• Journal of Pathology and Translational Medicine
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• v.52 no.6
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• pp.378-385
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• 2018

Background: BRCA1-associated protein 1 (BAP1) mutations are frequently reported in clear cell renal cell carcinoma (ccRCC); however, very few studies have evaluated the role of these mutations in other renal cell carcinoma (RCC) subtypes. Therefore, we analyzed BAP1 protein expression using immunohistochemistry in several RCC subtypes and assessed its relationship with clinicopathological characteristics of patients. Methods: BAP1 expression was immunohistochemically evaluated in tissue microarray blocks constructed from 371 samples of RCC collected from two medical institutions. BAP1 expression was evaluated based on the extent of nuclear staining in tumor cells, and no expression or expression in <10% of tumor cells was defined as negative. Results: Loss of BAP1 expression was observed in ccRCC (56/300, 18.7%), chromophobe RCC (6/26, 23.1%), and clear cell papillary RCC (1/4, 25%), while we failed to detect BAP1 expression loss in papillary RCC, acquired cystic disease-associated RCC, or collecting duct carcinoma. In ccRCC, loss of BAP1 expression was significantly associated with high World Health Organization (WHO)/International Society of Urological Pathology (ISUP) grade (p=.002); however, no significant correlation was observed between loss of BAP1 expression and survival in ccRCC. Loss of BAP1 expression showed no association with prognostic factors in chromophobe RCC. Conclusions: Loss of BAP1 nuclear expression was observed in both ccRCC and chromophobe RCC. In addition, BAP1 expression loss was associated with poor prognostic factors such as high WHO/ISUP grade in ccRCC.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.3
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• pp.297-304
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• 2016

Klotho functions as a tumor suppressor predominantly expressed in renal tubular cells, the origin of clear cell renal cell carcinoma (ccRCC). Altered expression and/or activity of growth factor receptor have been implicated in ccRCC development. Although Klotho suppresses a tumor progression through growth factor receptor signaling including insulin-like growth factor-1 receptor (IGF-1R), the role of Klotho acting on IGF-1R in ccRCC and its clinical relevance remains obscure. Here, we show that Klotho is favorable prognostic factor for ccRCC and exerts tumor suppressive role for ccRCC through inhibiting IGF-1R signaling. Our data shows the following key findings. First, in tumor tissues, the level of Klotho and IGF-1R expression are low or high, respectively, compared to that of adjacent non-neoplastic parenchyma. Second, the Klotho expression is clearly low in higher grade of ccRCC and is closely associated with clinical outcomes in tumor progression. Third, Klotho suppresses IGF-1-stimulated cell proliferation and migration by inhibiting PI3K/Akt pathway. These results provide compelling evidence supporting that Klotho acting on IGF-1R signaling functions as tumor suppressor in ccRCC and suggest that Klotho is a potential carcinostatis substance for ccRCC.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.315-320
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• 2013

Background: TGF-${\beta}$-activated kinase-1 (TAK1) has been found to be over-expressed in a variety of solid malignancies and related to tumor growth. The aim of this study was to evaluate the expression level of TAK1 in clear cell renal cell carcinoma (ccRCC) and assess its value as a novel prognostic marker. Methods: TAK1 mRNA was assessed in 51 paired ccRCC tissues and adjacent normal tissues (ADTs) by real-time PCR. Tissue TAK1 protein was also assessed in 91 ADTs and 177 samples of ccRCC immunohistochemically for evaluation of relationships with clinical characteristics. Results: RT-PCR showed that TAK1 RNA level was significantly higher in ccRCC tissues than in the paired ADTs and immunohistochemistry confirmed higher expression of TAK1 protein in ccRCC samples compared with ADTs. TAK1 protein expression in 177 ccRCC samples was significantly correlated with T stage, N classification, metastasis, recurrence and Fuhrman grade, but not age and gender. Patients with low TAK1 levels had a better survival outcome. TAK1 expression and N stage were independent prognosis factors for the overall survival of ccRCC patients. Conclusions: Overexpression of TAK1 predicts a poor prognosis in patients with ccRCC, so that TAK1 may serve as a novel prognostic marker.

• The Korean Journal of Urological Oncology
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• v.16 no.3
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• pp.119-125
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• 2018

Purpose: We compared subtypes of papillary renal cell carcinoma (pRCC; types 1 and 2) and clear cell renal cell carcinoma (ccRCC) in patients with T1-stage RCC to analyze the impact of the subtype on oncological outcomes. Materials and Methods: This paper reviewed 75 patients with pRCC and 252 patients with ccRCC at T1-stage from 1998-2012. Thus, we assessed the impact of subtype on oncologic outcomes among patients with T1-stage RCC. We used Kaplan-Meier analysis to estimate the overall survival and recurrence-free survival The median follow-up duration was 95 months (interquartile range, 75.4-119.3 months). Results: The 5-year recurrence-free survivals of pRCC and ccRCC were 95.4% and 97.6%, respectively. pRCC is worse than ccRCC in terms of recurrence-free survival (p=0.008) and there was no significant difference in the overall survival between pRCC and ccRCC (p=0.32). In addition, there was no significant statistical difference between type 1 pRCC and type 2 pRCC in terms of either recurrence-free survival (p=0.526) or overall survival (p=0.701). Age (hazard ratio [HR], 1.069; p<0.001) and recurrence (HR, 4.93; p<0.001) were predictors of overall survival. Only tumor size (HR, 1.071; p=0.004) was predictors in the case of cancer specific survival in the multivariate analysis. Conclusions: Among patients with T1-stage RCC, recurrence after surgery was more common in pRCC than ccRCC. The subtype of pRCC (types 1 and 2) had no impact on the recurrence-free survival or overall survival.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5789-5795
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• 2013

Background: The high mobility group box 1 (HMGB1) protein is a widespread nuclear protein present in most cell types. It typically locates in the nucleus and functions as a nuclear cofactor in transcription regulation. However, HMGB1 can also localize in the cytoplasm and be released into extracellular matrix, where it plays critical roles in carcinogenesis and inflammation. However, it remains elusive whether HMGB1 is relocated to cytoplasm in clear cell renal cell carcinoma (ccRCC). Methods: Nuclear and cytoplasmic proteins were extracted by different protocols from 20 ccRCC samples and corresponding adjacent renal tissues. Western blotting and immunohistochemistry were used to identify the expression of HMGB1 in ccRCC. To elucidate the potential mechanism of HMGB1 cytoplasmic translocation, HMGB1 proteins were enriched by immunoprecipitation and analyzed by mass spectrometry (MS). Results: The HMGB1 protein was overexpressed and partially localized in cytoplasm in ccRCC samples (12/20, 60%, p<0.05). Immunohistochemistry results indicated that ccRCC of high nuclear grade possess more HMGB1 relocation than those with low grade (p<0.05). Methylation of HMGB1 at lysine 112 in ccRCC was detected by MS. Bioinformatics analysis showed that post-translational modification might affect the binding ability to DNA and mediate its translocation. Conclusion: Relocation of HMGB1 to cytoplasm was confirmed in ccRCC. Methylation of HMGB1 at lysine 112 might the redistribution of this cofactor protein.

• Oncology Letters
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• v.18 no.6
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• pp.5731-5738
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• 2019

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer. Novel biomarkers of ccRCC may provide crucial information on tumor features and prognosis. The present study aimed to determine whether the expression of γ-aminobutyric acid (GABA) A receptor subunit θ (GABRQ) could serve as a novel prognostic marker of ccRCC. GABA is the main inhibitory neurotransmitter in the brain that activates the receptor GABAA, which is comprised of three subunit isoforms: GABRA3, GABRB3 and GABRQ. A recent study reported that GABRQ is involved in the initiation and progression of hepatocellular carcinoma; however, the role of GABRQ in ccRCC remains unknown. In the present study, clinical and transcriptomic data were obtained from cohorts of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). Differential GABRQ expression levels among early (TI and II), late (TIII and IV), nonmetastatic (M0) and metastatic (M1, primary tumor) stages of ccRCC samples were then identified. Furthermore, the use of GABRQ as a prognostic gene was analyzed using Uno's C-index based on the time-dependent area under the curve (AUC), the AUC of the receiver operating characteristic curve at 5 years, the Kaplan-Meier survival curve and multivariate analysis. The survival curve analysis revealed that low GABRQ mRNA expression was significantly associated with a poor prognosis of ccRCC (P<0.001 and P=0.0012 for TCGA and ICGC data, respectively). In addition, analyses of the C-index and AUC values further supported this discriminatory power. Furthermore, the prognostic value of GABRQ mRNA expression was confirmed by multivariate Cox regression analysis. Taken together, these results suggested that GABRQ mRNA expression may be considered as a novel prognostic biomarker of ccRCC.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1399-1404
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• 2016

We investigated the urinary levels of 14-3-3 protein beta/alpha to evaluate their diagnostic significance with regard to clear cell renal cell carcinoma (ccRCC) and angiomyolipoma (AML). Urine samples from 91 patients with ccRCC, 16 patients with AML and 24 healthy volunteers were assessed. We used an enzyme-linked immunosorbent assay (ELISA) to quantify 14-3-3 protein beta/alpha levels in urine. Values were higher in patients with ccRCC than in those with AML and in healthy volunteers. High levels were associated with pathologic stage, lymph node status, distant metastasis and poor survival. Urinary levels of 14-3-3 protein beta/alpha were significantly increased in patients with small-sized carcinoma, irrespective of being less than 4.0 cm and 2.0 cm, compared with levels in patients with AML. This study is the first to report that increased expression of 14-3-3 protein beta/alpha in urine is associated with advanced stage and poor survival in patients with ccRCC. In addition, urinary 14-3-3 protein beta/alpha may differentiate AML from RCC, even when small sized. These results suggest that examination of urinary 14-3-3 protein beta/alpha could serve as a diagnostic and prognostic marker in patients with ccRCC.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3403-3408
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• 2012

The molecular mechanisms involved in the progression of clear cell renal cell carcinomas (ccRCCs) are still unclear. The aim of this study was to analyse the relationships between expression of RALYL and clinical characteristics. In 41 paired samples of ccRCCs and adjacent normal tissues, we used real-time qPCR to evaluate the expression of RALYL mRNA. RALYL protein levels were determined in 146 samples of ccRCC and 37 adjacent normal tissues by immunohistochemistry. Statistical analysis was used to explore the relationships between expression of RALYL and the clinical characteristics (gender, age, tumor size, T stage, N stage, M stage, survival times and survival outcome) in ccRCC. In addition, these patients were follow-up period 64 months (range: 4~116months) to investigate the influence on prognosis. We found significantly differences between ccRCC tissues and normal tissues (p<0.001, paired-sample t test) in mRNA levels of RALYL. Immunohistochemistry analyses in 146 ccRCC samples and 37 adjacent normal tissues showed significantly lower RALYL protein levels in ccRCC samples (${\chi}^2$-test, p<0.001), inversely correlating with tumour size (p=0.024), T stage (0.005), N stage (p<0.001) as well as M stage (p=0.019), but not age (p=0.357) and gender (p=0.348). Kaplan-Meier survival analysis demonstrated that people with lower level of RALYL expression had a poorer survival rate than those with a higher level of RALYL expression, significantly different by the log-rank test (p=0.011). Cox regression analysis indicated that RALYL expression (p=0.039), N stage (p=0.008) and distant metastasis (p<0.001) were independent prognosis factors for the overall survival of ccRCC patients. We demonstrated that the expression of RALYL was significantly low in ccRCC and correlated with a poor prognosis in a large number of clinical samples. Our findings showed that RALYL may be a potential therapeutic target as well as a poor prognostic factor.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.791-800
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• 2019

Objective: To compare various models of diffusion-weighted imaging including monoexponential apparent diffusion coefficient (ADC), biexponential (fast diffusion coefficient [D_f], slow diffusion coefficient [D_s], and fraction of fast diffusion), stretched-exponential (distributed diffusion coefficient and anomalous exponent term [α]), and kurtosis (mean diffusivity and mean kurtosis [MK]) models in the differentiation of renal solid masses. Materials and Methods: A total of 81 patients (56 men and 25 women; mean age, 57 years; age range, 30-69 years) with 18 benign and 63 malignant lesions were imaged using 3T diffusion-weighted MRI. Diffusion model selection was investigated in each lesion using the Akaike information criteria. Mann-Whitney U test and receiver operating characteristic (ROC) analysis were used for statistical evaluations. Results: Goodness-of-fit analysis showed that the stretched-exponential model had the highest voxel percentages in benign and malignant lesions (90.7% and 51.4%, respectively). ADC, D_s, and MK showed significant differences between benign and malignant lesions (p < 0.05) and between low- and high-grade clear cell renal cell carcinoma (ccRCC) (p < 0.05). α was significantly lower in the benign group than in the malignant group (p < 0.05). All diffusion measures showed significant differences between ccRCC and non-ccRCC (p < 0.05) except D_f and α (p = 0.143 and 0.112, respectively). α showed the highest diagnostic accuracy in differentiating benign and malignant lesions with an area under the ROC curve of 0.923, but none of the parameters from these advanced models revealed significantly better performance over ADC in discriminating subtypes or grades of renal cell carcinoma (RCC) (p > 0.05). Conclusion: Compared with conventional diffusion parameters, α may provide additional information for differentiating benign and malignant renal masses, while ADC remains the most valuable parameter for differentiation of RCC subtypes and for ccRCC grading.

• Oncology Letters
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• v.42 no.1
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• pp.453-460
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• 2019

The present study aimed to identify novel methylation markers of clear cell renal cell carcinoma (ccRCC) using microarray methylation analysis and evaluate their prognostic relevance in patient samples. To identify cancer-specific methylated biomarkers, microarray profiling of ccRCC samples from our institute (n=12) and The Cancer Genome Atlas (TCGA) database (n=160) were utilized, and the prognostic relevance of candidate genes were investigated in another TCGA dataset (n=153). For validation, pyrosequencing analyses with ccRCC samples from our institute (n=164) and another (n=117) were performed and the potential clinical application of selected biomarkers was examined. We identified 22 CpG island loci that were commonly hypermethylated in ccRCC. Kaplan-Meier analysis of TCGA data indicated that only 4/22 loci were significantly associated with disease progression. In the internal validation set, Kaplan-Meier analysis revealed that hypermethylation of two loci, zinc finger protein 492 (ZNF492) and G protein-coupled receptor 149 (GPR149), was significantly associated with shorter time-to-progression. Multivariate Cox regression models revealed that hypermethylation of ZNF492 [hazard ratio (HR), 5.44; P=0.001] and GPR149 (HR, 7.07; P<0.001) may be independent predictors of tumor progression. Similarly, the methylation status of these two genes was significantly associated with poor outcomes in the independent external validation cohort. Collectively, the present study proposed that the novel methylation markers ZNF492 and GPR149 could be independent prognostic indicators in patients with ccRCC.