Comparisons of outcome and prognostic features among histologic subtypes of renal cell carcinoma

Utility of multiphasic multidetector computed tomography in discriminating between clear cell renal cell carcinomas with high and low carbonic anhydrase-IX expression

PURPOSE

To investigate if multiphasic multidetector computed tomography (MDCT) enhancement profiles can distinguish clear cell renal cell carcinomas (ccRCCs) with high carbonic anhydrase-IX (CA-IX) expression from ccRCCs with low CA-IX expression.

METHODS

With IRB approval for this retrospective study, we derived a cohort of 105 histologically proven ccRCCs with preoperative 4-phase renal mass MDCT from 2001 to 2013. Following manual segmentation, the computer-assisted detection algorithm selected a 0.5-cm-diameter region of maximal attenuation within each lesion in each phase. CA-IX expression level was determined by immunohistochemical staining of tumor specimens. In the high and low CA-IX expression subgroups, the magnitude of enhancement and washout were compared using t tests; the performance of contrast washout in differentiating between subgroups was assessed with logistic regression analysis.

RESULTS

ccRCCs with high and low CA-IX expression both exhibited peak enhancement in the corticomedullary phase. ccRCCs with high CA-IX expression demonstrated significantly greater relative nephrographic washout than those with low CA-IX expression (18.4% vs. 7.8%, p = 0.03). ccRCCs with high CA-IX expression had greater relative excretory washout than ccRCCs with low CA-IX expression with a trend toward significance (33.4% vs. 25.2%, p = 0.05). After controlling for tumor size and stage, for distinguishing ccRCCs with high and low CA-IX expression, relative excretory washout had a sensitivity, negative predictive value, accuracy, and positive predictive value of 99% (65/66), 88% (7/8), 69% (72/105), and 67% (65/97), respectively.

CONCLUSION

Relative nephrographic and excretory washout may have the potential to help distinguish ccRCCs with high and low CA-IX expression, but this requires further validation.

Diagnostic Accuracy of MRI for Detection of Papillary Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVE

The objective of our study was to perform a systematic review and meta-analysis of the diagnostic performance of MRI in differentiation of papillary renal cell carcinoma (RCC) from other renal masses.

MATERIALS AND METHODS

We performed searches of three electronic databases for studies that used MRI techniques to differentiate papillary RCC from other renal lesions. Methodologic quality was assessed, and diagnostic test accuracy was summarized using bivariate random-effects modeling or with construction of a summary ROC (SROC) curve.

RESULTS

Thirteen studies involving 275 papillary RCC lesions and 758 other renal masses met the inclusion criteria. Resulting summary estimates for the performance of MRI to differentiate papillary RCC from other renal lesions were a sensitivity of 79.6% (95% CI, 62.3-90.2%) and specificity of 88.1% (95% CI, 80.1-93.1%). In subgroup analysis, quantitative pooling of seven studies using enhancement in the corticomedullary phase resulted in a sensitivity of 85.6% (95% CI, 67.8-94.4%), specificity of 91.7% (95% CI, 76.0-97.5%), and area under the SROC curve of 0.894. Four studies used tumor appearance on T2-weighted imaging to detect papillary RCC, and results showed a pooled sensitivity of 89.9% (95% CI, 73.0-96.7%) and specificity of 84.9% (95% CI, 69.0-93.4%). Three studies used signal loss on T1-weighted in-phase imaging to detect papillary RCC but marked heterogeneity precluded pooling.

CONCLUSION

Meta-analysis supports moderate sensitivity and excellent specificity of quantitative enhancement in the corticomedullary phase for differentiating papillary RCC from other tumors. The accuracy of combining enhancement and T2 signal-intensity characteristics merits further evaluation as a potential aid for management decisions.

The downregulated long noncoding RNA DHRS4-AS1 is protumoral and associated with the prognosis of clear cell renal cell carcinoma

BACKGROUND

Long noncoding RNAs (lncRNAs) have been identified as important factors in cancer biology and are deregulated in many cancers. The present study aimed to determine the expression and roles of lncRNA DHRS4-AS1 in the progression of clear cell renal cell carcinoma (ccRCC).

METHODS AND RESULTS

Using high-throughput RNA-sequencing data of ccRCC tumors from the Cancer Genome Atlas project, we identified lncRNA DHRS4-AS1 as significantly associated with ccRCC patients' overall survival. We confirmed the downregulation of DHRS4-AS1 in ccRCC by assessing its expression levels in a cohort of 52 tumor and paired non-tumor samples. In addition, we found that low DHRS4-AS1 expression was significantly associated with a high tumor node metastasis stage, lymph node metastasis, advanced pathological grade and poor prognosis. Furthermore, DHRS4-AS1 overexpression inhibited the progression of cell cycles of ccRCC in vitro. These data indicate that DHRS4-AS1 functions by preventing the proliferation and invasion, inhibiting the cell cycle progression and promoting the apoptosis of ccRCC cells.

CONCLUSION

Taken together, our findings identify the role of DHRS4-AS1 as a tumor inhibitor in ccRCC for the first time, demonstrating that DHRS4-AS1 is a potential prognostic biomarker that could potentially be applied in ccRCC therapy.

Nomograms for predicting long-term overall survival and disease-specific survival of patients with clear cell renal cell carcinoma

Objectives

The aim of this study was to establish comprehensive and practical nomograms, based on significant clinicopathological parameters, for predicting the overall survival (OS) and the disease-specific survival (DSS) of patients with clear cell renal cell carcinoma (ccRCC).

Patients and methods

The data of 35,151 ccRCC patients, diagnosed between 2004 and 2014, were obtained from the database of the Surveillance, Epidemiology, and End Results (SEER) program. The Kaplan–Meier method and Cox proportional hazards regression model were used to evaluate the prognostic effects of multiple clinicopathological variables on survival. Based on Cox models, a nomogram was constructed to predict the probabilities of OS and DSS for an individual patient. The predictive performance of nomograms was evaluated using the concordance index (C-index) and calibration curves.

Results

According to univariate and multivariate analyses, age at diagnosis, sex, race, marital status, surgical approach, tumor node metastasis (TNM) stage, and Fuhrman grade significantly correlated with the survival outcomes. These characteristics were used to establish nomograms. The nomograms showed good accuracy in predicting 3-, 5-, and 10-year OS and DSS, with a C-index of 0.79 (95% CI, 0.79–0.80) for OS and 0.87 (95% CI, 0.86–0.88) for DSS. All calibration curves revealed excellent consistency between predicted and actual survival.

Conclusion

Nomograms were developed to predict death from ccRCC treated with nephrectomy. These new prognostic tools could aid in improving the predictive accuracy of survival outcomes, thus leading to reasonable individualized treatment.

Textural differences between renal cell carcinoma subtypes: Machine learning-based quantitative computed tomography texture analysis with independent external validation

OBJECTIVE

To develop externally validated, reproducible, and generalizable models for distinguishing three major subtypes of renal cell carcinomas (RCCs) using machine learning-based quantitative computed tomography (CT) texture analysis (qCT-TA).

MATERIALS AND METHODS

Sixty-eight RCCs were included in this retrospective study for model development and internal validation. Another 26 RCCs were included from public databases (The Cancer Genome Atlas-TCGA) for independent external validation. Following image preparation steps (reconstruction, resampling, normalization, and discretization), 275 texture features were extracted from unenhanced and corticomedullary phase CT images. Feature selection was firstly done with reproducibility analysis by three radiologists, and; then, with a wrapper-based classifier-specific algorithm. A nested cross-validation was performed for feature selection and model optimization. Base classifiers were the artificial neural network (ANN) and support vector machine (SVM). Base classifiers were also combined with three additional algorithms to improve generalizability performance. Classifications were done with the following groups: (i), non-clear cell RCC (non-cc-RCC) versus clear cell RCC (cc-RCC) and (ii), cc-RCC versus papillary cell RCC (pc-RCC) versus chromophobe cell RCC (chc-RCC). Main performance metric for comparisons was the Matthews correlation coefficient (MCC).

RESULTS

Number of the reproducible features is smaller for the unenhanced images (93 out of 275) compared to the corticomedullary phase images (232 out of 275). Overall performance metrics of the machine learning-based qCT-TA derived from corticomedullary phase images were better than those of unenhanced images. Using corticomedullary phase images, ANN with adaptive boosting algorithm performed best for discrimination of non-cc-RCCs from cc-RCCs (MCC = 0.728) with an external validation accuracy, sensitivity, and specificity of 84.6%, 69.2%, and 100%, respectively. On the other hand, the performance of the machine learning-based qCT-TA is rather poor for distinguishing three major subtypes. The SVM with bagging algorithm performed best for discrimination of pc-RCC from other RCC subtypes (MCC = 0.804) with an external validation accuracy, sensitivity, and specificity of 69.2%, 71.4%, and 100%, respectively.

CONCLUSIONS

Machine learning-based qCT-TA can distinguish non-cc-RCCs from cc-RCCs with a satisfying performance. On the other hand, the performance of the method for distinguishing three major subtypes is rather poor. Corticomedullary phase CT images provide much more valuable texture parameters than unenhanced images.

Efficacy of 3D VIBE Dixon fat quantification for differentiating clear-cell from non-clear-cell renal cell carcinoma

AIM

To assess the efficacy of three-dimensional (3D) volumetric interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) with Dixon quantification for differentiating clear-cell from non-clear-cell types of renal cell carcinoma (RCC).

MATERIALS AND METHODS

The 3D VIBE Dixon renal MRI examinations of 44 patients with 45 histologically confirmed RCCs was analysed. The fat fractions and signal intensity indexes (SI_index) of the solid portions of clear-cell and non-clear-cell RCCs were measured and compared using Student's t-test and receiver operating characteristic (ROC) curves. The agreement of measurements among observers was evaluated by the intraclass correlation coefficient (ICC), and Bland-Altman plots.

RESULTS

The mean values of fat fraction (13.16±7.16%) and SI_index (22.64±15.7%) in clear-cell RCCs were significantly higher than that in non-clear-cell RCCs (7.7±2% and 7.9±4.8%; p<0.001, respectively). With the area under the ROC curve (AUC) of the fat fraction at 0.811, 75% (95% CI: 55.1-89.43%) sensitivity and 76.5% (95% CI: 50.1-93.2%) specificity for diagnosing clear-cell RCC were obtained at a cut-off fat fraction value of 8.9%. With a cut-off value of 8.89%, the diagnostic sensitivity and specificity were 85.7% (95% CI: 67.3-96%) and 70.6% (95% CI: 44-89.7%), respectively. The AUC of the SI_index was 0.870 (0.766-0.973). ICC and Bland-Altman plots show excellent agreement of the tumour fat fraction and SI_index measurement between the two observers.

CONCLUSION

Intracellular lipid content analysis using the 3D Dixon technique can help to differentiate clear-cell from non-clear-cell RCCs.

Obesity and renal cell carcinoma risk by histologic subtype: A nested case-control study and meta-analysis

BACKGROUND

Although obesity is an established risk factor for renal cell carcinoma (RCC), it is unclear whether this relationship varies across histologic subtypes.

METHODS

We conducted a nested case-control study within the Kaiser Permanente Northern California (KPNC) health care network, and meta-analysis combining our results with those of previously published studies. Our KPNC study included 685 RCC cases [421 clear cell; 65 papillary; 24 chromophobe; 35 other; 141 not otherwise specified (NOS)] and 4266 controls. Subtype-specific odds ratios (ORs) and 95% confidence intervals (CIs) for categories of body mass index (BMI) and were computed from the case-control data using polytomous logistic regression. Findings from this and other relevant studies were combined by meta-analysis using a random effects model.

RESULTS

In the KPNC study, obesity (BMI ≥ 30 kg/m²) was associated with clear cell RCC (OR 1.5, 95% CI 1.1-2.1) and chromophobe RCC (OR 2.5, 95%CI 0.8-8.1), but not with papillary RCC (OR 1.0, 95% CI 0.5-1.9). In meta-analysis including three additional studies, a similar pattern of summary relative risks (SRR) for obesity was observed across subtypes (clear cell: SRR 1.8, 95% CI 1.5-2.2; chromophobe: SRR 2.2, 95% CI 1.3-3.7; papillary, SRR 1.2, 95% CI 0.8-1.6).

CONCLUSIONS

These findings support the hypothesis that histologic subtypes of RCC possess distinct etiologic pathways, with obesity important for the development of clear cell and, possibly, chromophobe RCC, but not papillary RCC.

Active Role of the Necrotic Zone in Desensitization of Hypoxic Macrophages and Regulation of CSC-Fate: A hypothesis

Fast-proliferating cancer cells in the hypoxic region face a shortage of oxygen and nutrients, undergo necrotic cell death, and release numerous signaling components. Hypoxia-induced chemo-attractants signal for macrophages/monocytes to clear debris and return the system to steady state. Accordingly, macrophages arrange into pre-necrotic positions, where they are continuously exposed to stress signals. It can thus be hypothesized that gradual alteration of gene expression in macrophages eventually turns off their phagocytic machinery. Uncleared cell corpses within the hypoxic region potentially provide a rich source of building blocks for anaerobic metabolism of cancer stem cells via macropinocytosis, and are conceivably implicated in tumor progression and invasion.

Vision Loss from Choroidal and Pituitary Metastases Secondary to Renal Cell Carcinoma: A Case Report

A 62-year-old male with a history of metastatic clear cell renal cell carcinoma (ccRCC) presented with decreased vision to 20/50 in the left eye. Fundus examination revealed an elevated, amelanotic mass lesion in the superotemporal macula, without involvement of the central macula by subretinal fluid or tumour. Given incongruity between the fundus findings and the degree of visual impairment, visual field testing was obtained, revealing a bitemporal hemianopia. Magnetic resonance imaging demonstrated optic chiasm compression by a pituitary mass, which had previously been overlooked on computed tomography imaging. Biopsy confirmed metastatic ccRCC to the pituitary, which presented simultaneously with the presumed choroidal metastasis.

Efficacy of percutaneous radiofrequency ablation may vary with clear cell renal cell cancer histologic subtype

PURPOSE

The purpose of the study is to determine if clear cell renal cell cancer (RCC) subtype predicts efficacy in percutaneous radiofrequency (RF) ablation of RCC.

METHODS AND MATERIALS

Patients who underwent percutaneous RF ablation for histologically proven RCC subtypes were retrospectively reviewed. Group comparisons were done using univariate and multivariate logistic regression analysis to determine factors impacting primary, secondary, and total technique effectiveness. A p value less than 0.05 was considered significant.

RESULTS

One hundred pathologically proven RCC lesions in 84 patients were analyzed. The median (mean) follow-up was 24 (27) months (range 1-106 months). Overall RF ablation primary, secondary and total technique effectiveness was 86%, 9%, and 95%, respectively. Clear cell subtype demonstrated worse treatment efficacy with primary, secondary, and total technique effectiveness of 42/55 (76.4%), 8/55 (14.5%), and 50/55 (90.9%), respectively. Non-clear cell subtypes had primary, secondary, and total technique effectiveness of 44/45(97.8%), 1/45 (2.2%), 45/45 (100%), respectively. The difference in primary (p = 0.002), secondary (p = 0.032), and total (p = 0.038) technique effectiveness between the two groups was statistically significant.

CONCLUSION

Clear cell RCC was a novel predictor of primary, secondary, and total technique efficacy in the percutaneous RF ablation of clear cell RCC.

Metabolomic study of human tissue and urine in clear cell renal carcinoma by LC-HRMS and PLS-DA

Renal cell carcinoma (RCC) is the most prevalent and lethal malignancy of the kidney. Despite all the efforts made, no tissue biomarker is currently used in the clinical management of patients with kidney cancer. A search for possible biomarkers in urine for clear cell renal cell carcinoma (ccRCC) has been conducted. Non-targeted metabolomic analyses were performed on paired samples of surgically removed renal cancer and normal tissue, as well as on urine samples. Extracts were analyzed by liquid chromatography/high-resolution mass spectrometry (LC-HRMS). Hydroxybutyrylcarnitine, decanoylcarnitine, propanoylcarnitine, carnitine, dodecanoylcarnitine, and norepinephrine sulfate were found in much higher concentrations in both cancer tissues (compared with the paired normal tissue) and in urine of cancer patients (compared with control urine). In contrast, riboflavin and acetylaspartylglutamate (NAAG) were present at significantly higher concentrations both in normal kidney tissue as well as in urine samples of healthy persons. This preliminary study resulted in the identification of several compounds that may be considered potential clear cell renal carcinoma biomarkers. Graphical abstract PLS-DA plot based on LC-MS data for normal and cancer human tissue samples. The aim of this work was the identification of up- and downregulated compounds that could potentially serve as renal cancer biomarkers.

The effect of AST/ALT (De Ritis) ratio on survival and its relation to tumor histopathological variables in patients with localized renal cell carcinoma

Purpose

To assess the relationship between De Ritis (aspartate aminotransaminase [AST]/Alanine aminotransaminase [ALT]) ratio and pathological variables and whether it is an independent prognostic factor.

Materials and Methods

We analyzed 298 consecutive patients who underwent radical or partial nephrectomy for non-metastatic renal cell carcinoma (RCC) between 2006 and 2015. The association between De Ritis ratio and pathological variables including tumor size, presence of renal vein invasion, vena cava invasion, renal capsule infiltration, Gerota fascia invasion, renal sinus involvement, renal pelvic invasion, angiolymphatic invasion, adrenal gland involvement, lymph node involvement, tumor necrosis, and Fuhrman's grade was tested. Multivariable Cox analysis was performed to evaluate the impact of this ratio on overall survival and cancer-specific survival.

Results

An increased preoperative De Ritis ratio was significantly associated with renal vein invasion, renal capsule infiltration and renal pelvis involvement (p<0.05) in non-metastatic RCC. On multivariate analysis we found that tumor size, Fuhrman grade and lymph node involvement were independent prognostic factors for cancer-specific survival. AST/ALT ratio had no influence on the risk of overall and cancer-specific survival.

Conclusion

An increased preoperative AST/ALT ratio had a significant association with renal vein invasion, renal capsule infiltration and renal pelvis involvement in patients with non-metastatic RCC. However, it does not appear to be an independent prognostic marker in non-metastatic RCC.

CT and MRI of small renal masses

Small renal masses are increasingly detected incidentally at imaging. They vary widely in histology and aggressiveness, and include benign renal tumors and renal cell carcinomas that can be either indolent or aggressive. Imaging plays a key role in the characterization of these small renal masses. While a confident diagnosis can be made in many cases, some renal masses are indeterminate at imaging and can present as diagnostic dilemmas for both the radiologists and the referring clinicians. This article will summarize the current evidence of imaging features that correlate with the biology of small solid renal masses, and discuss key approaches in imaging characterization of these masses using CT and MRI.

MiR-199a-3p acts as a tumor suppressor in clear cell renal cell carcinoma

OBJECTIVES

To explore the biological function and mechanism of miR-199a-3p in clear cell renal cell carcinoma (CCRCC).

METHODS

We investigated the expression of miR-199a-3p in CCRCC through quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Over expression of miR-199a-3p was performed in CCRCC cell lines, and cell growth curve, colony formation capacity, cell invasion, wound healing and cell apoptosis assay were used for investigating the roles of miR-199a-3p in CCRCC.

RESULTS

The expression of miR-199a-3p in CCRCC tissues was significantly lower than that in para-carcinoma tissues. Functional assay showed that over expression of miR-199a-3p influenced cell growth, colony formation, cell invasion, cell migration and cell apoptosis in CCRCC cell lines.

CONCLUSIONS

Our work suggested that miR-199a-3p was related to cell growth, colony formation, cell invasion, cell migration and cell apoptosis, which might act as a tumor suppressor in CCRCC.

Survival outcomes for advanced kidney cancer patients in the era of targeted therapies

Background

Advanced renal cell carcinoma (RCC) results in over 14,000 deaths each year in the United States alone. The therapeutic landscape for advanced RCC changed dramatically with the approval of tyrosine kinase inhibitors (TKI) between 2006 and 2012. A large-scale analysis of survival trends has not been performed in the TKI era to determine their impact on outcomes for advanced RCC patients.

Methods

The Surveillance, Epidemiology and End-Results (SEER) database was queried for adult patients with advanced RCC diagnosed between 2000 and 2013. Patients were divided into two cohorts based on the year of diagnosis-pre-TKI cohort [2000-2006] and TKI cohort [2007-2013]. Kaplan-Meier survival and multivariate Cox proportional hazards analyses were performed.

Results

A total of 14,976 patients were included in our study. Median age at diagnosis was 64 years (range, 18-89 years). Median (cancer-specific) overall survival was 10.0 months in the TKI cohort compared with 8.0 months in the pre-TKI cohort, corresponding to a 13% improvement in survival in the TKI area [hazard ratio (HR) for death 0.87; 95% confidence interval (CI), 0.84-0.91, P<0.0001]. Median survival was improved by 2 months for patients with clear-cell RCC histology [HR for death 0.86; 95% CI, 0.84-0.91, P<0.0001]. Patients with non-clear cell RCC had a 25% higher risk of mortality compared with those with clear-cell RCC. Additionally, median survival for non-clear cell RCC patients was not statistically different between the two cohorts (HR for death 0.98; 95% CI, 0.88-1.09, P=0.714). Subgroup analysis showed that elderly patients (age 71 years and above) had a 45% higher risk of death from advanced RCC compared with young patients (aged 18-50 years) [HR for death 1.45; 95% CI, 1.36-1.54, P<0.0001]. Gender and racial disparities in outcomes were also noted with women having a 10% higher risk of death compared with men (HR for death 1.10; 95% CI, 1.06-1.14, P<0.001) and Black patients having a 15% higher risk of death compared with White patients (HR for death 1.15; 95% CI, 1.08-1.23, P<0.0001).

Conclusions

Our study provides a largest registry-based analysis of survival outcomes in the TKI era. In majority of patients, the survival has improved significantly with the advent of TKIs as standard of care therapy. Survival for patients with non-clear cell RCC is clearly worse than clear-cell RCC and does not appear to have changed with TKIs. Elderly patients, women, and Black patients appear to have worse outcomes and these disparities merit further investigation.

Value of computed tomography texture analysis for prediction of perioperative complications during laparoscopic partial nephrectomy in patients with renal cell carcinoma

Purpose

Tumorous texture is a marker for tumor tissue inhomogeneity. Based on this assumption, this study aims to evaluate the value of computed tomography texture analysis for imaging-based prediction of perioperative complications during laparoscopic partial tumor nephrectomy.

Methods

A total of 106 patients with histologically confirmed renal cell carcinoma and pre-operative CT were included and volumetric texture analysis of the tumors was performed by two readers. Texture analysis parameter ratios and differences were calculated using the kidney parenchyma as reference (“reference-corrected”). Regression analysis was performed, regarding the value of the texture analysis parameters, for assessment of the tumor nuclear grade and the prediction of peri- and postoperative complications and approximated blood loss. Moreover, the inter-rater agreement in terms of the intra-class correlation coefficient (ICC) was calculated.

Results

Regarding the reference-corrected values, the predictive value of texture analysis parameters for severe perioperative complications was highest for the standard deviation of the mean attenuation (Area under curve/AUC, .615; sensitivity, 93.8%, specificity, 30.0%), followed by the uniformity (AUC, .599; sensitivity, 62.5%, specificity, 60.0%), and the uniformity of distribution of positive pixels (AUC, .597; sensitivity, 62.5%; specificity, 61.1%).

Regarding the blood loss, the uniformity of positive pixel values (UPP; AUC, 0.638), uniformity (AUC, 0.635), and entropy (AUC, 0.633) yielded the best predictive values, whilst the tumor grade was a weaker predictor (AUC, 0.574).

The applied texture analysis parameters did not correlate with the time of surgery or the warm ischemic time. All measured parameters were better predictors for complications than the tumor diameter alone. The inter-rater agreement was almost perfect (ICC, .982).

Conclusion

CT and CT texture analysis parameters are valuable for prediction of perioperative outcome before laparoscopic partial nephrectomy in patients with renal cell carcinoma.

Imaging and Management of Intrathoracic Renal Cell Carcinoma Metastases

OBJECTIVE

Renal cell carcinoma (RCC) has a propensity to metastasize to the chest, with the lungs being the most common distant metastatic site. The histologic subtype of RCC has implications for prognosis.

CONCLUSION

Significant advances have been made in the management of metastatic RCC, both in systemic and locoregional therapies. The aim of this article is to review appearances of intrathoracic metastases from RCC and to discuss treatment considerations.

The Study of Clear Cell Renal Cell Carcinoma with MR Diffusion Kurtosis Tensor Imaging and Its Histopathologic Correlation

RATIONALE AND OBJECTIVES

The objective of this study was to compare the performance of diffusion kurtosis tensor imaging and diffusion-weighted imaging in the characterization of clear cell renal cell carcinoma (ccRCC) and their correlations with tumor histopathology.

MATERIALS AND METHODS

Ninety-one patients diagnosed with ccRCC who underwent diffusion kurtosis tensor imaging were included in this study. Fractional anisotropy, mean diffusivity, radial diffusivity, axial diffusivity, mean kurtosis (MK), radial kurtosis (Krad), and axial kurtosis (Kax) data were produced. A nuclear grade of 1-4 (G1-4) was assigned for each case based on the Fuhrman grading system, whereas tumor histopathology was characterized by the nuclear-to-cytoplasm ratio, the cell nuclei count, and the cell volume fraction.

RESULTS

All of the metric values except for Kax and fractional anisotropy could be used to discriminate G1 vs G3, G1 vs G4, G2 vs G3, and G2 vs G4, whereas MK and Kax could be used to discriminate G3 vs G4 (P <0.05). Moreover, the MK and Krad values exhibited better performance in differentiating G2 from G3 (P < 0.04 compared to the other metrics). The nuclear-to-cytoplasm ratio was positively correlated with the MK, Krad, and Kax values (P <0.001) and negatively correlated with the mean diffusivity, radial diffusivity, and axial diffusivity values (P <0.001), whereas the cell volume fraction and the cell nuclei count did not correlate with any metric examined.

CONCLUSION

The kurtosis metrics were superior to the diffusion metrics in grading ccRCC.

Genomic classifications of renal cell carcinoma: a critical step towards the future application of personalized kidney cancer care with pan-omics precision

Over the past 20 years, classifications of kidney cancer have undergone major revisions based on morphological refinements and molecular characterizations. The 2016 WHO classification of renal tumors recognizes more than ten different renal cell carcinoma (RCC) subtypes. Furthermore, the marked inter- and intra-tumor heterogeneity of RCC is now well appreciated. Nevertheless, contemporary multi-omics studies of RCC, encompassing genomics, transcriptomics, proteomics, and metabolomics, not only highlight apparent diversity but also showcase and underline commonality. Here, we wish to provide an integrated perspective concerning the future 'functional' classification of renal cancer by bridging gaps among morphology, biology, multi-omics, and therapeutics. This review focuses on recent progress and elaborates the potential value of contemporary pan-omics approaches with a special emphasis on cancer genomics unveiled through next-generation sequencing technology, and how an integrated multi-omics approach might impact precision-based personalized kidney cancer care in the near future. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

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

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

STK39 blockage by RNA interference inhibits the proliferation and induces the apoptosis of renal cell carcinoma

Aim

Renal cell carcinoma (RCC), the most frequent type of primary renal malignancies, has a high mortality rate. Serine/threonine kinase 39 (STK39) is associated with various human diseases, including cancers. The current study aimed to investigate the functions of STK39 in RCC.

Materials and methods

STK39 expression levels in RCC and paired normal renal tissue samples were detected by real-time polymerase chain reaction and Western blotting analyses. The biological functions of STK39 were explored in two RCC cell lines with STK39 silence.

Results

STK39 expression was significantly increased in RCC tissues than in normal renal tissues. Suppression of STK39 expression in ACHN and 786-0 cells significantly suppressed cell proliferation and induced cell apoptosis. Consistently, the expression of PCNA and Bcl-2 was remarkably increased, while the expression of Bax was significantly in STK39 knockdown cells compared to control cells. Furthermore, gene set enrichment analysis identified STK39 as an important regulator of p53 and p38 signaling pathways. STK39 knockdown increased p53 expression and inhibited p38 phosphorylation. Moreover, ectopic expression of STK39 in ACHN cells resulted in a reduced p53 expression and increased c-Myc and p-p38 expression. Such effects were suppressed by p38 inhibitor (SB203580).

Conclusion

STK39 may exert its oncogenic function in RCC through p38 signaling. Our data suggest that STK39 may represent a potential therapeutic target against RCC.

MicroRNA-599 targets high-mobility group AT-hook 2 to inhibit cell proliferation and invasion in clear cell renal carcinoma

Dysregulation of microRNAs (miRNAs) is associated with the occurrence and development of clear cell renal cell carcinoma (ccRCC) through their participation in a number of critical biological processes. Therefore, an in‑depth investigation into miRNAs and their biological roles within ccRCC may provide useful insights and lead to the identification of novel therapeutic methods for patients with ccRCC. miRNA‑599 (miR‑599) serves critical roles in different types of human cancer. However, the expression pattern, biological function and molecular mechanism of miR‑599 in ccRCC remain unknown. The present study aimed to detect the expression level of miR‑599 in ccRCC, examine its effect on ccRCC progression and further explore the possible underlying mechanisms. It was observed that miR‑599 was significantly underexpressed in ccRCC tissues and cell lines compared with the control. Functional assays revealed that restored expression of miR‑599 restricted the proliferation and invasion of ccRCC cells. Bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis demonstrated that high‑mobility group AT‑hook 2 (HMGA2) was a direct target of miR‑599 in ccRCC. HMGA2 knockdown simulated the suppressive effects caused by miR‑599 overexpression in ccRCC. Recovered HMGA2 expression partially rescued the miR‑599‑mediated inhibition of ccRCC proliferation and invasion. These results suggest that miR‑599 may serve tumour suppressive roles in ccRCC by directly targeting HMGA2, indicating that miR‑599 may have potential as a treatment for patients with ccRCC.

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.

Verification of the International Society of Urological Pathology recommendations in Japanese patients with clear cell renal cell carcinoma

The aim of the present study was to evaluate the validity of potential prognostic parameters of clear cell renal cell carcinoma (ccRCC) recommended by the 2012 International Society of Urological Pathology (ISUP) Consensus Conference in the Japanese population. We reviewed 406 Japanese patients with localized or locally advanced ccRCC who underwent curative surgery during 2004-2014 at Tokai University Hospital (Isehara, Japan) and were followed up for >2 years after surgery. A single pathologist reviewed all the histological slides. Morphological subtype and pathological T stage were reassigned according to the 2016 World Health Organization and TNM classifications. Sarcomatoid differentiation (SD), rhabdoid differentiation (RD), tumor necrosis (TN) and microvascular invasion (MVI) were assessed according to the 2012 ISUP recommendations. Nuclear grade was reclassified according to both the Fuhrman and the ISUP grading systems. Recurrence‑free survival (RFS) and cancer-specific survival (CSS) were assessed through univariate and multivariate analyses. According to the Fuhrman grading system (group Fuhrman), TN and MVI were independent risk factors for postoperative recurrence in the multivariate analysis using the Cox proportional hazards model. According to the ISUP grading system (group ISUP), TN and MVI were independent risk factors for postoperative recurrence. In group Fuhrman, age, Fuhrman grade and TN were independent risk factors for CSS. In group ISUP, age, ISUP grade, and TN were independent risk factors for CSS. Furthermore, the group that was upgraded from Fuhrman grade 2 to ISUP grade 3 exhibited poorer CSS compared with the group that was reclassified from Fuhrman grade 2 to ISUP grade 2 (non-upgraded). Regardless of the nuclear grade, TN remained an independent predictor of RFS and CSS. To the best of our knowledge, this is the first report to prove the correlation between the 2012 ISUP recommendations and clinical outcomes in a Japanese ccRCC cohort. TN and upgrading to ISUP grade 3 were found to be potentially useful independent indicators of postoperative prognosis.

Clinical and Molecular Characteristics and Burden of Kidney Cancer Among Hispanics and Native Americans: Steps Toward Precision Medicine

Cancer disparities in Native Americans (NAs) and Hispanic Americans (HAs) vary significantly in terms of cancer incidence and mortality rates across geographic regions. This review reports that kidney and renal pelvis cancers are unevenly affecting HAs and NAs compared to European Americans of non-Hispanic origin, and that currently there is significant need for improved data and reporting to be able to advance toward genomic-based precision medicine for the assessment of such cancers in these medically underserved populations. More specifically, in states along the US-Mexico border, HAs and NAs have higher kidney cancer incidence rates as well as a higher prevalence of kidney cancer risk factors, including obesity and chronic kidney disease. They are also more likely to receive suboptimal care compared to European Americans. Furthermore, they are underrepresented in epidemiologic, clinical, and molecular genomic studies of kidney cancer. Therefore, we maintain that progress in precision medicine for kidney cancer care requires an understanding of various factors among HAs and NAs, including the real kidney cancer burden, variations in clinical care, issues related to access to care, and specific clinical and molecular characteristics.

Regulation of Tumor Progression by Programmed Necrosis

Rapidly growing malignant tumors frequently encounter hypoxia and nutrient (e.g., glucose) deprivation, which occurs because of insufficient blood supply. This results in necrotic cell death in the core region of solid tumors. Necrotic cells release their cellular cytoplasmic contents into the extracellular space, such as high mobility group box 1 (HMGB1), which is a nonhistone nuclear protein, but acts as a proinflammatory and tumor-promoting cytokine when released by necrotic cells. These released molecules recruit immune and inflammatory cells, which exert tumor-promoting activity by inducing angiogenesis, proliferation, and invasion. Development of a necrotic core in cancer patients is also associated with poor prognosis. Conventionally, necrosis has been thought of as an unregulated process, unlike programmed cell death processes like apoptosis and autophagy. Recently, necrosis has been recognized as a programmed cell death, encompassing processes such as oncosis, necroptosis, and others. Metabolic stress-induced necrosis and its regulatory mechanisms have been poorly investigated until recently. Snail and Dlx-2, EMT-inducing transcription factors, are responsible for metabolic stress-induced necrosis in tumors. Snail and Dlx-2 contribute to tumor progression by promoting necrosis and inducing EMT and oncogenic metabolism. Oncogenic metabolism has been shown to play a role(s) in initiating necrosis. Here, we discuss the molecular mechanisms underlying metabolic stress-induced programmed necrosis that promote tumor progression and aggressiveness.

Changing the Stage, Grade and Histological Subtypes of Renal Cell Carcinomas during 10 Years Period

Renal cell carcinomas (RCCs) account 80-85% of all primary renal neoplasms and originate from the renal cortex. The patients who underwent radical or partial nephrectomy for renal tumour in our unit between January 2005 and 2015 were evaluated retrospectively. The patients were divided into two groups; group 1 includes patients who were treated between January 2005 and December 2009, group 2 those from January 2010 to 2015. There were 103 patients in group 1. The patients were between 21 and 89 years with mean age of 61.46 year. Renal cell carcinomas account 83.4% of the patients, benign renal tumours were 8.7% and transitional cell carcinomas were 7.7% of the patients in group 1. A total of 32.5% RCCs were classified as pT1a, 24.4% as pT1b, 15.1% as pT2a, 11.6% as pT2b, 15.1% as pT3a and 1.1% as pT4. There were 202 patients in group 2 and the patients were between 27 and 81 years with mean age of 58.5 year. Renal cell carcinomas comprised the main bulk of the tumours with 182 nephrectomy specimens. According to the pathological classification of RCCs, 51 specimens were found as pT1a, 54 were pT1b, 13 were pT2a, 14 were pT2b, 48 were pT3a and 2 were pT4. Although, the incidence of small renal masses has been increasing with widespread use of imaging techniques and recent advancements, the proportion of high grade and advanced stage renal tumours increased during the study period.

Variation in nuclear size and PD-L2 positivity correlate with aggressive chromophobe renal cell carcinoma

Chromophobe renal cell carcinoma (CRCC) is not amenable to International Society for Urologic Pathology-endorsed nucleolar grading. Novel grading approaches were proposed, but the rarity of adverse pathology hampers their discriminatory value. We investigate simple linear micrometer measurements and a proposed immunostain in CRCCs. 32 patients' CRCCs were studied: 12 adverse cases (stage pT3, recurrence, or metastasis), 15 controls (stage ≤pT2, no recurrence or metastasis after >3 years), and 8 metastases (3 were paired with primary adverse cases). The ratio of greatest dimensions of largest and smallest nuclei, in each of 5 "worst" high-power fields, excluding those with degenerative features, was designated variation in nuclear size (VNS). Percent multinucleate cells (PMC) were also counted. Mouse anti PD-L2 monoclonal antibody immunostaining was performed. Mean VNS measured in adverse primary and control primary tumors were 3.7 ± 0.5 and 2.4 ± 0.4 respectively (P < .001), and 3.4 ± 0.4 for metastases (P < .001). Optimal VNS cut-off was 2.5, with sensitivity and specificity 0.85 and 0.81, respectively. PMCs were 6.0 ± 3.0 for adverse group, 5.7 ± 2.7 for controls, and 4.1 ± 1.6 for metastases (P = NS). PD-L2 could not discriminate adverse versus good primary tumors (χ²1.6, P = .2), but was higher in metastases (χ² 6.9, P < .01), or metastases plus adverse primary tumors (χ² 4.8, P = .03), compared to good-pathology primary tumors. In conclusion, VNS is an easily obtained measurement that can predict adverse behavior of chromophobe RCC, and may impart value for needle biopsy reporting and the choice of active surveillance. PD-L2 was elevated in metastases but was less useful for primary tumors.

Renal capsular invasion is a prognostic biomarker in localized clear cell renal cell carcinoma

Renal capsular invasion (RCI) and lymphovascular invasion (LVI) are potential prognostic factors of significance in renal cell carcinoma (RCC). We evaluated the independent prognostic implications of RCI and LVI in localized clear cell RCC based on a large multi-institutional cohort. 6, 849 patients who had undergone radical or partial nephrectomy for RCC were included. Associations between recurrence and RCI or LVI were analyzed by constructing statistical models that combined Cox proportional hazard regression and propensity score matching. To analyze RCI, 2, 733 patients including 603 patients with RCI were enrolled. To analyze LVI, 3, 586 patients including 121 patients with LVI were enrolled. Recurrence was observed in 75 (12.4%) patients with RCI and 134 (6.3%) patients without RCI. In all statistical models, RCI was significantly associated with an increased risk of recurrence. Recurrence was observed 29 (24.0%) patients with LVI and 207 (6.0%) patients without LVI. LVI was significantly associated with an increased risk of recurrence only in non-adjusted univariate models, but not in multivariate adjusted analysis or propensity score matching models. In conclusion, these findings suggest that RCI could be a significant risk factor for localized clear cell RCC recurrence. In contrast to RCI, LVI cannot be an independent prognostic variable.

Proximal CD13 Versus Distal GATA-3 Expression in Renal Neoplasia According to WHO 2016 Classification

Little is known about the aminopeptidase CD13 in renal neoplasia according to the new 2016 World Health Organization renal tumor classification. We selected 175 cases, including 79 clear cell, 31 papillary, 24 chromophobe, 8 clear cell papillary renal cell carcinomas (RCCs), 21 oncoytomas, and 12 microphthalmia transcription factor family translocation RCCs: 4 t(6;11)/transcription factor EB (TFEB), 7 t(Xp11) with 2 cystic variants and 1 t(X;17). GATA binding protein 3 (GATA-3) was inserted as control. Expression of proximal antigen CD13 was observed in 63/79 (80%) clear cell, 25/31 (81%) papillary, 3/8 (37%) clear cell papillary, 1/4 (25%) t(6;11)/TFEB, 2/7 (28%) cystic t(Xp11), and in 1/1 t(X;17) RCCs. All chromophobe RCC (0/24) and all oncocytomas (0/21) resulted negative. CD10 was seen in 76/79 (96%) clear cell, 15/31 (48%) papillary, 10/24 (42%) chromophobe, 1/8 (12%) clear cell papillary RCCs, 4/21 (19%) oncocytomas, 1/4 (25%) t(6;11)/TFEB, 2/7 (29%) cystic t(Xp11), and in 1/1 t(X;17) RCCs. GATA-3 was positive in 3/7 (42%) clear cell papillary RCCs and negative in all remaining RCCs, except a single chromophobe RCC and a single oncocytoma. We concluded that: (1) CD13 and GATA-3 immunostains may serve as a diagnostic aid in differentiating subtypes of RCC; (2) CD13 is always absent in chromophobe RCC and oncocytomas, whereas CD10 can be immunoexpressed in both; (3) CD13 should be included in a panel of antibodies to distinguish "proximal renal tumors" from "distal renal tumors" and between clear cell RCC versus microphthalmia transcription factor family translocations RCCs; and (4) when present, GATA-3 is specific for clear cell papillary RCC.

Epidemiology profile of renal cell carcinoma: A 10-year patients' experience at King Abdulaziz Medical City, National Guard Health Affairs, Saudi Arabia

Purpose

The purpose of this study is to describe the epidemiological profile, histopathological features, and outcomes of patients diagnosed with renal cell carcinoma (RCC) in a tertiary referral center over 10 years.

Methodology

This is a retrospective cohort of 219 Saudi patients diagnosed with RCC between June 2003 and May 2013. The variables collected included the sociodemographic details and clinical presentation. The histopathological features investigated include the tumors histological subtype, pathologic staging tumor, node, and metastasis descriptors, and lymph-vascular invasion. Patients were followed until May 2013. Bivariable analysis was calculated using Chi-square test, with level of significance set at P < 0.05. Kaplan-Meier estimate was used to calculate the survival rate.

Results

The mean age of patients was 57.18 (±14.68 standard deviation). The trend of patients diagnosed with RCC over the past 10 years was higher among males than females (60.27% vs. 39.73%). Noticeably, more than half (57.58%) were diagnosed incidentally. The most common histological subtype was clear cell (conventional) RCC (70.44%). Patients were usually diagnosed at the pT1 stage (48.1%).The histopathological features associated with worse patient outcome were the stage of the primary tumor (P = 0.01) and lymph-vascular invasion (P = 0.003). The overall mean survival rate was 2.03 years.

Conclusion

In the past 10 years, there are more patients diagnosed incidentally with RCC, which is in line with the global trend. Patients were more likely to be male and middle aged. We recommend further population-based studies in this area to establish a national epidemiological data for this common type of cancer.

High-dose interleukin 2 in patients with metastatic renal cell carcinoma with sarcomatoid features

Background

High-dose interleukin-2 (HD IL-2) is used in the treatment of metastatic renal cell carcinoma (mRCC) and has an overall response rate (ORR) of 12–20% and a complete response rate (CR) of 8% in unselected populations with predominantly clear cell type renal cell carcinoma. Nearly 10–15% of patients with renal cell carcinoma exhibit sarcomatoid differentiation, a feature which correlates with a median overall survival (OS) of 9 months and overall poor prognosis. We report a single institution experience with 21 patients with mRCC with sarcomatoid features post-nephrectomy who were treated with HD IL-2.

Methods

Twenty one patients with mRCC with sarcomatoid features post-nephrectomy who underwent therapy with HD IL-2 were identified at the University of Pittsburgh Medical Center from 2004 to 2016. Baseline patient characteristics, HD IL-2 cycles, time to progression, and subsequent therapies were evaluated. OS and progression-free survival (PFS) in the cohort were calculated using the Kaplan-Meier method. Disease characteristics were evaluated for significance using the Fischer′s exact test and Wilcoxon rank sum test.

Results

Patients were predominantly Caucasian males with a median age of 54 years. A majority, 86% of these patients, had metastatic disease at time of initial presentation, primarily with lung and lymph node involvement. The ORR and CR with HD IL-2 was 10% and 5%, respectively. Initial localized disease presentation is the only variable that was significantly associated with response to HD IL-2 (p = 0.0158). Number of HD IL-2 doses did not correlate with response with a mean of 16.5 and 15.0 total doses in responders and non-responders, respectively (p = 0.53). Median PFS with HD IL-2 was 7.9 months (95% CI, 5.0–21.3). Median OS was 30.5 months (95% CI 13.3–57.66). Within the subset of patients who had progression on IL-2, median OS was 19.4 months (95% CI, 13.3–35.3). In patients who received second-line therapy, median PFS was 7.9 months (95% CI 2.4–10.2).

Conclusion

In patients with mRCC with sarcomatoid features, use of HD IL-2 was associated with a modest ORR and a higher survival compared to historical controls (patients with mRCC and sarcomatoid features). Thus, HD IL-2 may have a role in treating selected patients with mRCC with sarcomatoid features.

Exploring Multiphoton Microscopy as a Novel Tool to Differentiate Chromophobe Renal Cell Carcinoma From Oncocytoma in Fixed Tissue Sections

Context.—

Distinguishing chromophobe renal cell carcinoma (chRCC), especially in the presence of eosinophilic cytoplasm, from oncocytoma on hematoxylin-eosin can be difficult and often requires time-consuming ancillary procedures that ultimately may not be informative.

Objective.—

To explore the potential of multiphoton microscopy (MPM) as an alternative and rapid diagnostic tool in differentiating oncocytoma from chRCC at subcellular resolution without tissue processing.

Design.—

Unstained, deparaffinized tissue sections from 27 tumors (oncocytoma [n = 12], chRCC [n = 12], eosinophilic variant of chRCC [n = 1], and atypical oncocytic renal neoplasm [n = 2]) were imaged with MPM. Morphologic evaluation and automated quantitative morphometric analysis were conducted to distinguish between chRCC and oncocytoma.

Results.—

The typical cases of oncocytomas (12 of 12) and chRCC (12 of 12) could be readily differentiated on MPM based on the morphologic features similar to hematoxylin-eosin. The most striking MPM signature of both of the tumors was the presence of autofluorescent intracytoplasmic granules, which are not seen on hematoxylin-eosin–stained slides. Although we saw these granules in both types of tumors, they appeared distinct, based on their size, shape, cytoplasmic distribution, and autofluorescence wavelengths, and were valuable in arriving at a definitive diagnosis. For oncocytomas and chRCC, high diagnostic accuracies of 100% and 83.3% were achieved on blinded MPM and morphometric analysis, respectively.

Conclusions.—

To the best of our knowledge, this is the first demonstration of MPM to distinguish chRCC from oncocytoma in fixed tissues. Our study was limited by small sample size and only a few variants of oncocytic tumors. Prospective studies are warranted to assess the utility of MPM as a diagnostic aid in oncocytic renal tumors.

Long non-coding RNA H19 regulates E2F1 expression by competitively sponging endogenous miR-29a-3p in clear cell renal cell carcinoma

Background

Numerous recent studies indicate that the long non-coding RNAs (lncRNAs) are frequently abnormal expressed and take critical roles in many cancers. Renal cell carcinoma is the secondary malignant tumors in the urinary system and has high mortality and morbidity. Around 80% of RCCs is clear cell renal cell carcinoma (ccRCC) and is characterized by high metastasis and relapse rate. However, the clinical significances of lncRNAs in ccRCC are still unknown.

Methods

The human cancer lncRNA PCR array (Yingbio) was performed to detect the differentially expressed lncRNAs in human ccRCC samples. Real-time PCR (RT-PCR), dual-luciferase assay, RNA binding protein immunoprecipitation (RIP) assay, transwell assay, CCK-8 assay, and western blot were performed to explore the molecular mechanism of lncRNAs in ccRCC cell migration and invasion.

Results

In this study, lncRNA-H19 was high expressed and negatively correlated with miR-29a-3p in ccRCC. By bioinformatics software, dual-luciferase reporter and RIP assays, we verified that miR-29a-3p was identified as a direct target of lncRNA-H19. RT-PCR and western blot demonstrated that down-regulated lncRNA-H19 could affect the expression of miR-29a-3p targeting E2F1 with competitively binding miR-29a-3p. Furthermore, transwell assays indicated that lncRNA-H19 knockdown inhibited cells migration and invasion, but this effect was attenuated by co-transfection of lncRNA-H19 siRNA and miR-29a-3p inhibitor. Over expression of E2F1 could rescue lncRNA-H19 siRNA induced suppression on cell migration and invasion in ccRCC cells.

Conclusions

These results show a possible competing endogenous RNAs regulatory network involving lncRNA-H19 regulates E2F1 expression by competitively sponging endogenous miR-29a-3p in ccRCC. This mechanism may contribute to a better understanding of ccRCC pathogenesis, and lncRNA-H19 may be further considered as a potential therapeutic target for ccRCC intervention.

The ABCs of BHD: An In-Depth Review of Birt-Hogg-Dubé Syndrome

OBJECTIVE

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant inherited syndrome involving multiple organs. In young patients, renal neoplasms that are multiple, bilateral, or both, such as oncocytomas, chromophobe renal cell carcinoma (RCC), hybrid chromophobe RCC-oncocytomas, clear cell RCC, and papillary RCC, can suggest BHD syndrome. Extrarenal findings, including dermal lesions, pulmonary cysts, and spontaneous pneumothoraces, also aid in diagnosis.

CONCLUSION

Radiologists may be one of the first medical specialists to suggest the diagnosis of BHD syndrome. Knowledge of pathogenesis and management, including the importance of the types of renal neoplasms in a given patient, is needed to properly recognize this rare condition.

Chemical shift magnetic resonance imaging for distinguishing minimal-fat renal angiomyolipoma from renal cell carcinoma: a meta-analysis

OBJECTIVES

To determine the performance of chemical shift signal intensity index (CS-SII) values for distinguishing minimal-fat renal angiomyolipoma (mfAML) from renal cell carcinoma (RCC) and to assess RCC subtype characterisation.

METHODS

We identified eligible studies on CS magnetic resonance imaging (CS-MRI) of focal renal lesions via PubMed, Embase, and the Cochrane Library. CS-SII values were extracted by lesion type and evaluated using linear mixed model-based meta-regression. RCC subtypes were analysed. Two-sided p value <0.05 indicated statistical significance. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Eleven articles involving 850 patients were included. Minimal-fat AML had significantly higher CS-SII value than RCC (p < 0.05); there were no significant differences between mfAML and clear cell RCC (cc-RCC) (p = 0.112). Clear cell RCC had a significantly higher CS-SII value than papillary RCC (p-RCC) (p < 0.001) and chromophobe RCC (ch-RCC) (p = 0.045). The methodological quality was relatively high, and Begg's test data points indicated no obvious publication bias.

CONCLUSIONS

The CS-SII value for differentiating mfAML from cc-RCC remains unproven, but is a promising method for differentiating cc-RCC from p-RCC and ch-RCC.

KEY POINTS

• RCC CS-SII values are significantly lower than those of mfAML overall. • CS-SII values cannot aid differentiation between mfAML and cc-RCC. • CS-SII values might help characterise RCC subtypes.

Sarcomatoid Renal Cell Carcinoma and Collecting Duct Carcinoma: Discrimination From Common Renal Cell Carcinoma Subtypes and Benign RCC Mimics on Multiphasic MDCT

RATIONALE AND OBJECTIVES

To investigate whether imaging features on multiphasic multidetector computed tomography (MDCT) can help discriminate sarcomatoid renal cell carcinoma (RCC) and collecting duct carcinoma (CDC) from other solid renal masses.

MATERIALS AND METHODS

With institutional review board approval for this HIPAA-compliant study, we derived a cohort of 7 sarcomatoid RCCs, 4 CDCs, 165 clear cell RCCs, 56 papillary RCCs, 22 chromophobe RCCs, 49 oncocytomas, and 16 lipid-poor angiomyolipomas with preoperative multiphasic MDCT with up to four phases (unenhanced, corticomedullary, nephrographic, and excretory). Each lesion was reviewed for contour, spread pattern, pattern of enhancement, neovascularity, and calcification.

RESULTS

Sarcomatoid RCCs and CDCs were more likely than other solid renal masses to have an irregular contour (64% vs 2%, P < 0.001) and an infiltrative spread pattern, defined as infiltration into adjacent renal parenchyma, collecting system, or neighboring structures (82% vs 7%, P < 0.001). When used to discriminate sarcomatoid RCC and CDC from other solid renal masses, an infiltrative spread pattern had a specificity of 93% (287/308) and sensitivity of 82% (9/11), and an irregular contour had a specificity of 98% (303/308) and sensitivity of 64% (7/11).

CONCLUSIONS

Solid renal lesions with an irregular contour or an infiltrative spread pattern are suspicious for sarcomatoid RCC or CDC.

Prognostic Value of Clinical and Pathological Features in Chinese Patients with Chromophobe Renal Cell Carcinoma: A 10-Year Single-Center Study

Objective: To evaluate the prognostic significance of clinicopathological features in a large series of Chinese patients with chromophobe renal cell carcinoma (RCC).

Materials and Methods: Patients with chromophobe RCC who were treated surgically for renal masses at Chinese PLA General Hospital from 2006 to 2015 were identified. Tissue slides were reviewed to verify diagnoses and collect clinicopathological variables. Cox proportional hazard regression models and the Kaplan-Meier method were performed to evaluate the significance of clinicopathological variables on survival outcomes.

Results: A total of 209 patients with chromophobe RCC were enrolled in this study. There were only 13 cancer-specific events, which included 7 local recurrences and 6 metastases. The estimated 5-year and 10-year disease-free survival (DFS) rates were 92.4% and 83.1%, respectively. Univariate analysis indicated that tumor size, 2010 AJCC TNM stage, grade, sarcomatoid differentiation and urinary collecting system invasion were correlated with poor DFS. Multivariate analysis revealed that tumor size, 2010 AJCC TNM stage and grade were independent predictors of DFS.

Conclusions: According to this long-term follow-up on a large number of Chinese patients, we found that chromophobe RCC was associated with a very low rate of cancer-specific events (6.2%) and has a better prognosis than clear cell RCC. Tumor size, 2010 AJCC TNM stage and grade were independent prognostic factors in Chinese patients with chromophobe RCC. The presence of these features in a nephrectomy specimen with chromophobe RCC warrants more active surveillance.

MicroRNA-212 inhibits the proliferation, migration and invasion of renal cell carcinoma by targeting X-linked inhibitor of apoptosis protein (XIAP)

MicroRNAs have been found to be critical regulator of cancer cell biology. MicroRNA-212 (miR-212) was identified to be a critical cancer-associated microRNA playing either oncogenic functions or tumor suppressive roles in different types of human cancers. In this study, we found that the level of miR-212 in renal cell carcinoma (RCC) tissues was significantly lower than that in adjacent non-tumor tissues. Decreased level of miR-212 was associated with advanced T stage and TNM stage of RCC. The expression of miR-212 was decreased in RCC cell lines as compared with the HK-2 cell line. Overexpression of miR-212 inhibited cell viability, proliferation, migration and invasion of CAKI-2 cells. Knockdown of miR-212 increased cell viability and proliferation, migration and invasion of ACHN cells. In vivo experiments showed that miR-212 inhibited the proliferation and promoted the apoptosis of ACHN cells in nude mice and thus inhibited the in vivo tumor growth of CAKI-2 cells. Furthermore, we confirmed that X-linked inhibitor of apoptosis protein (XIAP) was the downstream target of miR-212. The expression level of miR-212 was negatively correlated with XIAP expression in RCC tissues. Moreover, XIAP mediated the tumor suppressive roles of miR-212 in RCC. Finally, we demonstrated that the aberrant expression of miR-212 and XIAP was evidently correlated with poor prognosis of RCC patients. In all, miR-212 can act as a prognostic biomarker for RCC patients and inhibits the growth and metastasis of RCC cells by inhibiting XIAP.

Distribution of glucose transporters in renal diseases

Kidneys play an important role in glucose homeostasis. Renal gluconeogenesis prevents hypoglycemia by releasing glucose into the blood stream. Glucose homeostasis is also due, in part, to reabsorption and excretion of hexose in the kidney.Lipid bilayer of plasma membrane is impermeable for glucose, which is hydrophilic and soluble in water. Therefore, transport of glucose across the plasma membrane depends on carrier proteins expressed in the plasma membrane. In humans, there are three families of glucose transporters: GLUT proteins, sodium-dependent glucose transporters (SGLTs) and SWEET. In kidney, only GLUTs and SGLTs protein are expressed. Mutations within genes that code these proteins lead to different renal disorders and diseases. However, diseases, not only renal, such as diabetes, may damage expression and function of renal glucose transporters.

PBRM1 regulates proliferation and the cell cycle in renal cell carcinoma through a chemokine/chemokine receptor interaction pathway

PBRM1 is a novel tumor suppressor gene that can inhibit cancer cell proliferation and predict the outcome of renal cell carcinoma (RCC), but its biological role needs further elucidation. We examined expression of the PBRM1 gene in RCC cell lines and the effect of PBRM1 on cell proliferation and cell cycle in RCC ACHN cells. Microarray processing and analysis was used to explore novel pathways involved in tumorigenesis related to PBRM1 knockdown. PBRM1 was expressed at high levels in RCC ACHN cells and lentivirus-mediated PBRM1 knockdown in these cells caused an increase in the proportion of cells in S phase of the cell cycle and promoted in vitro proliferation and migration. In vivo experiments showed that downregulation of PBRM1 promoted tumorigenesis in nude mice. In pathway gene chip analysis, the chemokine/chemokine receptor interaction pathway showed the greatest difference in gene expression upon PBRM1 knockdown. Protein levels of IL6ST and CCL2 were increased, whereas levels of interleukin (IL)-8, IL-6, and CXCL2 were decreased, in knockdown cells. Re-expression of IL-8 in PBRM1 knockdown ACHN cells could significantly decrease cell proliferation/migration and induced cell arrest in the G2/M phase. These findings indicate that PBRM1 alters cell cycle progression and inhibits proliferation and migration of ACHN cells through the chemokine/chemokine receptor pathway.