Clinical and pathological impact of VHL, PBRM1, BAP1, SETD2, KDM6A, and JARID1c in clear cell renal cell carcinoma

KDM6A-SND1 interaction maintains genomic stability by protecting the nascent DNA and contributes to cancer chemoresistance

Genomic instability is one of the hallmarks of cancer. While loss of histone demethylase KDM6A increases the risk of tumorigenesis, its specific role in maintaining genomic stability remains poorly understood. Here, we propose a mechanism in which KDM6A maintains genomic stability independently on its demethylase activity. This occurs through its interaction with SND1, resulting in the establishment of a protective chromatin state that prevents replication fork collapse by recruiting of RPA and Ku70 to nascent DNA strand. Notably, KDM6A-SND1 interaction is up-regulated by KDM6A SUMOylation, while KDM6AK90A mutation almost abolish the interaction. Loss of KDM6A or SND1 leads to increased enrichment of H3K9ac and H4K8ac but attenuates the enrichment of Ku70 and H3K4me3 at nascent DNA strand. This subsequently results in enhanced cellular sensitivity to genotoxins and genomic instability. Consistent with these findings, knockdown of KDM6A and SND1 in esophageal squamous cell carcinoma (ESCC) cells increases genotoxin sensitivity. Intriguingly, KDM6A H101D & P110S, N1156T and D1216N mutations identified in ESCC patients promote genotoxin resistance via increased SND1 association. Our finding provides novel insights into the pivotal role of KDM6A-SND1 in genomic stability and chemoresistance, implying that targeting KDM6A and/or its interaction with SND1 may be a promising strategy to overcome the chemoresistance.

Genomic Profiling and Molecular Characterization of Clear Cell Renal Cell Carcinoma

Clear cell renal cell carcinoma (ccRCC) treatment has undergone three major paradigm shifts in recent years, first with the introduction of molecular targeted therapies, then with immune checkpoint inhibitors, and, more recently, with immune-based combinations. However, to date, molecular predictors of response to targeted agents have not been identified for ccRCC. The WHO 2022 classification of renal neoplasms introduced the molecularly defined RCC class, which is a first step in the direction of a better molecular profiling of RCC. We reviewed the literature data on known genomic alterations of clinical interest in ccRCC, discussing their prognostic and predictive role. In particular, we explored the role of VHL, mTOR, chromatin modulators, DNA repair genes, cyclin-dependent kinases, and tumor mutation burden. RCC is a tumor whose pivotal genomic alterations have pleiotropic effects, and the interplay of these effects determines the tumor phenotype and its clinical behavior. Therefore, it is difficult to find a single genomic predictive factor, but it is more likely to identify a signature of gene alterations that could impact prognosis and response to specific treatment. To accomplish this task, the interpolation of large amounts of clinical and genomic data is needed. Nevertheless, genomic profiling has the potential to change real-world clinical practice settings.

RNA modification: mechanisms and therapeutic targets

RNA modifications are dynamic and reversible chemical modifications on substrate RNA that are regulated by specific modifying enzymes. They play important roles in the regulation of many biological processes in various diseases, such as the development of cancer and other diseases. With the help of advanced sequencing technologies, the role of RNA modifications has caught increasing attention in human diseases in scientific research. In this review, we briefly summarized the basic mechanisms of several common RNA modifications, including m6A, m5C, m1A, m7G, Ψ, A-to-I editing and ac4C. Importantly, we discussed their potential functions in human diseases, including cancer, neurological disorders, cardiovascular diseases, metabolic diseases, genetic and developmental diseases, as well as immune disorders. Through the "writing-erasing-reading" mechanisms, RNA modifications regulate the stability, translation, and localization of pivotal disease-related mRNAs to manipulate disease development. Moreover, we also highlighted in this review all currently available RNA-modifier-targeting small molecular inhibitors or activators, most of which are designed against m6A-related enzymes, such as METTL3, FTO and ALKBH5. This review provides clues for potential clinical therapy as well as future study directions in the RNA modification field. More in-depth studies on RNA modifications, their roles in human diseases and further development of their inhibitors or activators are needed for a thorough understanding of epitranscriptomics as well as diagnosis, treatment, and prognosis of human diseases.

The expanding role of BAP1 in clear cell renal cell carcinoma

Mutations drive renal cell carcinoma biology and tumor growth. The BRCA1-associated protein-1 (BAP1) gene is frequently mutated in clear cell renal cell carcinoma (ccRCC) and has emerged as a prognostic and putative predictive biomarker. In this review, we discuss the role of BAP1 as a signature event of a subtype of ccRCC marked by aggressiveness, inflammation, and possibly a heightened response to immunotherapy.

Genome-wide CRISPR screens using isogenic cells reveal vulnerabilities conferred by loss of tumor suppressors

Exploiting cancer vulnerabilities is critical for the discovery of anticancer drugs. However, tumor suppressors cannot be directly targeted because of their loss of function. To uncover specific vulnerabilities for cells with deficiency in any given tumor suppressor(s), we performed genome-scale CRISPR loss-of-function screens using a panel of isogenic knockout cells we generated for 12 common tumor suppressors. Here, we provide a comprehensive and comparative dataset for genetic interactions between the whole-genome protein-coding genes and a panel of tumor suppressor genes, which allows us to uncover known and new high-confidence synthetic lethal interactions. Mining this dataset, we uncover essential paralog gene pairs, which could be a common mechanism for interpreting synthetic lethality. Moreover, we propose that some tumor suppressors could be targeted to suppress proliferation of cells with deficiency in other tumor suppressors. This dataset provides valuable information that can be further exploited for targeted cancer therapy.

Involvement of PBRM1 in VHL disease-associated clear cell renal cell carcinoma and its putative relationship with the HIF pathway

Von Hippel-Lindau (VHL) disease is the main cause of inherited clear-cell renal cell carcinoma (ccRCC) and is caused by germline mutations in the VHL tumor suppressor gene. Bi-allelic VHL alterations lead to inactivation of pVHL, which plays a major role by downstream activation of the hypoxia inducible factor (HIF) pathway. Somatic VHL mutations occur in 80% of sporadic ccRCC cases and the second most frequently mutated gene is polybromo 1 (PBRM1). As there is currently no data regarding PBRM1 involvement in VHL disease-associated ccRCC, the aim of the present study was to assess the PBRM1 mutational status, and PBRM1 and HIF expression in VHL disease-associated ccRCC series compared with a sporadic series. PBRM1 gene was screened by Sanger sequencing for 23 VHL-disease-associated ccRCC and 22 sporadic ccRCC cases. Immunohistochemical studies were performed to detect the expression of PBRM1, HIF1 and HIF2 for all cases. In VHL-associated tumors, 13.0% (n=3/23) had PBRM1 somatic mutations and 17.4% (n=4/23) had a loss of PBRM1 nuclear expression. In sporadic cases, 27.3% (n=6/22) showed PBRM1 somatic mutations and 45.5% (n=10/22) had a loss of PBRM1 nuclear expression. Loss of PBRM1 was associated with an advanced tumor stage. HIF1-positive tumors were observed more frequently in the VHL-associated ccRCC than in the sporadic series. Furthermore, in the VHL cohort, PBRM1 expression appeared to be associated more with HIF1 than with HIF2. Given that hereditary tumors tend to be less aggressive, these results would suggest that co-expression of PBRM1 and HIF1 may have a less oncogenic role in VHL-associated ccRCC.

Determinants of renal cell carcinoma invasion and metastatic competence

Metastasis is the principal cause of cancer related deaths. Tumor invasion is essential for metastatic spread. However, determinants of invasion are poorly understood. We addressed this knowledge gap by leveraging a unique attribute of kidney cancer. Renal tumors invade into large vessels forming tumor thrombi (TT) that migrate extending sometimes into the heart. Over a decade, we prospectively enrolled 83 ethnically-diverse patients undergoing surgical resection for grossly invasive tumors at UT Southwestern Kidney Cancer Program. In this study, we perform comprehensive histological analyses, integrate multi-region genomic studies, generate in vivo models, and execute functional studies to define tumor invasion and metastatic competence. We find that invasion is not always associated with the most aggressive clone. Driven by immediate early genes, invasion appears to be an opportunistic trait attained by subclones with diverse oncogenomic status in geospatial proximity to vasculature. We show that not all invasive tumors metastasize and identify determinants of metastatic competency. TT associated with metastases are characterized by higher grade, mTOR activation and a particular immune contexture. Moreover, TT grade is a better predictor of metastasis than overall tumor grade, which may have implications for clinical practice.

SETD2 as a regulator of N6-methyladenosine RNA methylation and modifiers in cancer

Cancer is an unpleasant, painful disease. It is one of the most devastating diseases worldwide diminishing many lives. Many genetic and epigenetic changes occur before cancer develops. Mutation in SETD2 gene is one such example. RNA splicing, DNA damage repair, DNA methylation and histone methylation are some of the biological processes mediated by SETD2. SETD2 (histone H3 lysine 36 methyltransferase) is a frequently mutated gene in different types of cancer. Loss of SETD2 is associated with worse prognosis and aggressive phenotypes. Histone modification is one of the epigenetic regulation having a significant effect on gene regulation. N6-methyladenosine (m6A) mRNA modification is a well-known posttranscriptional modification playing a pivotal role in many normal and pathological processes affecting RNA metabolism. SETD2 catalyses H3K36 trimethylation and in turn H3K36me3 guides the deposition of m6A on nascent RNA transcripts. Finally, this review summarizes the deep understanding of the role of SETD2 in RNA methylation/modification and how SETD2 mutation contributes to tumour development.

Predictive Value of KDM5C Alterations for Immune Checkpoint Inhibitors Treatment Outcomes in Patients With Cancer

Lysine (K)-specific demethylase 5C (KDM5C) plays a significant role in the tumor cell proliferation, invasion, drug resistance and the regulation of tumor-related gene expression. Here, we aimed to investigate its predictive value in patients with cancers received immune checkpoint inhibitors (ICIs). We explored the predictive value of KDM5C alterations and the association between KDM5C alteration and immune landscape by using published cohort with clinical outcome and sequenced data from online database. The frequency of KDM5C alterations was 2.1% across 48045 tumor samples with different cancers from 185 studies. KDM5C alterations were correlated with markedly inferior overall survival (OS, 53 vs. 102 months, P<0.0001) than those without. However, in ICI-treated group, patients with KDM5C alterations had a substantially prolonged OS than the wild-type group (not reached vs. 18 months, P=0.0041). The predictive value of KDM5C alterations for ICI treatment outcome was not observed in patients with microsatellite-stable tumors (P=0.2875). Intriguingly, patients with non-small-cell lung cancer and KDM5C alterations receiving ICI had the better progression-free survival than wild type group (13.2 vs. 3.2 months, P=0.0762). Mechanistically, KDM5C altered tumors had dramatically higher TMB level and was associated with significantly higher level of CD8+ T cell infiltration and T effector signature. In conclusion, KDM5C alterations was correlated with enhanced tumor immunogenicity and inflamed anti-tumor immunity, thus resulting in better treatment outcome in cancer patients receiving ICIs.

SWI/SNF-deficient neoplasms of the genitourinary tract

Since the discovery of association of SMARCB1 mutations with malignant rhabdoid tumors and renal medullary carcinoma, mutations in genes of the SWI/SNF chromatin remodeling complex have been increasingly identified across a diverse spectrum of neoplasms. As a group, SWI/SNF complex subunit mutations are now recognized to be the second most frequent type of mutations across tumors. SMARCB1 mutations were originally reported in malignant rhabdoid tumors of the kidney and thought to be pathognomonic for this tumor. However, more broadly, recognition of typical rhabdoid cytomorphology and SMARCB1 mutations beyond rhabdoid tumors has changed our understanding of the pathobiology of these tumors. While mutations of SWI/SNF complex are diagnostic of rhabdoid tumors and renal medullary carcinoma, their clinical relevance extends to potential prognostic and predictive utility in other tumors as well. Beyond SMARCB1, the PBRM1 and ARID1A genes are the most frequently altered members of the SWI/SNF complex in genitourinary neoplasms, especially in clear cell renal cell carcinoma and urothelial carcinoma. In this review, we provide an overview of alterations in the SWI/SNF complex encountered in genitourinary neoplasms and discuss their increasing clinical importance.

Hypoxia-Driven Effects in Cancer: Characterization, Mechanisms, and Therapeutic Implications

Hypoxia, a common feature of solid tumors, greatly hinders the efficacy of conventional cancer treatments such as chemo-, radio-, and immunotherapy. The depletion of oxygen in proliferating and advanced tumors causes an array of genetic, transcriptional, and metabolic adaptations that promote survival, metastasis, and a clinically malignant phenotype. At the nexus of these interconnected pathways are hypoxia-inducible factors (HIFs) which orchestrate transcriptional responses under hypoxia. The following review summarizes current literature regarding effects of hypoxia on DNA repair, metastasis, epithelial-to-mesenchymal transition, the cancer stem cell phenotype, and therapy resistance. We also discuss mechanisms and pathways, such as HIF signaling, mitochondrial dynamics, exosomes, and the unfolded protein response, that contribute to hypoxia-induced phenotypic changes. Finally, novel therapeutics that target the hypoxic tumor microenvironment or interfere with hypoxia-induced pathways are reviewed.

Clinicopathological and prognostic impact of somatic mutations in Chinese patients with clear cell renal cell carcinoma

Background

The study of the genomic landscape of Chinese clear cell renal cell carcinoma (ccRCC) entered its nascence in recent years, and the clinical relevance of individual genes in Chinese ccRCC has not yet been researched. The study aimed to explore the relationships between somatic mutations and clinical behaviors in Chinese ccRCC.

Methods

Tumor tissue samples were obtained from 105 Chinese patients with ccRCC and deep sequencing targeting 556 cancer genes was performed. Correlation analysis, receiver operator characteristic (ROC) analysis and survival analysis were carried out using SPSS software.

Results

A total of 41 genes were used to investigate the relationship between genes and clinical behaviors. We found that different clinical indices were mutually correlated, and there were 12 genes associated with clinical indices. The Kaplan-Meier curves showed that high Fuhrman grade and metastatic disease at diagnosis were significantly associated with poor prognosis. Mutations in BAP1, PTEN, ERBB2, TP53, CDK8, TSC1, SETD2, or SPEN were significantly associated with poor prognosis, consistent with the results of The Cancer Genome Atlas (TCGA) cohort. Mutation of BTG1 occurred much more frequently in Chinese ccRCC (10.5%) than in the TCGA cohort (0.60%), and it was associated with a better prognosis.

Conclusions

A total of 8 genes (BAP1, PTEN, ERBB2, TP53, CDK8, TSC1, SETD2, and SPEN) were found to be associated with poor prognosis of ccRCC, and a new gene (BTG1) was possibly associated with the good prognosis of Chinese ccRCC.

CCL5-dependent mast cell infiltration into the tumor microenvironment in clear cell renal cell carcinoma patients

We investigated the mechanisms affecting tumor progression and survival outcomes in Polybromo-1-mutated (PBRM1^MUT) clear cell renal cell carcinoma (ccRCC) patients. PBRM1^MUT ccRCC tissues contained higher numbers of mast cells and lower numbers of CD8⁺ and CD4⁺ T cells than tissues from PBRM1^WT ccRCC patients. Hierarchical clustering, pathway enrichment and GSEA analyses demonstrated that PBRM1 mutations promote tumor progression by activating hypoxia inducible factor (HIF)-related signaling pathways and increasing expression of vascular endothelial growth factor family genes. PBRM1^MUT ccRCC tissues also show increased expression of C-C motif chemokine ligand 5 (CCL5). PBRM1-silenced ccRCC cells exhibited greater Matrigel tube formation and cell proliferation than controls. In addition, HMC-1 human mast cells exhibited CCL5-dependent in vitro migration on Transwell plates. High CCL5 expression in PBRM1^MUT ccRCC patients correlated with increased expression of genes encoding IFN-γ, IFN-α, IL-6, JAK-STAT3, TNF-α, and NF-ΚB. Moreover, high CCL5 expression was associated with poorer survival outcomes in ccRCC patients. These findings demonstrate that CCL5-dependent mast cell infiltration promotes immunosuppression within the tumor microenvironment, resulting in tumor progression and adverse survival outcomes in PBRM1^MUT ccRCC patients.

Hypoxia contributes to galectin-3 expression in renal carcinoma cells

Galectin-3 is supposed as a prognostic factor and therapeutic target for many cancers. In a previous study, we have reported that galectin-3 was related to the development of renal cell cancer and served a therapeutic target for renal cell carcinoma (RCC). However, the mechanisms underlying the regulation of galectin-3 in RCC are still not known. In this study, we detected the expression of galectin-3 and hypoxia-inducible factor 1 (HIF-1) α in RCC using immunohistochemistry, and then conducted in vitro experiments to verify the regulation of galectin-3 by hypoxia in RCC. Our results showed that the expression of galectin-3 and HIF-1α were remarkably high in RCC tissues compared with those in the paracancerous tissues. Interestingly, hypoxia significantly promoted cytoplasmic and nuclear HIF-1α and galectin-3 expression in renal carcinoma cell lines, but not in renal tubular epithelial cell (HK-2). Renal carcinoma cell line (Caki-1), but not HK-2 showed significant increase of luciferase reporter activity of galectin-3 encoding the fragment from the site of -845 to +50 upon hypoxic insult. Moreover, HIF-1α overexpression vector promoted, while HIF-1α silencing vector reduced luciferase reporter activity of galectin-3 in Caki-1 and HK-2 cells in both normal and hypoxia conditions. A direct interaction of HIF-1α with Gal-3 promoter was also verified by electrophoretic mobility shift assay and chromatin immunoprecipitation. Together, our data indicated that hypoxia was critical for galectin-3 expression in RCC in a HIF-1α-dependent manner.

Expression of the epigenetic H3K27me3 modifier genes KDM6A and EZH2 in patients with upper tract urothelial carcinoma

The development of upper tract urothelial carcinoma (UTUC) has been associated with the ingestion of aristolochic acid (AA) in Chinese herbs. The tumors are more malignant and patients have a worse prognosis in China compared with that in Western countries. Recently, whole-genome and exome sequencing of AA-associated UTUCs found that the most frequently mutated gene was lysine demethylase 6A (KDM6A). However, its biological role and clinical significance have not yet been defined in patients with UTUC in China. A total of 108 surgically resected UTUC samples were obtained. Using immunohistochemistry, the protein expression level of KDM6A in the tumors was investigated together with the clinical and pathological characteristics of the patients, including survival times. In the present study, the expression level of KDM6A was significantly lower in UTUC specimens compared with that in samples from the normal urothelium. Lower KDM6A expression was also found to be significantly associated with a higher tumor grade and shorter cancer-specific and disease-free survival times (P=0.023 and P=0.033, respectively). In addition, using immunohistochemical analysis, no positive association was found between KDM6A expression and the expression of H3K27me3 or histone-lysine N-methyltransferase EZH2, a histone methyltransferase that generates H3K27me3. The results of the present study indicated that decreased KDM6A expression level was significantly associated with tumor grade and decreased survival time in UTUC, suggesting that KDM6A expression could be used as a prognostic marker in patients with UTUC in China.

Renal Cell Cancer Syndromes: Identification and Management of Patients and Families at Increased Risk

There are many inherited renal cell cancer syndromes that increase an individual's risk of developing renal cell cancer. The age of onset for these renal cell cancer syndromes ranges from infancy to age 65 years. Clinical manifestations vary widely, and multiple body systems can be involved and present unique challenges to the healthcare team. With the advancement of genetic panels, clinicians can screen individuals with known hereditary syndromes for genetic mutations. This article offers clinically relevant information specific to various major renal cell cancer syndromes.

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.

Prognostic significance of proteomics and multi-omics studies in renal carcinoma

INTRODUCTION

Renal carcinoma, and in particular its most common variant, the clear cell subtype, is often diagnosed incidentally through abdominal imaging and frequently, the tumor is discovered at an early stage. However, 20% to 40% of patients undergoing nephrectomy for clinically localized renal cancer, even after accurate histological and clinical classification, will develop metastasis or recurrence, justifying the associated mortality rate. Therefore, even if renal carcinoma is not among the most frequent nor deadly cancers, a better prognostication is needed.

AREAS COVERED

Recently proteomics or other omics combinations have been applied to both cancer tissues, on the neoplasia itself and surrounding microenvironment, cultured cells, and biological fluids (so-called liquid biopsy) generating a list of prognostic molecular tools that will be reviewed in the present paper.

EXPERT OPINION

Although promising, none of the approaches listed above has been yet translated in clinics. This is likely due to the peculiar genetic and phenotypic heterogeneity of this cancer, which makes nearly each tumor different from all the others. Attempts to overcome this issue will be also revised. In particular, we will discuss how the application of omics-integrated approaches could provide the determinants of response to the different targeted drugs.

Machine learning-based unenhanced CT texture analysis for predicting BAP1 mutation status of clear cell renal cell carcinomas

BACKGROUND

BRCA1-associated protein 1 (BAP1) mutation is an unfavorable factor for overall survival in patients with clear cell renal cell carcinoma (ccRCC). Radiomics literature about BAP1 mutation lacks papers that consider the reliability of texture features in their workflow.

PURPOSE

Using texture features with a high inter-observer agreement, we aimed to develop and internally validate a machine learning-based radiomic model for predicting the BAP1 mutation status of ccRCCs.

MATERIAL AND METHODS

For this retrospective study, 65 ccRCCs were included from a public database. Texture features were extracted from unenhanced computed tomography (CT) images, using two-dimensional manual segmentation. Dimension reduction was done in three steps: (i) inter-observer agreement analysis; (ii) collinearity analysis; and (iii) feature selection. The machine learning classifier was random forest. The model was validated using 10-fold nested cross-validation. The reference standard was the BAP1 mutation status.

RESULTS

Out of 744 features, 468 had an excellent inter-observer agreement. After the collinearity analysis, the number of features decreased to 17. Finally, the wrapper-based algorithm selected six features. Using selected features, the random forest correctly classified 84.6% of the labelled slices regarding BAP1 mutation status with an area under the receiver operating characteristic curve of 0.897. For predicting ccRCCs with BAP1 mutation, the sensitivity, specificity, and precision were 90.4%, 78.8%, and 81%, respectively. For predicting ccRCCs without BAP1 mutation, the sensitivity, specificity, and precision were 78.8%, 90.4%, and 89.1%, respectively.

CONCLUSION

Machine learning-based unenhanced CT texture analysis might be a potential method for predicting the BAP1 mutation status of ccRCCs.

Novel and recurrent germline mutations in the VHL gene in 5 Arab patients with Von Hippel-Lindau disease

Inherited germline mutations in the VHL gene cause predisposition to Von Hippel-Lindau (VHL) disease. Patients exhibit benign and cancerous lesions in multiple tissues, including hemangioblastomas, clear cell renal cell carcinoma, cysts in kidneys and pancreas, and pheochromocytomas. Although pathogenic germline mutations in the VHL gene have been widely described in different populations, only a single mutation was previously reported in a family from mixed Arab-Persian ethnicity. Here, we present five Arab patients with two new and two recurrent germline mutations in the VHL gene. These mutations include three in-frame deletions and a missense mutation. Infrequent in-frame deletions in previously described patients from other populations, as well as the presence of new mutations, suggests a distinct spectrum of VHL gene mutations in Arab patients. While pulmonary manifestation has been described rarely in VHL disease, we have identified two patients with a recurrent p.Phe76del in-frame deletion exhibiting multiple nodules in lungs. We also describe a first-ever in-frame deletion in the VHL gene in a patient with VHL type 2C disease, exhibiting bilateral pheochromocytoma. Overall, the study provides an insight into the genotype-phenotype relationship of VHL disease in Arab patients and provides a comparison with previously described patients from other ethnicities.

Histone methyltransferase SETD2: a potential tumor suppressor in solid cancers

Epigenetic regulation plays an important role in the occurrence, development and treatment of malignant tumors; and a great deal of attention has been paid to the histone methylation level in recent years. As a 230-kD epigenetic regulator, the histone H3 lysine 36 histone (H3K36) methyltransferase SETD2 is a key enzyme of the nuclear receptor SET domain-containing (NSD) family, which is associated with a specific hyperphosphorylated domain, a large subunit of RNA polymerase II (RNAPII), named RNAPII subunit B1 (RPB1), and SETD2 which methylates the ly-36 position of dimethylated histone H3 (H3K36me2) to generate trimethylated H3K36 (H3K36me3). SETD2 is involved in various cellular processes, including transcriptional regulation, DNA damage repair, non-histone protein-related functions and some other processes. Great efforts of high-throughput sequencing have revealed that SETD2 is mutated or its function is lost in a range of solid cancers, including renal cancer, gastrointestinal cancer, lung cancer, pancreatic cancer, osteosarcoma, and so on. Mutation, or functional loss, of the SETD2 gene produces dysfunction in corresponding tumor tissue proteins, leading to tumorigenesis, progression, chemotherapy resistance, and unfavorable prognosis, suggesting that SETD2 possibly acts as a tumor suppressor. However, its underlying mechanism remains largely unexplored. In the present study, we summarized the latest advances of effects of SETD2 expression at the mRNA and protein levels in solid cancers, and its potential molecular and cellular functions as well as clinical applications were also reviewed.

Inactivation of BRM/SMARCA2 sensitizes clear cell renal cell carcinoma to histone deacetylase complex inhibitors

BRM, a key subunit of the SWI/SNF chromatin remodeling complex, is an important tumor suppressor gene in multiple tumors. BRM is not mutated, but rather epigenetically silenced in a variety of tumor types, which is different from many anti-cancer genes. In addition, histone deacetylase complex (HDAC) inhibitors are known to reverse BRM silencing, but they also inactivate it via acetylation of its c-terminus. HDAC inhibitors have been reported to be effective at pharmacologically restoring BRM and thereby inhibiting cancer cell growth. But we do not know which HDAC inhibitor, if any, regulate BRM in clear cell renal cell carcinoma (RCC). By using seven types of HDAC inhibitors, we found that Pan-HDAC inhibitors restored BRM protein expression. Despite their ability to restore BRM expression, these HDAC inhibitors also blocked BRM function when present. However, after their removal, we observed that BRM expression remained elevated for several days, and during this period, BRM activity was detected. In addition, HDAC3 and HDAC9 regulate BRM expression and function, especially for HDAC3 inhibitor, RGFP966. Our study demonstrated that knockdown of BRM promoted RCC cells proliferation, migration and invasion. RGFP966 inhibited the tumor progression of clear cell RCC by restoring BRM expression both in vivo and in vitro. In conclusion, HDAC3 is potential targets for clinical treatment, and our study provides a new approach for targeted therapy of BRM-negative clear cell RCC.

Prognostic and Predictive Value of PBRM1 in Clear Cell Renal Cell Carcinoma

Renal cell carcinoma (RCC) is the most frequent kidney solid tumor, the clear cell RCC (ccRCC) being the major histological subtype. The probability of recurrence and the clinical behavior of ccRCC will greatly depend on the different clinical and histopathological features, already incorporated to different scoring systems, and on the genomic landscape of the tumor. In this sense, ccRCC has for a long time been known to be associated to the biallelic inactivation of Von Hippel-Lindau (VHL) gene which causes aberrant hypoxia inducible factor (HIF) accumulation. Recently, next generation-sequencing technologies have provided the bases for an in-depth molecular characterization of ccRCC, identifying additional recurrently mutated genes, such as PBRM1 (≈40-50%), SETD2 (≈12%), or BAP1 (≈10%). PBRM1, the second most common mutated gene in ccRCC after VHL, is a component of the SWI/SNF chromatin remodeling complex. Different studies have investigated the biological consequences and the potential role of PBRM1 alterations in RCC prognosis and as a drug response modulator, although some results are contradictory. In the present article, we review the current evidence on PBRM1 as potential prognostic and predictive marker in both localized and metastatic RCC.

Biomarkers of Prognosis and Efficacy of Anti-angiogenic Therapy in Metastatic Clear Cell Renal Cancer

In the last decades, the prognosis of metastatic renal cell carcinoma (mRCC) has remarkably improved following the advent of the "targeted therapy" era. The expanding knowledge on the prominent role played by angiogenesis in RCC pathogenesis has led to approval of multiple anti-angiogenic agents such as sunitinib, pazopanib, axitinib, cabozantinib, sorafenib, and bevacizumab. These agents can induce radiological responses and delay cancer progression for months or years before onset of resistance, with a clinically meaningful activity. The need for markers of prognosis and efficacy of anti-angiogenic agents has become more compelling as novel systemic immunotherapy agents have also been approved in RCC and can be administered as an alternative to angiogenesis inhibitors. Anti PD-1 monoclonal antibody nivolumab has been approved in the second-line setting after tyrosine kinase inhibitors failure, while combination of nivolumab plus anti CTLA-4 monoclonal antibody ipilimumab has been approved as first-line therapy of RCC patients at intermediate or poor prognosis. In this review article, biomarkers of prognosis and efficacy of antiangiogenic therapies are summarized with a focus on those that have the potential to affect treatment decision-making in RCC. Biomarkers predictive of toxicity of anti-angiogenic agents have also been discussed.

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.

Downregulation of CIP2A inhibits cancer cell proliferation and vascularization in renal clear cell carcinoma

BACKGROUND

CIP2A has been proved to play a role as an oncogene in various types of malignancies while its functionality in renal clear cell carcinoma has not been investigated. Our study aimed to investigate the role of CIP2A in renal clear cell carcinoma and to explore the possible mechanisms.

METHODS

A total of 80 patients with renal clear cell carcinoma and 32 healthy people were included in the study. Expression of CIP2A was detected by qRT-PCR. CIP2A silencing renal clear cell carcinoma cell line was established. Its effects on cell proliferation and migration were verified by CCK-8 assay and Transwell cell assay, respectively. The effects of CIP2A overexpression on AKT and VEGF were investigated.

RESULTS

CIP2A expression level was increased in tumor tissues compared to adjacent healthy tissues. Serum levels of CIP2A protein were higher in cancer patients than in healthy controls, and serum levels of CIP2A protein were increased with increased stage of primary tumor. Serum CIP2A protein can be used to accurately predict renal clear cell carcinoma and its prognosis. CIP2A siRNA silencing inhibited tumor cell proliferation, and treatment with Akt activator reduced this inhibitory effect. CIP2A siRNA silencing decreased the expression level of VEGF and phosphorylation levels of AKT in renal clear cell carcinoma cells, while AKT activator treatment showed no significant effects on CIP2A expression.

CONCLUSION

Downregulation of CIP2A can inhibit cancer cell proliferation and vascularization in renal clear cell carcinoma through inactivation of the Akt pathway and its downstream VEGF.

Mutations of the MAPK/TSC/mTOR pathway characterize periventricular glioblastoma with epithelioid SEGA-like morphology-morphological and therapeutic implications

Epithelioid glioblastoma is a recognized glioblastoma variant, recently added to the World Health Organization brain tumor classification, with similar prognosis as the classic variant and B-Raf V600E mutations in 50% of the cases. We identified a new subset of epithelioid glioblastoma with periventricular location and subependymal giant cell astrocytoma (SEGA)-like morphology. Genomic profiling of these tumors revealed driver mutations in NF1, subclonal mutations in TSC1, and a novel driver mutation in MTOR, suggesting upregulation of the MAPK/TSC1/mTOR pathway. Strong mTOR activation was confirmed by immunohistochemistry for the mTOR kinase target 4E-BP1. TSC1 and MTOR mutations have been previously described in low-grade glioma, such as SEGA, and focal cortical dysplasia, respectively, that display large cells with abundant cytoplasm, most likely resulting from the biogenetic signaling of mTOR. Unlike these, the mutations in SEGA-like glioblastoma occurred in the context of other genetic aberrations present in high-grade neoplasms, including in the CDKN2A/B, PIK3R1, PIK3CA and EGFR genes. For one patient with two temporally distinct specimens, the subclonal TSC1 pathogenic mutation was detected only in the specimen showing SEGA-like morphology, indicating requirement for mTOR activation as trigger for specific epithelioid/SEGA-like morphology. As FDA-approved kinase inhibitors are available and target many steps of the MAPK/mTOR pathway, recognition of this new subset of periventricular high-grade gliomas with clear phenotypic-genotypic correlates is essential for prompt biomarker testing and appropriate targeted therapeutic management of these patients.

Extracellular Vesicles and Carried miRNAs in the Progression of Renal Cell Carcinoma

The formation and maintenance of renal cell carcinomas (RCC) involve many cell types, such as cancer stem and differentiated cells, endothelial cells, fibroblasts and immune cells. These all contribute to the creation of a favorable tumor microenvironment to promote tumor growth and metastasis. Extracellular vesicles (EVs) are considered to be efficient messengers that facilitate the exchange of information within the different tumor cell types. Indeed, tumor EVs display features of their originating cells and force recipient cells towards a pro-tumorigenic phenotype. This review summarizes the recent knowledge related to the biological role of EVs, shed by renal tumor cells and renal cancer stem cells in different aspects of RCC progression, such as angiogenesis, immune escape and tumor growth. Moreover, a specific role for renal cancer stem cell derived EVs is described in the formation of the pre-metastatic niche. We also highlight the tumor EV cargo, especially the oncogenic miRNAs, which are involved in these processes. Finally, the circulating miRNAs appear to be a promising source of biomarkers in RCC.

G Protein γ subunit 7 loss contributes to progression of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is a common urinary neoplasm, looking for useful candidates to establish scientific foundation for the therapy of ccRCC is urgent. We downloaded genomic profiles of GSE781, GSE6244, GSE53757, and GSE66271 from the Gene Expression Omnibus (GEO) database. GEO2R was used to analyze the derivative genes, while hub genes were screened by protein-protein interactions and cytoscape. Further, overall survival, gene methylation, gene mutation, and gene expression were all analyzed using bioinformatics tools. Colony formation and cell-cycle assay were used to detect the biological function of GNG7 in vitro. We found that GNG7 was downregulated in ccRCC tissues and negatively associated with overall survival in ccRCC patients. We also found that promoter methylation and frequent gene mutation were responsible for GNG7 gene suppression. GNG7 low expression was related to upregulation of enhancer of zeste homolog 2 and downregulation of disabled homolog 2-interacting protein. Further, Gene Set Enrichment Analysis results showed that mTOR1, E2F, G2M, and MYC pathways were all significantly altered in response to GNG7 low expression. In vitro, A498 and 786-O cells in which GNG7 expression was silenced, exhibited a lower G1 phase when compared to the negative control cells. Taken together, our findings suggest that GNG7 is a tumor suppressor gene in ccRCC progression and represents a novel candidate for ccRCC treatment.

Comprehensive Study of the Clinical Phenotype of Germline BAP1 Variant-Carrying Families Worldwide

Background

The BRCA1-associated protein-1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is a hereditary tumor syndrome caused by germline pathogenic variants in BAP1 encoding a tumor suppressor associated with uveal melanoma, mesothelioma, cutaneous melanoma, renal cell carcinoma, and cutaneous BAP1-inactivated melanocytic tumors. However, the full spectrum of tumors associated with the syndrome is yet to be determined. Improved understanding of the BAP1-TPDS is crucial for appropriate clinical management of BAP1 germline variant carriers and their families, including genetic counseling and surveillance for new tumors.

Methods

We collated germline variant status, tumor diagnoses, and information on BAP1 immunohistochemistry or loss of somatic heterozygosity on 106 published and 75 unpublished BAP1 germline variant-positive families worldwide to better characterize the genotypes and phenotypes associated with the BAP1-TPDS. Tumor spectrum and ages of onset were compared between missense and null variants. All statistical tests were two-sided.

Results

The 181 families carried 140 unique BAP1 germline variants. The collated data confirmed the core tumor spectrum associated with the BAP1-TPDS and showed that some families carrying missense variants can exhibit this phenotype. A variety of noncore BAP1-TPDS -associated tumors were found in families of variant carriers. Median ages of onset of core tumor types were lower in null than missense variant carriers for all tumors combined (P < .001), mesothelioma (P < .001), cutaneous melanoma (P < .001), and nonmelanoma skin cancer (P < .001).

Conclusions

This analysis substantially increases the number of pathogenic BAP1 germline variants and refines the phenotype. It highlights the need for a curated registry of germline variant carriers for proper assessment of the clinical phenotype of the BAP1-TPDS and pathogenicity of new variants, thus guiding management of patients and informing areas requiring further research.

Mutations in renal cell carcinoma

Renal cell carcinoma (RCC) is a commonly diagnosed and histologically diverse urologic malignancy. Clear cell RCC (ccRCC) is by far the most common, followed by the papillary and chromophobe subtypes. Sarcomatoid differentiation is a morphologic change that can be seen in all subtypes that typically portends a poor prognosis. In the past, treatment options for RCC were limited to cytokine-based therapy with a high-toxicity profile and low response rate. An increased understanding of the molecular basis of RCC has led to substantial improvement in treatment options in the form of targeted therapy and immunotherapy. A significant early discovery in RCC was frequent inactivation of the Von Hippel Lindau gene in ccRCC, which ultimately led to the development of vascular endothelial growth factor and mammalian target of rapamycin inhibitors. Further genomic sequencing of ccRCC tumors has identified other common mutations including BAP-1, PBRM1, SETD2, and PIK3CA. Many recent studies have explored how these mutations can affect prognosis and response to treatment. Likewise, papillary RCC has also been studied at the molecular level, which has shown a high level of mutations in the MET gene; early clinical data suggest the utility of MET targeted therapy. Finally, regarding the rarer sarcomatoid tumors, mutations in TP53 and NF2 may be important to their development. As we continue to learn more about what drives RCC at the molecular level, treatment options for RCC patients are diversifying.

Comprehensive Analysis of BAP1 Somatic Mutation in Clear Cell Renal Cell Carcinoma to Explore Potential Mechanisms in Silico

Purpose: Aim of this study was to comprehensively analyze BRCA1-associated protein-1 (BAP1) somatic mutation in clear cell renal cell carcinoma (ccRCC) and explore potential therapeutic pathways and molecules. Patients and methods: In this study, we analyzed 445 ccRCC cases from The Cancer Genome Atlas (TCGA). Comprehensive analysis including survival, transcriptome and methylation between BAP1 mutated and wild-type cases was performed using bioinformatics tools in silico. Pathways and molecules related to BAP1 mutation were analyzed using Database for Annotation, Visualization and Integrated Discovery (DAVID) and protein-protein interaction (PPI) network. Results: BAP1 mutated ccRCC patients had a worse overall survival (OS) and disease free survival (DFS) than BAP1 wild-type patients. We found 583 up-regulated and 1216 down-regulated different expressed genes (DEGs) in BAP1 mutated tumors. Up-regulated DEGs were enriched in molecular functions and biological processes like protein binding, protein transport and ubiquitin protein ligase binding. Down-regulated DEGs were enriched in pathways like Rap1 signaling pathway, Notch pathway and altered molecular functions like metal ion binding and ubiquitin-protein transferase activity. Furthermore, CAD, TSPO, CTNNB1 and MAPK3 were top hub genes selected using PPI network analysis. Finally, BAP1 mutation had a strong correlation with CpG island methylator phenotype (CIMP). Conclusion: Our study provides a comprehensive understanding of BAP1 functional somatic mutation in ccRCC patients. Several hub genes like CAD and TSPO may become potential therapeutic targets.

Presence of Intratumoral Calcifications and Vasculature Is Associated With Poor Overall Survival in Clear Cell Renal Cell Carcinoma

PURPOSE

The objective of this study was to explore the prognostic significance of the preoperative computed tomography (CT) features in clear cell renal cell carcinoma.

PATIENTS AND METHODS

The clinical data and CT data from 210 patients (1 grade 1, 84 grade 2, 92 grade 3, and 32 grade 4) generated with The Cancer Imaging Archive were reviewed. Overall survival was assessed using Kaplan-Meyer analysis. The relationship between CT features and survivals were evaluated using univariate and multivariable Cox regression analysis.

RESULTS

The follow-up occurred between 13 and 3989 days (median, 1405 days; mean, 1434 days).On univariate Cox regressions, 4 preoperative CT features (intratumoral calcifications: yes vs no hazard ratio [HR], 2.054; 95% confidence interval [CI], 1.231-3.428; renal vein invasion: yes vs no HR, 2.013; 95% CI, 1.218-3.328; collecting system invasion: yes vs no HR, 2.139; 95% CI, 1.286-3.558; gross appearance of intratumoral vasculature: yes vs no HR, 2.385; 95% CI, 1.454-3.915) were significantly associated with overall survival (all P < 0.05). On multivariable Cox regression analysis, predictors of mortality in clear cell renal cell carcinoma were the presence of intratumoral calcifications (HR, 1.718; 95% CI, 1.014-2.911; P = 0.044) and gross appearance of intratumoral vasculature (HR, 2.137; 95% CI, 1.284-3.557; P = 0.003).

CONCLUSIONS

Presence of intratumoral calcifications and vasculature can be potential prognostic features to screen patients for unfavorable prognosis.

The genomics of renal cell carcinoma and its role in renal mass biopsy

PURPOSE OF REVIEW

Large-scale genomic profiling has shed new light on the molecular underpinnings of renal cell carcinoma (RCC), spurring a much needed refinement of RCC subclassification based on an integrative assessment of histopathologic features and molecular alterations. At the same time, renal mass biopsies have become increasingly commonplace, necessitating ancillary tools to help guide clinical management. Herein, we briefly review our current understanding of RCC genomics, highlighting areas of possible clinical utility, as well as potential limitations, for renal mass biopsies.

RECENT FINDINGS

Distinct RCC subtypes harbor characteristic molecular features, including somatic mutations, copy number alterations, and genomic rearrangements. Existing ancillary tools, including fluorescent in-situ hybridization and immunohistochemistry, may be useful for diagnostic subclassification. Recurrent secondary molecular alterations in clear cell RCC (BAP1, SETD2, PBRM1, and TP53) and papillary RCC (CDKN2A) may be associated with poor prognosis; however, intratumoral genomic heterogeneity may limit the clinical utility of these molecular biomarkers in renal mass biopsies.

SUMMARY

Recent technological advances have the potential to fundamentally alter the clinical management of RCC by leveraging our increasing understanding of RCC genomics to assess hundreds of molecular biomarkers simultaneously. Additional focused molecular analyses of renal mass biopsy cohorts are needed prior to widespread implementation of molecular biomarker assays.

Molecular and Metabolic Basis of Clear Cell Carcinoma of the Kidney

Renal cell carcinoma (RCC) is a heterogenous group of tumors, >70% of which belong to the category of clear cell carcinoma. In recent years, crucial advances have been made in our understanding of the molecular and metabolic basis of clear cell carcinoma. This tumor manifests significant alterations in the cellular metabolism, so that the tumor cells preferentially induce the hypoxia response pathway using aerobic glycolysis, rather than the normal oxidative phosphorylation for energy. Most of the clear cell carcinomas (sporadic as well as familial) have mutations and deletions in the VHL gene located at 3p (p3.25). Normally, pVHL plays a crucial role in the proteasomal degradation of hypoxia-inducible factors (HIF)1 and HIF2. Lack of a functioning pVHL owing to genetic alterations results in stabilization and accumulation of these factors, which promotes cell growth, cell proliferation, and angiogenesis, contributing to a neoplastic phenotype. Several other genes normally located adjacent to VHL (BAP1, SETD2, PBRM1) may also be lost. These are tumor suppressor genes whose loss not only plays a role in carcinogenesis but may also influence the clinical course of these neoplasms. In addition, interaction among a variety of other genes located at several different chromosomes may also play a role in the genesis and progression of clear cell carcinoma.

Ubiquitin carboxyl-terminal hydrolases: involvement in cancer progression and clinical implications

Protein ubiquitination and deubiquitination participate in a number of biological processes, including cell growth, differentiation, transcriptional regulation, and oncogenesis. Ubiquitin C-terminal hydrolases (UCHs), a subfamily of deubiquitinating enzymes (DUBs), includes four members: UCH-L1/PGP9.5 (protein gene product 9.5), UCH-L3, UCHL5/UCH37, and BRCA1-associated protein-1 (BAP1). Recently, more attention has been paid to the relationship between the UCH family and malignancies, which play different roles in the progression of different tumors. It remains controversial whether UCHL1 is a tumor promoter or suppressor. UCHL3 and UCH37 are considered to be tumor promoters, while BAP1 is considered to be a tumor suppressor. Studies have showed that UCH enzymes influence several signaling pathways that play crucial roles in oncogenesis, tumor invasion, and migration. In addition, UCH families are associated with tumor cell sensitivity to therapeutic modalities. Here, we reviewed the roles of UCH enzymes in the development of tumors, highlighting the potential consideration of UCH enzymes as new interesting targets for the development of anticancer drugs.

Molecular profiling of renal cell carcinoma: building a bridge toward clinical impact

PURPOSE OF REVIEW

The daunting task of identifying key molecular drivers of renal cell carcinoma (RCC) has begun to reveal significant insights into tumor biology. This review provides an update on recent discoveries in this field and their possible clinical implications.

RECENT FINDINGS

Molecular profiles within the classic RCC histologic subtypes present distinctive appreciation of tumor biology and also allow for exploitation of targeted treatment regimens for patients with metastatic disease. Prognostic signatures have demonstrated the ability to accurately predict many clinical outcomes.

SUMMARY

The molecular and genomic profiling of RCC subtypes has identified a unique and diverse spectrum of alterations. Utilization of these characteristics to improve our prognostic and therapeutic outcomes in the clinical realm remains in its infancy but is rapidly advancing.

VHL status regulates transforming growth factor-β signaling pathways in renal cell carcinoma

To evaluate the role of pVHL in the regulation of TGF-β signaling pathways in clear cell renal cell carcinoma (ccRCC) as well as in non-ccRCC; the expression of pVHL, and the TGF-β pathway components and their association with clinicopathological parameters and patient’s survival were explored. Tissue samples from 143 ccRCC and 58 non-ccRCC patients were examined by immunoblot. ccRCC cell lines were utilized for mechanistic in-vitro studies. Expression levels of pVHL were significantly lower in ccRCC compared with non-ccRCC. Non-ccRCC and ccRCC pVHL-High expressed similar levels of pVHL. Expression of the TGF-β type I receptor (ALK5) and intra-cellular domain were significantly higher in ccRCC compared with non-ccRCC. In non-ccRCC, expressions of ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 had no association with clinicopathological parameters and survival. In ccRCC pVHL-Low, ALK5-FL, ALK5-ICD, pSMAD2/3, and PAI-1 were significantly related with tumor stage, size, and survival. In ccRCC pVHL-High, the expression of PAI-1 was associated with stage and survival. In-vitro studies revealed that pVHL interacted with ALK5 to downregulate its expression through K48-linked poly-ubiquitination and proteasomal degradation, thus negatively controlling TGF-β induced cancer cell invasiveness. The pVHL status controls the ALK5 and can thereby regulate the TGF-β pathway, aggressiveness of tumors, and survival of the ccRCC and non-ccRCC patients.

Knockdown of long non-coding RNA PVT1 induces apoptosis and cell cycle arrest in clear cell renal cell carcinoma through the epidermal growth factor receptor pathway

Previous years have witnessed the importance of long non-coding RNAs (lncRNAs) in cancer research. The lncRNA Pvt1 oncogene (non-protein coding) (PVT1) was revealed to be upregulated in various cancer types. The aim of the present study was to investigate the function of PVT1 in clear cell renal cell carcinoma (ccRCC). The expression of PVT1 in ccRCC was analyzed using reverse transcription-quantitative polymerase chain reaction, and it was revealed that PVT1 expression was upregulated in ccRCC tissues compared with that in normal adjacent tissues. Next, PVT1 expression from The Cancer Genome Atlas datasets was validated, and it was also revealed that the high expression of PVT1 was associated with advanced disease stage and a poor prognosis. Furthermore, the knockdown of PVT1 induced apoptosis by increasing the expression of poly ADP ribose polymerase and Bcl-2-associated X protein, and promoted cell cycle arrest at the G1 phase by decreasing the expression of cyclin D1. Study of the mechanism involved indicated that PVT1 promoted the progression of ccRCC partly through activation of the epidermal growth factor receptor pathway. Altogether, the results of the present study suggested that PVT1 serves oncogenic functions and may be a biomarker and therapeutic target in ccRCC.

Genetic characterization of Polish ccRCC patients: somatic mutation analysis of PBRM1, BAP1 and KDMC5, genomic SNP array analysis in tumor biopsy and preliminary results of chromosome aberrations analysis in plasma cell free DNA

BACKGROUND

Mutation analysis and cytogenetic testing in clear cell renal cell carcinoma (ccRCC) is not yet implemented in a routine diagnostics of ccRCC.

MATERIAL AND METHODS

We characterized the chromosomal alterations in 83 ccRCC tumors from Polish patients using whole genome SNP genotyping assay. Moreover, the utility of next generation sequencing of cell free DNA (cfDNA) in patients plasma as a potential tool for non-invasive cytogenetic analysis was tested. Additionally, tumor specific somatic mutations in PBRM1, BAP1 and KDM5C were determined.

RESULTS

We confirmed a correlation between deletions at 9p and higher tumor size, and deletion of chromosome 20 and the survival time. In Fuhrman grade 1, only aberrations of 3p and 8p deletion, gain of 5q and 13q and gains of chromosome 7 and 16 were present. The number of aberrations increased with Fuhrman grade, all chromosomes displayed cytogenetic changes in G3 and G4. ccRCC specific chromosome aberrations were observed in cfDNA, although discrepancies were found between cfDNA and tumor samples. In total 12 common and 94 rare variants were detected in PBRM1, BAP1 and KDM5C, with four potentially pathogenic variants. We observed markedly lower mutation load in PBRM1.

CONCLUSIONS

Cytogenetic analysis of cfDNA may allow more accurate diagnosis of tumor aberrations and therefore the correlation between the chromosome aberrations in cfDNA and clinical outcome should be studied in larger cohorts. The functional studies on in BAP1, KDM5C, PBRM1 mutations in large, independent sample set would be necessary for the assessment of their prognostic and diagnostic potential.

MULTIFOCAL CHOROIDAL MELANOMA IN A PATIENT WITH GERM LINE BRCA-ASSOCIATED PROTEIN 1 MUTATION

PURPOSE

To report a case of unilateral multifocal melanoma in a patient with germ line BRCA-associated protein 1 mutation.

METHODS

Case report.

RESULTS

A 67-year-old white woman with a family history of lung and liver cancers developed blurred visual acuity of 20/30 in the left eye. She was discovered to have two independent pigmented choroidal melanomas in the macula and superotemporally, both demonstrating overlying subretinal fluid and orange pigment. Both melanomas were treated with a single custom-designed Iodine 125 brachytherapy device. Upon systemic evaluation, asymptomatic renal cell carcinoma was found, and blood lymphocyte testing for germ line BRCA-associated protein 1 mutation was positive.

CONCLUSION

Multifocal choroidal melanoma is exceedingly rare. Patients with uveal melanoma, especially if multifocal, and those with other systemic malignancy or family history of cancers should be tested for germ line BRCA-associated protein 1 mutation. Lifelong monitoring for other systemic malignancies is advised.

Genetic mutations associated with metastatic clear cell renal cell carcinoma

Metastasis is the major cause of death among cancer patients, yet early detection and intervention of metastasis could significantly improve their clinical outcomes. We have sequenced and analyzed RNA (Expression) and DNA (Mutations) from the primary tumor (PT), tumor extension (TE) and lymphatic metastatic (LM) sites of patients with clear cell renal cell carcinoma (CCRCC) before treatment. Here, we report a three-nucleotide deletion near the C-region of Plk5 that is specifically associated with the lymphatic metastasis. This mutation is un-detectable in the PT, becomes detectable in the TE and dominates the LM tissue. So while only a few primary cancer cells carry this mutation, the majority of metastatic cells have this mutation. The increasing frequency of this mutation in metastatic tissue suggests that this Plk5 deletion could be used as an early indicator of CCRCC metastasis, and be identified by low cost PCR assay. A large scale clinical trial could reveal whether a simple PCR assay for this mutation at the time of nephrectomy could identify and stratify high-risk CCRCC patients for treatments.

Genotypic and Phenotypic Features of BAP1 Cancer Syndrome: A Report of 8 New Families and Review of Cases in the Literature

Importance

Patients with germline mutations in BAP1 may develop several flesh-colored melanocytic BAP1-mutated atypical intradermal tumors (MBAITs). These tumors generally develop earlier than other BAP1-associated tumors, highlighting an important role for dermatologists in identifying and screening patients with a history suggestive of a germline mutation.

Objective

To describe 8 new families with germline mutations in BAP1 and provide a comprehensive review of reported cases.

Design, Settings and Participants

Patients were identified in an outpatient dermatology clinical setting over a 6-month period (10 mutation carriers from 8 families) and through a literature review using PubMed (205 patients).

Exposures

Mutations were identified through next-generation sequencing of saliva or blood samples, and RNA was extracted from fibroblasts cultured from a patient with an intronic variant to determine the impact of the mutation on the coding sequence.

Main Outcomes and Measures

All 215 patients were assessed for personal and/or family history and genotype. These findings were compiled and assessed for any association between genotype and phenotype.

Results

Overall, this study included 215 patients (108 women, 91 men, and 16 gender unspecified; median [range] age, 46.5 [10.0-79.0] years). Nine of the 10 patients who were identified in the outpatient dermatology setting were found to have MBAITs on clinical examination. Forty of 53 patients (75%) identified in the literature review who underwent total-body skin examinations (TBSE) were found to have MBAITs, suggesting a high penetrance in patients who have undergone TBSE. The most prevalent malignancies among BAP1 mutation carriers were uveal melanoma (n =  60 [28%]), mesothelioma (n = 48 [22%]), cutaneous melanoma (n = 38 [18%]), and renal cell carcinoma (n = 20 [9%]). A total of 71 unique mutations in BAP1 have been reported.

Conclusions and Relevance

Our results indicate that germline mutations in both coding and noncoding regions throughout the BAP1 gene can impair protein function, leading to an increased risk for several associated malignancies. Four of the 8 probands we present had no history of BAP1-associated malignancies and were assessed for germline mutations when found to have MBAITs on dermatologic examination. Dermatologists can identify patients with a high likelihood of the BAP1 cancer syndrome through personal and family history and TBSE for the presence of possible MBAITs.

BAF180: Its Roles in DNA Repair and Consequences in Cancer

In 2011, Varela et al. reported that the PBRM1 gene is mutated in approximately 40% of clear cell renal cell carcinoma cases. Since then, the number of studies relating PBRM1 mutations to cancers has substantially increased. BAF180 has now been linked to more than 30 types of cancers, including ccRCC, cholangiocarcinomas, esophageal squamous cell carcinoma, bladder cancer, and breast cancer. The mutations associated with BAF180 are most often truncations, which result in a loss of protein expression. This loss has been shown to adversely affect the expression of genes, likely because BAF180 is the chromatin recognition subunit of PBAF. In addition, BAF180 functions in numerous DNA repair mechanisms. Its roles in mediating DNA repair are likely the mechanism by which BAF180 acts a tumor suppressor protein. As research on this protein gains more interest, scientists will begin to piece together the complicated puzzle of the BAF180 protein and why its loss often results in cancer.

Whole-Exome Sequencing in Two Extreme Phenotypes of Response to VEGF-Targeted Therapies in Patients With Metastatic Clear Cell Renal Cell Carcinoma

Advances in next-generation sequencing have provided a unique opportunity to understand the biology of disease and mechanisms of sensitivity or resistance to specific agents. Renal cell carcinoma (RCC) is a heterogeneous disease and highly variable clinical responses have been observed with vascular endothelial growth factor (VEGF)-targeted therapy (VEGF-TT). We hypothesized that whole-exome sequencing analysis might identify genotypes associated with extreme response or resistance to VEGF-TT in metastatic (mRCC). Patients with mRCC who had received first-line sunitinib or pazopanib and were in 2 extreme phenotypes of response were identified. Extreme responders (ERs) were defined as those with partial response or complete response for 3 or more years (n=13) and primary refractory patients (PRPs) were defined as those with progressive disease within the first 3 months of therapy (n=14). International Metastatic RCC Database Consortium prognostic scores were not significantly different between the groups (P=.67). Considering the genes known to be mutated in RCC at significant frequency, PBRM1 mutations were identified in 7 ERs (54%) versus 1 PRP (7%) (P=.01). In addition, mutations in TP53 (n=4) were found only in PRPs (P=.09). Our data suggest that mutations in some genes in RCC may impact response to VEGF-TT.

A BAP1 Mutation-specific MicroRNA Signature Predicts Clinical Outcomes in Clear Cell Renal Cell Carcinoma Patients with Wild-type BAP1

Background: Clear cell renal cell carcinoma (ccRCC) is the most prevalent histologic subtype of kidney cancers in adults, which could be divided into two distinct subgroups according to the BRCA1 associated protein-1 (BAP1) mutation status. In the current study, we comprehensively analyzed the genome-wide microRNA (miRNA) expression profiles in ccRCC, with the aim to identify the differentially expressed miRNAs between BAP1 mutant and wild-type tumors, and generate a BAP1 mutation-specific miRNA signature for ccRCC patients with wild-type BAP1.

Methods: The BAP1 mutation status and miRNA profiles in BAP1 mutant and wild-type tumors were analyzed. Subsequently, the association of the differentially expressed miRNAs with patient survival was examined, and a BAP1 mutation-specific miRNA signature was generated and examined with Kaplan-Meier survival, univariate and multivariate Cox regression analyses. Finally, the bioinformatics methods were adopted for the target prediction of selected miRNAs and functional annotation analyses.

Results: A total of 350 treatment-naïve primary ccRCC patients were selected from The Cancer Genome Atlas project, among which 35 (10.0%) subjects carried mutant BAP1 and had a shorter overall survival (OS) time. Furthermore, 33 miRNAs were found to be differentially expressed between BAP1 mutant and wild-type tumors, among which 11 (miR-149, miR-29b-2, miR-182, miR-183, miR-21, miR-365-2, miR-671, miR-365-1, miR-10b, miR-139, and miR-181a-2) were significantly associated with OS in ccRCC patients with wild-type BAP1. Finally, a BAP1 mutation-specific miRNA signature consisting of 11 miRNAs was generated and validated as an independent prognostic parameter.

Conclusions: In summary, our study identified a total of 33 miRNAs differentially expressed between BAP1 mutant and wild-type tumors, and generated a BAP1 mutation-specific miRNA signature including eleven miRNAs, which could serve as a novel prognostic biomarker for ccRCC patients with wild-type BAP1.