metastatic sarcomatoid renal cell carcinoma and intermediate or poor International Metastatic RCC Database Consortium (IMDC) risk score, five of whom were successfully subjected to cytoreductive nephrectomy. Results: All six patients received the combination regimen of ipilimumab with nivolumab. Five of these patients underwent upfront cytoreductive nephrectomy followed by systemic treatment without any significant delay, with a durable treatment outcome. Notably, two patients with poor prognostic features achieved a long-term major partial response to therapy. We also performed a review of the literature on optimal treatment strategies for patients with sarcomatoid renal cell carcinoma. Conclusion: Herein, we highlight the feasibility of performing cytoreductive nephrectomy in patients with intermediate/poor prognosis metastatic renal cell carcinoma with sarcomatoid dedifferentiation followed by immunotherapy with ipilimumab and nivolumab. To enhance the chances of immunotherapy success, cytoreductive nephrectomy should also be considered for patients presenting with a disease with adverse prognostic parameters.

Genomic alteration of MTAP/CDKN2A predicts sarcomatoid differentiation and poor prognosis and modulates response to immune checkpoint blockade in renal cell carcinoma

Sarcomatoid differentiation is a highly aggressive pathological characteristic of renal cell carcinoma (RCC) and is characterized by susceptibility to progression and extremely poor prognosis. In this study, we included all genomic alteration events that led to a loss of protein function of MTAP and CDKN2A, and enrolled 5,307 RCC patients with genomic sequencing data from Western and Chinese cohorts. Notably, MTAP/CDKN2A^MUT occurred in the Chinese population ~2 times more frequently than in the Western cohort and showed significant co-mutation trends. We found significantly higher proportions of sarcomatoid-positive patients with MTAP^MUT or CDKN2A^MUT compared with MTAP/CDKN2A wild-type (WT) patients (P < 0.001). Of the 574 RCC samples from the FUSCC cohort and 3,563 RCC samples from 17 independent cohorts, the MTAP/CDKN2A^MUT significantly predicted extremely poor outcomes (P < 0.0001). The Western cohort suggested a concordant relationship between MTAP/CDKN2A^MUT and sarcomatoid differentiation in RCC. Moreover, although MTAP/CDKN2A^MUT RCC may be insensitive to targeted therapy, the high degree of tumor heterogeneity and higher PD-L1 and CXCL13 expression characterizations reflected that MTAP/CDKN2A-deficient features could benefit from immunotherapy for patients with RCC. This study utilized RCC samples from large-scale, global, multicenter sequencing cohorts and first proved that MTAP/CDKN2A deficiency significantly correlates with sarcomatoid differentiation in RCC and predicts aggressive progression, poor prognosis, and primary resistance to targeted therapy and potential favorable responses to immune checkpoint blockade. Unlike conventional targeted therapies, emerging drugs such as immunotherapies or synthetic lethal PRMT5 inhibitors may become novel therapeutic options for patients with MTAP/CDKN2A^MUT RCC.

Papillary renal cell carcinoma: current and controversial issues

PURPOSE OF THE REVIEW

Papillary renal cell carcinoma (pRCC) is the second most frequent renal cancer subtype and represents 15-20% of all RCC. Classification of pRCC is changing because novel tumour entities have been discovered in the last years. In this review, we summarise recent studies relevant for the understanding of the molecular complexity and the broader differential diagnosis of pRCC.

RECENT FINDINGS

It has been 25 years ago, that pRCC was morphologically subdivided into type 1 and type 2. Recently described tumour entities in the 2022 WHO classification challenged this concept and allow a new view on the molecular background in pRCC. Biphasic hyalinizing psammomatous RCC and papillary renal neoplasm with reversed polarity are emerging tumour entities derived from the new concept of molecularly defined RCC subtypes. Immune checkpoint inhibition and tyrosine kinase inhibitors have been introduced as the new backbone in the first-line treatment of advanced pRCCs. To identify novel targeted treatments for patients with pRCC it is crucial to investigate the specific molecular background of pRCC considering emerging pRCC subtypes.

SUMMARY

In the future, a deeper understanding of the correlation between molecular aberrations and new pRCC subtypes may improve the classification of pRCC patients and could reveal potential predictive biomarkers for each subgroup.

Multiregion sequencing of sarcomatoid renal cell carcinoma arising from autosomal dominant polycystic kidney disease

Background

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited cystic kidney disease associated with a spectrum of various renal and extrarenal manifestations, including increased risk of kidney cancers. Here, we present the initial molecular description of sarcomatoid renal cell carcinoma (sRCC) arising in the setting of ADPKD.

Methods

Multiregion whole‐exome sequencing and whole transcriptomic sequencing were used to examine intratumoral molecular heterogeneity among histologically‐distinct spindle (sarcomatoid), epithelioid, or biphasic compartments within the tumor and compared with the non‐malignant ADPKD component.

Results

Spindle and biphasic components harbored several overlapping driver gene mutations, but do not share any with the epithelioid component. Mutations in ATM, CTNNB1, and NF2 were present only in the biphasic and spindle components, while mutations in BID, FLT3, ARID1B, and SMARCA2 were present only in the epithelioid component. We observed dichotomous evolutionary pathways in the development of epithelioid and spindle compartments, involving early mutations in TP53 and ATM/CTNNB1/NF2 respectively. Wnt, PI3K‐mTOR, and MAPK signaling pathways, known key mechanisms involved in ADPKD development, featured prominently in the sarcomatoid component.

Conclusion

This highlights that common pro‐oncogenic signals are present between ADPKD and sRCC providing insights into their shared pathobiology.

Patient Characteristics and Survival Outcomes of Non-Metastatic, Non-Clear Cell Renal Cell Carcinoma

Background

Non-clear cell renal cell carcinoma (ccRCC) includes histologically and molecularly distinct subtypes such as papillary, chromophobe, collecting duct, and sarcomatoid RCC, with an incidence ranging from 20% to 25%. Oncologic outcomes and the role of adjuvant systemic therapy [vascular endothelial growth factor inhibitor (VEGFi) or immunotherapy] for non-ccRCC are not well-described.

Objective

To assess the incidence and survival outcomes of non-ccRCC subtypes in comparison to ccRCC.

Methods

The National Cancer Database was utilized to identify patients with non-metastatic RCC (T1–T4, N0–N1) between 2004 and 2015. The non-ccRCC cohort was further stratified by histologic subtype: papillary, chromophobe, sarcomatoid, and collecting duct RCC. Multivariable Cox regression models were used to compare overall survival (OS).

Results

The 5-year OS for chromophobe, papillary, clear cell, collecting duct, and sarcomatoid RCC was 91%, 82%, 81%, 44%, and 40%, respectively. After adjusting for clinicopathologic and treatment characteristics, there was no significant difference in OS between papillary RCC and ccRCC (p = 0.17). Patients with collecting duct and sarcomatoid subtypes were at over two times increased risk of death compared to patients with clear cell (p < 0.01 and p < 0.01, respectively). Conversely, patients with chromophobe RCC were at 36% decreased risk of death compared to ccRCC (p < 0.01).

Conclusions

This hospital-based analysis confirms that collecting duct and sarcomatoid histologic subtypes are uncommon and associated with poor survival after surgery when compared to the other RCC subtypes. Further studies are needed to evaluate the role of neoadjuvant and adjuvant systemic therapies in these subtypes to improve oncologic outcomes.

Sarcomatoid Renal Cell Carcinoma: The Present and Future of Treatment Paradigms

Sarcomatoid renal cell carcinoma (sRCC) is an aggressive form of kidney cancer that is associated with poor prognosis. It can arise from any histologic type of renal cell carcinoma. The majority of cases will present with advanced or metastatic disease requiring systemic therapy. Nephrectomy is the treatment of choice in locally resectable disease. The therapeutic options for sRCC have evolved in the past decade. Cytotoxic chemotherapy and monotherapy with targeted therapy (VEGF and mTOR) have historically shown poor response rates and survival in the treatment of metastatic sRCC. The use of checkpoint inhibitors and their combination with targeted therapy against VEGF has changed the landscape and outcomes for renal cell carcinoma. Given the rarity of sRCC most of the data on treatment is from small cohorts or extrapolation from larger clinical trials. The benefit from the combination of checkpoint inhibitors and targeted therapy to VEGF has shown promise in the sRCC population in post hoc analysis of large clinical trials. Future research focusing on further characterizing the unique biologic and clinical features of sRCC is critical in advancing the knowledge and developing effective therapy to improve clinical outcomes and survival.

Undifferentiated and dedifferentiated urological carcinomas: lessons learned from the recent developments

Loss of the morphological and immunophenotypic characteristics of a neoplasm is a well-known phenomenon in surgical pathology and occurs across different tumor types in almost all organs. This process may be either partial, characterized by transition from well differentiated to undifferentiated tumor component (=dedifferentiated carcinomas) or complete (=undifferentiated carcinomas). Diagnosis of undifferentiated carcinoma is significantly influenced by the extent of sampling. Although the concept of undifferentiated and dedifferentiated carcinoma has been well established for other organs (e.g. endometrium), it still has not been fully defined for urological carcinomas. Accordingly, undifferentiated/ dedifferentiated genitourinary carcinomas are typically lumped into the spectrum of poorly differentiated, sarcomatoid, or unclassified (NOS) carcinomas. In the kidney, dedifferentiation occurs across all subtypes of renal cell carcinoma (RCC), but certain genetically defined RCC types (SDH-, FH- and PBRM1- deficient RCC) seem to have inherent tendency to dedifferentiate. Histologically, the undifferentiated component displays variable combination of four patterns: spindle cells, pleomorphic giant cells, rhabdoid cells, and undifferentiated monomorphic cells with/without prominent osteoclastic giant cells. Any of these may occasionally be associated with heterologous mesenchymal component/s. Their immunophenotype is often simple with expression of vimentin and variably pankeratin or EMA. Precise subtyping of undifferentiated (urothelial versus RCC and the exact underlying RCC subtype) is best done by thorough sampling supplemented as necessary by immunohistochemistry (e.g. FH, SDHB, ALK) and/ or molecular studies. This review discusses the morphological and molecular genetic spectrum and the recent develoments on the topic of dedifferentiated and undifferentiated genitourinary carcinomas.

PD-1/PD-L1 inhibitors-based treatment for advanced renal cell carcinoma: Mechanisms affecting efficacy and combination therapies

With the widespread use of PD-1/PD-L1 monoclonal antibodies (mAbs) in the treatment of multiple malignant tumors, they were also gradually applied to advanced renal cell carcinoma (aRCC). Nowadays, multiple PD-1/PD-L1 mAbs, such as nivolumab, avelumab, and pembrolizumab, have achieved considerable efficacy in clinical trials. However, due to the primary, adaptive, and acquired resistance to these mAbs, the efficacy of this immunotherapy is not satisfactory. Theories also vary as to why the difference in efficacy occurs. The alterations of PD-L1 expression and the interference of cellular immunity may affect the efficacy. These mechanisms demand to be revealed to achieve a sustained and complete objective response in patients with aRCC. Tyrosine kinase inhibitors have been proven to have synergistic mechanisms with PD-1/PD-L1 mAb in the treatment of aRCC, and CTLA-4 mAb has been shown to have a non-redundant effect with PD-1/PD-L1 mAb to enhance efficacy. Although combinations with targeted agents or other checkpoint mAbs have yielded enhanced clinical outcomes in multiple clinical trials nowadays, the potential of PD-1/PD-L1 mAbs still has a large development space. More potential mechanisms that affect the efficacy demand to be developed and transformed into the clinical treatment of aRCC to search for possible combination regimens. We elucidate these mechanisms in RCC and present existing combination therapies applied in clinical trials. This may help physicians' select treatment options for patients with refractory kidney cancer.

Sarcomatoid hepatocellular carcinoma: From clinical features to cancer genome

Background

Sarcomatoid hepatocellular carcinoma (HCC) is a rare and highly lethal histological subtype of HCC, with completely unknown genetic etiology and therapeutic targets.

Methods

We included 16 patients with sarcomatoid HCC receiving radical resection among 6731 cases of pathological confirmed HCC in year 2008 to 2018 in our hospital. We compared the clinical features, prognosis and cancer genome between 15 sarcomatoid HCC and propensity score‐matched 75 non‐sarcomatoid HCC patients. The other concurrent case was analyzed using phylogenetic tree to assess the tumor heterogeneity and evolution.

Results

Sarcomatoid HCC group showed larger tumor size, more advanced differentiation grade, lower tumor free survival (p = 0.038) and overall survival (p = 0.001), and sarcomatoid type was an independent risk factor for patient death. Integrating sarcomatoid subtype into AJCC staging could increase the diagnostic curve in predicting patient survival. The cancer genome spectrum showed sarcomatoid HCC group had significant higher mutation rates in CDKN2A, EPHA5, FANCM and MAP3K1. Mutations in CDKN2A significantly reduced tumor‐free and overall survival in sarcomatoid HCC patients. Moreover, 46.6% sarcomatoid HCC patients had druggable mutations in cell cycle pathway genes, which were targeted by Abemaciclib, et al. We also found sarcomatoid and non‐sarcomatoid lesions might originate from a common progenitor but progress differently.

Conclusion

Our cancer genome analysis showed a specific genomic profile of sarcomatoid HCC, which were characterized by a high mutation rate in cell cycle genes particularly CDKN2A. The results indicate CDK4/6 inhibitors including abemaciclib, ribociclib and palbociclib as potential therapeutic targets and may help for therapeutic decision making.

New developments in existing WHO entities and evolving molecular concepts: The Genitourinary Pathology Society (GUPS) update on renal neoplasia

The Genitourinary Pathology Society (GUPS) reviewed recent advances in renal neoplasia, particularly post-2016 World Health Organization (WHO) classification, to provide an update on existing entities, including diagnostic criteria, molecular correlates, and updated nomenclature. Key prognostic features for clear cell renal cell carcinoma (RCC) remain WHO/ISUP grade, AJCC/pTNM stage, coagulative necrosis, and rhabdoid and sarcomatoid differentiation. Accrual of subclonal genetic alterations in clear cell RCC including SETD2, PBRM1, BAP1, loss of chromosome 14q and 9p are associated with variable prognosis, patterns of metastasis, and vulnerability to therapies. Recent National Comprehensive Cancer Network (NCCN) guidelines increasingly adopt immunotherapeutic agents in advanced RCC, including RCC with rhabdoid and sarcomatoid changes. Papillary RCC subtyping is no longer recommended, as WHO/ISUP grade and tumor architecture better predict outcome. New papillary RCC variants/patterns include biphasic, solid, Warthin-like, and papillary renal neoplasm with reverse polarity. For tumors with 'borderline' features between oncocytoma and chromophobe RCC, a term "oncocytic renal neoplasm of low malignant potential, not further classified" is proposed. Clear cell papillary RCC may warrant reclassification as a tumor of low malignant potential. Tubulocystic RCC should only be diagnosed when morphologically pure. MiTF family translocation RCCs exhibit varied morphologic patterns and fusion partners. TFEB-amplified RCC occurs in older patients and is associated with more aggressive behavior. Acquired cystic disease (ACD) RCC-like cysts are likely precursors of ACD-RCC. The diagnosis of renal medullary carcinoma requires a negative SMARCB1 (INI-1) expression and sickle cell trait/disease. Mucinous tubular and spindle cell carcinoma (MTSCC) can be distinguished from papillary RCC with overlapping morphology by losses of chromosomes 1, 4, 6, 8, 9, 13, 14, 15, and 22. MTSCC with adverse histologic features shows frequent CDKN2A/2B (9p) deletions. BRAF mutations unify the metanephric family of tumors. The term "fumarate hydratase deficient RCC" ("FH-deficient RCC") is preferred over "hereditary leiomyomatosis and RCC syndrome-associated RCC". A low threshold for FH, 2SC, and SDHB immunohistochemistry is recommended in difficult to classify RCCs, particularly those with eosinophilic morphology, occurring in younger patients. Current evidence does not support existence of a unique tumor subtype occurring after chemotherapy/radiation in early childhood.

A challenging frontier - the genomics and therapeutics of nonclear cell renal cell carcinoma

PURPOSE OF REVIEW

As molecular profiling of renal cell carcinoma (RCC) continues to elucidate novel targets for nonclear cell histologies, understanding the landscape of these targets is of utmost importance. In this review, we highlight the genomic landscape of nonclear cell RCC and its implications for current and future systemic therapies.

RECENT FINDINGS

Several genomic studies have described the mutational burden among nonclear cell histologies. These studies have highlighted the importance of MET in papillary RCC and led to several clinical trials evaluating the efficacy of MET inhibitors for papillary RCC. The success of immune checkpoint inhibitors, such as ipilimumab and nivolumab, in clear cell RCC has led to ongoing trials evaluating these novel therapeutics in nonclear cell RCC.

SUMMARY

Genomic profiling has allowed for the evaluation of novel targets for nonclear cell RCC. This evolving therapeutic landscape is being explored in promising, ongoing trials that have the potential for changing how nonclear cell RCC is managed.

Clear cell renal cell carcinoma ontogeny and mechanisms of lethality

The molecular features that define clear cell renal cell carcinoma (ccRCC) initiation and progression are being increasingly defined. The TRACERx Renal studies and others that have described the interaction between tumour genomics and remodelling of the tumour microenvironment provide important new insights into the molecular drivers underlying ccRCC ontogeny and progression. Our understanding of common genomic and chromosomal copy number abnormalities in ccRCC, including chromosome 3p loss, provides a mechanistic framework with which to organize these abnormalities into those that drive tumour initiation events, those that drive tumour progression and those that confer lethality. Truncal mutations in ccRCC, including those in VHL, SET2, PBRM1 and BAP1, may engender genomic instability and promote defects in DNA repair pathways. The molecular features that arise from these defects enable categorization of ccRCC into clinically and therapeutically relevant subtypes. Consideration of the interaction of these subtypes with the tumour microenvironment reveals that specific mutations seem to modulate immune cell populations in ccRCC tumours. These findings present opportunities for disease prevention, early detection, prognostication and treatment.

Dissecting Outcomes: Should Cytoreductive Nephrectomy Be Performed for Patients With Metastatic Renal Cell Carcinoma With Sarcomatoid Dedifferentiation?

Background

It is highly contested whether cytoreductive nephrectomy for treating advanced renal cell carcinoma (RCC) with sarcomatoid features (sRCC) benefits overall survival. Patients with sRCC are known to have a poor prognosis, and these tumors have a more aggressive biology than those without sarcomatoid features.

Methods

Patients with clear cell RCC or non–clear cell RCC underwent cytoreductive nephrectomy in efforts to improve overall survival (OS). Patients were stratified by presence or absence of histologic sarcomatoid features within tumor samples.

Results

Of 167 patients who underwent cytoreductive nephrectomy, 127 had clear cell RCC, of whom 14 had sarcomatoid features, and 40 had non–clear cell RCC, of whom 13 had sarcomatoid features. Median age of the cohort was 62 years (range, 56.5–69 years). The cohort included 119 male (71.3%) and 48 (28.7%) female patients. Among all patients with advanced RCC, having sRCC had a significantly worse OS after cytoreductive nephrectomy (30 vs 8 months; hazard ratio [HR], 2.88; P <0.0001). Additionally, favorable-risk patients had significantly longer OS compared to intermediate- or poor-risk patients (56 vs 30 vs 10 months; HR, 0.21; P =0.00016). For patients with clear cell RCC, having sRCC conferred a significantly poorer survival (30 vs 9 months; HR, 2.82; P=0.0035). Patients with non–clear cell sRCC also had significantly worse outcomes compared to patients whose tumors did not have sarcomatoid features (30 vs 6.5 months; HR, 3; P =0.009). When patients with sRCC were stratified by whether there was >10% or ≤10% sarcomatoid features present within the sample, there was no significant difference in OS (8 vs 8.5 months; P =0.32).

Conclusions

Sarcomatoid features within tumor histology confer significantly poor prognosis. Patients with sRCC, regardless of clear cell vs non–clear cell histology, have significantly shorter OS. Even among patients with 10% or less sarcomatoid features, there was no OS benefit to cytoreductive nephrectomy. Based on our findings, there appears to be a limited to no role of cytoreductive nephrectomy if sRCC is identified on pretreatment biopsy. The role of radiomics and pre-operative biopsies may confer significant benefit in this patient population.

Integrative molecular characterization of sarcomatoid and rhabdoid renal cell carcinoma

Sarcomatoid and rhabdoid (S/R) renal cell carcinoma (RCC) are highly aggressive tumors with limited molecular and clinical characterization. Emerging evidence suggests immune checkpoint inhibitors (ICI) are particularly effective for these tumors, although the biological basis for this property is largely unknown. Here, we evaluate multiple clinical trial and real-world cohorts of S/R RCC to characterize their molecular features, clinical outcomes, and immunologic characteristics. We find that S/R RCC tumors harbor distinctive molecular features that may account for their aggressive behavior, including BAP1 mutations, CDKN2A deletions, and increased expression of MYC transcriptional programs. We show that these tumors are highly responsive to ICI and that they exhibit an immune-inflamed phenotype characterized by immune activation, increased cytotoxic immune infiltration, upregulation of antigen presentation machinery genes, and PD-L1 expression. Our findings build on prior work and shed light on the molecular drivers of aggressivity and responsiveness to ICI of S/R RCC.

Sarcomatoid and rhabdoid tumours are highly aggressive forms of renal cell carcinoma that are also responsive to immunotherapy. In this study, the authors perform a comprehensive molecular characterization of these tumours discovering an enrichment of specific alterations and an inflamed phenotype.

Landscape of Immunotherapy in Genitourinary Malignancies

The past decade has witnessed a revolution in the development of immune checkpoint inhibitors for the treatment of multiple tumor types, including genitourinary cancers. Immune checkpoint inhibitors have notably improved the treatment outcomes of patients with metastatic renal cell carcinoma and metastatic urothelial carcinoma. In prostate cancer, the role of immunotherapy with checkpoint inhibitors is not yet established except for microsatellite instability high (MSI-H) tumors. Other immunotherapeutic approaches that have been explored in these malignancies include cytokines, vaccines, and cellular therapy. Ongoing studies are exploring the use of immunotherapy combinations as well as combination with chemotherapy and targeted therapy in these types of tumors. The use of immunotherapy beyond the metastatic setting is an active area of research. Moreover, there is great interest in biomarker development to predict response to immunotherapy and risk of toxicity. This book chapter is a comprehensive review of immunotherapeutic approaches, both approved and investigational, for the treatment of renal cell carcinoma, urothelial carcinoma, and prostate cancer.

Prognostic Significance of Sarcomatoid Differentiation in Patients With Metastatic Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

Background

To date, the prognostic value of sarcomatoid differentiation in patients having metastatic renal cell carcinoma (mRCC) remains inconclusive. A systematic review and meta-analysis were conducted.

Materials and Methods

Relevant literatures were obtained from PubMed, Embase, and Cochrane Library published prior to May, 2020. All patients were diagnosed with mRCC and treated with surgery, cytokine therapy, targeted therapy, and immunotherapy. Sarcomatoid differentiation in the pathological specimens was identified. Each endpoint [overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS)] was assessed using a multivariable adjusted hazard ratio (HR) and 95% confidence interval (CI).

Results

Fifteen observational studies having 5,828 patients with mRCC were included. The merged results showed that patients presenting sarcomatoid differentiation had a significantly inferior OS (HR: 2.26, 95% CI: 1.82-2.81; P < 0.001), PFS (HR: 2.28, 95% CI: 1.63-3.19; P < 0.001), and CSS (HR: 2.27, 95% CI: 1.51-3.40; P < 0.001) compared to those without sarcomatoid differentiation. Subgroup analysis based on publication year, patient population, country, number of cases, and NOS score did not change the direction of results. A significant publication bias was identified for OS, but no publication bias was identified for PFS. Moreover, sensitivity analysis also verified the robustness of the results.

Conclusion

This study suggested that sarcomatoid differentiation was correlated to unfavorable clinical outcomes in mRCC and may be a poor prognostic factor incorporating to prognostic models for mRCC patients.

Sarcomatoid renal cell carcinoma: biology, natural history and management

Sarcomatoid dedifferentiation is an uncommon feature that can occur in most histological subtypes of renal cell carcinomas (RCCs) and carries a decidedly poor prognosis. Historically, conventional treatments for sarcomatoid RCCs (sRCCs) have shown little efficacy, and median survival is commonly 6–13 months. Despite being first described in 1968, the mechanisms driving sarcomatoid dedifferentiation remain poorly understood, and information and treatment options available to physicians and patients are limited. When diagnosed at an early stage, surgical intervention remains the treatment of choice. However, preoperative identification through routine imaging or biopsy is unreliable and most patients present with advanced disease and systemic symptoms. For these patients, the role of cytoreductive nephrectomy is disputed. The expansion of immunotherapies approved for RCCs has generated a search for biomarkers that might be indicative of treatment response in sRCCs, although a proven effective systemic agent remains elusive. PDL1 expression is increased in sarcomatoid dedifferentiated renal tumours, which suggests that patients with sRCCs could benefit from PD1 and/or PDL1 immune checkpoint blockade therapy. Treatment outcomes for sarcomatoid tumours have remained relatively consistent compared with other RCCs, but further investigation of the tumour–immune cell microenvironment might yield insights into further therapeutic possibilities.

In this Review, Blum et al. summarize the current knowledge on sarcomatoid renal cell carcinoma, a diagnosis characterized by the presence of sarcomatoid dedifferentiation and a poor prognosis. They discuss the origin, presentation, molecular biology and treatment of this disease.

Sarcomatoid dedifferentiation is not considered to be a unique histological subtype of renal cell carcinomas (RCCs); rather, it can be present within any subtype of RCCs.

Sarcomatoid dedifferentiation appears in ~4% of all RCCs, but is present in ~20% of all metastatic RCCs. According to WHO guidelines, any RCC with sarcomatoid dedifferentiation is a WHO–International Society of Urological Pathology grade 4 lesion.

Sarcomatoid dedifferentiation is often heterogeneously present within RCCs, making routine imaging and biopsy unreliable for preoperative detection. Surgical resection for localized disease is the standard of care, with subsequent close monitoring of patients following surgery.

In patients with metastatic disease, conventional therapies such as surgery and systemic agents have been ineffective and overall 5-year survival remains at 23.5–33%.

Previous genomic analyses have failed to identify definitive mutational drivers of disease. However, sarcomatoid RCCs (sRCCs) have been shown to have higher PD1 and PDL1 expression than other subtypes of RCCs. Newer combinations of immune checkpoint inhibitor immunotherapies could yield improved responses and outcomes.

Studies investigating sRCCs are limited by patient numbers owing to the low incidence of sRCCs and their advanced stage at presentation. Multi-institutional efforts to establish a consensus on treatment recommendations based on highly powered data are essential.

Genetic Alterations in Renal Cancers: Identification of The Mechanisms Underlying Cancer Initiation and Progression and of Therapeutic Targets

Renal cell cancer (RCC) involves three most recurrent sporadic types: clear-cell RCC (70-75%, CCRCC), papillary RCCC (10-15%, PRCC), and chromophobe RCC (5%, CHRCC). Hereditary cases account for about 5% of all cases of RCC and are caused by germline pathogenic variants. Herein, we review how a better understanding of the molecular biology of RCCs has driven the inception of new diagnostic and therapeutic approaches. Genomic research has identified relevant genetic alterations associated with each RCC subtype. Molecular studies have clearly shown that CCRCC is universally initiated by Von Hippel Lindau (VHL) gene dysregulation, followed by different types of additional genetic events involving epigenetic regulatory genes, dictating disease progression, aggressiveness, and differential response to treatments. The understanding of the molecular mechanisms that underlie the development and progression of RCC has considerably expanded treatment options; genomic data might guide treatment options by enabling patients to be matched with therapeutics that specifically target the genetic alterations present in their tumors. These new targeted treatments have led to a moderate improvement of the survival of metastatic RCC patients. Ongoing studies based on the combination of immunotherapeutic agents (immune check inhibitors) with VEGF inhibitors are expected to further improve the survival of these patients.

Patients with sarcomatoid renal cell carcinoma - re-defining the first-line of treatment: A meta-analysis of randomised clinical trials with immune checkpoint inhibitors

BACKGROUND

Sarcomatoid renal cell carcinoma (sRCC) represents a rare form of renal cell carcinoma marked by an aggressive biology, poor prognosis and little benefit from anti-angiogenic targeted therapy. More promising results come from the recent therapeutic strategy based on immune checkpoint inhibitor (ICI) combinations.

MATERIALS AND METHODS

For this meta-analysis, we searched MEDLINE/PubMed, the Cochrane Library and American Society of Medical Oncology (ASCO) Meeting abstracts for phase II or III randomised clinical trials. Data extraction was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. The hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS) with the relative 95% confidence intervals were extracted from studies. Summary HRs were calculated using random- or fixed-effects models, depending on the heterogeneity of the included studies.

RESULTS

Four studies were selected for final analysis, including 467 patients (226 treated in with ICI combinations and 241 received sunitinib in the control arms). ICI-based combinations were associated with an improved PFS and OS compared with sunitinib, with a reduction of more than 40% of progression (HR = 0.56; p < 0.0001) and mortality (HR = 0.56; p = 0.001) risk. Moreover, ICI-based combinations are associated with a objective response rate (ORR) of more than 50% (versus 20% with sunitinib), corresponding to a doubled risk of achieving an ORR compared with controls (relative risk [RR] = 2.15; p < 0.00001). Finally, immunotherapy significantly increased the possibility to obtain complete responses (RR = 8.15, p = 0.0002) with an incidence of 11%.

CONCLUSION

Our data support the efficacy of ICI-based combinations for sRCC therapy, redefining the first-line treatment.

GYS1 induces glycogen accumulation and promotes tumor progression via the NF-κB pathway in Clear Cell Renal Carcinoma

Metabolism reprogramming is a hallmark of many cancer types. We focused on clear cell renal carcinoma (ccRCC) which is characterized by its clear and glycogen-enriched cytoplasm with unknown reasons. The aim of this study was to identify the clinical significance, biological function, and molecular regulation of glycogen synthase 1 (GYS1) in ccRCC glycogen accumulation and tumor progression. Methods: We determined the clinical relevance of GYS1 and glycogen in ccRCC by immunohistochemistry and periodic acid-schiff staining in fresh tissue and by tissue micro-array. Metabolic profiling with GYS1 depletion was performed by metabolomics analysis. In vitro and xenograft mouse models were used to evaluate the impact of GYS1 on cell proliferation. High-throughput RNA-Seq analyses and co-immunoprecipitation-linked mass spectrometry were used to investigate the downstream targets of GYS1. Flow cytometry and CCK8 assays were performed to determine the effect of GYS1 and sunitinib on cell viability. Results: We observed that GYS1 was significantly overexpressed and glycogen was accumulated in ccRCC tissues. These effects were correlated with unfavorable patient survival. Silencing of GYS1 induced metabolomic perturbation manifested by a carbohydrate metabolism shift. Overexpression of GYS1 promoted tumor growth whereas its silencing suppressed it by activating the canonical NF-κB pathway. The indirect interaction between GYS1 and NF-κB was intermediated by RPS27A, which facilitated the phosphorylation and nuclear import of p65. Moreover, silencing of GYS1 increased the synthetic lethality of ccRCC cells to sunitinib treatment by concomitantly suppressing p65. Conclusions: Our study findings reveal an oncogenic role for GYS1 in cell proliferation and glycogen metabolism in ccRCC. Re-sensitization of ccRCC cells to sunitinib suggests that GYS1 is a useful indicator of unfavorable prognosis as well as a therapeutic target for patients with ccRCC.

Facing treatment of non-urothelial bladder cancers in the immunotherapy era

Non-urothelial Bladder Cancer (BC) and variants of urothelial carcinoma account for up to 25 % of all BCs. Given their heterogeneity, these entities are not well represented in clinical trials and treatment remains challenging. Checkpoint inhibitor therapy has shown a role in the treatment of urothelial BC. By contrast, robust evidence regarding its use in other histological types is lacking. We aimed to provide a comprehensive update of non-urothelial and variant urothelial BC, exploring the evidence for immune checkpoint inhibitor therapy. A detailed analysis of the literature was conducted regarding epidemiology, aetiology, diagnosis, prognosis, treatment and outcomes of these patients in the immunotherapy era. A growing body of evidence suggests that immune checkpoint inhibition might have a role to play in non-urothelial BC, similarly to what happened with urothelial carcinomas.

Genomic profiling in renal cell carcinoma

The treatment landscape of metastatic renal cell carcinoma (RCC) has been revolutionized over the past two decades, bringing forth an era in which more than a dozen therapeutic agents are now available to treat patients. As a consequence, personalized care has become a critical part of developing effective treatment guidelines and improving patient outcomes. One of the most important emerging aspects of precision medicine in cancer is matching patients and treatments based on the genomic characteristics of an individual and their tumour. Despite the lack of a single genomic predictor of treatment response or prognostication feature in RCC, emerging research suggests that the identification of such markers remains promising. Mutations in VHL and alterations in its downstream pathways are the mainstay of RCC development and progression. However, the predictive value of VHL mutations has been questioned. Further research has examined mutations in genes involved in chromosome remodelling (for example, PBRM1, BAP1 and SETD2), DNA methylation and DNA damage repair, all of which have been associated with clinical outcomes. Here, we provide a comprehensive overview of genomic evidence in the context of RCC and its potential predictive and prognostic value.

Epidemiology, Risk Assessment, and Biomarkers for Patients with Advanced Renal Cell Carcinoma

In the preceding two decades, several milestones have been reached in the management of patients with metastatic renal cell carcinoma (mRCC), including the development of novel targeted agents paralleling an increased understanding of the molecular biology of this disease process. Recently, a renewed enthusiasm for immunotherapy in the form of immune checkpoint blockade has resulted in significant strides in the treatment of mRCC. Despite these advances, treatment remains challenging for clinicians, and only modest survival benefits are observed with current treatment paradigms. The risk-stratification tools and investigated predictive and prognostic biomarkers in patients with mRCC are detailed in this review.

Interplay of somatic alterations and immune infiltration modulates response to PD-1 blockade in advanced clear cell renal cell carcinoma

PD-1 blockade has transformed the management of advanced clear cell renal cell carcinoma (ccRCC), but the drivers and resistors of the PD-1 response remain incompletely elucidated. Here, we analyzed 592 tumors from patients with advanced ccRCC enrolled in prospective clinical trials of treatment with PD-1 blockade by whole-exome and RNA sequencing, integrated with immunofluorescence analysis, to uncover the immunogenomic determinants of the therapeutic response. Although conventional genomic markers (such as tumor mutation burden and neoantigen load) and the degree of CD8⁺ T cell infiltration were not associated with clinical response, we discovered numerous chromosomal alterations associated with response or resistance to PD-1 blockade. These advanced ccRCC tumors were highly CD8⁺ T cell infiltrated, with only 27% having a non-infiltrated phenotype. Our analysis revealed that infiltrated tumors are depleted of favorable PBRM1 mutations and enriched for unfavorable chromosomal losses of 9p21.3, as compared with non-infiltrated tumors, demonstrating how the potential interplay of immunophenotypes with somatic alterations impacts therapeutic efficacy.

Recurrent metastatic clear cell renal carcinoma with sarcomatoid dedifferentiation treated with surgery and Cabozantinib

Renal cell carcinoma with sarcomatoid dedifferentiation is an entity of RCC that has undergone an anaplastic transformation with both a carcinomatous and a sarcomatous component. The standard treatment in metastatic patients is immunotherapy.

The aim of this article is to describe our case of metastatic recurrent RCC with sarcomatoid dedifferentiation in a 59 year old male patient treated with nephrectomy and multiple metastasectomies followed by Cabozantinib.

Consecutive PET-CT scans showed no evidence of recurrence, three years after the last metastasectomy, and the patient is having currently a normal life.

Sarcomatoid dedifferentiation remains a poor prognosis factor in RCC. Surgery for metastases followed by Cabozantinib may be a therapeutic option in metastatic young patients. However, a prospective randomized trial would be the best option to validate this approach.

Immunotherapy in Renal Cell Carcinoma: The Future Is Now

Renal cell carcinoma is the third type of urologic cancer and has a poor prognosis with 30% of metastatic patients at diagnosis. The antiangiogenics and targeted immunotherapies led to treatment remodeling emphasizing the role of the tumour microenvironment. However, long-term responses are rare with a high rate of resistance. New strategies are emerging to improve the efficacy and the emerging drugs are under evaluation in ongoing trials. With the different treatment options, there is an urgent need to identify biomarkers in order to predict the efficacy of drugs and to better stratify patients. Owing to the limitations of programmed death-ligand 1 (PD-L1), the most studied immunohistochemistry biomarkers, and of the tumor mutational burden, the identification of more reliable markers is an unmet need. New technologies could help in this purpose.

Evolving treatment paradigm in metastatic non clear cell renal cell carcinoma

The treatment landscape for renal cell cancer (RCC) has evolved tremendously over the last two decades. Treatment algorithms have shifted from the highly toxic drugs with marginal benefit to better tolerated and more effective targeted therapy drugs. The latter include tyrosine kinase inhibitors, vascular endothelial growth factor inhibitors, MET inhibitors and, more recently, immunotherapy drugs alone and in various combinations. The majority of treatment algorithms for non-clear cell carcinoma have been based on extrapolating results from clear cell RCC trials and retrospective reviews. However, now that we understand that non-clear cell RCC is morphologically and clinically distinct from its clear cell counterpart, several collaborative clinical trials are underway for non-clear cell RCC. This review will delve into the historical aspects of treating non-clear cell RCC and the evolution of treatment paradigms over the last few decades with a focus on immunotherapy based trials.

Involvement of the TNF-α Pathway in TKI Resistance and Suggestion of TNFR1 as a Predictive Biomarker for TKI Responsiveness in Clear Cell Renal Cell Carcinoma

BACKGROUND

Mechanism and predictive biomarkers for tyrosine kinase inhibitor (TKI) resistance of advanced clear cell renal cell carcinoma (ccRCC) have not been fully evaluated.

METHODS

We performed gene expression profiling on samples from an acquired TKI resistance cohort that consisted of 10 cases of TKI-treated ccRCC patients with matched tumor tissues harvested at pre-treatment and TKI-resistant post-treatment periods. In addition, a public microarray dataset from patient-derived xenograft model for TKI-treated ccRCC (GSE76068) was retrieved. Commonly altered pathways between the datasets were investigated by Ingenuity Pathway Analysis using commonly regulated differently expressed genes (DEGs). The significance of candidate DEG on intrinsic TKI resistance was assessed through immunohistochemistry in a separate cohort of 101 TKI-treated ccRCC cases.

RESULTS

TNFRSF1A gene expression and tumor necrosis factor (TNF)-α pathway were upregulated in ccRCCs with acquired TKI resistance in both microarray datasets. Also, high expression (> 10% of labeled tumor cells) of TNF receptor 1 (TNFR1), the protein product of TNFRSF1A gene, was correlated with sarcomatoid dedifferentiation and was an independent predictive factor of clinically unfavorable response and shorter survivals in separated TKI-treated ccRCC cohort.

CONCLUSION

TNF-α signaling may play a role in TKI resistance, and TNFR1 expression may serve as a predictive biomarker for clinically unfavorable TKI responses in ccRCC.

Molecular characterization of sarcomatoid clear cell renal cell carcinoma unveils new candidate oncogenic drivers

Sarcomatoid clear-cell renal cell carcinomas (sRCC) are associated with dismal prognosis. Genomic alterations associated with sarcomatoid dedifferentiation are poorly characterized. We sought to define the genomic landscape of sRCC and uncover potentially actionable therapeutic targets. We assessed the genomic landscape of sRCC using targeted panel sequencing including patients with microdissected sarcomatoid and epithelial components. Along with common genomic alterations associated with clear-cell histology, we found that Hippo was one of the most frequently altered pathways in these tumours. Hippo alterations were differentially enriched in sRCC compared to non-sRCC. Functional analysis showed that Hippo members mutations were associated with higher nuclear accumulation of YAP/TAZ, core effectors of the Hippo pathway. In a NF2-mutant sRCC model, YAP1 knockdown and NF2 reconstitution suppressed cell proliferation, tumour growth and invasion, both in vitro and in vivo. Overall, we show that Hippo pathway alterations are a feature of sRCC, and enable the exploration of the Hippo pathway as a novel potential therapeutic target.

Plasma Circulating Tumor DNA and Clonal Hematopoiesis in Metastatic Renal Cell Carcinoma

BACKGROUND

There is a lack of molecularly-informed biomarkers for patients with metastatic renal cell carcinoma (RCC). Plasma cell-free DNA (cfDNA) sequencing is a minimally-invasive alternative to tissue for profiling the genome in other cancers but relevance in metastatic RCC remains unclear.

MATERIALS AND METHODS

Whole blood was collected from 55 patients with metastatic RCC. Plasma cfDNA and leukocyte DNA were subjected to targeted sequencing across 981 cancer genes. Matched tumor tissue from 14 patients was analyzed.

RESULTS

Thirty-three percent of patients had evidence for RCC-derived circulating tumor DNA (ctDNA), significantly lower than patients with metastatic prostate or bladder cancer analyzed using the same approach. Among ctDNA-positive patients, ctDNA fraction averaged only 3.9% and showed no strong association with clinical variables. In these patients, the most commonly mutated genes were VHL, BAP1, and PBRM1, and matched tissue concordance was 77%. Evidence of somatic expansions unrelated to RCC, such as clonal hematopoiesis of indeterminate potential, were detected in 43% of patients. Pathogenic germline mutations in DNA repair genes were detected in 11% of patients. CtDNA-positive patients had shorter overall survival and progression-free survival on first-line therapy. Patients with evidence of clonal hematopoiesis of indeterminate potential had an intermediate prognosis compared with ctDNA-positive and -negative patients.

CONCLUSIONS

CfDNA sequencing enables straightforward characterization of the somatic RCC genome in a minority of patients with metastatic RCC. Owing to low ctDNA abundance, and the presence of non-RCC derived somatic clones in circulation, cfDNA sequencing may not be a simple pan-patient alternative to tissue biopsy in metastatic RCC.

YAP/TAZ Inhibition Induces Metabolic and Signaling Rewiring Resulting in Targetable Vulnerabilities in NF2-Deficient Tumor Cells

Merlin/NF2 is a bona fide tumor suppressor whose mutations underlie inherited tumor syndrome neurofibromatosis type 2 (NF2), as well as various sporadic cancers including kidney cancer. Multiple Merlin/NF2 effector pathways including the Hippo-YAP/TAZ pathway have been identified. However, the molecular mechanisms underpinning the growth and survival of NF2-mutant tumors remain poorly understood. Using an inducible orthotopic kidney tumor model, we demonstrate that YAP/TAZ silencing is sufficient to induce regression of pre-established NF2-deficient tumors. Mechanistically, YAP/TAZ depletion diminishes glycolysis-dependent growth and increases mitochondrial respiration and reactive oxygen species (ROS) buildup, resulting in oxidative-stress-induced cell death when challenged by nutrient stress. Furthermore, we identify lysosome-mediated cAMP-PKA/EPAC-dependent activation of RAF-MEK-ERK signaling as a resistance mechanism to YAP/TAZ inhibition. Finally, unbiased analysis of TCGA primary kidney tumor transcriptomes confirms a positive correlation of a YAP/TAZ signature with glycolysis and inverse correlations with oxidative phosphorylation and lysosomal gene expression, supporting the clinical relevance of our findings.

Sarcomatoid Dedifferentiation in Renal Cell Carcinoma: From Novel Molecular Insights to New Clinical Opportunities

Sarcomatoid features in renal cell carcinoma (RCC) have long been associated with dismal prognosis and poor response to therapy, while biological mechanisms underpinning sarcomatoid dedifferentiation remained obscure. Several efforts have been conducted to break down the molecular profile of sarcomatoid RCC and investigate different targeted therapeutic approaches. Mutations enriched for in sarcomatoid RCC involve, notably, TP53, BAP1, cell cycle, and chromatin-remodeling genes. The immunological landscape of these tumors is also gradually being uncovered, showing frequent expression of programmed cell death ligand-1 (PD-L1) and high levels of tumor-infiltrating lymphocytes. These features may be major determinants for the activity of immune checkpoint inhibitors in this population, which has been confirmed by retrospective studies and subgroup analyses of large randomized phase 3 trials. Combinations based on PD-1/PD-L1 inhibition have demonstrated response rates and complete responses in >50% and >10% of patients in the first-line metastatic setting, respectively, with median overall survival exceeding two years. This remarkable improvement in outcomes effectively establishes immune checkpoint inhibitor combinations as a new standard of care in patients with sarcomatoid RCC. New research fields, including epigenetic regulations and tumor-microenvironment interactions, may further sharpen understanding of sarcomatoid RCC and advance therapeutic developments.

Prognostic and predictive molecular biomarkers in metastatic renal cell carcinoma patients treated with immune checkpoint inhibitors: a systematic review

Introduction: In recent years, the treatment landscape of metastatic renal cell carcinoma (mRCC) has been improved using immune-checkpoint inhibitors (ICI). Nevertheless, the number of patients experiencing clinical benefit from immunotherapy is still limited, while others obtain more benefit from tyrosine kinase inhibitors (TKI). The identification of prognostic and predictive factors would be crucial to better select patients most likely to benefit from immunotherapy among the other potentially available therapeutic options.Areas covered: This systematic review summarizes the current knowledge (2010-2019) on molecular prognostic and predictive biomarkers, assessed in peripheral blood and/or from tumor tissue, in mRCC patients treated with ICI.Expert opinion: Among all the biomarkers analyzed, PD-L1 expression on tumor tissue is the most studied. It has an unfavorable prognostic role for patients treated with TKI, which seems to be overcome by ICI-based combinations. Nevertheless, no clear predictive role of immunotherapy efficacy has been observed for PD-L1 in mRCC. Emerging evidence regarding pro-angiogenic or pro-immunogenic genomic and transcriptomic signatures suggests a potential predictive role in patients treated with ICI-based combinations. The rationale for TKI-ICI combinations is based on tumor microenvironment and genomic background, which represent the target of these two main therapeutic options for mRCC.

Epigenetic modifiers: activities in renal cell carcinoma

Renal cell carcinomas (RCCs) are a diverse set of malignancies that have recently been shown to harbour mutations in a number of chromatin modifier genes - including PBRM1, SETD2, BAP1, KDM5C, KDM6A, and MLL2 - through high-throughput sequencing efforts. Current research focuses on understanding the biological activities that chromatin modifiers employ to suppress tumorigenesis and on developing clinical approaches that take advantage of this knowledge. Unsurprisingly, several common themes unify the functions of these epigenetic modifiers, particularly regulation of histone post-translational modifications and nucleosome organization. Furthermore, chromatin modifiers also govern processes crucial for DNA repair and maintenance of genomic integrity as well as the regulation of splicing and other key processes. Many chromatin modifiers have additional non-canonical roles in cytoskeletal regulation, which further contribute to genomic stability, expanding the repertoire of functions that might be essential in tumorigenesis. Our understanding of how mutations in chromatin modifiers contribute to tumorigenesis in RCC is improving but remains an area of intense investigation. Importantly, elucidating the activities of chromatin modifiers offers intriguing opportunities for the development of new therapeutic interventions in RCC.