Searching for the hereditary causes of renal-cell carcinoma

Investigating the association of VHL gene variants with disease risk and clinicopathological outcomes in ccRCC patients from West Bengal, India

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is a prevalent and aggressive malignancy, with the von Hippel-Lindau (VHL) gene playing a critical role in its pathogenesis. However, the association between VHL gene variants and sporadic ccRCC risk remains unexplored in the Indian population. This study aimed to investigate the somatic and germline variants of the VHL gene in sporadic ccRCC patients from West Bengal, India, and their association with disease risk and clinicopathological parameters.

METHODS

A total of 210 ccRCC patients and 255 ethnicity-matched healthy controls were enrolled. Genomic DNA from blood and tissue samples was analyzed using PCR-based Sanger sequencing. The association of VHL variants with ccRCC risk was assessed using Chi-square tests. The impact of genetic variants on patient clinicopathological features and overall survival was evaluated using Kaplan-Meier survival analysis and Cox proportional hazards models.

RESULTS

We identified twenty-three single nucleotide variants (SNVs) in the VHL gene, including 3 novel variants, OR250433 T > G, OR125589 C > T and OQ627404 G > C. The intronic variant rs61758376 G > C and 3'UTR variant rs1642742 A > G were significantly associated with an increased risk of ccRCC (OR = 1.676, P = 0.0074; OR = 1.735, P = 0.0171, respectively). The rs1642742 GG genotype was also significantly associated with larger tumor size (P < 0.05) and advanced tumor stage (pT4). Kaplan-Meier analysis indicated poorer overall survival for patients with the rs1642742 GG genotype (log-rank P = 0.029).

CONCLUSION

Our study is the first to document the association of VHL gene variants with sporadic ccRCC risk and clinical outcomes in the Indian population. The identified variants, particularly rs61758376 and rs1642742, could serve as potential biomarkers for ccRCC susceptibility and prognosis.

Cyclin dependent kinase inhibitor 3 (CDKN3) upregulation is associated with unfavorable prognosis in clear cell renal cell carcinoma and shapes tumor immune microenvironment: A bioinformatics analysis

Cell cycle regulatory proteins plays a pivotal role in the development and progression of many human malignancies. Identification of their biological functions as well as their prognostic utility presents an active field of research. As a continuation of the ongoing efforts to elucidate the molecular characteristics of clear cell renal cell carcinoma (ccRCC); we present a comprehensive bioinformatics study targeting the prognostic and mechanistic role of cyclin-dependent kinase inhibitor 3 (CDKN3) in ccRCC. The ccRCC cohort from the Cancer Genome Atlas Program was accessed through the UCSC Xena browser to obtain CDKN3 mRNA expression data and their corresponding clinicopathological variables. The independent prognostic signature of CDKN3 was evaluated using univariate and multivariate Cox logistic regression analysis. Gene set enrichment analysis and co-expression gene functional annotations were used to discern CDKN3-related altered molecular pathways. The tumor immune microenvironment was evaluated using TIMER 2.0 and gene expression profiling interactive analysis. CDKN3 upregulation is associated with shortened overall survival (hazard ratio [HR] = 2.325, 95% confident interval [CI]: 1.703-3.173, P < .0001) in the Cancer Genome Atlas Program ccRCC cohort. Univariate (HR: 0.426, 95% CI: 0.316-0.576, P < .001) and multivariate (HR: 0.560, 95% CI: 0.409-0.766, P < .001) Cox logistic regression analyses indicate that CDKN3 is an independent prognostic variable of the overall survival. High CDKN3 expression is associated with enrichment within the following pathways including allograph rejection, epithelial-mesenchymal transition, mitotic spindle, inflammatory response, IL-6/JAK/STAT3 signaling, spermatogenesis, TNF-α signaling via NF-kB pathway, complement activation, KRAS signaling, and INF-γ signaling. CDKN3 is also associated with significant infiltration of a wide spectrum of immune cells and correlates remarkably with immune-related genes. CDKN3 is a poor prognostic biomarker in ccRCC that alters many molecular pathways and impacts the tumor immune microenvironment.

Two Single Nucleotide Polymorphisms in the Von Hippel-Lindau Tumor Suppressor Gene in Patients with Clear Cell Renal Cell Carcinoma

The most common subtype of renal cell carcinoma (RCC) is clear cell type (ccRCC), which accounts for approximately 75% of cases. von Hippel-Lindau (VHL) gene has been shown to be affected in more than half of ccRCC cases. Two single nucleotide polymorphisms (SNPs) located in VHL gene, rs779805 and rs1642742, are reported to be involved in the occurrence of ccRCC. The aim of this study was to assess their associations with clinicopathologic and immunohistochemical parameters, as well as risk and survival of ccRCC. The study population consisted of 129 patients. No significant differences in genotype or allele frequencies of VHL gene polymorphisms were observed between ccRCC cases and control population, and we have found that our results do not indicate a significant relationship of these SNPs with respect to ccRCC susceptibility. Additionally, we did not observe a significant association of these two SNPs with ccRCC survival. However, our results conclude that rs1642742 and rs779805 in the VHL gene are associated with increased tumor size, which is the most important prognostic indicator of renal cancer. Moreover, our analysis showed that patients with genotype AA of rs1642742 have a trend towards higher likelihood of developing ccRCC within their lifetime, while allele G of rs779805 can have a preventive effect against the development of renal cancer in stage 1. Therefore, these SNPs in VHL may be useful as genetic tumor markers for the molecular diagnostics for ccRCC patients.

Dealing with malignancy involving the inferior vena cava in the 21st century

INTRODUCTION

Malignancies involving the inferior vena cava (IVC) have historically been considered not amendable to surgery. More recently, involvement of the IVC by neoplastic processes in the kidney, liver or in the retroperitoneum can be managed successfully.

EVIDENCE ACQUISITION

In this systematic review we summarize the current evidence regarding the surgical management of the IVC in cases of involvement in neoplastic processes. Current literature was searched, and studies selected on the base of the PRISMA guidelines. Evidence was synthesized in narrative form due to heterogeneity of studies.

EVIDENCE SYNTHESIS

Renal cell carcinoma accounts for the greatest proportion of studied patients and can be managed with partial or complete vascular exclusion of the IVC, thrombectomy and direct closure or patch repair with good oncological prognosis. Hepatic malignancies or metastases may involve the IVC, and the joint expertise of hepatobiliary and vascular surgeons has developed various strategies, according to the location of tumor and the need to perform a complete vascular exclusion above the hepatic veins. In retroperitoneal lymph node dissection, the IVC can be excised en-block to guarantee better oncological margins. Also, in retroperitoneal sarcomas not arising from the IVC a vascular substitution may be required to improve the overall survival by clearing all the neoplastic cells in the retroperitoneum. Leiomyoma can have a challenging presentation with involvement of the IVC requiring either thrombectomy, partial or complete substitution, with good oncological outcomes.

CONCLUSIONS

A multidisciplinary approach with specialist expertise is required when dealing with IVC involvement in surgical oncology. Multiple techniques and strategies are required to deliver the most efficient care and achieve the best possible overall survival. The main aim of these procedures must be the complete clearance of all neoplastic cells and achievement of a safe margin according to the perioperative treatment strategy.

An integrated somatic and germline approach to aid interpretation of germline variants of uncertain significance in cancer susceptibility genes

Genomic profiles of tumors are often unique and represent characteristic mutational signatures defined by DNA damage or DNA repair response processes. The tumor-derived somatic information has been widely used in therapeutic applications, but it is grossly underutilized in the assessment of germline genetic variants. Here, we present a comprehensive approach for evaluating the pathogenicity of germline variants in cancer using an integrated interpretation of somatic and germline genomic data. We have previously demonstrated the utility of this integrated approach in the reassessment of pathogenic germline variants in selected cancer patients with unexpected or non-syndromic phenotypes. The application of this approach is presented in the assessment of rare variants of uncertain significance (VUS) in Lynch-related colon cancer, hereditary paraganglioma-pheochromocytoma syndrome, and Li-Fraumeni syndrome. Using this integrated method, germline VUS in PMS2, MSH6, SDHC, SHDA, and TP53 were assessed in 16 cancer patients after genetic evaluation. Comprehensive clinical criteria, somatic signature profiles, and tumor immunohistochemistry were used to re-classify VUS by upgrading or downgrading the variants to likely or unlikely actionable categories, respectively. Going forward, collation of such germline variants and creation of cross-institutional knowledgebase datasets that include integrated somatic and germline data will be crucial for the assessment of these variants in a larger cancer cohort.

Machine learning-based prognostic and metastasis models of kidney cancer

Background

Kidney cancer originates from the urinary tubule epithelial system of the renal parenchyma, accounting for 20% of all urinary system tumors. Approximately 70% of cases are localized at diagnosis, and 30% are metastatic. Most localized kidney cancers can be cured by surgery, but most metastatic patients relapse after surgery and eventually die of kidney cancer. Therefore, accurately predicting patient survival and identifying high-risk metastatic patients will effectively guide interventions and improve prognosis.

Methods

This study used the data of 12,394 kidney cancer patients from the surveillance, epidemiology, and end results database to construct a research cohort related to kidney cancer survival and metastasis. Eight machine learning models (including support vector machines, logistic regression, decision tree, random forest, XGBoost, AdaBoost, K-nearest neighbors, and multilayer perceptron) were developed to predict the survival and metastasis of kidney cancer and six evaluation indicators (accuracy, precision, sensitivity, specificity, F1 score, and area under the receiver operating characteristic [AUROC]) were used to verify, evaluate, and optimize the models.

Results

Among the eight machine learning models, Logistic Regression has the highest AUROC in both prediction scenarios. For 3-year survival prediction, the Logistic Regression model had an accuracy of 0.684, a sensitivity of 0.702, a specificity of 0.670, a precision of 0.686, an F1 score of 0.683, and an AUROC of 0.741. For tumor metastasis prediction, the Logistic Regression model had an accuracy of 0.800, a sensitivity of 0.540, a specificity of 0.830, a precision of 0.769, an F1 score of 0.772, and an AUROC of 0.804.

Conclusion

In this study, we selected appropriate variables from both statistical and clinical significance and developed and compared eight machine learning models for predicting 3-year survival and metastasis of kidney cancer. The prediction results and evaluation results demonstrated that our model could provide decision support for early intervention for kidney cancer patients.

An optimized protocol for evaluating pathogenicity of VHL germline variants in patients suspected with von Hippel-Lindau syndrome: Using somatic genome to inform the role of germline variants

The interpretation of hereditary genetic sequencing variants is often limited due to the absence of functional data and other key evidence to assess the role of variants in disease. Cancer genetics is unique, as two sets of genomic information are often available from a cancer patient: somatic and germline. Despite the progress made in the integrated analysis of somatic and germline findings, the assessment of pathogenicity of germline variants in high penetrance genes remains grossly underutilized. Indeed, standard ACMG/AMP guidelines for interpreting germline sequence variants do not address the evidence derived from tumor data in cancer. Previously, we have demonstrated the utility of somatic tumor data as supporting evidence to elucidate the role of germline variants in patients suspected with VHL syndrome and other cancers. We have leveraged the key elements of cancer genetics in these cases: genes with expected high disease penetrance and those with a known biallelic mechanism of tumorigenicity. Here we provide our optimized protocol for evaluating the pathogenicity of germline VHL variants using informative somatic profiling data. This protocol provides details of case selection, assessment of personal and family evidence, somatic tumor profiles, and loss of heterozygosity (LOH) as supporting evidence for the re-evaluation of germline variants.

Integration of Tumor Microenvironment in Patient-Derived Organoid Models Help Define Precision Medicine of Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a common urological tumor, with a poor prognosis, as the result of insensitivity to chemotherapy and radiotherapy. About 20%–30% of patients with RCC have metastasis at the first diagnosis, so only systemic treatment is possible. Due to the heterogeneity of renal tumors, responses to drugs differ from person to person. Consequently, patient-derived organoid, highly recapitulating tumor heterogeneity, becomes a promising model for high-throughput ex vivo drug screening and thus guides the drug choice of patients with RCC. Systemic treatment of RCC mainly targets the tumor microenvironment, including neovasculature and immune cells. We reviewed several methods with which patient-derived organoid models mimic the heterogeneity of not only tumor epithelium but also the tumor microenvironment. We further discuss some new aspects of the development of patient-derived organoids, preserving in vivo conditions in patients with RCC.

A rare case of tuberous sclerosis complex-associated renal cell carcinoma

Renal cell carcinoma is rarely described in paediatric patients with tuberous sclerosis complex. This report describes a case of an 11-year-old male with tuberous sclerosis-associated renal cell carcinoma.

Pathogenicity of VHL variants in families with non-syndromic von Hippel-Lindau phenotypes: An integrated evaluation of germline and somatic genomic results

Von Hippel-Lindau (VHL) syndrome is a hereditary tumor syndrome associated with germline loss-of-function pathogenic variants (PVs) in the VHL gene. VHL is classically associated with a high penetrance for many different tumor types. The same tumors may be sporadic in the setting of somatic VHL PVs. With more large-scale genome sequencing, variants with low penetrance or variable expressivity are identified. This has introduced challenges in patient management and the clinical interpretation of germline VHL variants identified in non-classic families. Herein, we report individuals from 3 non-classic families with VHL variants who presented with unexpected or non-syndromic phenotypes, but often with a VHL component tumor. In family 1, two siblings, age 61, with pathogenic VHL p.Leu188Val presented with clear cell renal cell carcinoma and lobular breast cancer. In family 2, the proband, age 82, was found to have pathogenic germline VHL p.Tyr98His on testing for metastatic bladder cancer. In family 3, four members carried germline VHL p.Pro81Ser (variant of uncertain significance), after the proband, age 40, presented with cerebellar hemangioblastoma. None of the individuals in the above three families met clinical criteria of classic VHL, suggesting germline VHL p.Leu188Val, p.Y98H, and p.Tyr98His may be low penetrant variants. Large studies are needed to evaluate penetrance and possible effect of genetic and non-genetic modifiers. Somatic sequencing performed on their respective tumors could help discern the etiology of the component tumors, highlighting the role of somatic evaluation in these cases. Paired examination of somatic and germline findings provided a more complete landscape of genome alterations in cancer development.

Down-regulation of BCL2L13 renders poor prognosis in clear cell and papillary renal cell carcinoma

BACKGROUND

BCL2L13 belongs to the BCL2 super family, with its protein product exhibits capacity of apoptosis-mediating in diversified cell lines. Previous studies have shown that BCL2L13 has functional consequence in several tumor types, including ALL and GBM, however, its function in kidney cancer remains as yet unclearly.

METHODS

Multiple web-based portals were employed to analyze the effect of BCL2L13 in kidney cancer using the data from TCGA database. Functional enrichment analysis and hubs of BCL2L13 co-expressed genes in clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) were carried out on Cytoscape. Evaluation of BCL2L13 protein level was accomplished through immunohistochemistry on paraffin embedded renal cancer tissue sections. Western blotting and flow cytometry were implemented to further analyze the pro-apoptotic function of BCL2L13 in ccRCC cell line 786-0.

RESULTS

BCL2L13 expression is significantly decreased in ccRCC and pRCC patients, however, mutations and copy number alterations are rarely observed. The poor prognosis of ccRCC that derived from down-regulated BCL2L13 is independent of patients' gender or tumor grade. Furthermore, BCL2L13 only weakly correlates with the genes that mutated in kidney cancer or the genes that associated with inherited kidney cancer predisposing syndrome, while actively correlates with SLC25A4. As a downstream effector of BCL2L13 in its pro-apoptotic pathway, SLC25A4 is found as one of the hub genes that involved in the physiological function of BCL2L13 in kidney cancer tissues.

CONCLUSIONS

Down-regulation of BCL2L13 renders poor prognosis in ccRCC and pRCC. This disadvantageous factor is independent of any well-known kidney cancer related genes, so BCL2L13 can be used as an effective indicator for prognostic evaluation of renal cell carcinoma.

A 17-Gene Signature Predicted Prognosis in Renal Cell Carcinoma

Renal cell carcinoma (RCC), which was one of the most common malignant tumors in urinary system, had gradually increased incidence and mortality in recent years. Although significant advances had been made in molecular and biology research on the pathogenesis of RCC, effective treatments and prognostic indicators were still lacking. In order to predict the prognosis of RCC better, we identified 17 genes that were associated with the overall survival (OS) of RCC patients from The Cancer Genome Atlas (TCGA) dataset and a 17-gene signature was developed. Through SurvExpress, we analyzed the expression differences of the 17 genes and their correlation with the survival of RCC patients in five datasets (ZHAO, TCGA, KIPAN, KIRC, and KIRP), and then evaluated the survival prognostic significance of the 17-gene signature for RCC. Our results showed that the 17-gene signature had a predictive prognostic value not only in single pathologic RCC, but also in multiple pathologic types of RCC. In conclusion, the 17-gene signature model was related to the survival of RCC patients and could help predict the prognosis with significant clinical implications.

Retreatment after focal therapy for failure: a bridge too far?

PURPOSE OF REVIEW

To summarize the current knowledge about the evaluation of disease persistence and recurrence after focal therapy ablation (FTA) for small renal masses and to assess the outcomes and complications of related treatment options.

RECENT FINDINGS

FTA procedures continuously increased over the last 20 years, being now performed in more than one on 10 patients with T1a renal cell carcinoma. Disease recurrence seems to occur more often following radiofrequency ablation (RFA) compared with cryoablation. Evidence about the management of disease recurrence is scarce. Treatment options are similar to those available for de novo renal cell carcinomas, and include reablation, partial or radical nephrectomy and observation. Reablation is feasible, safe and can be easily done in the majority of cases. Oncological outcomes of repeated ablation, although encouraging, remain mostly uninvestigated and unreported.

SUMMARY

In case of disease persistence or recurrence after FTA, observation may be an acceptable approach, reserving repeated ablation or surgery only in those exhibiting significant tumor growth. In these patients repeated ablation with RFA is safe and noninvasive. Surgery after FTA presents technical difficulties related to perinephric scarring, especially with regards to nephron-sparing surgery. This should be taken into consideration in patients' counseling as well as in decision-making process.

Treatment of advanced renal cell carcinoma patients with cabozantinib, an oral multityrosine kinase inhibitor of MET, AXL and VEGF receptors

Von Hippel-Lindau (VHL), a tumor suppressor gene, is frequently inactivated in renal cell carcinoma (RCC). It drives tumorigenesis by activating downstream hypoxia responsive genes and proangiogenic factors like VEGFR, and is responsible for the activity of tyrosine kinase inhibitors in RCC. Resistance to VEGFR therapy eventually occurs, in part due to activation of alternative signaling pathways like AXL and MET. Cabozantinib is a potent inhibitor of VEGF, AXL and MET receptors providing rationale for its use in RCC. Cabozantinib has been approved for use in the first- and second-line setting in patients with advanced RCC. This manuscript reviews the preclinical data, pharmacology, clinical efficacy and safety of the use of cabozantinib in RCC.

Key miRNAs and target genes played roles in the development of clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (CCRCC) is the most aggressive form of renal cell carcinoma (RCC).

OBJECTIVE

This study was aimed to identify the differentially expressed miRNAs and target genes in CCRCC.

METHODS

The miRNA and mRNA next-generation sequencing data were downloaded from The Cancer Genome Atlas (TCGA) dataset. Differential expression analysis was performed, followed by correlation analysis of miRNA-mRNA. Functional enrichment and survival analysis was also performed.

RESULTS

Seven hundred and eighty-seven patients with CCRCC from TCGA data portal were included in this study. A total of 52 differentially expressed miRNAs were identified in CCRCC. Then 2361 differentially expressed genes (DEGs) were identified. Prediction analysis and correlation analysis revealed that 89 miRNA-mRNA pairs were not only predicted by algorithms but also had a significant inverse relationship. Several differentially expressed miRNAs such as hsa-mir-501 and their target genes including AK1, SLC25A15 and PCDHGC3 had a significant prognostic value for CCRCC patients.

CONCLUSIONS

Alterations of differentially expressed miRNAs and target genes may be involved in the development of CCRCC and can be considered as the prognostic markers for CCRCC.

Fructose 1,6-Bisphosphatase 1 Expression Reduces 18F-FDG Uptake in Clear Cell Renal Cell Carcinoma

Purpose

To determine the relationship between fructose 1,6-bisphosphatase 1 (FBP1) expression and fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) uptake in patients with clear cell renal cell carcinoma (ccRCC), and to investigate how ¹⁸F-FDG uptake and FBP1 expression are related to tumor metabolism and tumor differentiation grade.

Materials and Methods

A total of 54 patients with ccRCC underwent ¹⁸F-FDG combined positron emission tomography and computed tomography (PET/CT) before tumor resection. The maximum standardized uptake value (SUVmax) for the primary tumor was calculated from the ¹⁸F-FDG uptake. The relationship between SUVmax of primary tumor and the expression of FBP1, hexokinase 2 (HK2), and glucose transporter 1 (GLUT1) was analyzed via immunohistochemical analysis.

Results

We identified an inverse relationship between FBP1 expression and SUVmax (P=0.031). SUVmax was higher in patients with high-grade ccRCC (mean, 11.6 ± 5.0) than in those with low-grade ccRCC (mean, 3.8 ± 1.6, P < 0.001). FBP1 expression was significantly lower in patients with high-grade ccRCC (mean, 0.23 ± 0.1) than in those with low-grade ccRCC (mean, 0.57 ± 0.08; P=0.018). FBP1 status could be predicted with an accuracy of 66.7% when a SUVmax cutoff value of 3.55 was used. GLUT1 expression in ccRCC was positively correlated with ¹⁸F-FDG uptake and FBP1 status, whereas HK2 expression was not.

Conclusion

SUVmax in patients with ccRCC is inversely associated with the expression of FBP1, and FBP1 may inhibit ¹⁸F-FDG uptake via regulating GLUT1. SUVmax is higher in patients with high-grade ccRCC than in those with low-grade ccRCC, which could be the result of lower FBP1 expression in patients with high-grade ccRCC.

Germline genetic variants in somatically significantly mutated genes in tumors are associated with renal cell carcinoma risk and outcome

Genome-wide association studies (GWAS) have identified 13 susceptibility loci for renal cell carcinoma (RCC). Additional genetic loci of risk remain to be explored. Moreover, the role of germline genetic variants in predicting RCC recurrence and overall survival (OS) is less understood. In this study, we focused on 127 significantly mutated genes from The Cancer Genome Atlas (TCGA) Pan-Cancer Analysis across 12 major cancer sites to identify potential genetic variants predictive of RCC risk and clinical outcomes. In a three-phase design with a total of 2657 RCC cases and 5315 healthy controls, two single nucleotide polymorphisms (SNPs) that map to PIK3CG (rs6466135:A, ORmeta = 0.85, 95% CI = 0.77-0.94, Pmeta = 1.4 × 10-3) and ATM (rs611646:T, ORmeta = 1.17, 95% CI = 1.05-1.31, Pmeta = 3.5 × 10-3) were significantly associated with RCC risk. With respect to RCC recurrence and OS, two separate datasets with a total of 661 stages I-III RCC patients (discovery: 367; validation: 294) were analyzed. The most significant association was observed for rs10932384:C (ERBB4) with both outcomes (recurrence: HRmeta = 0.52, 95% CI = 0.39-0.68, Pmeta = 3.81 × 10-6; OS: HRmeta = 0.50, 95% CI = 0.37-0.67, Pmeta = 6.00 × 10-6). In addition, six SNPs were significantly associated with either RCC recurrence or OS but not both (Pmeta < 0.01). Rs10932384:C was significantly correlated with mutation frequency of ERBB4 in clear cell RCC (ccRCC) patients (P = 0.003, Fisher's exact test). Cis-eQTL was observed for several SNPs in blood/transformed fibroblasts but not in RCC tumor tissues. In summary, we identified promising genetic predictors of recurrence and OS among RCC patients with localized disease.

Rhein inhibits malignant phenotypes of human renal cell carcinoma by impacting on MAPK/NF-κB signaling pathways

Background

Rhein, an anthraquinone derivative of rhubarb, is traditionally used in Chinese herbal medicine. Now emerging studies suggest its antitumor properties in many human cancers. The present study aims to investigate the antitumor role of Rhein and its possible mechanism in human renal cell carcinoma (RCC).

Materials and methods

Three RCC cell lines (A489, 786-O and ACHN) were used as the cell models. We applied CCK-8, cell counting, colony formation, wound healing and Transwell assays to assess the antitumor roles of Rhein in RCC cells in vitro. The therapeutic efficacy of Rhein was further evaluated by intraperitoneal administrations in tumor formation of mice. Western blot was used to investigate the underlying mechanisms of action of Rhein.

Results

Rhein inhibited RCC cell proliferation in a dose- and time-dependent manner. It also suppressed RCC cell migration and invasion in vitro. Moreover, Rhein was able to inhibit tumor growth in nude mice by intraperitoneal administration in vivo. Mechanistically, the protein levels of phosphorylated MAPK (mitogen-activated protein kinase, extracellular signal-regulated kinase and c-Jun N-terminal kinase), phosphorylated Akt and two targets of NF-κB (nuclear factor kappa-light-chain enhancer of activated B cells) pathway, matrix metalloproteinase 9 and CCND1 were all markedly reduced by Rhein treatment.

Conclusion

Rhein processed the antitumor effects in RCC cells by inhibiting cell proliferation, migration and invasion, and these tumor-suppressing functions might be mediated by MAPK/NF-κB signaling pathways.

Systematic Analysis of Transcriptomic Profile of Renal Cell Carcinoma under Long-Term Hypoxia Using Next-Generation Sequencing and Bioinformatics

Patients with clear cell renal cell carcinoma (ccRCC) are often diagnosed with both von Hippel-Lindau (VHL) mutations and the constitutive activation of hypoxia-inducible factor-dependent signaling. In this study, we investigated the effects of long-term hypoxia in 786-O, a VHL-defective renal cell carcinoma cell line, to identify potential genes and microRNAs associated with tumor malignancy. The transcriptomic profiles of 786-O under normoxia, short-term hypoxia and long-term hypoxia were analyzed using next-generation sequencing. The results showed that long-term hypoxia promoted the ability of colony formation and transwell migration compared to normoxia. In addition, the differentially expressed genes induced by long-term hypoxia were involved in various biological processes including cell proliferation, the tumor necrosis factor signaling pathway, basal cell carcinoma and cancer pathways. The upregulated (L1CAM and FBN1) and downregulated (AUTS2, MAPT, AGT and USH1C) genes in 786-O under long-term hypoxia were also observed in clinical ccRCC samples along with malignant grade. The expressions of these genes were significantly correlated with survival outcomes in patients with renal cancer. We also found that long-term hypoxia in 786-O resulted in decreased expressions of hsa-mir-100 and hsa-mir-378 and this effect was also observed in samples of metastatic ccRCC compared to samples of non-metastatic ccRCC. These findings may provide a new direction for the study of potential molecular mechanisms associated with the progression of ccRCC.

Single nucleotide polymorphisms as prognostic and predictive biomarkers in renal cell carcinoma

Despite major advances in the knowledge of the molecular basis of renal cell carcinoma, prognosis is still defined using clinical and pathological parameters. Moreover, no valid predictive biomarkers exist to help us selecting the best treatment for each patient. With these premises, we aimed to analyse the expression and to determine the prognostic and predictive value of 64 key single nucleotide polymorphisms in 18 genes related with angiogenesis or metabolism of antiangiogenics in two cohorts of patients with localized and advanced renal cell cancer treated at our institution. The presence of the selected single nucleotide polymorphisms was correlated with clinical features, disease free survival, overall survival and response rate. In patients with localized renal cell cancer, 5 of these polymorphisms in 3 genes involved in angiogenesis predicted for worse disease free survival (VEGFR2: rs10013228; PDGFRA: rs2228230) or shorter overall survival (VEGFR2: rs10013228; VEGFR3: rs6877011, rs307826) (p < 0.05). Rs2071559 in VEGFR2 showed a protective effect (p = 0.01). In the advanced setting, 5 SNPs determined inferior overall survival (IL8: rs2227543, PRKAR1B: rs9800958, PDGFRB: rs2302273; p = 0.05) or worse response rate (VEGFA: rs699947, rs3025010 p ≤ 0.01)). Additionally 1 single nucleotide polymorphism in VEGFB predicted for better response rate rs594942 (p = 0.03). Genetic analysis of renal cell carcinoma patients might provide valuable prognostic/predictive information. A set of SNPs in genes critical to angiogenesis and metabolism of antiangiogenics drugs seem to determine post-surgical outcomes and treatment response in our series.

Renal Cell Carcinoma: Molecular Aspects

Renal cell carcinoma is the most common form of the kidney cancer accounting for more than 85% of the cases of which clear cell renal cell carcinoma (ccRCC) is the major histological subtype. The central molecular signature for ccRCC pathogenesis is the biallelic inactivation of VHL gene due to the presence of mutations/hyper-methylation/complete gene loss, which results in the downstream HIF activation. These events lead to increased tyrosine kinase receptor signalling pathways (RAS/MEK/ERK pathway, PI3K/AKT/mTOR pathway and NF-κB pathway), which through their downstream effector proteins causes the cell to proliferate and migrate. Recent studies have shown that VHL inactivation alone is not sufficient to induce the tumor. Mutations in numerous other genes that codes for chromatin modifiers (PBRM1, SETD2 and BAP1) and signalling proteins (PTEN and mTOR) have been identified along with activation of alternate signalling pathways like STAT and Sonic Hedgehog (SHH) pathway. It has also been shown that STAT pathway also works cooperatively with HIF to enhance the tumor progression. However, SHH pathway reactivation resulted in tumor regardless of the VHL status, indicating the complex nature of the tumor at the molecular level. Therefore, understanding the complete aetiology of ccRCC is important for future therapeutics.

A CARP-1 functional mimetic loaded vitamin E-TPGS micellar nano-formulation for inhibition of renal cell carcinoma

Current treatments for Renal Cell Carcinoma (RCC) include a combination of surgery, targeted therapy, and immunotherapy. Emergence of resistant RCCs contributes to failure of drugs and poor prognosis, and thus warrants development of new and improved treatment options for RCCs. Here we generated and characterized RCC cells that are resistant to Everolimus, a frontline mToR-targeted therapy, and tested whether our novel class of CARP-1 functional mimetic (CFM) compounds inhibit parental and Everolimus-resistant RCC cells. CFMs inhibited RCC cell viability in a dose-dependent manner that was comparable to Everolimus treatments. The GI₅₀ dose of Everolimus for parental A498 cells was ∼1.2μM while it was <0.02μM for the parental UOK262 and UOK268 cells. The GI₅₀ dose for Everolimus-resistant A498, UOK262, and UOK268 cells were ≥10.0μM, 1.8-7.0μM, and 7.0-≥10.0μM, respectively. CFM-4 and its novel analog CFM-4.16 inhibited viabilities of Everolimus resistant RCC cells albeit CFM-4.16 was more effective than CFM-4. CFM-dependent loss of RCC cell viabilities was due in part to reduced cyclin B1 levels, activation of pro-apoptotic, stress-activated protein kinases (SAPKs), and apoptosis. CFM-4.16 suppressed growth of resistant RCC cells in three-dimensional suspension cultures. However, CFMs are hydrophobic and their intravenous administration and dose escalation for in-vivo studies remain challenging. In this study, we encapsulated CFM-4.16 in Vitamin-E TPGS-based- nanomicelles that resulted in its water-soluble formulation with higher CFM-4.16 loading (30% w/w). This CFM-4.16 formulation inhibited viability of parental and Everolimus-resistant RCC cells in vitro, and suppressed growth of parental A498 RCC-cell-derived xenografts in part by stimulating apoptosis. These findings portent promising therapeutic potential of CFM-4.16 for treatment of RCCs.

Cabozantinib: an Active Novel Multikinase Inhibitor in Renal Cell Carcinoma

Clear cell renal cell carcinoma (RCC) is characterized by inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene. VHL loss drives tumor angiogenesis and accounts for the clinical activity of VEGF receptor (VEGFR) tyrosine kinase inhibitors (TKIs), the first-line standard of care for advanced RCC. Within the last year, three new second-line treatments have received FDA approval for use after anti-angiogenic therapy: the immune checkpoint inhibitor nivolumab, the TKI cabozantinib, and the combination of the TKI lenvatinib and the mTOR inhibitor everolimus. Cabozantinib inhibits VEGFRs, MET, and AXL, kinases that promote tumorigenesis, angiogenesis, metastasis, and drug resistance. Compared with everolimus, cabozantinib has shown statistically significant improvements in the three key efficacy endpoints of overall survival, progression-free survival, and objective response rate in patients with RCC who were previously treated with a VEGFR TKI. Herein, we summarize the translational research and clinical development that led to approval of cabozantinib as second-line therapy in RCC.

Paclitaxel Promotes Cell Apoptosis in Uterine Leiomyomas

Uterine leiomyomas are common clinical gynecological tumors, which are a major health concern for many women. In the current study, we aimed to investigate the effect of paclitaxel (PTX) on uterine leiomyomas. A mouse model of uterine leiomyomas was established by estradiol benzoate, followed by treatment with increasing doses of PTX. PTX showed no dose-limiting toxicity that affected the survival of mice, and was able to restore the apoptosis level of uterus tissues of the model mice to normal levels. In this study, we discovered that PTX played a critical role in promoting apoptosis in the mouse model of uterine leiomyomas, which provides a new insight into the therapy of uterine leiomyomas.

Action of YM155 on clear cell renal cell carcinoma does not depend on survivin expression levels

The dioxonapthoimidazolium YM155 is a survivin suppressant which has been investigated as an anticancer agent in clinical trials. Here, we investigated its growth inhibitory properties on a panel of immortalized and patient derived renal cell carcinoma (RCC) cell lines which were either deficient in the tumour suppressor von Hippel-Lindau (VHL) protein or possessed a functional copy. Neither the VHL status nor the survivin expression levels of these cell lines influenced their susceptibility to growth inhibition by YM155. Of the various RCC lines, the papillary subtype was more resistant to YM155, suggesting that the therapeutic efficacy of YM155 may be restricted to clear cell subtypes. YM155 was equally potent in cells (RCC786.0) in which survivin expression had been stably silenced or overexpressed, implicating a limited reliance on survivin in the mode of action of YM155. A follow-up in-vitro high throughput RNA microarray identified possible targets of YM155 apart from survivin. Selected genes (ID1, FOXO1, CYLD) that were differentially expressed in YM155-sensitive RCC cells and relevant to RCC pathology were validated with real-time PCR and western immunoblotting analyses. Thus, there is corroboratory evidence that the growth inhibitory activity of YM155 in RCC cell lines is not exclusively mediated by its suppression of survivin. In view of the growing importance of combination therapy in oncology, we showed that a combination of YM155 and sorafenib at ½ x IC50 concentrations was synergistic on RCC786.0 cells. However, when tested intraperitoneally on a murine xenograft model derived from a nephrectomised patient with clear cell RCC, a combination of suboptimal doses of both drugs failed to arrest tumour progression. The absence of synergy in vivo highlighted the need to further optimize the dosing schedules of YM155 and sorafenib, as well as their routes of administration. It also implied that the expression of other oncogenic proteins which YM155 may target is either low or absent in this clear cell RCC.

The potential of organoids in urological cancer research

Technical advances in the development of organoid systems enable cell lines, primary adult cells, or stem or progenitor cells to develop into diverse, multicellular entities, which can self-renew, self-organize, and differentiate. These 3D organoid cultures have proven to be of value in increasing our understanding of the biology of disease and offer the potential of regenerative and genetic therapies. The successful application of 3D organoids derived from adult tissue into urological cancer research can further our understanding of these diseases and could also provide preclinical cancer models to realize the precision medicine paradigm by therapeutic screening of individual patient samples ex vivo. Kidney organoids derived from induced pluripotent stem cells provide personalized biomarkers, which can be correlated with genetic and clinical information. Organoid models can also improve our comprehension of aspects of particular diseases; for example, in prostate cancer, 3D organoids can aid in the identification of tumour-initiating cells from an epithelial cell lineage. Furthermore, kidney organoid differentiation from human pluripotent stem cells enables gene editing to model disease in kidney tubular epithelial cells. State-of-the-art human organoid cultures have potential as tools in basic and clinical research in renal, bladder, and prostatic diseases.

Hereditary leiomyomatosis and renal cell cancer syndrome: An update and review

Hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome is a rare genetic disorder that predisposes individuals to multiple cutaneous leiomyomas, renal cell carcinomas, and in women, uterine leiomyomas. Also known as Reed syndrome, it is caused by a germline heterozygous mutation of the fumarate hydratase tumor suppressor gene. HLRCC is associated with significant morbidity because of pain from cutaneous and uterine leiomyomas, the cutaneous pain often of unique character. Although genetic testing is currently considered the criterion standard to diagnose HLRCC, newer immunohistochemistry markers may provide rapid and cost effective alternatives to genetic testing. Because of the potentially aggressive nature of renal cell carcinomas that develop as early as in childhood, close annual cancer surveillance is desirable in individuals with HLRCC. In this review, we offer an update and an approach to the diagnosis, management, and renal cancer surveillance in HLRCC.

Effective implementation of novel MET pharmacodynamic assays in translational studies

MET tyrosine kinase (TK) dysregulation is significantly implicated in many types of cancer. Despite over 20 years of drug development to target MET in cancers, a pure anti-MET therapeutic has not yet received market approval. The failure of two recently concluded phase III trials point to a major weakness in biomarker strategies to identify patients who will benefit most from MET therapies. The capability to interrogate oncogenic mutations in MET via circulating tumor DNA (ctDNA) provides an important advancement in identification and stratification of patients for MET therapy. However, a wide range in type and frequency of these mutations suggest there is a need to carefully link these mutations to MET dysregulation, at least in proof-of-concept studies. In this review, we elaborate how we can utilize recently developed and validated pharmacodynamic biomarkers of MET not only to show target engagement, but more importantly to quantitatively measure MET dysregulation in tumor tissues. The MET assay endpoints provide evidence of both canonical and non-canonical MET signaling, can be used as "effect markers" to define biologically effective doses (BEDs) for molecularly targeted drugs, confirm mechanism-of-action in testing combination of drugs, and establish whether a diagnostic test is reporting MET dysregulation. We have established standard operating procedures for tumor biopsy collections to control pre-analytical variables that have produced valid results in proof-of-concept studies. The reagents and procedures are made available to the research community for potential implementation on multiple platforms such as ELISA, quantitative immunofluorescence assay (qIFA), and immuno-MRM assays.

Potential role of gene-environment interactions in ion transport mechanisms in the etiology of renal cell cancer

We investigated the ion transport mechanism (ITM) in renal cell cancer (RCC) etiology using gene-environment interactions between candidate single nucleotide polymorphisms (SNPs) and associated environmental factors, including dietary intakes of sodium, potassium and fluid, hypertension and diuretic medication. A literature-based selection of 13 SNPs in ten ITM genes were successfully genotyped in toenail DNA of 3,048 subcohort members and 419 RCC cases from the Netherlands Cohort Study. Diet and lifestyle were measured with baseline questionnaires. Cox regression analyses were conducted for main effects and gene-environment interactions. ADD1_rs4961 was significantly associated with RCC risk, showing a Hazard Ratio (HR) of 1.24 (95% confidence intervals (CI): 1.01–1.53) for the GT + TT (versus GG) genotype. Four of 65 tested gene-environment interactions were statistically significant. Three of these interactions clustered in SLC9A3_rs4957061, including the ones with fluid and potassium intake, and diuretic medication. For fluid intake, the RCC risk was significantly lower for high versus low intake in participants with the CC genotype (HR(95% CI): 0.47(0.26–0.86)), but not for the CT + TT genotype (P-interaction = 0.002). None of the main genetic effects and gene-environment interactions remained significant after adjustment for multiple testing. Data do not support the general hypothesis that the ITM is a disease mechanism in RCC etiology.

Structured assessment and followup for patients with hereditary kidney tumour syndromes

INTRODUCTION

Optimal clinical assessment and subsequent followup of patients with or suspected of having a hereditary renal cell carcinoma syndrome (hRCC) is not standardized and practice varies widely. We propose protocols to optimize these processes in patients with hRCC to encourage a more uniform approach to management that can then be evaluated.

METHODS

A review of the literature, including existing guidelines, was carried out for the years 1985-2015. Expert consensus was used to define recommendations for initial assessment and followup.

RESULTS

Recommendations for newly diagnosed patients' assessment and optimal ages to initiate followup protocols for von Hippel Lindau disease (VHL), hereditary papillary renal cancer (HPRC), hereditary leiomyomatosis with renal cell carcinoma (HLRCC), Birt-Hogg-Dubé syndrome (BHD), familial paraganglioma-pheochromocytoma syndromes (PGL-PCC), and tuberous sclerosis (TSC) are proposed.

CONCLUSIONS

Our proposed consensus for structured assessment and followup is intended as a roadmap for the care of patients with hRCC to guide healthcare providers. Although the list of syndromes included is not exhaustive, the document serves as a starting point for future updates.

CHIP-mediated degradation of transglutaminase 2 negatively regulates tumor growth and angiogenesis in renal cancer

The multifunctional enzyme transglutaminase 2 (TG2) primarily catalyzes cross-linking reactions of proteins via (γ-glutamyl) lysine bonds. Several recent findings indicate that altered regulation of intracellular TG2 levels affects renal cancer. Elevated TG2 expression is observed in renal cancer. However, the molecular mechanism underlying TG2 degradation is not completely understood. Carboxyl-terminus of Hsp70-interacting protein (CHIP) functions as an ubiquitin E3 ligase. Previous studies reveal that CHIP deficiency mice displayed a reduced life span with accelerated aging in kidney tissues. Here we show that CHIP promotes polyubiquitination of TG2 and its subsequent proteasomal degradation. In addition, TG2 upregulation contributes to enhanced kidney tumorigenesis. Furthermore, CHIP-mediated TG2 downregulation is critical for the suppression of kidney tumor growth and angiogenesis. Notably, our findings are further supported by decreased CHIP expression in human renal cancer tissues and renal cancer cells. The present work reveals that CHIP-mediated TG2 ubiquitination and proteasomal degradation represent a novel regulatory mechanism that controls intracellular TG2 levels. Alterations in this pathway result in TG2 hyperexpression and consequently contribute to renal cancer.

Renal cell carcinoma: Review of etiology, pathophysiology and risk factors

BACKGROUND AND AIMS

The global incidence of renal cell cancer is increasing annually and the causes are multifactorial. Early diagnosis and successful urological procedures with partial or total nephrectomy can be life-saving. However, only up to 10% of RCC patients present with characteristic clinical symptoms. Over 60% are detected incidentally in routine ultrasound examination. The question of screening and preventive measures greatly depends on the cause of the tumor development. For the latter reason, this review focuses on etiology, pathophysiology and risk factors for renal neoplasm.

METHODS

A literature search using the databases Medscape, Pubmed, UpToDate and EBSCO from 1945 to 2015.

RESULTS AND CONCLUSIONS

Genetic predisposition/hereditary disorders, obesity, smoking, various nephrotoxic industrial chemicals, drugs and natural/manmade radioactivity all contribute and enviromental risks are a serious concern in terms of prevention and the need to screen populations at risk. Apropos treatment, current oncological research is directed to blocking cancer cell division and inhibiting angiogenesis based on a knowledge of molecular pathways.

Isoform-specific interactions of the von Hippel-Lindau tumor suppressor protein

Deregulation of the von Hippel-Lindau tumor suppressor protein (pVHL) is considered one of the main causes for malignant renal clear-cell carcinoma (ccRCC) insurgence. In human, pVHL exists in two isoforms, pVHL19 and pVHL30 respectively, displaying comparable tumor suppressor abilities. Mutations of the p53 tumor suppressor gene have been also correlated with ccRCC insurgence and ineffectiveness of treatment. A recent proteomic analysis linked full length pVHL30 with p53 pathway regulation through complex formation with the p14ARF oncosuppressor. The alternatively spliced pVHL19, missing the first 53 residues, lacks this interaction and suggests an asymmetric function of the two pVHL isoforms. Here, we present an integrative bioinformatics and experimental characterization of the pVHL oncosuppressor isoforms. Predictions of the pVHL30 N-terminus three-dimensional structure suggest that it may exist as an ensemble of structured and disordered forms. The results were used to guide Yeast two hybrid experiments to highlight isoform-specific binding properties. We observed that the physical pVHL/p14ARF interaction is specifically mediated by the 53 residue long pVHL30 N-terminal region, suggesting that this N-terminus acts as a further pVHL interaction interface. Of note, we also observed that the shorter pVHL19 isoform shows an unexpected high tendency to form homodimers, suggesting an additional isoform-specific binding specialization.

Quantitative proteomic analysis reveals potential diagnostic markers and pathways involved in pathogenesis of renal cell carcinoma

There are no serum biomarkers for the accurate diagnosis of clear cell renal cell carcinoma (ccRCC). Diagnosis and decision of nephrectomy rely on imaging which is not always accurate. Non-invasive diagnostic biomarkers are urgently required. In this study, we preformed quantitative proteomics analysis on a total of 199 patients including 30 matched pairs of normal kidney and ccRCC using isobaric tags for relative and absolute quantitation (iTRAQ) labeling and LC-MS/MS analysis to identify differentially expressed proteins. We found 55 proteins significantly dysregulated in ccRCC compared to normal kidney tissue. 54 were previously reported to play a role in carcinogenesis, and 39 are secreted proteins. Dysregulation of alpha-enolase (ENO1), L-lactate dehydrogenase A chain (LDHA), heat shock protein beta-1 (HSPB1/Hsp27), and 10 kDa heat shock protein, mitochondrial (HSPE1) was confirmed in two independent sets of patients by western blot and immunohistochemistry. Pathway analysis, validated by PCR, showed glucose metabolism is altered in ccRCC compared to normal kidney tissue. In addition, we examined the utility of Hsp27 as biomarker in serum and urine. In ccRCC patients, Hsp27 was elevated in the urine and serum and high serum Hsp27 was associated with high grade (Grade 3-4) tumors. These data together identify potential diagnostic biomarkers for ccRCC and shed new light on the molecular mechanisms that are dysregulated and contribute to the pathogenesis of ccRCC. Hsp27 is a promising diagnostic marker for ccRCC although further large-scale studies are required. Also, molecular profiling may help pave the road to the discovery of new therapies.

Two single nucleotide polymorphisms in the von Hippel-Lindau tumor suppressor gene in Taiwanese with renal cell carcinoma

Background

Renal cell carcinoma, a common malignant tumor arising from the kidney, occurs in 3.62 and 1.95 cases per one hundred thousand people among men and women, respectively, in Taiwan each year. Approximately 80% of cases are classified as clear-cell renal cell carcinoma. Inactivation of the von Hippel-Lindau tumor suppressor gene has been implicated in the tumorigenic pathway of renal cell carcinoma. Two single nucleotide polymorphisms, rs779805 and rs1642742, located in the promoter and 3′ untranslated regions of the von Hippel-Lindau gene are informative and implicated in the occurrence of renal cell carcinoma worldwide. The aim of this study is to clarify whether these polymorphisms are associated with renal cell carcinoma in Taiwanese. Genomic DNA was isolated from normal and tumor tissues of 19 renal cell carcinoma patients. The samples were screened for allelic polymorphisms by restriction fragment length polymorphism with BsaJ I and Acc I digestion. Reconfirmation was carried out by direct sequencing.

Results

Consistent with Knudson’s two-hit theory, AA to AG somatic mutations were observed in rs779805. In addition, loss of heterozygosity in both rs779805 and rs1642742 was demonstrated in 10 out of 15 RCC patients aged 50 or over. The G allele or AG heterozygote frequencies at these two loci were much higher in patient germline DNA when compared with the control group. After adjusting for age, the frequency of the G allele in both loci was much higher for late onset renal cell carcinoma in the Taiwanese population.

Conclusions

Our current results confirmed that the existence of G allele in both rs779805 and rs1642742 in the von Hippel-Lindau tumor suppressor gene is of importance in renal cell carcinoma tumorigenesis. However, more comprehensive and detailed research is needed to address the clinical relevance. Larger sample size is required to determine the exact power of correlation between these two genetic polymorphisms and renal cell carcinoma.

Electronic supplementary material

The online version of this article (doi:10.1186/1756-0500-7-638) contains supplementary material, which is available to authorized users.

Current understanding of somatic stem cells in leiomyoma formation

OBJECTIVE

To provide a detailed summary of current scientific knowledge of somatic stem cells (SSCs) in murine and human myometrium and their putative implication in leiomyoma formation, as well as to establish new therapeutic options.

DESIGN

Pubmed and Scholar One manuscripts were used to identify the most relevant studies on SSCs and their implications in human myometrium and leiomyomas.

SETTING

University research laboratory-affiliated infertility clinic.

PATIENT(S)

Not applicable.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Not applicable.

RESULT(S)

Despite numerous publications on SSCs, it was not until 2007 that scientific evidence based on the use of 5-bromo-2'-deoxyuridine (BrdU) and side population (SP) methods in murine and human myometrium were first published. Recently, it has been reported that SP cells are present in human leiomyomas; however, to date the pathogenesis of this benign tumor remains unclear. Besides many genetic/epigenetic alterations, changes to steroid hormones and growth factors may also be associated with the impaired function, proliferation, and differentiation of a subset of putative SSCs in human myometrium.

CONCLUSION(S)

These findings open up new possibilities for understanding the origin of this benign tumor and help to develop new nonsurgical approaches for their management.

Lactate dehydrogenase A is a potential prognostic marker in clear cell renal cell carcinoma

Background

Over 90% of cancer-related deaths in clear cell renal cell carcinoma (RCC) are caused by tumor relapse and metastasis. Thus, there is an urgent need for new molecular markers that can potentiate the efficacy of the current clinical-based models of prognosis assessment. The objective of this study is to evaluate the potential significance of lactate dehydrogenase A (LDHA), assessed by immunohistochemical staining, as a prognostic marker in clear cell renal cell carcinoma in relation to clinicopathological features and clinical outcome.

Methods

We assessed the expression of LDHA at the protein level, by immunohistochemistry, and correlated its expression with multiple clinicopathological features including tumor size, clinical stage, histological grade, disease-free and overall survival in 385 patients with primary clear cell renal cell carcinoma. We also correlated the LDHA expression with overall survival, at mRNA level, in an independent data set of 170 clear cell renal cell carcinoma cases from The Cancer Genome Atlas databases. Cox proportional hazards models adjusted for the potential clinicopathological factors were used to test for associations between the LDHA expression and both disease-free survival and overall survival.

Results

There is statistically significant positive correlation between LDHA level of expression and tumor size, clinical stage and histological grade. Moreover, LDHA expression shows significantly inverse correlation with both disease-free survival and overall survival in patients with clear cell renal cell carcinoma. Our results are validated by examining LDHA expression, at the mRNA level, in the independent data set of clear cell renal cell carcinoma cases from The Cancer Genome Atlas databases which also shows that higher lactate dehydrogenase A expression is associated with significantly shorter overall survival.

Conclusion

Our results indicate that LDHA up-regulation can be a predictor of poor prognosis in clear cell renal cell carcinoma. Thus, it represents a potential prognostic biomarker that can boost the accuracy of other prognostic models in patients with clear cell renal cell carcinoma.

Repression of PLA2R1 by c-MYC and HIF-2alpha promotes cancer growth

Loss of secreted phospholipase A2 receptor (PLA2R1) has recently been found to render human primary cells more resistant to senescence whereas increased PLA2R1 expression is able to induce cell cycle arrest, cancer cell death or blockage of cancer cell transformation in vitro, suggesting that PLA2R1 displays tumor suppressive activities. Here we report that PLA2R1 expression strongly decreases in samples of human renal cell carcinoma (RCC). Knockdown of PLA2R1 increases renal cancer cell tumorigenicity supporting a role of PLA2R1 loss to promote in vivo RCC growth. Most RCC result from Von Hippel-Lindau (VHL) tumor suppressor loss-of-function and subsequent gain-of-function of the oncogenic HIF-2alpha/c-MYC pathway. Here, by genetically manipulating VHL, HIF-2alpha and c-MYC, we demonstrate that loss of VHL, stabilization of HIF-2alpha and subsequent increased c-MYC activity, binding and transcriptional repression, through induction of PLA2R1 DNA methylation closed to PLA2R1 transcriptional start site, results in decreased PLA2R1 transcription. Our results describe for the first time an oncogenic pathway leading to PLA2R1 transcriptional repression and the importance of this repression for tumor growth.

Biomarkers in rare diseases

BACKGROUND

Nowadays 7,000 rare diseases (RDs) have been identified with a prevalence less than 5/10,000. Despite of the enormous effort the European Union (EU) has already invested in this field, still 4,000 RDs remain orphan of genetic diagnosis and causative gene identification. The genetic definition of RDs represents a prerequisite for being diagnosed, for having a robust prevention, for entering in a specific standard of care, and ultimately, for being included in clinical trials, often via personalized medicine. It is well established that biomarkers can offer a way to speed up research by understanding the pathophysiological mechanisms of diseases. In particular, biomarkers will offer an invaluable tool for monitoring disease progression, prognosis and response to drug treatment.

METHODS

In this review, we summarize the different types of biomarkers and their importance as well as their translational applications in RDs. We have reviewed the current knowledge on biomarkers state-of-the-art via literature data, specific websites and EU sources regarding past, pending and current projects.

RESULTS

Here we provide a comprehensive scenario of biomarkers research, its applications in clinical practice, with special emphasis on translational research applicable to diagnostic and clinical trials. The experience of the EU project BIO-NMD is also mentioned.

CONCLUSION

Biomarkers represent key features in both diagnostics and research on rare diseases and will encounter wide exploitation in translational and personalized medicine.

Significance of gene expression analysis of renal cell carcinoma

Renal cell carcinoma (RCC) describes a family of epithelial tumors arising from within the kidney. Each subtype of RCC presents a unique clinical picture with varied tumor biology, patient prognosis and response to treatment. Gene expression profiling offers the ability to analyze thousands of candidate genes in high-throughput arrays and has led to a greater knowledge of the molecular genetics of RCC. This powerful technology can identify RCC subtypes, recapitulating and refining the current histological classifications. Gene expression data also promise to advance current staging systems and improve prognostic information for patients and clinicians. Understanding the genetic signature of RCC tumors will allow for sophisticated application of systemic and targeted therapies, improving patient response and minimizing unnecessary exposure of patients to treatment toxicities. This article reviews the significance of gene expression analysis in the understanding of tumor biology and RCC treatment.

FUT11 as a potential biomarker of clear cell renal cell carcinoma progression based on meta-analysis of gene expression data

In this paper, we provide a comprehensive summary of available clear cell renal cell carcinoma (ccRCC) microarray data in the form of meta-analysis of genes differentially regulated in tumors as compared to healthy tissue, using effect size to measure the strength of a relationship between the disease and gene expression. We identified 725 differentially regulated genes, with a number of interesting targets, such as TMEM213, SMIM5, or ATPases: ATP6V0A4 and ATP6V1G3, of which limited or no information is available in terms of their function in ccRCC pathology. Downregulated genes tended to represent pathways related to tissue remodeling, blood clotting, vasodilation, and energy metabolism, while upregulated genes were classified into pathways generally deregulated in cancers: immune system response, inflammatory response, angiogenesis, and apoptosis. One hundred fifteen deregulated genes were included in network analysis, with EGLN3, AP-2, NR3C1, HIF1A, and EPAS1 (gene encoding HIF2-α) as points of functional convergence, but, interestingly, 610 genes failed to join previously identified molecular networks. Furthermore, we validated the expression of 14 top deregulated genes in independent sample set of 32 ccRCC tumors by qPCR and tested if it could serve as a marker of disease progression. We found a correlation of high fucosyltransferase 11 (FUT11) expression with non-symptomatic course of the disease, which suggests that FUT11's expression might be potentially used as a biomarker of disease progression.

Mechanisms of chemical carcinogenesis in the kidneys

Chemical carcinogens are substances which induce malignant tumours, increase their incidence or decrease the time taken for tumour formation. Often, exposure to chemical carcinogens results in tissue specific patterns of tumorigenicity. The very same anatomical, biochemical and physiological specialisations which permit the kidney to perform its vital roles in maintaining tissue homeostasis may in fact increase the risk of carcinogen exposure and contribute to the organ specific carcinogenicity observed with numerous kidney carcinogens. This review will address the numerous mechanisms which play a role in the concentration, bioactivation, and uptake of substances from both the urine and blood which significantly increase the risk of cancer in the kidney.

A novel germline mutation in BAP1 predisposes to familial clear-cell renal cell carcinoma

Renal cell carcinoma (RCC) clusters in some families. Familial RCC arises from mutations in several genes, including the von Hippel-Lindau (VHL) tumor suppressor, which is also mutated in sporadic RCC. However, a significant percentage of familial RCC remains unexplained. Recently, we discovered that the BRCA1-associated protein-1 (BAP1) gene is mutated in sporadic RCC. The BAP1 gene encodes a nuclear deubiquitinase and appears to be a classic two-hit tumor suppressor gene. Somatic BAP1 mutations are associated with high-grade, clear-cell RCC (ccRCC) and poor patient outcomes. To determine whether BAP1 predisposes to familial RCC, the BAP1 gene was sequenced in 83 unrelated probands with unexplained familial RCC. Interestingly, a novel variant (c.41T>A; p.L14H) was uncovered that cosegregated with the RCC phenotype. The p.L14H variant targets a highly conserved residue in the catalytic domain, which is frequently targeted by missense mutations. The family with the novel BAP1 variant was characterized by early-onset ccRCC, occasionally of high Fuhrman grade, and lacked other features that typify VHL syndrome. These findings suggest that BAP1 is an early-onset familial RCC predisposing gene.

IMPLICATIONS

BAP1 mutations may drive tumor development in a subset of patients with inherited renal cell cancer.