2009 update on the classification of renal epithelial tumors in adults

Preclinical Modeling of Tumor Growth and Angiogenesis Inhibition to Describe Pazopanib Clinical Effects in Renal Cell Carcinoma

The objective was to leverage tumor size data from preclinical experiments to propose a model of tumor growth and angiogenesis inhibition for the analysis of pazopanib efficacy in renal cell carcinoma (RCC) patients. We analyzed tumor data in mice with RCC CAKI‐2 cell line treated with pazopanib. Clinical tumor size data obtained in a subset of patients with RCC were also analyzed. A model accounting for the processes of tumor growth, angiogenesis, and drug effect was developed. The final tumor model was composed of two variables: the tumor and its vasculature. Our results show that, both in mice and in humans, pazopanib exhibits a dual mechanism of action, and parameter estimation values highlight the inherent difference between mice and humans on the time scale of tumor size response. We developed a semimechanistic tumor growth inhibition model that takes into account tumor angiogenesis in order to describe the effects of pazopanib in mice. Analyzing rich preclinical data with a semimechanistic model may be a relevant approach to facilitate the description of sparse clinical longitudinal tumor size data and to provide insights for the understanding of the drug mechanisms of action in patients.

iTRAQ-Based Quantitative Proteomic Analysis Identified HSC71 as a Novel Serum Biomarker for Renal Cell Carcinoma

Renal cell carcinoma (RCC) is one of the most lethal urologic cancers and about 80% of RCC are of the clear-cell type (ccRCC). However, there are no serum biomarkers for the accurate diagnosis of RCC. In this study, we performed a quantitative proteomic analysis on serum samples from ccRCC patients and control group by using isobaric tag for relative and absolute quantitation (iTRAQ) labeling and LC-MS/MS analysis to access differentially expressed proteins. Overall, 16 proteins were significantly upregulated (ratio > 1.5) and 14 proteins were significantly downregulated (ratio < 0.67) in early-stage ccRCC compared to control group. HSC71 was selected and subsequently validated by Western blot in six independent sets of patients. ELISA subsequently confirmed HSC71 as a potential serum biomarker for distinguishing RCC from benign urologic disease with an operating characteristic curve (ROC) area under the curve (AUC) of 0.86 (95% confidence interval (CI), 0.76~0.96), achieving sensitivity of 87% (95% CI 69%~96%) at a specificity of 80% (95% CI 61~92%) with a threshold of 15 ng/mL. iTRAQ-based quantitative proteomic analysis led to identification of serum HSC71 as a novel serum biomarker of RCC, particularly useful in early diagnosis of ccRCC.

The Axl-Regulating Tumor Suppressor miR-34a Is Increased in ccRCC but Does Not Correlate with Axl mRNA or Axl Protein Levels

BACKGROUND

High expression of the receptor tyrosine kinase Axl is associated with poor prognosis in patients with Renal Cell Carcinoma (RCC), the most common malignancy of the kidney. The miR-34a has been shown to directly regulate Axl in cancer cells. The miR-34a is a mediator of p53-dependent tumor suppression, and low expression of miR-34a has been associated with worse prognosis in several cancers. Our aim was to elucidate whether miR-34a or the other members of the miR-34 family (miR-34b/c) regulate Axl in RCC.

METHODOLOGY AND RESULTS

Using western blot, flow cytometry, and RT-qPCR, we showed that Axl mRNA and protein are downregulated in 786-O cells by miR-34a and miR-34c but not by miR-34b. A luciferase reporter assay demonstrated direct interaction between the Axl 3' UTR and miR-34a and miR-34c. The levels of miR-34a/b/c were measured in tumor tissue in a cohort of 198 RCC patients, and the levels of miR-34a were found to be upregulated in clear cell RCC (ccRCC) tumors, but not associated with patient outcome. Neither of the miR-34 family members correlated with Axl mRNA, soluble Axl protein in serum, nor with immunohistochemistry of Axl in tumor tissue. In addition, we measured mRNA levels of a known miR-34a target, HNF4A, and found the HNF4A levels to be decreased in ccRCC tumors, but unexpectedly correlated positively rather than negatively with miR-34a.

CONCLUSIONS

Although miR-34a and miR-34c can regulate Axl expression in vitro, our data indicates that the miR-34 family members are not the primary regulators of Axl expression in RCC.

Renal cell carcinoma: histological classification and correlation with imaging findings

Renal cell carcinoma (RCC) is the seventh most common histological type of cancer in the Western world and has shown a sustained increase in its prevalence. The histological classification of RCCs is of utmost importance, considering the significant prognostic and therapeutic implications of its histological subtypes. Imaging methods play an outstanding role in the diagnosis, staging and follow-up of RCC. Clear cell, papillary and chromophobe are the most common histological subtypes of RCC, and their preoperative radiological characterization, either followed or not by confirmatory percutaneous biopsy, may be particularly useful in cases of poor surgical condition, metastatic disease, central mass in a solitary kidney, and in patients eligible for molecular targeted therapy. New strategies recently developed for treating renal cancer, such as cryo and radiofrequency ablation, molecularly targeted therapy and active surveillance also require appropriate preoperative characterization of renal masses. Less common histological types, although sharing nonspecific imaging features, may be suspected on the basis of clinical and epidemiological data. The present study is aimed at reviewing the main clinical and imaging findings of histological RCC subtypes.

Molecular aberrations, targeted therapy, and renal cell carcinoma: current state-of-the-art

Renal cell carcinoma (RCC) is among the most prevalent malignancies in the USA. Most RCCs are sporadic, but hereditary syndromes associated with RCC account for 2-3 % of cases and include von Hippel-Lindau, hereditary leiomyomatosis, Birt-Hogg-Dube, tuberous sclerosis, hereditary papillary RCC, and familial renal carcinoma. In the past decade, our understanding of the genetic mutations associated with sporadic forms of RCC has increased considerably, with the most common mutations in clear cell RCC seen in the VHL, PBRM1, BAP1, and SETD2 genes. Among these, BAP1 mutations are associated with aggressive disease and decreased survival. Several targeted therapies for advanced RCC have been approved and include sunitinib, sorafenib, pazopanib, axitinib (tyrosine kinase inhibitors (TKIs) with anti-vascular endothelial growth factor (VEGFR) activity), everolimus, and temsirolimus (TKIs that inhibit mTORC1, the downstream part of the PI3K/AKT/mTOR pathway). High-dose interleukin 2 (IL-2) immunotherapy and the combination of bevacizumab plus interferon-α are also approved treatments. At present, there are no predictive genetic markers to direct therapy for RCC, perhaps because the vast majority of trials have been evaluated in unselected patient populations, with advanced metastatic disease. This review will focus on our current understanding of the molecular genetics of RCC, and how this may inform therapeutics.

Foci of Entotic Nuclei in Different Grades of Noninherited Renal Cell Cancers

We report here an intriguing pattern in nuclear appearance of renal clear cell cancer. In low grade clear cell cancer, detailed examination showed that in many cells, two or more nuclei were within the confines of a single cell membrane. This likely resulted from a cell being contained within its neighboring cell. Consequently, this resulted in appearance of multicellularity. This appearance of the nuclei were not associated with mitotic figures, suggesting that these did not result from nuclear fission. Additionally, the cells containing this nuclei did not show any evidence of cytokinesis including equatorial tapering, suggesting that the process may have resulted from cytokinesis failure. In some sections of higher grade clear cell cancer, these appearance were higher, though we did not observe any frank syncytium formation. On careful observation, there were isolated events of fusion of nuclei within a single cell in different grades of renal cell cancers. There occurrence was more frequent in higher grades of clear cell renal cancer and metastatic clear cell carcinoma. These features were also demonstrable in multiple fields of lower grades of clear cell carcinoma. This phenomenon of entosis may contribute to aneuploidy and tumor progression to dysplastic stages and genomic instability in renal cancers. Future studies are aimed at delineating the cell-cell boundaries and the mechanism contributing to this observation, either from peripheral cell engulfing or failure of cytosolic division for cell separation.

Kidney cancer in Lebanon: a specific histological distribution?

BACKGROUND

Kidney cancer is the third most frequent urologic cancer in Lebanon after prostate and bladder cancer, accounting for 1.5% of all diagnosed cancers. In this paper, we report the histologic characteristics and distribution of kidney cancer, never described in Lebanon or the Middle East.

MATERIALS AND METHODS

Pathology results of operated kidney cancer were collected during a two year period (2010-2011) from two different Lebanese hospitals (Hotel-Dieu de France University Hospital and Saint Joseph Hospital). A total of 124 reports were reviewed and analyzed according to WHO classification of 2009.

RESULTS

The 124 patients diagnosed with kidney cancer had a median age of 62.4 [18-86], 75% being men and 25% women. Some 71 % of the lesions were renal cell carcinoma (RCC), 25.8% had a urothelial histology, 1.6% were lymphomas and 1.6% were metastases to the kidney. Patients having RCC had a median age of 60.3 [18-85], 77.3% were men and 22.7% women. Of the RCCs, 59.1% were clear cell carcinoma, 22.7% papillary, 11.4% chromophobic, 3.4% rom the collecting ducts of Bellini and 3.4% were not otherwise classified.

CONCLUSIONS

Histological distribution of Lebanese kidney cancer seems unusual when compared to the literature. The percentage of urothelial renal pelvis tumors is strikingly high. Moreover, clear cell carcinoma accounts for only 59.1% of RCCS in contrast to the 75% described elsewhere, while papillary carcinoma represents more than 22.7% compared to 10%.

A tumor-specific microRNA signature predicts survival in clear cell renal cell carcinoma

PURPOSE

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancers in adults, and microRNAs (miRNAs) differentially expressed in ccRCC tumors have been identified and proposed to predict prognosis. In the present study, we comprehensively analyzed the genome-wide miRNA expression profiles in ccRCC, with the aim to generate a tumor-specific miRNA signature of prognostic values.

METHODS

The miRNA profiles in tumor and the adjacent normal tissue were analyzed, and the association of the differentially expressed miRNAs with patient survival was examined with univariate Cox regression analysis. Finally, a tumor-specific miRNA signature was generated and examined with Kaplan-Meier survival, univariate, and multivariate Cox regression analyses.

RESULTS

A total of 147 miRNAs were found differentially expressed between tumor and matched non-tumor tissues from 58 ccRCC patients. The prognostic values of these differentially expressed miRNAs were subsequently analyzed in the 411 ccRCC patients, and 22 miRNAs were found significantly correlated with patient survival. Finally, a tumor-specific miRNA signature of 22 miRNAs was generated and validated as an independent prognostic parameter.

CONCLUSIONS

A tumor-specific miRNA signature consisting of 22 miRNAs was identified and validated as an independent prognostic factor, which could serve as a novel biomarker for ccRCC prognostication and help in predicting treatment outcome.

Survival Outcomes and Tumor IMP3 Expression in Patients with Sarcomatoid Metastatic Renal Cell Carcinoma

Metastatic renal cell carcinoma with sarcomatoid histology (SmRCC) is associated with poor survival. No data is available from randomized trials on the efficacy of vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTOR) inhibitors in SmRCC. We identified SmRCC patients from a single institutional database. To identify predictive and prognostic biomarkers, immunohistochemistry (IHC) analysis was performed on the tumor samples for downstream targets of VEGF and mTOR pathways. Survival outcomes were stratified by IHC analysis, extent of sarcomatoid component, Memorial Sloan-Kettering Cancer Center (MSKCC), and Heng risk criteria. Twenty-seven patients with SmRCC were included. First line therapy included targeted therapy (n = 19), immunotherapy (n = 4), cytotoxic chemotherapy (n = 1), and no treatment (n = 3). Median OS was 8.2 months (95% CI 3.8-14.2 months). Median survival in months, based on MSKCC and Heng risk groups, was favorable 89.3 versus 84.5, intermediate 9.5 versus 12.7, and poor 3.9 versus 5.1. None of the IHC markers predicted outcomes of treatment with VEGF or mTOR inhibitors. Only tumor IMP3 expression was associated with inferior OS, although not statistically significant (IMP3 negative 14.2 versus IMP3 positive 4.9 months; HR 0.46, 95% CI 0.16-1.21; P = 0.12). The study was limited by small sample size.

Loss of PBRM1 and BAP1 expression is less common in non-clear cell renal cell carcinoma than in clear cell renal cell carcinoma

BACKGROUND

Recurrent mutations in polybromo-1 (PBRM1, ~40%) and BRCA1-associated protein-1 (BAP1, ~10%) occur in clear cell renal cell carcinoma (ccRCC), but their prevalence in non-ccRCC or renal oncocytoma (RO) is unknown. We evaluated loss of PBRM1 and BAP1 staining in ccRCC, papillary RCC (pRCC), chromophobe RCC (chRCC), and RO tumors using an immunohistochemistry assay in which negative staining was associated with loss-of-function mutations.

METHODS

We identified 458 patients treated surgically for ccRCC, pRCC, chRCC, and RO between 2004 and 2012. We performed immunohistochemistry assays to evaluate PBRM1 and BAP1 protein expression to classify tumors as PBRM1 or BAP1 negative. We compared loss of staining of these 2 proteins in ccRCC and non-ccRCC using the Fisher exact test.

RESULTS

For the total cohort of 458 patients, we successfully stained both PBRM1 and BAP1 in 408 tumor samples. Consistent with the mutation rate, loss of PBRM1 and BAP1 staining occurred in 43% (80/187) and 10% (18/187) of ccRCC cases, respectively. However, loss of PBRM1 staining occurred in only 3% (2/59), 6% (1/17), and 0% (0/34) of pRCC, chRCC, and RO tumors, respectively (P<0.0001). BAP1 loss was not observed in any of the pRCC (n = 61), chRCC (n = 17), or RO (n = 34) tumors, (P = 0.00021).

CONCLUSION

Our data suggest that biallelic inactivation of PBRM1 or BAP1 is less common in non-ccRCC when compared with ccRCC tumors. These findings suggest that loss of PBRM1 or BAP1 are key events in ccRCC, whereas other pathways may support tumorigenesis in non-ccRCC subtypes.

DNA methylation profiling reveals novel diagnostic biomarkers in renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is the tenth most commonly diagnosed cancer in the United States. While it is usually lethal when metastatic, RCC is successfully treated with surgery when tumors are confined to the kidney and have low tumor volume. Because most early stage renal tumors do not result in symptoms, there is a strong need for biomarkers that can be used to detect the presence of the cancer as well as to monitor patients during and after therapy.

METHODS

We examined genome-wide DNA methylation alterations in renal cell carcinomas of diverse histologies and benign adjacent kidney tissues from 96 patients.

RESULTS

We observed widespread methylation differences between tumors and benign adjacent tissues, particularly in immune-, G-protein coupled receptor-, and metabolism-related genes. Additionally, we identified a single panel of DNA methylation biomarkers that reliably distinguishes tumor from benign adjacent tissue in all of the most common kidney cancer histologic subtypes, and a second panel does the same specifically for clear cell renal cell carcinoma tumors. This set of biomarkers were validated independently with excellent performance characteristics in more than 1,000 tissues in The Cancer Genome Atlas clear cell, papillary, and chromophobe renal cell carcinoma datasets.

CONCLUSIONS

These DNA methylation profiles provide insights into the etiology of renal cell carcinoma and, most importantly, demonstrate clinically applicable biomarkers for use in early detection of kidney cancer.

The emerging role of extracellular vesicles as biomarkers for urogenital cancers

The knowledge gained from comprehensive profiling projects that aim to define the complex genomic alterations present within cancers will undoubtedly improve our ability to detect and treat those diseases, but the influence of these resources on our understanding of basic cancer biology is still to be demonstrated. Extracellular vesicles have gained considerable attention in past years, both as mediators of intercellular signalling and as potential sources for the discovery of novel cancer biomarkers. In general, research on extracellular vesicles investigates either the basic mechanism of vesicle formation and cargo incorporation, or the isolation of vesicles from available body fluids for biomarker discovery. A deeper understanding of the cargo molecules present in extracellular vesicles obtained from patients with urogenital cancers, through high-throughput proteomics or genomics approaches, will aid in the identification of novel diagnostic and prognostic biomarkers, and can potentially lead to the discovery of new therapeutic targets.

PD-1 as an emerging therapeutic target in renal cell carcinoma: current evidence

Renal cell carcinoma (RCC) is the most common primary malignant tumor of the kidney in adults, representing approximately 4% of all adult cancers in the United States. Metastatic RCC is poorly responsive to conventional cytotoxic chemotherapies but can be sensitive to T-cell-directed immunotherapies such as interferon-α or interleukin-2. Despite recent progress in the application of antiangiogenic "targeted therapies" for metastatic RCC, high-dose interleukin-2 remains an appropriate first-line therapy for select patients and is associated with durable complete remissions in a small fraction of treated patients. Thus, advanced RCC provides a unique opportunity to investigate the requirements for effective antitumor immunotherapy. Accumulating evidence suggests that resistance mechanisms exploited by RCC and other tumor types may play a dominant role in limiting the effectiveness of tumor-reactive adaptive immune responses. Expression of the inhibitory coreceptor programmed cell death-1 (PD-1) on tumor-infiltrating lymphocytes within RCC tumors, as well as the expression of the PD-1 ligand (PD-L1) on RCC tumor cells, are strong negative prognostic markers for disease-specific death in RCC patients. Monoclonal antibodies targeting either PD-1 or PD-L1 have now entered clinic trials and have demonstrated promising antitumor effects for refractory metastatic RCC. This review summarizes the results of published and reported studies of PD-1- and PD-L1-targeted therapies enrolling patients with advanced RCC, focusing on key safety, toxicity, and efficacy end points. Prospects for advanced phase clinical testing and novel therapy combinations with PD-1- and PD-L1-targeted agents are discussed.

Subtyping of renal cortical neoplasms in fine needle aspiration biopsies using a decision tree based on genomic alterations detected by fluorescence in situ hybridization

OBJECTIVES

To improve the overall accuracy of diagnosis in needle biopsies of renal masses, especially small renal masses (SRMs), using fluorescence in situ hybridization (FISH), and to develop a renal cortical neoplasm classification decision tree based on genomic alterations detected by FISH.

PATIENTS AND METHODS

Ex vivo fine needle aspiration biopsies of 122 resected renal cortical neoplasms were subjected to FISH using a series of seven-probe sets to assess gain or loss of 10 chromosomes and rearrangement of the 11q13 locus. Using specimen (nephrectomy)-histology as the 'gold standard', a genomic aberration-based decision tree was generated to classify specimens. The diagnostic potential of the decision tree was assessed by comparing the FISH-based classification and biopsy histology with specimen histology.

RESULTS

Of the 114 biopsies diagnostic by either method, a higher diagnostic yield was achieved by FISH (92 and 96%) than histology alone (82 and 84%) in the 65 biopsies from SRMs (<4 cm) and 49 from larger masses, respectively. An optimized decision tree was constructed based on aberrations detected in eight chromosomes, by which the maximum concordance of classification achieved by FISH was 79%, irrespective of mass size. In SRMs, the overall sensitivity of diagnosis by FISH compared with histopathology was higher for benign oncocytoma, was similar for the chromophobe renal cell carcinoma subtype, and was lower for clear-cell and papillary subtypes. The diagnostic accuracy of classification of needle biopsy specimens (from SRMs) increased from 80% obtained by histology alone to 94% when combining histology and FISH.

CONCLUSION

The present study suggests that a novel FISH assay developed by us has a role to play in assisting in the yield and accuracy of diagnosis of renal cortical neoplasms in needle biopsies in particular, and can help guide the clinical management of patients with SRMs that were non-diagnostic by histology.

MET is a potential target across all papillary renal cell carcinomas: result from a large molecular study of pRCC with CGH array and matching gene expression array

PURPOSE

Papillary renal cell carcinomas (pRCC) are the most common nonclear cell RCC subtype. Germline mutations of the MET oncogene at 7q31 have been detected in patients with hereditary type I pRCC and in 13% of sporadic type I pRCC. Recent report of MET inhibition strengthened the role of c-Met inhibition across pRCC.

EXPERIMENTAL DESIGN

We collected 220 frozen samples of sporadic pRCC through the French RCC Network and quality controlled for percentage of malignant cells >70%. Gene expression was assessed on 98 pRCC using human whole-genome Agilent 8 × 60K arrays. Copy number alterations were analyzed using Agilent Human 2 × 400K and 4× 180K array for type II pRCC and comparative genomic microarray analysis method for type I pRCC. MET gene sequencing was performed on type I pRCC.

RESULTS

MET expression level was high across all pRCC. We identified copy number alterations (gain) in 46% of type II pRCC and in 81% of type I pRCC. Correlation between DNA copy number alterations and mRNA expression level was highly significant. Eleven somatic mutations of MET gene were identified amongst 51 type I pRCC (21.6%), including 4 new mutations. We validated LRRK2 cokinase as highly correlated to MET expression.

CONCLUSION

The present report expands the role of MET activation as a potential target across all pRCC subtypes. These data support investigating MET inhibitors in pRCC in correlation with MET activation status.

Systemic therapy for non-clear cell renal cell carcinomas: a systematic review and meta-analysis

CONTEXT

Clinical data supporting the use of targeted agents for the treatment of metastatic renal cell carcinoma (RCC) are based predominantly on patients with clear cell histology. Little is known about the efficacy of these drugs in non-clear cell variants.

OBJECTIVE

To evaluate the efficacy of different clear cell RCC (ccRCC)-approved targeted agents among patients with non-ccRCC compared with ccRCC.

EVIDENCE ACQUISITION

We conducted a systematic review of electronic databases to identify publications evaluating the outcomes of patients with non-ccRCC treated with targeted agents approved for treatment of ccRCC. Patients with sarcomatoid variant RCC were excluded from the main analysis but were evaluated as an independent cohort. End points of interest were response rate, median progression-free survival (PFS), and median overall survival (OS). Where possible, data were pooled in a meta-analysis. For studies of unselected patients with RCC, the outcomes of patients with non-ccRCC histology were compared with ccRCC. In exploratory analyses, outcomes of non-ccRCC with nonapproved agents were assessed.

EVIDENCE SYNTHESIS

A total of 49 studies comprising 7771 patients were included in the analysis. Of these, 1244 patients (16.0%) had non-ccRCC, 6300 (83.1%) had ccRCC, and 227 (2.9%) had sarcomatoid tumours. The overall response rate for non-ccRCC with targeted agents was 10.5%. In studies directly comparing non-ccRCC and ccRCC, there were significantly lower response rates for non-ccRCC (odds ratio for response: 0.52; 95% confidence interval, 0.40-0.68; p<0.001). For non-ccRCC treated with targeted agents, median PFS and OS were 7.4 and 13.4 mo, respectively; for patients with ccRCC, these were 10.5 mo and 15.7 mo, respectively (p value for difference<0.001 for both parameters).

CONCLUSIONS

Patients with non-clear cell renal cell carcinoma (non-ccRCC) have significantly lower response rates and poorer median progression-free survival and overall survival than those with ccRCC. The optimal treatment of patients with non-ccRCC remains unclear and warrants further study.

PATIENT SUMMARY

Systemic treatments for patients with renal cell carcinoma (RCC) tend to be significantly less effective for non-clear cell RCC, with lower response rates and worse progression-free survival and overall survival when compared with clear cell RCC. Optimal therapy remains unclear and warrants further study.

The miR(21/10b) ratio as a prognostic marker in clear cell renal cell carcinoma

PURPOSE

Clear cell renal cell carcinoma (ccRCC) is the most common type of cancer in the adult kidney, and the prognosis of metastatic ccRCC remains poor with high mortality. In ccRCC, microRNAs (miRs) differentially expressed in tumour tissue have been identified and have been proposed to predict prognosis. The purpose of this study was to evaluate candidate miR markers identified from analysis of The Cancer Genome Atlas (TCGA) datasets in a large RCC cohort and to elucidate whether a ratio of miRs provided additional prognostic information.

EXPERIMENTAL DESIGN

Deep sequencing data from TCGA datasets were analysed using biostatistical methods to identify candidate miRs that correlate with factors such as survival and stage of disease. Candidate miRs were analysed by reverse transcription and quantitative polymerase chain reaction (RT-qPCR) in a cohort of 198 RCC tumours (ccRCC, n=152) and 50 normal kidney samples.

RESULTS

Four candidate miRs (miR-10b, miR-21, miR-101 and miR-223) were selected from the TCGA analysis and analysed in our cohort. Of these, miR-21 and miR-10b were differentially expressed in RCC subtypes and in ccRCC nuclear grades. Individually, the two miRs demonstrated a non-significant trend to correlate with survival. Importantly, the ratio of miR-21/miR10b (miR(21/10b)) correlated significantly with disease severity and survival, a high miR(21/10b) being associated with poor prognosis (P=0.0095). In particular, the miR(21/10b) was found to be an independent prognostic factor in metastasis-free patients (P=0.016; confidence interval (CI) 1.201-5.736).

CONCLUSIONS

We have shown that the miR(21/10b) ratio is an independent prognostic factor for M0 ccRCC patients, which could be useful to identify high-risk M0 patients who could benefit from increased surveillance.

MRI phenotype in renal cancer: is it clinically relevant?

Renal cell carcinoma (RCC) is most commonly diagnosed as an incidental finding on cross-sectional imaging and represents a significant clinical challenge. Although most patients have a surgically curable lesion at the time of diagnosis, the variability in the biologic behavior of the different histologic subtypes and tumor grade of RCC, together with the increasing array of management options, creates uncertainty for the optimal clinical approach to individual patients. State-of-the-art magnetic resonance imaging (MRI) provides a comprehensive assessment of renal lesions that includes multiple forms of tissue contrast as well as functional parameters, which in turn provides information that helps to address this dilemma. In this article, we review this evolving and increasingly comprehensive role of MRI in the detection, characterization, perioperative evaluation, and assessment of the treatment response of renal neoplasms. We emphasize the ability of the imaging "phenotype" of renal masses on MRI to help predict the histologic subtype, grade, and clinical behavior of RCC.

Oncogenic micro-RNAs and Renal Cell Carcinoma

Tumor formation is a complex process that occurs in different steps and involves many cell types, including tumor cells, endothelial cells, and inflammatory cells, which interact to promote growth of the tumor mass and metastasization. Epigenetic alterations occurring in transformed cells result in de-regulation of miRNA expression (a class of small non-coding RNA that regulates multiple functions), which contributes to tumorigenesis. The specific miRNAs, which have an aberrant expression in tumors, are defined as oncomiRNAs, and may be either over- or under-expressed, but down-regulation is most commonly observed. Renal cell carcinoma (RCC) is a frequent form of urologic tumor, associated with an alteration of multiple signaling pathways. Many molecules involved in the progression of RCCs, such as HIF, VEGF, or mammalian target of rapamycin, are possible targets of de-regulated miRNAs. Within tumor mass, the cancer stem cell (CSC) population is a fundamental component that promotes tumor growth. The CSC hypothesis postulates that CSCs have the unique ability to self-renew and to maintain tumor growth and metastasis. CSCs present in RCC were shown to express the mesenchymal stem cell marker CD105 and to exhibit self-renewal and clonogenic properties, as well as the ability to generate serially transplantable tumors. The phenotype of CSC has been related to the potential to undergo the epithelial–mesenchymal transition, which has been linked to the expression pattern of tumorigenic miRNAs or down-regulation of anti-tumor miRNAs. In addition, the pattern of circulating miRNAs may allow discrimination between healthy and tumor patients. Therefore, a miRNA signature may be used as a tumor biomarker for cancer diagnosis, as well as to classify the risk of relapse and metastasis, and for a guide for therapy.

Expression of methionine adenosyltransferase 2A in renal cell carcinomas and potential mechanism for kidney carcinogenesis

Background

Methionine adenosyltransferase 2A (MAT2A) is an enzyme that catalyzes the formation of S-adenosylmethionine (SAMe) by joining methionine and ATP. SAMe is a methyl donor for transmethylation and has an important role for DNA and/or protein methylation. MAT2A is expressed widely in many tissues especially in kidney. Several studies have demonstrated that there are abnormal expressions of MAT2A in several kinds of cancers such as liver and colon cancers. But the relationship of MAT2A between renal cell carcinomas (RCC) is less understood.

Methods

The mRNA expression level of the MAT2A gene was determined in 24 RCC patients and 4 RCC cell lines, using real-time quantitative-polymerase chain reaction (RT-PCR). The MAT2A protein content was measured by western blotting and immunohistochemical analysis in 55 RCC patients. The mRNA levels of heme oxygenase-1 (HO-1) and cyclooxygenase-2 (COX-2) were also analysized in patients using RT-PCR. The correlations between the MAT2A and HO-1 as well as COX-2 were analyzed with nonparametric Spearman method.

Results

MAT2A transcript was significantly downregulated in cancer tissues compared to normal tissues (P < 0.05). Immunohistochemical analysis and western blotting indicated that level of MAT2A protein was decreased in cancer tissues. The statistical analysis reveals a negative correlation between MAT2A and HO-1 expression in RCC patients and cell lines (P < 0.01).

Conclusions

This study demonstrated that MAT2A was lower expression in cancer tissues, suggesting that it may be involved in the development of RCC. MAT2A is a transcriptional corepressor for HO-1 expression by supplying SAM for methyltransferases, which may be one of potential mechanism of MAT2A as tumor suppressor in kidney carcinogenesis.

Prognostic prediction and diagnostic role of intercellular adhesion molecule-1 (ICAM1) expression in clear cell renal cell carcinoma

The intercellular adhesion molecule-1 (ICAM1) has been reported to function in multiple malignancies, but its effect on clear cell renal cell carcinoma (ccRCC) hasn't been discussed yet. This study aimed to identify the potential role of ICAM1 in prognostic prediction and early diagnosis of ccRCC. ICAM1 expression was inspected by immunohistochemistry and correlated with clinicopathologic variables. Association between protein expression and cancer-specific survival (CSS) of ccRCC patients was evaluated and the value of area under the receiver operating characteristics (ROC) curve (AUC) was calculated to measure the protein's diagnostic accuracy. ICAM1 was positively immunostained in 83.2% of 173 ccRCC tissues, but negatively immunostained in all the para-cancerous normal epitheliums of renal tubules. High ICAM1 expression was significantly related to male sex (P = 0.00241), T3/T4 stage (P = 0.02249), non-N0M0 stage (P = 0.03797) and positive renal pelvis invasion (P = 0.04227). Kaplan-Meier survival analysis illustrated that high ICAM1 expression was significantly correlated to a decreased CSS (P = 0.00006). Multivariate Cox analysis indicated that ICAM1 was an independent predictor for CSS of patients (P = 0.00451). Furthermore, the AUC value of ICAM1 in diagnosing ccRCC was 0.916 (P < 0.00001). In conclusion, high ICAM1 expression on tumor cells indicates a poor outcome of patients and ICAM1 is likely to be an independent predictor for the prognosis of ccRCC. Moreover, ICAM1 has a high AUC value and may be a potential and useful diagnostic marker.

Collecting duct carcinoma of the kidney: Imaging observations of a rare tumor

Collecting duct carcinoma (CDC) is a rare type of renal neoplasm. Early diagnosis is possibly the only factor leading to a prolonged survival for patients with CDC. The purpose of the present study was to characterize the imaging features of CDC and improve its diagnosis. Radiological data of six patients were retrospectively reviewed by three experienced radiologists, including six cases examined with non-contrast computed tomography (CT) scans, five with contrast-enhanced CT scans, one with magnetic resonance urography, one with renal dynamic imaging and two with conventional whole-body ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scans. All patients were pathologically confirmed with CDC. In total, seven tumors were detected in the six cases, with a mean size of 5.3 cm. Of the tumors, two were solid and the rest were complex solid and cystic. In addition, six tumors were located in medullary areas and only one tumor was found in the cortical location. Cystic components were observed in five tumors. Weak enhancements were observed in all six tumors examined with contrast-enhanced CT, and heterogeneous enhancements were also observed in the majority of these tumors with the exception of one tumor. Infiltrative growth and expansible growth were found in five and two tumors, respectively. Metastatic lesions were detected in all six patients. On MR urography, the involved kidney exhibited similar imaging observations to the CT scan. Renal dynamic imaging revealed a decreased renal function in the involved kidney and an increased renal function in the contralateral kidney. On PET/CT imaging, a marked uptake of ¹⁸F-FDG was found in primary and metastatic lesions. The results of the present study indicated that medullary location, weak and heterogeneous enhancement, infiltrative growth, damage of renal function in the involved kidney and a marked uptake of ¹⁸F-FDG are imaging observations commonly identified in patients with CDC. When a renal tumor exhibits these imaging features, CDC may be suggested as a valuable differential diagnosis.

Thyroid dysfunction and tyrosine kinase inhibitors in renal cell carcinoma

The most recent World Health Organization classification of renal neoplasms encompassed nearly 50 distinctive renal neoplasms. Different histological subtypes have different clinical outcomes and show different responses to therapy. Overall, the incidence of kidney cancer has increased worldwide in the last years. Although the most common type of kidney cancer is localized renal cell carcinoma (RCC), with a 5-year survival rate of 85%, about one third of patients present advanced or metastatic disease at diagnosis, with a 5-year survival rate of only 10%. Multi-targeted receptor tyrosine kinase inhibitors (TKIs, sunitinib and sorafenib), the anti-VEGF MAB bevacizumab in association with interferon-α, and the mTOR inhibitors are now approved for the treatment of mRCC. Recently, the novel agents pazopanib and axitinib have also demonstrated efficacy in mRCC patients. Several recent retrospective and prospective trials have suggested that some of their adverse events, such as hypertension, hypothyroidism, and hand foot syndrome (HFS) may act as potential biomarkers of response and efficacy of treatment. In this review, we analyzed the studies that have suggested a relationship between hypothyroidism onset and a better outcome of mRCC patients treated with TKIs. The biological mechanisms suggesting and explaining this correlation are not well known and different speculative theories have been considered in order to investigate the clinical link between hypothyroidism occurrence and the prolonged therapy with TKIs in solid tumors. Furthermore, the management of this unexplained side effect is very important to maximize the efficacy of therapy in mRCC patients because there is a clear and consistent relationship between drug dose and efficacy of treatment. Certainly, other studies are needed to clarify whether a better outcome is associated with hypothyroidism induced to TKIs in patients with mRCC.

Radiologic-pathologic correlation of renal cell carcinoma associated with Xp11.2 translocation

BACKGROUND

The prognosis of translocation RCCs in adult patients is relatively poor compared to that of other subtypes of RCCs. Although there have been several reports regarding radiologic findings of translocation RCC, studies with histologic correlation could help to understand the imaging features.

PURPOSE

To explore the correlation between radiologic and pathologic findings in Xp11.2 translocation renal cell carcinoma (RCC) and provide clues for translocation RCC diagnosis.

MATERIAL AND METHODS

CT scans of six patients (one man and five women; age range, 8-71 years; mean age, 34 years) with histologically-proven Xp11.2 translocation RCCs were retrospectively evaluated in consensus by two radiologists. Tumor size, presence of necrosis, hemorrhage, fat or calcification, enhancement patterns of the tumor, presence of lymphadenopathy, and distant metastases were evaluated.

RESULTS

The average size of the tumors was 6 cm (range, 2.7-12 cm). All six tumors appeared as well-defined masses with areas of low attenuation representing hemorrhage or necrosis. Four tumors contained high attenuating solid portions, compared to the surrounding renal cortex seen on unenhanced images, where representing dense cellular component on microscopic examination. Peripheral rim enhancement pattern that correlated with histologic finding of a fibrous capsule was seen in five cases. In two patients who underwent kidney MR, the masses showed low signal intensity on T2-weighted images. One patient had lymphadenopathy. No distant metastasis was noted in any patient.

CONCLUSION

Translocation RCC appeared as a well-defined mass that contain high attenuating solid portions on unenhanced images and low attenuating necrotic or hemorrhagic foci; the tumor also showed gradual peripheral rim enhancement due to a fibrous capsule surrounding the tumor.

Evaluation of renal masses with contrast-enhanced ultrasound

The clinical need for characterising small renal masses (SRMs) is increasing due to their rising incidental detection. This increase is especially seen in younger and older generations and concerns mainly SRMs. Diagnostics is mainly made by contrast-enhanced CT or MRI. However, these imaging methods fail to accurately distinguishing benign from malignant SRMs. Other disadvantages of CT or MRI are high costs, the use of ionizing radiation, nephrotoxicity induced by iodine contrast agents or nephrogenic systemic fibrosis (NSF) induced by gadolinium contrast agents. Contrast-enhanced ultrasound (CEUS) is based on ultrasonography and microbubbles to real-time visualize the renal blood flow without the use of nephrotoxic agents or ionizing radiation. This comprehensive review evaluates the capabilities of CEUS in the diagnostics of benign (angiomyolipomas, cysts, oncocytomas, pseudotumors) and malignant masses (renal cell carcinomas), and focuses on possible future treatment.

Loss of caspase 7 expression is associated with poor prognosis in renal cell carcinoma clear cell subtype

OBJECTIVE

To investigate the expression of CASP7 protein in renal cell carcinoma clear cell subtype (ccRCC) and its value to predict cancer-specific survival (CSS).

METHODS

A tissue microarray containing 120 samples of ccRCC, 45 non-ccRCC, and 66 nontumor paired samples from patients who underwent partial or radical nephrectomy was hybridized with anti-CASP7 antibody. Tissue sections were scored according to intensity and the percentage of stained cells. CASP7 immunostaining scores were used to estimate the association with clinicopathologic parameters and calculate Kaplan-Meier survival curves.

RESULTS

Reduced CASP7 expression was observed in ccRCC and non-ccRCC subtypes in comparison with nontumor renal tissues (P <.0001). CASP7 immunostaining was associated (P <.05) with clinicopathologic parameters (size, incidental tumor, clinical stage, renal vein invasion, and tumor necrosis) and correlated with CSS (P = .032) and global survival (P = .046) of patients with ccRCC. In addition, CASP7 expression was able to substratify patients with ccRCC with favorable prognosis according to low clinical stage, in which negative CASP7 staining was associated with patients with lower CSS (P = .045). Finally, CASP7 staining was able to provide significant stratification according to CSS (P = .018) among patients with ccRCC with disease relapse.

CONCLUSION

Our results implicate the loss of CASP7 expression in the aggressiveness of ccRCC and indicate its potential use as a clinical prognostic marker of the disease.

Deregulation of PAX2 expression in renal cell tumours: mechanisms and potential use in differential diagnosis

Expression of PAX2 (Paired-box 2) is suppressed through promoter methylation at the later stages of embryonic development, but eventually reactivated during carcinogenesis. Pax-2 is commonly expressed in the most prevalent renal cell tumour (RCT) subtypes—clear cell RCC (ccRCC), papillary RCC (pRCC) and oncocytoma—but not in chromophobe RCC (chrRCC), which frequently displays chromosome 10 loss (to which PAX2 is mapped). Herein, we assessed the epigenetic and/or genetic alterations affecting PAX2 expression in RCTs and evaluated its potential as biomarker. We tested 120 RCTs (30 of each main subtype) and four normal kidney tissues. Pax-2 expression was assessed by immunohistochemistry and PAX2 mRNA expression levels were determined by quantitative RT-PCR. PAX2 promoter methylation status was assessed by methylation-specific PCR and bisulfite sequencing. Chromosome 10 and PAX2 copy number alterations were determined by FISH. Pax-2 immunoexpression was significantly lower in chrRCC compared to other RCT subtypes. Using a 10% immunoexpression cut-off, Pax-2 immunoreactivity discriminated chrRCC from oncocytoma with 67% sensitivity and 90% specificity. PAX2 mRNA expression was significantly lower in chrRCC, compared to ccRCC, pRCC and oncocytoma, and transcript levels correlated with immunoexpression. Whereas no promoter methylation was found in RCTs or normal kidney, 69% of chrRCC displayed chromosome 10 monosomy, correlating with Pax-2 immunoexpression. We concluded that Pax-2 expression might be used as an ancillary tool to discriminate chrRCC from oncocytomas with overlapping morphological features. The biological rationale lies on the causal relation between Pax-2 expression and chromosome 10 monosomy, but not PAX2 promoter methylation, in chrRCC.

Targeted therapies and the treatment of non-clear cell renal cell carcinoma

BACKGROUND

Targeted therapies have shown profound effects on the outcome of patients with advanced renal cell carcinoma (RCC). However, the optimal treatment for RCC of non-clear cell histology (nccRCC)-typically excluded from trials of targeted agents-remains uncertain.

MATERIALS AND METHODS

By carrying out extensive searches of PubMed and ASCO databases, we identified and summarised research into the biological characteristics, clinical behaviour and treatment of different histological subtypes of nccRCC, focusing on targeted therapy.

RESULTS

The available data suggest that treatments currently approved for RCC are active in ncc subtypes, although the overall clinical benefit may be less than for clear cell RCC. Temsirolimus has proven benefit over interferon-alfa (IFN-α) in patients with nccRCC, based on phase III data, while everolimus, sunitinib and sorafenib have all demonstrated some degree of activity in nccRCC in expanded-access trials. No clear picture has emerged of whether individual histological subtypes are particularly responsive to any individual treatment.

CONCLUSIONS

Further molecular studies into the pathogenesis of RCC histological subtypes will help direct the development of novel, appropriate targeted agents. Clinical trials specifically designed to evaluate the role of targeted agents in nccRCC are ongoing, and data from trials with sunitinib and everolimus will be reported soon.

Extensive peritoneal carcinomatosis secondary to renal cell carcinoma with sarcomatoid and rhabdoid differentiation

Renal cell carcinoma (RCC), the most common malignancy of kidney, originates from renal tubular epithelium. It is subclassified based on histological and molecular features. Rarely, RCC can show focal to extensive sarcomatoid or rhabdoid differentiation. RCC with extensive sarcomatoid differentiation and no identifiable epithelial component is designated as unclassified RCC with sarcomatoid differentiation. Presence of sarcomatoid or rhabdoid differentiation is associated with poor prognosis. We describe autopsy findings in a case of RCC with extensive sarcomatoid and focal rhabdoid differentiation presenting with malignant ascites secondary to peritoneal carcinomatosis and multiorgan metastasis.

Human de novo papillary renal-cell carcinomas in a kidney graft: evidence of recipient origin with adenoma-carcinoma sequence

Papillary renal-cell carcinoma (pRCC) is unusual for its occurrence in kidneys with chronic dysfunction, for its frequent multifocality and for its common association with papillary adenoma, a benign renal lesion morphologically indistinguishable from pRCC. Concomitant development of papillary adenoma and pRCC in five transplanted kidneys, where donor and recipient characteristics are well established, provided a unique opportunity for molecular studies of de novo pRCC carcinogenesis. We aimed to study this tumor type to determine whether or not the different papillary tumors have the same origin, and whether or not papillary adenomas are precursor lesions of pRCC. We performed XY-FISH in sex-mismatched kidney transplants, and polymorphic microsatellite DNA and high-resolution melting of mitochondrial DNA analyzes in all five patients on laser-microdissected tumor cells, then compared these molecular profiles to donor and recipient profiles. This study (i) identified the recipient origin of de novo papillary adenomas and pRCCs in a kidney transplant, (ii) demonstrated an identical origin for precursor cells of papillary adenomas and pRCCs and (iii) showed additional genetic alterations in pRCCs compared to papillary adenomas. This molecular approach of papillary tumors developed in transplanted kidney identified successive steps in carcinogenesis of human de novo papillary renal-cell carcinoma.

Development and validation of a microRNA-based diagnostic assay for classification of renal cell carcinomas

Renal cancers account for more than 3% of adult malignancies and cause more than 13,000 deaths per year in the US alone. The four most common types of kidney tumors include the malignant renal cell carcinomas; clear cell, papillary, chromophobe and the benign oncocytoma. These histological subtypes vary in their clinical course and prognosis, and different clinical strategies have been developed for their management. In some kidney tumor cases it can be very difficult for the pathologist to distinguish between tumor types on the basis of morphology and immunohistochemistry (IHC). In this publication we present the development and validation of a microRNA-based assay for classifying primary kidney tumors. The assay, which classifies the four main kidney tumor types, was developed based on the expression of a set of 24 microRNAs. A validation set of 201 independent samples was classified using the assay and analyzed blindly. The assay produced results for 92% of the samples with an accuracy of 95%.

The oncolytic activity of Newcastle disease virus in clear cell renal carcinoma cells in normoxic and hypoxic conditions: the interplay between von Hippel-Lindau and interferon-β signaling

Viral-mediated oncolysis is a promising cancer therapeutic approach offering an increased efficacy with less toxicity than the current therapies. The complexity of solid tumor microenvironments includes regions of hypoxia. In these regions, the transcription factor, hypoxia inducible factor (HIF), is active and regulates expression of many genes that contribute to aggressive malignancy, radio-, and chemo-resistance. To investigate the oncolytic efficacy of a highly virulent (velogenic) Newcastle disease virus (NDV) in the presence or absence of HIF-2α, renal cell carcinoma (RCC) cell lines with defective or reconstituted wild-type (wt) von Hippel-Lindau (VHL) activity were used. We show that these RCC cells responded to NDV by producing only interferon (IFN)-β, but not IFN-α, and are associated with increased STAT1 phosphorylation. Restoration of wt VHL expression enhanced NDV-induced IFN-β production, leading to prolonged STAT1 phosphorylation and increased cell death. Hypoxia augmented NDV oncolytic activity regardless of the cells' HIF-2α levels. These results highlight the potential of oncolytic NDV as a potent therapeutic agent in the killing of hypoxic cancer cells.

Reduced cilia frequencies in human renal cell carcinomas versus neighboring parenchymal tissue

Background

Cilia are essential organelles in multiple organ systems, including the kidney where they serve as important regulators of renal homeostasis. Renal nephron cilia emanate from the apical membrane of epithelia, extending into the lumen where they function in flow-sensing and ligand-dependent signaling cascades. Ciliary dysfunction underlies renal cyst formation that is in part caused by deregulation of planar cell polarity and canonical Wnt signaling. Renal cancer pathologies occur sporadically or in heritable syndromes caused by germline mutations in tumor suppressor genes including VHL. Importantly, Von Hippel-Lindau (VHL) patients frequently develop complex renal cysts that can be considered a premalignant stage. One of the well-characterized molecular functions of VHL is its requirement for the maintenance of cilia. In this study, tissue from 110 renal cancer patients who underwent nephrectomy was analyzed to determine if lower ciliary frequency is a common hallmark of renal tumorigenesis by comparing cilia frequencies in both tumor and adjacent parenchymal tissue biopsies from the same kidney.

Methods

We stained sections of human renal material using markers for cilia. Preliminary staining was performed using an immunofluorescent approach and a combination of acetylated-α-tubulin and pericentrin antibodies and DAPI. After validation of an alternative, higher throughput approach using acetylated-α-tubulin immunohistochemistry, we continued to manually quantify cilia in all tissues. Nuclei were separately counted in an automated fashion in order to determine ciliary frequencies. Similar staining and scoring for Ki67 positive cells was performed to exclude that proliferation obscures cilia formation potential.

Results

Samples from renal cell carcinoma patients deposited in our hospital tissue bank were previously used to compose a tissue microarray containing three cores of both tumor and parenchymal tissue per patient. Cilia frequencies in a total of eighty-nine clear cell, eight papillary, five chromophobe renal cell carcinomas, two sarcomatoid renal tumors and six oncocytomas were determined. A marked decrease of primary cilia across renal cell carcinoma subtypes was observed compared to adjacent nontumorigenic tissue.

Conclusions

Our study shows that cilia are predominantly lost in renal cell carcinomas compared to tissue of the tumor parenchyma. These results suggest that ciliary loss is common in renal tumorigenesis, possibly participating in the sequence of cellular events leading to malignant tumor development. Future therapies aimed at restoring or circumventing cilia signaling might therefore aid in current treatment efficacy.

Vasoactive intestinal peptide induces oxidative stress and suppresses metastatic potential in human clear cell renal cell carcinoma

Molecular mechanisms involved in progression of clear-cell renal-cell carcinomas (ccRCCs) are poorly understood. A common genetic mutation found in ccRCC is the loss of the von Hippel-Lindau (VHL) gene, which contributes to cancer progression and metastasis. We investigated VIP effects on metastatic and angiogenic factors in human VHL-null A498 ccRCC and HK2 renal cells. VIP increased adhesion but decreased expression of metalloproteinases, MMP2 and MMP9, as well as cell migration and VEGF expression and secretion in A498 but not in HK2 cells. VIP enhanced ROS levels and decreased nuclear levels of β-catenin and NFκB p50-subunit in A498 cells, suggesting neuropeptide involvement in the observed decrease of metastatic ability in clear-cell carcinoma. VIP effects in A498 cells were blocked by the VPAC(1/2)-receptor antagonist JV-1-53. In conclusion, present data point to a role of VIP in preventing invasion and metastasis in ccRCCs and support its potential therapeutic usefulness in this disease.

Cannabinoid CB1 receptor is expressed in chromophobe renal cell carcinoma and renal oncocytoma

OBJECTIVE

To analyze the mRNA and protein expression of cannabinoid receptors CB1 and CB2 in chromophobe renal cell carcinoma (ChRCC) and renal oncocytoma (RO).

DESIGN AND METHODS

Fresh and formalin-fixed tissue samples of ChRCC and RO were analyzed by using real-time quantitative RT-PCR and immunohistochemical techniques (n=40).

RESULTS

Quantitative RT-PCR analysis showed that CB1 mRNA was underexpressed by 12-fold in ChRCC and had a variable expression in RO. CB1 protein showed intense positive immunostaining in both neoplasms. Both CB2 mRNA and protein were not expressed in tumor and non tumor renal tissue.

CONCLUSION

This distinct immunoprofile may eventually be used as an additional tool with practical interest in the differential diagnosis of renal tumors.

Clear cell papillary renal cell carcinoma: a report of 15 cases including three cases of concurrent other-type renal cell carcinomas

Background

Clear cell papillary renal cell carcinoma (CCPRCC) is a recently established subtype of renal epithelial tumor. The aim of this study was to identify the diagnostic criteria of CCPRCC with an emphasis on immunohistochemical studies, and to report three cases with concurrent other-type renal cell carcinoma (RCC).

Methods

A total of 515 RCC patients that consecutively underwent surgical resection at Seoul National University Hospital from 1 January 2010 to 31 December 2011 were screened. Each case was reviewed based on the histologic features and was evaluated immunohistochemically.

Results

A total of 15 CCPRCCs were identified, which composed 2.9% of the total RCCs. The mean age was 52 years, and the average tumor size was 1.65 cm. All 15 cases showed low nuclear grade, no lymph node metastasis and no distant metastasis. The CCPRCCs showed variable architectural patterns including cystic, trabecular, papillary, and acinar. All of the cases showed moderate to intense immunoreactivity for cytokeratin 7 (CK7). CD10 was negative or showed focal weak positivity. Three cases had concurrent other-type RCC, including a clear cell RCC and an acquired cystic disease-associated RCC.

Conclusions

The strong CK7 and negative or focal weak CD10 expression will be useful for the diagnosis of CCPRCC.

Spectrum of nontumoral renal pathologies in tumor nephrectomies: nontumoral renal parenchyma changes

Non-neoplastic changes are not rarely seen in renal parenchyma of nephrectomy specimens removed for primary renal neoplasms. These changes often involve both kidneys, thus causing impairment of renal function, reducing patient's quality of life and sometimes threatening it. Renal tissue accompanying the tumor provides an opportunity in order to evaluate these changes. However, the clinician should make available clinical and laboratory findings involving renal functions of the patient to the pathologist. It is also important that the pathologist must have appropriate knowledge and experience in nephropathology. In this study, we aimed to correlate these changes with the clinical data and make inquiries regarding our experience with nonneoplastic kidney pathology. Consecutive 403 nephrectomy specimens with primary renal neoplasms submitted to our department between 2003 and 2009 were re-examined. Twenty-three nephrectomy materials from 21 patients had non-neoplastic changes, 2 of which were bilateral. Patient follow-up data were obtained from electronic medical records. Of all cases, eight had diabetic nephropathy; 2, amyloidosis; 5, segmental proliferative and/or sclerotic glomerulonephritis; and 6, cystic renal changes. These findings were seen in 5% of nephrectomy specimens diagnosed as clear cell renal cell carcinoma (RCC), chromophobe cell RCC and oncocytoma, whereas this rate was two times higher in nephrectomy specimens with papillary RCC. Most patients with renal failure who were diagnosed with clear cell carcinoma died within the first two years. Despite limited number of cases in our series, prognosis of cases with clear cell RCC were poorer. Consequently, we think that non-neoplastic changes should be reported along with the details regarding the tumor in order to achieve best treatment planning.

[Xp11.2 translocation renal carcinoma in adults over 50 years of age: about four cases]

OBJECTIVE

To describe demographic, therapeutic and follow-up data of four cases of renal cell carcinoma with Xp11.2 translocation in adults older than 50 years of age.

PATIENTS AND METHODS

Between January 2008 and December 2011, 170 patients underwent surgery for renal cell carcinoma in our center. Systematic histopathologic analysis of specimen removed was performed. Complementary immunohistochemical analysis was performed only in cases with uncertain diagnosis or in patients younger than 40 years of age.

RESULTS

Among these 170 patients with a median age of 59years old (21-89), immunohistochemistry helped find a TFE3 translocation in four cases (2.4%). There were three women and one man of 53, 71, 75 and 86years old respectively. One patient was metastatic at diagnosis. Radical nephrectomy was first performed in all cases. TNM staging was T3aN2R0, T3bN0R0, T2N2R0 and T3aN2R2, with a Furhman grade of 4. Two patients progressed with metastasis 5 and 7months after surgery, and two with lymphatic invasion 2 and 9months after nephrectomy. One patient died during follow-up.

CONCLUSION

Xp11.2 translocation renal cell carcinoma was uncommon after 50years of age in our series, but probably under estimated. It seemed to be associated with a poor prognosis. Larger studies must be performed to optimize its specific treatment.

The epigenetics of renal cell tumors: from biology to biomarkers

Renal cell tumors (RCT) collectively constitute the third most common type of genitourinary neoplasms, only surpassed by prostate and bladder cancer. They comprise a heterogeneous group of neoplasms with distinctive clinical, morphological, and genetic features. Epigenetic alterations are a hallmark of cancer cells and their role in renal tumorigenesis is starting to emerge. Aberrant DNA methylation, altered chromatin remodeling/histone onco-modifications and deregulated microRNA expression not only contribute to the emergence and progression of RCTs, but owing to their ubiquity, they also constitute a promising class of biomarkers tailored for disease detection, diagnosis, assessment of prognosis, and prediction of response to therapy. Moreover, due to their dynamic and reversible properties, those alterations represent a target for epigenetic-directed therapies. In this review, the current knowledge about epigenetic mechanisms and their altered status in RCT is summarized and their envisaged use in a clinical setting is also provided.

Role of immunohistochemistry in diagnosing renal neoplasms: when is it really useful?

CONTEXT

With the refinement of molecular and histologic classifications of renal neoplasms and the availability of more-effective molecular targeted therapy for specific renal neoplasms, immunohistochemical techniques will play an increasingly important role in the diagnosis of renal neoplasm. During the past few decades, many markers have been evaluated for their role in the diagnosis, prognosis, and prediction of treatment for renal neoplasms. The number of useful markers in our routine practice continues to increase. The challenge will be to choose among them and to decide in which situations immunohistochemistry will be truly useful.

OBJECTIVES

To review the diagnostic utility of molecular markers for renal neoplasms and common diagnostic scenarios that call for immunohistochemistry in routine practice.

DATA SOURCES

This review is based on published literature and personal experience.

CONCLUSIONS

Some of the most important and useful markers for the diagnosis of renal neoplasm include cytokeratins, vimentin, PAX2, PAX8, RCC marker, CD10, E-cadherin, kidney-specific cadherin, parvalbumin, claudin-7, claudin-8, α-methylacyl coenzyme A racemase, CD117, TFE3, thrombomodulin, uroplakin III, p63, CD57, and carbonic anhydrase IX. Each marker has its diagnostic role in a specific diagnostic setting. The common diagnostic situations that call for immunohistochemical staining are differential diagnoses of renal versus nonrenal neoplasms, histologic subtyping of renal cell carcinoma, diagnosis of rare primary renal neoplasms, diagnosis of renal neoplasms in small core-biopsy specimens, diagnosis of possible metastatic renal carcinomas, and less frequently, molecular prognostication.

The expanding role of imaging in the management of renal cell carcinoma

The management of renal cell carcinoma (RCC) is evolving owing to the increasing detection of small renal masses, greater understanding of the metabolic pathways involved, new targeted medical treatments for metastatic RCC, and evolving surgical and minimally invasive image-guided treatment techniques. Consequently, the role of imaging and radiology has expanded, with new challenges encompassing all aspects of management, including diagnosis, predicting cell type, staging, preoperative vascular mapping, image-guided treatment and biopsy, detection of recurrence and the use of imaging as a biomarker to assess response to treatment. This article is a comprehensive review of RCC, outlining the etiology of the disease, RCC histological subtypes and their imaging characteristics, imaging modality techniques for evaluation of RCC, treatment strategies and the management of small renal masses.