Oxidative stress and DNA hypermethylation status in renal cell carcinoma arising in patients on dialysis

Renal Cell Carcinoma in End-Stage Kidney Disease and the Role of Transplantation

Kidney transplant patients have a higher risk of renal cell carcinoma (RCC) compared to non-transplanted end-stage kidney disease (ESKD) patients. This increased risk has largely been associated with the use of immunosuppression; however, recent genetic research highlights the significance of tissue specificity in cancer driver genes. The implication of tissue specificity becomes more obscure when addressing transplant patients, as two distinct metabolic environments are present within one individual. The oncogenic potential of donor renal tissue is largely unknown but assumed to pose minimal risk to the kidney transplant recipient (KTR). Our review challenges this notion by examining how donor and recipient microenvironments impact a transplant recipient's associated risk of renal cell carcinoma. In doing so, we attempt to encapsulate how ESKD-RCC and KTR-RCC differ in their incidence, pathogenesis, outcome, and approach to management.

Renal Cell Carcinoma in End-Stage Renal Disease: A Review and Update

Renal cell carcinoma (RCC) occurring in the setting of end-stage renal disease (ESRD) shows unique clinicopathological characteristics. The two most frequent types of ESRD-associated RCC are acquired cystic kidney disease-associated renal cell carcinoma (ACKD-RCC) and clear-cell papillary renal cell carcinoma (ccpRCC). Other types of RCC also occur in ESRD, albeit with different frequencies from the non-ESRD general population. The histological features of RCC do not vary in the setting of ESRD vs. non-ESRD, yet other findings, such as multifocality and multiple tumor types, are more frequent in ESRD. Studies have generated novel and important knowledge of the etiology, epidemiology, diagnosis, treatment, immunophenotype, and molecular characteristics of ESRD-associated RCC. Knowledge of these data is important for both pathologists and other physicians who may encounter ESRD patients with RCC. This review presents a comprehensive summary and update of the literature on RCC in ESRD, with a focus on the two most frequent types, ACKD-RCC and ccpRCC.

Alcohol promotes renal fibrosis by activating Nox2/4-mediated DNA methylation of Smad7

Alcohol consumption causes renal injury and compromises kidney function. The underlying mechanism of the alcoholic kidney disease remains largely unknown. In the present study, an alcoholic renal fibrosis animal model was first employed which mice received liquid diet containing alcohol for 4 to 12 weeks. The Masson's Trichrome staining analysis showed that kidney fibrosis increased at week 8 and 12 in the animal model that was further confirmed by albumin assay, Western blot, immunostaining and real-time PCR of fibrotic indexes (collagen I and α-SMA). In vitro analysis also confirmed that alcohol significantly induced fibrotic response (collagen I and α-SMA) in HK2 tubular epithelial cells. Importantly, both in vivo and in vitro studies showed alcohol treatments decreased Smad7 and activated Smad3. We further determined how the alcohol affected the balance of Smad7 (inhibitory Smad) and Smad3 (regulatory Smad). Genome-wide methylation sequencing showed an increased DNA methylation of many genes and bisulfite sequencing analysis showed an increased DNA methylation of Smad7 after alcohol ingestion. We also found DNA methylation of Smad7 was mediated by DNMT1 in ethyl alcohol (EtOH)-treated HK2 cells. Knockdown of Nox2 or Nox4 decreased DNMT1 and rebalanced Smad7/Smad3 axis, and thereby relieved EtOH-induced fibrotic response. The inhibition of reactive oxygen species by the intraperitoneal injection of apocynin attenuated renal fibrosis and restored renal function in the alcoholic mice. Collectively, we established novel in vivo and in vitro alcoholic kidney fibrosis models and found that alcohol induces renal fibrosis by activating oxidative stress-induced DNA methylation of Smad7. Suppression of Nox-mediated oxidative stress may be a potential therapy for long-term alcohol abuse-induced kidney fibrosis.

RASSF1A promoter methylation correlates development, progression, and poor cancer-specific survival of renal cell carcinoma: trial sequential analysis

Background

This meta-analysis evaluated the clinicopathologic and prognostic significance of RASSF1A promoter methylation in renal cell carcinoma (RCC).

Materials and methods

The ORs or HRs and their 95% CIs were calculated. Trial sequential analysis was conducted.

Results

Twenty-two articles that included 1,421 patients with RCC and 724 controls were identified. RASSF1A promoter methylation correlated with RCC in tissue, blood, and urine samples. On multivariate analysis, RASSF1A promoter methylation was associated with tumor grade (grade 3–4 vs 1–2: OR=3.59), clinical stage (stage 3–4 vs 1–2: OR=2.15), T classification (pT2–4 vs pT1: OR=2.66), histologic subtypes (papillary vs clear cell: OR=2.91), and cancer-specific survival (HR=1.78), but it was not linked to age, gender, lymph node status, distant metastasis, or overall survival. The Cancer Genome Atlas data also showed that RASSF1A methylation was significantly more likely to be seen in papillary vs clear-cell RCC (OR=23.19).

Conclusion

RASSF1A promoter methylation may be associated with the development and progression of RCC, as well as poor cancer-specific survival. Methylation was more frequent in papillary vs clear-cell RCC. More studies are needed to confirm these findings in blood or urine samples.

Occupational class and risk of renal cell cancer

OBJECTIVES

We sought to examine the association between occupational class linked to job stress and the risk of renal cell cancer. To identify potential mediators, we additionally examined whether any observed associations persisted even after controlling for the contribution of stress-related factors (eg, smoking, hypertension, and obesity).

METHODS

Using nationwide inpatient records (1984 to 2016) from the Rosai Hospital group in Japan, we identified 3316 cases of renal cell cancer (excluding upper tract urothelial cancer) and 168 418 controls. We classified patients' occupational class (blue-collar workers, service workers, professionals, and managers) and cross-classified it by industry type (blue-collar, service, and white-collar) based on a standardized national classification. Unconditional logistic regression with multiple imputation was used for the analyses.

RESULTS

A significantly elevated risk of renal cell cancer was found among men in higher occupational class (eg, professionals and managers). The elevated odds in male managers across all industries persisted even after controlling for smoking and alcohol consumption, with the association being more pronounced in blue-collar industries (OR, 1.61; 95% CI, 1.34-1.93). The association appeared to be mainly mediated by hypertension.

CONCLUSION

Occupational class is associated with the risk of renal cell cancer in men, particularly through modifiable risk factors.

The incidence of urinary tract cancers is related to preserved diuresis: a single-center report

PURPOSE

Residual diuresis progressively decreases with longer dialysis vintage, and higher incidence of renal and urinary tract cancers was often observed in hemodialyzed patients compared to the general population so we hypothesized that patients without preserved residual diuresis have higher risk of renal and urinary tract cancers than patients with preserved residual diuresis.

METHODS

Retrospective clinical data and pathology reports were completed for 307 uremic patients undergoing chronic hemodialysis. Patients were divided into two subgroups regarding residual diuresis: the first group with residual diuresis < 500 mL, 133 of 173 (76.8%) patients from this group were completely anuric, and the second group with 134 patients with residual diuresis > 500 mL.

RESULTS

Site- and type-specific cancers in our population of ESRD patients were all localized in estrogen-positive receptor organs. The increased risk of all types of urinary tract cancers occurred in the whole group, men and women, when compared to general population. There were a significantly higher number of patients with all types of cancers in the group with residual diuresis < 250 mL compared to patients with residual diuresis > 500 mL. Importantly, all urinary tract cancers were present in patients with residual diuresis < 500 mL.

CONCLUSION

Higher incidence of urinary tract cancers found in ESRD patients undergoing chronic hemodialysis is associated with lost residual diuresis. Residual diuresis in these patients might be considered a risk marker for future urinary tract cancers as well as already established markers.

Clinical significance of p16INK4A and p14ARF promoter methylation in renal cell carcinoma: a meta-analysis

The inactivation of p16INK4A and p14ARF via promoter methylation has been investigated in various cancers. However, the clinical effects of p16INK4A and p14ARF promoter methylation on renal cell carcinoma (RCC) remain to be clarified. The pooled data were calculated and summarized. Finally, an investigation of 14 eligible studies with 1231 RCC patients and 689 control patients was performed. Methylated p16INK4A and p14ARF were observed to be significantly higher in RCC than in control subjects without malignancies (OR = 2.77, P = 0.005; OR = 11.73, P < 0.001, respectively). Methylated p16INK4A was significantly associated with the risk of RCC in the tissue subgroup, but not in the serum and urine subgroups. Methylated p16INK4A was significantly associated with tumor size. We did not find that p16INK4A promoter methylation was associated with sex, tumor grade, lymph node status, and tumor histology. Methylated p14ARF was significantly correlated with sex and tumor histology. Three studies reported that p16INK4A methylation was not significantly correlated with the prognosis of RCC. The results suggested that p16INK4A and p14ARF promoter methylation may be correlated with the carcinogenesis of RCC, and that methylated p14ARF , especially, can be a major susceptibility gene. We also found the different clinicopathological significance of 16INK4A and p14ARF in RCC. Additional studies with sufficient data are essential to further evaluate the clinical features and prognostic effect of p16INK4A and p14ARF promoter methylation in RCC.

DNA hypermethylation of sFRP5 contributes to indoxyl sulfate-induced renal fibrosis

Renal fibrosis is the most common outcome of chronic kidney disease (CKD), while the pathogenesis of renal fibrosis is not fully understood. In this study, we first showed that the progress of renal fibrosis was positively related to serum levels of indoxyl sulfate, a typical protein-bound toxin, and that there was a close correlation between serum indoxyl sulfate levels and β-catenin expression in the kidneys (r = 0.908, p < 0.001) of CKD patients. We then demonstrated that intraperitoneal injections of indoxyl sulfate (100 mg/kg/day) for 4 weeks in uninephrectomized mice explicitly induced renal fibrosis, which was accompanied by a significant activation of Wnt/β-catenin signaling. In vitro investigations in human renal tubular HK-2 cells revealed that indoxyl sulfate exhibited a potent ability to induce Wnt/β-catenin activation through the downregulation of sFRP5, a gene that codes for an extracellular antagonist of Wnt signaling, by increasing the DNA methylation level of its promoter CpG islands. The increased expression of DNA methyltransferases following the activation of ROS/ERK1/2 signaling was responsible for the DNA hypermethylation of sFRP5 induced by indoxyl sulfate. Conversely, treatment with 5-aza-2'-deoxycytidine, an inhibitor of DNA methyltransferases, significantly reduced indoxyl sulfate-induced sFRP5 downregulation and Wnt/β-catenin activation. In vivo, intraperitoneal injections of recombinant sFRP5 protein or 5-aza-2'-deoxycytidine substantially alleviated renal fibrosis in indoxyl sulfate-treated uninephrectomized mice. Our results suggest that indoxyl sulfate promotes renal fibrosis through the induction of DNA hypermethylation of sFRP5, and thereafter the activation of Wnt/β-catenin signaling. These findings provide new insights into the pathogenesis of renal fibrosis in CKD patients.

KEY MESSAGES

IS induces renal fibrosis by increasing ß-catenin expression in CKD mice. IS-induced Wnt signaling activation is due to sFRP5 hypermethylation in HK-2 cells. ROS/ERK1/2 signaling activation is involved in IS-induced sFRP5 hypermethylation. sFRP5 upregulation attenuates IS-induced renal fibrosis by inhibiting Wnt signaling.

Surgical and Oncologic Outcomes of Laparoscopic Radical Nephrectomy for Non-Metastatic Renal Cancer in Long-Term Dialysis Patients

This study aimed to compare the outcomes of laparoscopic radical nephrectomy (LRN) between patients undergoing dialysis for ≤240 and >240 months. Data from all dialysis patients with non-metastatic renal cell carcinoma (RCC) treated with LRN between 2008 and 2015 in our hospital were evaluated retrospectively. Patients were divided into two groups, shorter- and longer-term dialysis patients, according to the preoperative duration of dialysis (≤240 vs. >240 months). Of 174 patients, 58 (33.3%) were on longer-term dialysis. Perioperative minor complications were significantly more frequent in the longer-term dialysis patients (P = 0.03). There was no significant difference between the two groups in other perioperative outcomes. Patients on longer-term dialysis more frequently had pathologically advanced RCC (P = 0.009) with poorer prognosis (P = 0.005). LRN for RCC in longer-term dialysis patients appears to be safe and feasible; however, careful follow-up is needed because these patients tend to have poorer prognosis.

DNA methylation: hemodialysis versus hemodiafiltration

Aberrant DNA methylation is an emerging characteristic of chronic kidney disease including dialysis patients. It appears to be associated to inflammation. We compared the global DNA methylation status in 10 control subjects compared to 80 dialysis patients (N = 40 on-line hemodiafiltration, N = 40 high-flux hemodialysis) in relation to the dialysis technique and inflammation. Whole blood DNA methylation was assessed with a 5-mc DNA enzyme linked immunosorbent assay Kit. Global DNA methylation was higher in hemodialysis (HD) compared to on-line hemodiafiltration (HDF) patients (0.045 vs. 0.039; P < 0.0001) and controls (0.045 vs. 0.0284; P = 0.0002 for HD; 0.039 vs. 0.0284; P = 0.0254 for on-line HDF). To study the influence of the dialysis technique on DNA methylation we divided dialysis patients according to the median value of 5-mC. DNA methylation was highest in inflamed patients on hemodialysis. The dialysis technique was the only independent predictor of global DNA methylation in dialysis patients. On-line HDF could be associated with a favorable DNA methylation profile.

VPAC1 overexpression is associated with poor differentiation in colon cancer

Vasoactive intestinal peptide (VIP) is a neurotransmitter that primarily functions as a vasodilator. VIP plays its role through binding to its receptors known as VIP/pituitary adenylate cyclase-activating peptide receptors (VPACs). In this study, we examined the expression of VPAC1 in human colon cancer tissues, analyzed the relationship between VPAC1 expression and cancer malignancy, and explored the possible mechanisms using immunohistochemistry and immunofluorescence double staining. The results showed that (1) poorly differentiated colon cancers have significantly higher VPAC1 expression than well-differentiated colon cancers do (p < 0.01); (2) phospho-epithelial growth factor receptor (EGFR) overexpression/activation in the cytoplasm of cancer cells is related to VPAC1 overexpression; (3) blood vessels surrounding colon cancer have significantly more VPAC1-positive than normal colon mucosa does; (4) tumor-associated macrophages (TAMs) of colon cancer have a higher level of VPAC1 expression than macrophages in normal colon mucosa do. These data suggest that VPAC1 overexpression is associated with poorer differentiation of colon cancer, which is likely caused by subsequent EGFR activation in cancer cells. In addition, VPAC1 overexpression in both blood vessels and macrophages in tumors may also play an important role in the development of aggressive cancer.

Clinical and pathological outcomes of renal cell carcinoma (RCC) in native kidneys of patients with end-stage renal disease: a long-term comparative retrospective study with RCC diagnosed in the general population

PURPOSE

Patients with end-stage renal disease (ESRD) have an increased risk of developing renal cell carcinoma (RCC). This retrospective study compared clinical and pathological outcomes of RCC occurring in native kidneys of patients with ESRD (whether they underwent kidney transplantation or not) with those of renal tumors diagnosed in the general population.

METHODS

The study included a total of 533 patients with RCC. The ESRD cohort included 92 patients with RCC in native kidneys. Of these, 58 and 34 cases were identified before (pre-Tx group) and after kidney transplantation (post-Tx group), respectively. The control group was composed of 441 RCCs diagnosed in the general population. Variables were compared by chi-square and Student's t tests. Cancer-specific survival was assessed by Kaplan-Meier and Cox methods.

RESULTS

The ESRD groups had smaller (P = 0.001), lower-grade, and lower-stage tumors than the non-ESRD group (P = 0.001). The papillary RCC rate was higher in the ESRD groups (P = 0.01). Ten-year cancer-specific survivals were 94.5, 87.9, and 74.6 % in pre-Tx, post-Tx, and non-ESRD patients, respectively (P = 0.003). Mean follow-up was 90.2 months. At multivariate analysis, tumor size (HR = 1.10), pathological stage (HR = 1.46), presence of nodal (HR = 2.22) and visceral metastases (HR = 3.49), and Fuhrman grade (HR = 1.48) were independent adverse prognostic factors for cancer-specific survival.

CONCLUSIONS

Native kidney RCCs arising in ESRD patients are lower stage and lower grade as compared to RCCs diagnosed in the general population, and these tumors exhibit favorable clinical and outcome features.

Alternative splicing events is not a key event for gene expression regulation in uremia

Background

The control of gene expression in the course of chronic kidney disease (CKD) is not well addressed. Alternative splicing is a common way to increase complexity of proteins. More than 90% of human transcripts are alternatively spliced. We hypothesised that CKD can induce modification of the alternative splicing machinery.

Methods

During mutation screening in autosomal dominant polycystic kidney disease, we identified in mononuclear cells (PBMC), an alternative splicing event on the exon 30 of PKD1 gene, the gene implicated in this disease. This alternative splice variant was not correlated with the cystic disease but with CKD. To confirm the association between this variant and CKD, a monocentric clinical study was performed with 3 different groups according to their kidney function (CKD5D, CKD3-5 and normal kidney function). An exon microarray approach was used to highlight splicing events in whole human genome in a normal cell model (fibroblasts) incubated with uremic serum. Alternative splicing variants identified were confirmed by RT-PCR.

Results

The splicing variant of the exon 30 of PKD1 was more frequent in PBMCs from patients with CKD compared to control. With the microarray approach, despite the analysis of more than 230 000 probes, we identified 36 genes with an abnormal splicing index evocating splicing event in fibroblasts exposed to uremic serum. Only one abnormal splicing event in one gene, ADH1B, was confirmed by RT-PCR.

Conclusion

We observed two alternative spliced genes in two different cell types associated with CKD. Alternative splicing could play a role in the control of gene expression during CKD but it does not seem to be a major mechanism.

Molecular targets on the horizon for kidney and urothelial cancer

As whole-genome sequencing technology rapidly advances, the insights gained from deciphering cancer genomes are shifting the paradigm in the diagnosis and treatment of cancer with the promise of individualized treatment for each patient. Information gained in this way is extensive for certain cancers, but fairly limited in renal cell carcinomas and urothelial carcinoma. Mutations in multiple, potentially druggable genes have been identified in urothelial carcinomas; however, the association between molecular alterations and clinical outcome has not yet been robustly demonstrated. Data in this area are emerging in renal cell carcinoma, leading to the development of targeted agents that have improved overall survival. Unfortunately, these treatments rarely yield complete responses, are not curative, and development of resistance ensues. This Review will focus on the biology of non-hormonally driven urological cancers. We discuss how approaches using whole-genome sequencing can facilitate the discovery of biomarkers of drug sensitivity in both renal cell carcinomas and urothelial carcinomas. For renal cell carcinomas, we will describe how genomic and epigenomic mining has uncovered novel genes and pathways involved in tumorigenesis, tumour classification and mechanisms of resistance in the various subsets of this disease and the potential for exploiting these discoveries in the clinic.

Determination of low urinary 8-hydroxy-2`-deoxyguanosine excretion with capillary electrophoresis and molecularly imprinted monolith solid phase microextraction

As a sensitive biomarker, the level of 8-hydroxy-2`-deoxyguanosine (8-OHdG) indicates the extent of DNA oxidative damage of subject. However its determination in human urine is confounded by trace content and a complex matrix. In this study, a new approach of solid phase microextraction (SPME) coupled to capillary electrophoresis and electrochemical detection was developed with molecularly imprinted monolithic column as extraction sorbent. The tailor made monolith exhibited high extraction efficiency with the enrichment factor 73 for 8-OHdG owing to its special porous structure and inherent selectivity. Under optimal conditions, appreciable sensitivity had been achieved with a limit of detection of 2.61 nmol/L (signal/noise=3) and a limit of quantification of 8.63 nmol/L (signal/noise=10), respectively. As an alternative of precise 8-OHdG determination, wide range linearity had been achieved with 0.01-1.50 μmol/L and RSDs with 3.70% for migration time and 4.80% for peak current (10-1000 nmol/L). 106 samples with relative low extents of DNA oxidative damage were collected and analyzed which including coke plant workers, traffic policemen, taxi drivers and healthy students. Elevated urinary 8-OHdG excretions of subjects may correlate to working condition, occupational exposure, or lifestyle.

MC-12, an annexin A1-based peptide, is effective in the treatment of experimental colitis

Annexin A1 (ANXA1) inhibits NF-κB, a key regulator of inflammation, the common pathophysiological mechanism of inflammatory bowel diseases (IBD). MC-12, an ANXA1-based tripeptide, suppresses NF-κB activation. Here, we determined the efficacy of MC-12 in the control of IBD. Mice with colitis induced by dextran sodium sulfate (DSS) or 2,4,6-trinitro benzene sulfonic acid (TNBS) were treated with various doses of MC-12 administered intraperitoneally, orally or intrarectally. We determined colon length and the histological score of colitis, and assayed: in colon tissue the levels of TNF-α, IFN-γ, IL-1β, IL-6 and IL-10 by RT-PCR; prostaglandin E₂ (PGE₂), cytoplasmic phospholipase A₂ (cPLA₂) and myeloperoxidase by immunoassay; and COX-2 and NF- κB by immunohistochemistry; and in serum the levels of various cytokines by immunoassay. In both models MC-12: reversed dose-dependently colonic inflammation; inhibited by up to 47% myeloperoxidase activity; had a minimal effect on cytoplasmic phospholipase A₂; reduced significantly the induced levels of TNF-α, IFN-γ, IL-1β, IL-6 and IL-10, returning them to baseline. DSS and TNBS markedly activated NF-κB in colonic epithelial cells and MC-12 decreased this effect by 85.8% and 72.5%, respectively. MC-12 had a similar effect in cultured NCM460 normal colon epithelial cells. Finally, MC-12 suppressed the induction of COX-2 expression, the level of PGE₂ in the colon and PGE₂ metabolite in serum. In conclusion, MC-12, representing a novel class of short peptide inhibitors of NF-κB, has a strong effect against colitis in two preclinical models recapitulating features of human IBD. Its mechanism of action is complex and includes pronounced inhibition of NF-κB. MC-12 merits further development as an agent for the control of IBD.

Supplementation of Emblica Officinalis (Amla) Extract Reduces Oxidative Stress in Uremic Patients

Emblica Officinalis (also known as Amla or Indian Gooseberry), a natural, traditional and functional food in Asia, has physiological benefits such as hepato-, cyto- and radio- protection, as well as hypolipidemic effects. In addition, Amla often functions as a potent antioxidant due to the high level of ascorbic acid (ranging from 1,100 to 1,700 mg/100 g of fruit) in its fruit. The aim of this study was to determine whether supplementation with Amla extract could reduce oxidative stress in patients with uremia. The findings show that supplementation with Amla extract for 4 months reduced the plasma oxidative marker, 8-iso-prostaglandin, (M0 vs. M4 = 1415 ± 1234 pg/ml vs. 750 ± 496 pg/ml, p < 0.05) and increased plasma total antioxidant status (TAS) (M0 vs. M4 = 2.32 ± 0.14 mM vs. 2.55 ± 0.24 mM, p < 0.05) in uremic patients. On the other hand, there were no significant differences observed in liver function (GOP and GPT), renal function (creatinine, blood urea nitrogen and uric acid), diabetic index (plasma glucose and adiponectin) and atherogenic index (LDL/HDL ratio, total cholesterol and homocysteine) in patients treated with Amla for 4 months. Our data suggest that Amla supplementation may increase plasma antioxidant power and decrease oxidative stress in uremic patients. However, Amla extract did not influence hepatic or renal function, or diabetic and atherogenic indices in uremic patients.

Genomic profiling of renal cell carcinoma in patients with end-stage renal disease

The purpose of the present study was to determine the genomic profile of renal cell carcinoma (RCC) in end-stage renal disease (ESRD) by analyzing genomic copy number aberrations. Seventy-nine tumor samples from 63 patients with RCC-ESRD were analyzed by array comparative genomic hybridization using the Agilent Whole Human Genome 4 × 44K Oligo Micro Array (Agilent Technologies Inc., Palo Alto, CA, USA). Unsupervised hierarchical clustering analysis revealed that the 63 cases could be divided into two groups, Clusters A and B. Cluster A was comprised mainly of clear cell RCC (CCRCC), whereas Cluster B was comprised mainly of papillary RCC (PRCC), acquired cystic disease (ACD)-associated RCC, and clear cell papillary RCC. Analysis of the averaged frequencies revealed that the genomic profiles of Clusters A and B resembled those of sporadic CCRCC and sporadic PRCC, respectively. Although it has been proposed on the basis of histopathology that ACD-associated RCC, clear cell papillary RCC and PRCC-ESRD are distinct subtypes, the present data reveal that the genomic profiles of these types, categorized as Cluster B, resemble one another. Furthermore, the genomic profiles of PRCC, ACD-associated RCC and clear cell papillary RCC admixed in one tissue tended to resemble one another. On the basis of genomic profiling of RCC-ESRD, we conclude that the molecular pathogenesis of CCRCC-ESRD resembles that of sporadic CCRCC. Although various histologic subtypes of non-clear cell RCC-ESRD have been proposed, their genomic profiles resemble those of sporadic PRCC, suggesting that the molecular pathogenesis of non-CCRCC-ESRD may be related to that of sporadic PRCC.

Immunochemical detection of oxidatively damaged DNA

Oxidatively damaged DNA is implicated in various diseases, including neurodegenerative disorders, cancer, diabetes, cardiovascular and inflammatory diseases as well as aging. Several methods have been developed to detect oxidatively damaged DNA. They include chromatographic techniques, the Comet assay, (32)P-postlabelling and immunochemical methods that use antibodies to detect oxidized lesions. In this review, we discuss the detection of 8-oxo-7,8-dihydro-29-deoxyguanosine (8-oxodG), the most abundant oxidized nucleoside. This lesion is frequently used as a marker of exposure to oxidants, including environmental pollutants, as well as a potential marker of disease progression. We concentrate on studies published between the years 2000 and 2011 that used enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry to detect 8-oxodG in humans, laboratory animals and in cell lines. Oxidative damage observed in these organisms resulted from disease, exposure to environmental pollutants or from in vitro treatment with various chemical and physical factors.

Expression of regulatory proteins and proliferative activity in relation to phenotypic characteristics of upper urothelial carcinoma

BACKGROUND/AIM

Deregulation of the normal cell cycle is common in upper urothelial carcinoma (UUC). The aim of this study was to investigate the expression of regulatory proteins of the cell cycle (p53, p16, cyclin D1, HER-2) and proliferative Ki-67 activity in UUC, and to determine their interaction and influence on the phenotypic characteristics of UUC.

METHODS

In 44 patients with UUC, histopathological and immunohistochemical analyses (p53, p16, cyclin D1, HER-2, and Ki-67) of tumors were done.

RESULTS

Overexpression/altered expression of p53, p16, cyclin D1 or HER-2 was detected in 20%, 57%, 64%, and 57% of tumors, respectively. Eleven (25%) UUC had a high proliferative Ki-67 index. Forty patients (91%) had at least one marker altered, while four (9%) tumors had a wild-type status. Analysis of relationship between expressions of molecular markers showed that only high expression of p53 was significantly associated with altered p16 activity (p < 0.05). High Ki-67 index was associated with the high stage (p < 0.005), solid growth (p < 0.01), high grade (p < 0.05), and multifocality p < 0.05) of UUC, while high expression of p53 was associated with the solid growth (p < 0.05). In regression models that included all molecular markers and phenotypic characteristics, only Ki-67 correlated with the growth (p < 0.0001), stage (p < 0.01), grade (p < 0.05) and multifocality (p < 0.05) of UCC; (Ki-67 and HER-2 expression correlated with the lymphovascular invasion (p < 0.05).

CONCLUSIONS

This investigation showed that only negative regulatory proteins of the cell cycle, p53 and p16, were significantly associated in UUC, while proliferative marker Ki-67 was in relation to the key phenotypic characteristics of UUC in the best way.

Prognosis and characteristics of renal cell carcinoma in hemodialysis patients: bilateral occurrence does not influence cancer-specific survival

OBJECTIVES

To compare characteristics and prognosis unilateral and bilateral renal cell carcinoma (RCC) in hemodialysis (HD) patients.

METHODS

Overall 246 HD patients who had undergone a radical nephrectomy for RCC were enrolled in this study. Unilateral RCC occurred in 201 patients, synchronous bilateral RCC in 15 and metachronous bilateral RCC in 30. Cancer-specific survival (CSS) was accessed by the Kaplan-Meier method.

RESULTS

Five-year CSS was not significantly different between the two groups (unilateral, 90%; bilateral, 90%; P=0.9509). In total 17 of the 201 patients (8.5%) with unilateral occurrence and four of the 45 patients (8.9%) with bilateral occurrence died from kidney cancer during the follow-up period. The presence of acquired cystic disease of kidney (unilateral, 73%; bilateral 91%; P=0.00319) and the mean duration of HD before surgery (unilateral: 157±91 months, bilateral: 189±83.5, P = 0.0319) were significantly different between the two groups. There were more multifocal tumors in bilateral than in unilateral occurrence (bilateral: 74%, unilateral: 30%, P<0.0001). There were significant differences in CSS according to HD duration before surgery (5-year CSS >180 months 82%, ≤180 months 95%; P=0.0004), tumor grade (G1 100%, G2 90%, G3 38%; P<0.0001), and tumor size (>4 cm 75%, ≤4 cm 98%; P<0.0001).

CONCLUSIONS

The type of occurrence of RCC, unilateral or bilateral, in HD patients does not appear to influence CSS. Patients with a longer duration of HD have to be followed up rigorously because they tend to have poor cancer prognosis.

Renal cell carcinoma (RCC) in patients with end-stage renal disease exhibits many favourable clinical, pathologic, and outcome features compared with RCC in the general population

BACKGROUND

Patients with end-stage renal disease (ESRD) are at risk of developing renal tumours.

OBJECTIVE

Compare clinical, pathologic, and outcome features of renal cell carcinomas (RCCs) in ESRD patients and in patients from the general population.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-four French university departments of urology participated in this retrospective study.

INTERVENTION

All patients were treated according to current European Association of Urology guidelines.

MEASUREMENTS

Age, sex, symptoms, tumour staging and grading, histologic subtype, and outcome were recorded in a unique database. Categoric and continuous variables were compared by using chi-square and student statistical analyses. Cancer-specific survival (CSS) was assessed by Kaplan-Meier and Cox methods.

RESULTS AND LIMITATIONS

The study included 1250 RCC patients: 303 with ESRD and 947 from the general population. In the ESRD patients, age at diagnosis was younger (55 ± 12 yr vs 62 ± 12 yr); mean tumour size was smaller (3.7 ± 2.6 cm vs 7.3 ± 3.8 cm); asymptomatic (87% vs 44%), low-grade (68% vs 42%), and papillary tumours were more frequent (37% vs 7%); and poor performance status (PS; 24% vs 37%) and advanced T categories (≥ 3) were more rare (10% vs 42%). Consistently, nodal invasion (3% vs 12%) and distant metastases (2% vs 15%) occurred less frequently in ESRD patients. After a median follow-up of 33 mo (range: 1-299 mo), 13 ESRD patients (4.3%), and 261 general population patients (27.6%) had died from cancer. In univariate analysis, histologic subtype, symptoms at diagnosis, poor PS, advanced TNM stage, high Fuhrman grade, large tumour size, and non-ESRD diagnosis context were adverse predictors for survival. However, only PS, TNM stage, and Fuhrman grade remained independent CSS predictors in multivariate analysis. The limitation of this study is related to the retrospective design.

CONCLUSIONS

RCC arising in native kidneys of ESRD patients seems to exhibit many favourable clinical, pathologic, and outcome features compared with those diagnosed in patients from the general population.

Epigenetics of renal cell carcinoma: the path towards new diagnostics and therapeutics

Aberrant DNA methylation, in particular promoter hypermethylation and transcriptional silencing of tumor suppressor genes, has an important role in the development of many human cancers, including renal cell carcinoma (RCC). Indeed, apart from mutations in the well studied von Hippel-Lindau gene (VHL), the mutation frequency rates of known tumor suppressor genes in RCC are generally low, but the number of genes found to show frequent inactivation by promoter methylation in RCC continues to grow. Here, we review the genes identified as epigenetically silenced in RCC and their relationship to pathways of tumor development. Increased understanding of RCC epigenetics provides new insights into the molecular pathogenesis of RCC and opportunities for developing novel strategies for the diagnosis, prognosis and management of RCC.

Altered expression of MUTYH and an increase in 8-hydroxydeoxyguanosine are early events in ulcerative colitis-associated carcinogenesis

8-Hydroxy-guanine (8-OH-G) mismatches readily with adenine residues, leading to a G : C to T : A transversion mutation. The human mutY homologue (MUTYH) excises adenine misincorporated opposite 8-OH-G during replication and suppresses mutations caused by reactive oxygen species. We defined the expression of 8-hydroxydeoxyguanosine (8-OHdG) and MUTYH in ulcerative colitis (UC)-associated neoplasia by immunohistochemistry and compared this with expression in UC patients without neoplasia and patients unaffected by UC. We also performed mutation analyses for MUTYH and K-ras. 8-OHdG was expressed more intensely in the mucosa of UC-associated neoplasia and UC without neoplasm than in the mucosa unaffected by UC. Immunohistochemistry with two different types of MUTYH antibody showed that UC-associated neoplasia and UC without neoplasia exhibited strong cytoplasmic expression and attenuated nuclear expression of MUTYH when compared with patients unaffected by UC. No pathological MUTYH mutations were detected in any of the UC-associated neoplasia cases. However, K-ras mutation was detected in two cases, one of which showed G : C to T : A transversion mutation and attenuated nuclear staining of MUTYH. In conclusion, inflamed mucosa of UC is exposed to oxidative damage. An increase in cytoplasmic MUTYH, rather than its mutation, may contribute to the promotion of carcinogenesis in UC.

Renal cell carcinoma in patients with end-stage renal disease: relationship between histological type and duration of dialysis

OBJECTIVE

To evaluate the clinical outcomes and histological types of renal cell carcinoma (RCC) arising in patients with end-stage renal disease (ESRD), and to analyse the relationship of histopathological features with the duration of dialysis.

PATIENTS AND METHODS

Clinical characteristics and outcomes of 34 patients who had a radical nephrectomy for RCC arising in ESRD between November 1994 and June 2008 were investigated. Archive paraffin-embedded tissue specimens obtained from 27 patients were histochemically and immunohistochemically analysed to determine the histopathological type.

RESULTS

There was one death from cancer and one patient with local progression within a median observation period of 29.5 months. Acquired cystic disease (ACD)-associated RCC, clear cell-papillary RCC, mucinous tubular and spindle-cell carcinoma, and Xp11.2 translocation/TFE3 gene fusion were identified in eight, two, three and one patient, respectively. Conventional clear-cell RCC was the predominant histological type (nine of 15) in patients with a duration of dialysis of <10 years, while ACD-associated RCC was predominant (seven of 12) in those with dialysis for > or =10 years. Sarcomatoid foci were identified in three patients with dialysis for > or =10 years. Papillary adenoma was microscopically identified as a satellite tumour in 10 patients.

CONCLUSION

The spectrum of histological types of RCCs arising in ESRD is distinct from that of sporadic RCCs. Patients with a longer duration of dialysis should have particular attention for progression and metastasis. Immunohistochemical profiling is efficient in the histological classification of RCCs arising in ESRD, although knowledge about genetic changes remains to be accumulated.

Genetics and epigenetics of renal cell cancer

Renal cell carcinoma (RCC) is not a single disease, but comprises a group of tumors of renal epithelial origin, each with a different histology, displaying a different clinical course and caused by different genetic alterations. Since cure rates are inversely associated with stage and response to the available treatment regimes is limited to a subgroup of patients, diagnostic methods facilitating early detection and new therapeutic modalities are necessary. Increased knowledge of the underlying pathophysiology of RCC has resulted in the identification of genetic alterations involved in renal cell cancer carcinogenesis. Promising agents to target these pathways, especially the angiogenesis pathway, are being developed, some of which are already standard of care. In addition to genetics, knowledge on epigenetics in the process of renal tumorigenesis has been significantly increased in the last decades. Epigenetics will play an increasing role in the development of new therapeutic modalities and may deliver new prognostic and early diagnostic markers. In this review we discuss the background of RCC and the clinical applications of RCC genetics and epigenetics.