Geographic variation of mutagenic exposures in kidney cancer genomes.

International differences in the incidence of many cancer types indicate the existence of carcinogen exposures that have not yet been identified by conventional epidemiology make a substantial contribution to cancer burden1. In clear cell renal cell carcinoma, obesity, hypertension and tobacco smoking are risk factors, but they do not explain the geographical variation in its incidence2. Underlying causes can be inferred by sequencing the genomes of cancers from populations with different incidence rates and detecting differences in patterns of somatic mutations. Here we sequenced 962 clear cell renal cell carcinomas from 11 countries with varying incidence. The somatic mutation profiles differed between countries. In Romania, Serbia and Thailand, mutational signatures characteristic of aristolochic acid compounds were present in most cases, but these were rare elsewhere. In Japan, a mutational signature of unknown cause was found in more than 70% of cases but in less than 2% elsewhere. A further mutational signature of unknown cause was ubiquitous but exhibited higher mutation loads in countries with higher incidence rates of kidney cancer. Known signatures of tobacco smoking correlated with tobacco consumption, but no signature was associated with obesity or hypertension, suggesting that non-mutagenic mechanisms of action underlie these risk factors. The results of this study indicate the existence of multiple, geographically variable, mutagenic exposures that potentially affect tens of millions of people and illustrate the opportunities for new insights into cancer causation through large-scale global cancer genomics.

Sarcoid-like reaction and hypothyroidism induced by PD-1 inhibitor treatment in metastatic renal cell carcinoma: a case report and literature review.

BACKGROUND: Pembrolizumab is among the approved treatments for a variety of cancer types, including clear cell renal cell carcinoma (ccRCC). It has contributed to enhancing the prognosis of renal cell carcinoma. However, it is essential to be aware of the numerous potential immune-related side effects associated with its use. CASE PRESENTATION: A 69-year-old patient with a history of metastatic renal cell carcinoma has been undergoing treatment with Pembrolizumab, an immune checkpoint inhibitor. The medication has led to the development of a sarcoid-like reaction, initially misinterpreted as cancer recurrence and progression. Additionally, the patient has experienced new-onset hypothyroidism, which has been attributed to the immunotherapy. CONCLUSION: Clinicians, including oncologists, endocrinologists, and radiologists, should maintain a high level of suspicions and awareness regarding the potential adverse events associated with newly introduced immunotherapies like pembrolizumab. This knowledge is crucial for the accurate diagnosis and appropriate management of patients receiving these treatments.

Evaluation of statin use and renal cell carcinoma risk identifies sex-specific associations with RCC subtypes.

Background: The association between statin use and risk of renal cell carcinoma (RCC) has been debated. We aimed to evaluate whether statin use is associated with RCC risk.Material and methods: We studied 100,195 women in the Nurses' Health Study (NHS) from 1994 to 2016; 91,427 women in the Nurses' Health Study II (NHS II) from 1999 to 2015; and 45,433 men in the Health Professionals Follow-up Study (HPFS) from 1990 to 2016. Statins and covariate data were collected at baseline and then biennially. Outcome was measured as incidence of total RCC and clinically relevant disease subgroups. Cox proportional hazards models estimated covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).Results: During follow-up, 661 participants developed RCC. There was no significant association between the use of statins and the risk of overall RCC, fatal RCC, or advanced or localized disease. Across cohorts, the adjusted HR for ever vs. never users was 0.97 (95% CI 0.81-1.16). Female ever users of statins were at increased risk of high-grade disease in the NHS only (HR 1.75, 95% CI 1.07-2.85). Among men only, ≥4 years of statin use was associated with an increased risk of clear cell RCC (HR 1.65, 95% CI 1.10-2.47).Conclusions: Statin use was not associated with the overall risk of RCC. However, it was associated with an increased risk of high-grade disease among women in the NHS cohort and an increased risk of clear cell RCC among men. The reasons for these inconsistent results by sex are unclear.

Fulminant Type 1 Diabetes Mellitus Caused by Long-Term Nivolumab Administration Followed by Nivolumab plus Cabozantinib Combination.

Nivolumab, an immune checkpoint inhibitor (ICI), is now used to treat many advanced cancers, including non-small cell lung cancer (NSCLC) and renal cancer. Immune-related adverse events are characteristic side effects of ICIs. Among them, fulminant type 1 diabetes mellitus is an infrequent but potentially life-threatening and clinically significant concern. Cabozantinib is known as a multikinase inhibitor. In recent years, combination therapy with nivolumab and cabozantinib has begun to be used to treat renal cell carcinoma. A 74-year-old man with no history of diabetes was treated with nivolumab for 5 years for NSCLC, followed by the combination of nivolumab and cabozantinib for clear cell renal cell carcinoma. He was diagnosed with fulminant type 1 diabetes 5 weeks after starting combination therapy, with symptoms of nausea and dry mouth. He was admitted to the intensive care unit and improved clinically with continuous insulin infusion and saline. The involvement of cabozantinib in the development of fulminant type 1 diabetes with long-term nivolumab use, which has not been reported previously, is unknown, but caution may be necessary in terms of glycemic control in combination therapy with nivolumab and cabozantinib.

Anti-programmed death-1 inhibitor nivolumab-induced immune-related adverse events: hepatitis, renal insufficiency, myositis, vitiligo, and hypothyroidism: a case-based review.

Nivolumab (NIVO) is a monoclonal antibody used to treat renal cell cancer. It is an anti-programmed death-1 (anti-PD-1) inhibitor, enhancing the tumor-targeted immune response of T lymphocytes, resulting in immune-mediated adverse events (AEs). We present five immunological AEs in a single patient treated with NIVO. A 68-year-old male patient with metastatic renal cell carcinoma and right-sided nephrectomy received NIVO after pazopanib and sunitinib treatment. Two and a half months after starting NIVO, hepatocellular enzymes and creatinine were elevated. Concomitantly, the patient noticed hypopigmentation of the hand skin and a change in voice and speech. Due to hepatitis, he has been treated with dexamethasone 16 mg daily for 22 days, after which hypothyroidism and increased creatine kinase were found without muscle pain and functional impairment. Dexamethasone was continued, and a rapid decline in all parameters except thyroid-stimulating hormone (TSH) and vitiligo was observed. Myositis was initially considered a part of hypothyroidism and elevated renal parameters due to hypohydration. The rapid regression on glucocorticoid treatment and a longer time for creatinine normalization than expected with hydration were noticed. Nivolumab likely induced those side effects as assessed by Naranjo Adverse Drug Reaction Probability Scale. The literature review shows that the consequences of PD-1 inhibition are not uniform. Side effects of checkpoint inhibitors should be monitored carefully in the early and later treatment schedules evaluating subclinical manifestations like myositis and worsening of kidney parameters. Early administered higher doses of glucocorticoids can stop drug toxicity and reverse-induced tissue damage.

Ferroptosis resistance determines high susceptibility of murine A/J strain to iron-induced renal carcinogenesis.

Cancer susceptibility is a critical factor in the understanding of carcinogenesis. Intraperitoneal (i.p.) injection of an iron chelate, ferric nitrilotriacetate (Fe-NTA), produces hydroxyl radicals via Fenton reaction to induce ferroptosis in renal proximal tubules. Rats or mice subjected to repeated i.p. injections of Fe-NTA develop renal cell carcinoma (RCC). To elucidate the molecular mechanisms that cause susceptibility to renal carcinogenesis, we first established an inter-strain difference in the susceptibility to Fe-NTA-induced renal carcinogenesis in mice. Based on a previous observation of a low incidence of RCC with this model in C57BL/6J strain mice, we investigated A/J strain mice here, which demonstrated significantly higher susceptibility to Fe-NTA-induced renal carcinogenesis. Homozygous deletion of the Cdkn2a/2b tumor suppressor locus was detected for the first time in A/J strain mice. Focusing on ferroptosis and iron metabolism, we explored the mechanisms involved that lead to the difference in RCC development. We compared the protective responses in the kidney of A/J and C57BL/6J strains after Fe-NTA treatment. After 3-week Fe-NTA treatment, A/J mice maintained higher levels of expression of glutathione peroxidase 4 and xCT (SLC7A11), leading to a lower level of lipid peroxidation. Simultaneously, A/J mice had decreased expression of transferrin receptor and increased expression of ferritin to greater degrees than C57BL/6 mice. After a single Fe-NTA injection, higher levels of oxidative cell damage and cytosolic catalytic Fe(II) were observed in C57BL/6J mice, accompanied by a greater increase in lipocalin-2. Lipocalin-2 deficiency significantly decreased oxidative renal damage. Our results suggest that a genetic trait favoring ferroptosis resistance contributes to high susceptibility to Fe-NTA-induced RCC in A/J strain.

Mechanistic Target of Rapamycin (mTOR) Inhibitors.

Mechanistic target of rapamycin (mTOR) inhibitors are macrocyclic lactone antibiotics derived from Streptomyces hygroscopicus that prevent T lymphocyte activation and B cell differentiation. Unlike calcineurin inhibitors (CNIs) that inhibit cytokine production, mTOR inhibitors block the cytokine signal transduction to arrest cells in the G1 to S phase. This class of drugs is commonly used for post-transplantation and cancer management because of its immunosuppressive and antiproliferative properties, respectively. The potential uses of mTOR inhibitors are heavily explored because of their impact on cell growth and proliferation. However, mTOR inhibitors have a broad range of effects that can result in adverse reactions, but side effects can occur with other immunosuppressive agents as well. Thus, the performance of mTOR inhibitors is compared to the outcomes and adverse effects of other immunosuppressive drugs or the combination of other immunosuppressants and mTOR inhibitors. Because mTOR regulates many downstream pathways, mTOR inhibitors can affect these pathways to manage various diseases. Sirolimus (rapamycin) is approved by the Food and Drug Administration (FDA) to treat post-renal transplantation and lymphangioleiomyomatosis (LAM). Everolimus is approved by the FDA to treat postmenopausal advanced hormone receptor-positive, HER2-negative breast cancer in women, progressive neuroendocrine tumors of pancreatic origin (PNET), advanced renal cell carcinoma (RCC), renal angiomyolipoma (AML) and tuberous sclerosis complex (TSC), and subependymal giant cell astrocytoma (SEGA) associated with TSC as well as renal and liver transplantation. Temsirolimus is approved by the FDA to treat advanced RCC. Opportunities to use mTOR inhibitors as therapy for other transplantation, metabolic disease, and cancer management are being researched. mTOR inhibitors are often called proliferation signal inhibitors (PSIs) because of their effects on proliferation pathways.

Alcohol consumption, tobacco smoking, and subsequent risk of renal cell carcinoma: The JPHC study.

The effects of alcohol consumption and tobacco smoking on renal cell carcinoma (RCC) incidence have not been well-investigated in Asian populations. Here, we evaluated these effects in a large Japanese prospective cohort. We collected data on eligible participants in the Japan Public Health Center-based Prospective Study, and undertook multivariable-adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of RCC incidence. We identified 340 cases (230 men and 110 women) among the 105 663 eligible participants (50 262 men and 55 741 women), who were followed for an average of 19.1 years, with a cumulative total of 2 020 364 person-years. A slightly inverse but nonsignificant association was observed between alcohol drinking and RCC incidence. In contrast, the risk of RCC was increased in those with heavy smoking (≥40 pack-years) when men and women were combined (HR 1.50; 95% CI, 1.01-2.25). We identified no significant association between alcohol consumption and RCC incidence. In contrast, heavy smoking (≥40 pack-years) was associated with a significant increase in incidence.

Risk of Renal Cell Carcinoma Associated with Calcium Channel Blockers: A Nationwide Observational Study Focusing on Confounding by Indication.

BACKGROUND: We examined whether the apparent association between renal cell carcinoma (RCC) and use of dihydropyridine calcium channel blockers (CCBs) was explained by confounding by indication since hypertension, the main indication for CCBs, is a risk factor for RCC. METHODS: Using Danish health registries, we conducted a nested case-control study including 7315 RCC cases during 2000-2015. We matched each case with up to 20 controls on age and sex using risk-set sampling. We estimated odds ratios (ORs) for long-term CCB use associated with RCC using conditional logistic regression. We addressed confounding by indication by (1) adjusting for hypertension severity indicators; (2) evaluating dose-response patterns; (3) examining whether other first-line anti-hypertensives were associated with RCC; and (4) using an active comparator new user design by nesting the study in new users of CCBs or angiotensin-converting enzyme inhibitors (ACEIs). RESULTS: The adjusted OR for RCC associated with long-term CCB use compared to non-use was 1.76 (1.63-1.90). After we additionally adjusted for hypertension severity indicators, the OR remained elevated (OR 1.37; confidence interval [CI] 1.25, 1.49) with evidence of a dose-response pattern. Other anti-hypertensives were also associated with RCC, for example, ACEIs (OR 1.27; 95% CI = 1.16, 1.39) and thiazides (OR 1.22; 95% CI = 1.12, 1.34). In the active comparator new user design, the OR was 1.21 (95% CI = 0.95, 1.53) for use of CCBs compared with ACEIs. CONCLUSIONS: In this population, confounding by indication appeared to explain at least part of the association between RCC and dihydropyridine CCBs.

Renal cell cancer after kidney transplantation.

PURPOSE: This study aims to identify modifiable risk factors for de novo renal cell carcinoma (RCC) after kidney transplantation in a matched-pair approach matching for unmodifiable factors. PATIENTS AND METHODS: One thousand six hundred fifty-five adults who underwent kidney transplantation in the period 1 January 2000 to 31 December 2012 were analyzed. Patients with RCC after kidney transplantation were matched in a 1:2 ratio with those without RCC using the indication for transplantation, age at transplantation (± 10 years), recipient sex (male/female), number of received transplants, living organ donor transplantation (yes/no), and time of follow-up in days as matching criteria. The paired t test was used to compare continuous variables and the Cochran-Mantel-Haenszel test for categorical variables. Multivariable conditional logistic regression modeling was used to identify independent risk factors for RCC. RESULTS: In matched-pair analysis, a total number of 26 incident cases with RCC after kidney transplantation could be matched. Post-transplant RCC was significantly associated with longer durations of pre-transplant hemodialysis (p = 0.007) and post-transplant immunosuppression with cyclosporine (p = 0.029) and/or mycophenolate mofetil (p = 0.020) and with larger proportions of post-transplant time on mycophenolate mofetil (p = 0.046) and/or prednisolone medication (p = 0.042). Multivariable conditional logistic regression modeling revealed a significant risk increasing multiplicative factor interaction between the duration of pre-transplant dialysis (years) and the time of prednisolone usage (percent/100). Cyclosporine A usage and mycophenolate mofetil usage were also revealed as independent, significant risk factors for RCC development. CONCLUSIONS: Longer pre-transplant dialysis, cyclosporine-based protocols and/or intensified immunosuppression with additional mycophenolate mofetil, and larger proportions of time of prednisolone treatment during follow-up increase de novo RCC risk.

Anti-carcinogenic effect of hesperidin against renal cell carcinoma by targeting COX-2/PGE2 pathway in Wistar rats.

The present study was designed to evaluate the protective effects of hesperidin, a flavonoid on DEN initiated and Fe-NTA promoted renal carcinogenesis in Wistar rats. Renal cancer was initiated by a single i.p. injection of DEN (200 mg/kg b.wt.) and promoted with Fe-NTA (9 mg Fe/kg b.wt. i.p.) twice a week for 16 weeks. Rats were simultaneously administered with hesperidin (100 and 200 mg/kg b.wt.) for 16 consecutive weeks. The chemopreventive effect of hesperidin was assessed in terms of antioxidant activities, renal function, PGE2 level, and the expressions of COX-2 and VEGF. Hesperidin decreased the DEN and Fe-NTA induced lipid peroxidation, improved the renal function (by decreasing the levels of BUN, creatinine, and KIM-1) and restored the renal antioxidant armory (GSH, GPx, GR, SOD, and catalase). Hesperidin was also found to decrease the level of PGE2 and downregulate the expressions of COX-2 and VEGF. Histological findings further revealed the protective effects of hesperidin against DEN and Fe-NTA induced kidney damage. The result of our present findings suggest that hesperidin may be a promising modulator in preventing renal cancer possibly by virtue of its ability to alleviate oxidative stress and inhibit COX-2/PGE2 pathway.

Association between coffee consumption and risk of renal cell carcinoma: a meta-analysis.

BACKGROUND/OBJECTIVES: The risk of renal cell carcinoma (RCC) in individuals who regularly drink coffee is controversial. Several antioxidant compounds in coffee have been proposed to reduce the risk of RCC, while the findings from several studies raise concerns regarding a potential increased risk of RCC with coffee consumption. AIM: This meta-analysis aims to evaluate the association between coffee consumption and RCC. METHODS: A literature search was performed using MEDLINE, EMBASE and Cochrane Database of Systematic Reviews from inception until December 2016. Studies that reported odd ratios or hazard ratios comparing the risk of RCC in individuals who consumed a significant amount of coffee (at least one cup of coffee per day) versus those who did not consume coffee were included. Pooled risk ratios (RR) and 95% confidence intervals (CI) were computed using a random-effect, generic inverse variance method. RESULTS: Twenty-two observational studies (16 case-control and 6 cohort studies) were included in our analysis to assess the association between RCC and coffee consumption. The pooled RR of RCC in individuals consuming coffee was 0.99 (95% CI, 0.89-1.11). Subgroup analyses stratified by gender showed pooled RRs of RCC of 1.15 (95% CI, 0.85-1.55) in females and 0.87 (95% CI, 0.72-1.04) in males. CONCLUSIONS: Our study demonstrates no significant association between coffee consumption and RCC. Thus, coffee consumption is likely not a risk factor for RCC. Whether coffee consumption has a potential role in reduced risk of RCC, particularly in men, requires further investigations.

Gene-environment interaction of genome-wide association study-identified susceptibility loci and meat-cooking mutagens in the etiology of renal cell carcinoma.

BACKGROUND: Meat-cooking mutagens may be associated with renal cell carcinoma (RCC) risk. In the current study, the authors examined associations between meat-cooking mutagens, genetic susceptibility variants, and risk of RCC. METHODS: The authors used 659 newly diagnosed RCC cases and 699 healthy controls to investigate the association between dietary intake of meat-cooking mutagens and RCC. They examined whether associations varied by risk factors for RCC and genetic susceptibility variants previously identified from genome-wide association studies. Odds ratios and 95% confidence intervals were estimated using tertiles of intake of dietary polycyclic aromatic hydrocarbons/heterocyclic amines. RESULTS: Dietary intake of the mutagenic compounds 2-amino-3,8-dimethylimidazo-(4,5-f) quinoxaline (MeIQx) and 2-amino-1 methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) were found to be significantly associated with an increased risk of RCC (odds ratios across tertiles: 1.00 [referent], 1.28 [95% confidence interval, 0.94-1.74], and 1.95 [95% confidence interval, 1.43-2.66] [P for trend <.001], respectively; and 1.00 [referent], 1.41 [95% confidence interval, 1.04-1.90], and 1.54 [95% confidence interval, 1.14-2.07] [P for trend =.02], respectively). The authors observed evidence of interactions between PhIP and RCC susceptibility variants in 2 genes: inositol 1,4,5-trisphosphate receptor, type 2 (ITPR2) (rs718314; multiplicative P for interaction = .03 and additive P for interaction =.002) and endothelial PAS domain-containing protein 1 (EPAS1) (rs7579899; additive P for interaction =.06). CONCLUSIONS: The intake of meat may increase the risk of RCC through mechanisms related to the cooking compounds MeIQx and PhIP. These associations may be modified by genetic susceptibility to RCC. Further research is necessary to understand the biological mechanisms underlying these interactions.

Aristolochic acid exposure in Romania and implications for renal cell carcinoma.

BACKGROUND: Aristolochic acid (AA) is a nephrotoxicant associated with AA nephropathy (AAN) and upper urothelial tract cancer (UUTC). Whole-genome sequences of 14 Romanian cases of renal cell carcinoma (RCC) recently exhibited mutational signatures consistent with AA exposure, although RCC had not been previously linked with AAN and AA exposure was previously reported only in localised rural areas. METHODS: We performed mass spectrometric measurements of the aristolactam (AL) DNA adduct 7-(deoxyadenosin-N(6)-yl) aristolactam I (dA-AL-I) in nontumour renal tissues of the 14 Romanian RCC cases and 15 cases from 3 other countries. RESULTS: We detected dA-AL-I in the 14 Romanian cases at levels ranging from 0.7 to 27 adducts per 10(8) DNA bases, in line with levels reported in Asian and Balkan populations exposed through herbal remedies or food contamination. The 15 cases from other countries were negative. INTERPRETATION: Although the source of exposure is uncertain and likely different in AAN regions than elsewhere, our results demonstrate that AA exposure in Romania exists outside localised AAN regions and provide further evidence implicating AA in RCC.

Transcriptional and post-translational modifications of B-Raf in quinol-thioether induced tuberous sclerosis renal cell carcinoma.

Increased activity of B-Raf has been identified in approximately 7% of human cancers. Treatment of Eker rats (Tsc-2(EK/+) ), bearing a mutation in one allele of the tuberous sclerosis-2 (Tsc-2) gene, with the nephrocarcinogen 2,3,5-tris-(glutathion-S-yl) hydroquinone (TGHQ) results in loss of the wild-type allele of Tsc-2 in renal preneoplastic lesions and tumors. These tumors have increased protein expression of B-Raf, C-Raf (Raf-1), and increased expression and activity of ERK kinase. Similar changes are observed in Raf kinases following TGHQ-mediated transformation of primary renal epithelial cells derived from Tsc-2(EK/+) rats (QTRRE cells), cells that are also null for tuberin. Herein, we utilized LC-MS/MS to identify constitutive phosphorylation of S345 and S483 in both 100- and 95-kDa forms of B-Raf in QTRRE cells. Using microRotofor liquid-phase isoelectric focusing, we identified four fractions of B-Raf that contain different post-translational modification profiles in QTRRE cells. Amplification of the kinase domain of B-Raf from QTRRE cells, outer-stripe of the outer medulla of 8-month TGHQ- or vehicle-treated Tsc-2(+/+) and Tsc-2(EK/+) rats, as well as tumors excised from 8-month TGHQ-treated Tsc-2(EK/+) rats revealed three splice variants of B-Raf within the kinase domain. These splice variants differed by approximately 340, 544, and 600 bp; confirmed by sequencing. No point mutations within the kinase domain of B-Raf were identified. In addition, B-Raf/Raf-1/14-3-3 complex formation in the QTRRE cells was decreased by sorafenib, with concomitant selective decreases in p-ERK levels. Transcriptional and post-translational characterization of critical kinases, such as B-Raf, may contribute to the progression of tuberous sclerosis RCC. (246/250) © 2015 Wiley Periodicals, Inc.

Renal Cell Carcinomas in Vinylidene Chloride-exposed Male B6C3F1 Mice Are Characterized by Oxidative Stress and TP53 Pathway Dysregulation.

Vinylidene chloride (VDC) has been widely used in the production of plastics and flame retardants. Exposure of B6C3F1 mice to VDC in the 2-year National Toxicology Program carcinogenicity bioassay resulted in a dose-dependent increases in renal cell hyperplasia, renal cell adenoma, and renal cell carcinomas (RCCs). Among those differentially expressed genes from controls and RCC of VDC-exposed mice, there was an overrepresentation of genes from pathways associated with chronic xenobiotic and oxidative stress as well as c-Myc overexpression and dysregulation of TP53 cell cycle checkpoint and DNA damage repair pathways in RCC. Trend analysis comparing RCC, VDC-exposed kidney, and chamber control kidney showed a conservation of pathway dysregulation in terms of overrepresentation of xenobiotic and oxidative stress, and DNA damage and cell cycle checkpoint pathways in both VDC-exposed kidney and RCC, suggesting that these mechanisms play a role in the pathogenesis of RCC in VDC-exposed mice.

Risk of renal cell carcinoma following exposure to metalworking fluids among autoworkers.

OBJECTIVES: Metalworking fluids (MWF), used to cool and lubricate metal in occupational settings, are linked to several cancers but data on kidney cancer are limited. We examine how MWF influence the rate of renal cell carcinoma (RCC) in a large prospective study. METHODS: A cohort of Michigan autoworkers consisting of 33 421 individuals was followed from 1985 to 2009. The cohort was linked to the Michigan Cancer Registry to identify new cases of RCC. We analysed RCC in relation to cumulative exposure to each specific type of MWF (straight, soluble and synthetic) and all 3 types pooled into a single MWF variable, with a 15-year lag. Cox proportional hazards regression with splines were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), controlling for age, gender, race, calendar year, year hired, time since hire, plant and other MWF types. RESULTS: There were 135 incident cases. A linear increase in the log-HR was observed for RCC with increasing cumulative exposure to each MWF type and total MWF exposure. At the mean of total MWF exposure (18.80 mg/m(3)-year), the estimated HR was 1.11 (95% CI 1.04 to 1.19). CONCLUSIONS: Our results provide evidence for a dose-dependent association between MWF exposure and RCC. The influence of components of oil-based and water-based MWF needs further examination.

MAPKs' status at early stages of renal carcinogenesis and tumors induced by ferric nitrilotriacetate.

Renal cell carcinoma (RCC) is asymptomatic at early stages, and thus, initial diagnosis frequently occurs at advanced or even metastatic stages, leading to a high rate of mortality. Ferric nitrilotriacetate (FeNTA)-induced RCC model is a useful tool to analyze molecular events at different stages of the carcinogenesis process in vivo. MAPKs' alterations seem to play an important role in the development and maintenance of human RCC tumors. Based on the above, p38α/ß/γ, JNK1/2, and ERK1/2 statuses were studied at early stages of FeNTA-induced renal carcinogenesis (1 and 2 months of carcinogen treatment) as well as in tumor tissue. MAPKs showed distinct response along carcinogenesis process, either as total proteins and/or as their phosphorylated forms. While the increase in total and phospho-p38α/ß levels became lower as carcinogenesis progressed, p38γ overexpression grew. Instead, total JNK2 diminished, but JNK1 was elevated at all studied times, and p-JNK1 levels increased at early stages, but not in tumors. In contrast, p-JNK2 rose at 2 months of treatment and in tumor tissue. Increased levels of p-ERK1/2 were observed at all stages analyzed. Very interestingly, at 1 and 2 months of FeNTA treatment, no alterations in MAPKs were found in liver or lung, where no primary tumors are induced with the scheme of FeNTA administration followed here. In conclusion, MAPKs' behavior evolved differentially as renal carcinogenesis advanced, even among isoforms of the same family, but it did not change in other tissues. All this strongly suggests a role of these kinases in FeNTA-induced RCC tumor development and maintenance.

Chemopreventive efficacy of hesperidin against chemically induced nephrotoxicity and renal carcinogenesis via amelioration of oxidative stress and modulation of multiple molecular pathways.

In the present study, chemopreventive efficacy of hesperidin was evaluated against ferric nitrilotriacetate (Fe-NTA) induced renal oxidative stress and carcinogenesis in wistar rats. Nephrotoxicity was induced by single intraperitoneal injection of Fe-NTA (9 mg Fe/kg b.wt). Renal cancer was initiated by the administration of N-nitrosodiethylamine (DEN 200mg/kg b.wt ip) and promoted by Fe-NTA (9 mg Fe/kg b.wt ip) twice weekly for 16 weeks. Efficacy of hesperidin against Fe-NTA-induced nephrotoxicity was assessed in terms of biochemical estimation of antioxidant enzyme activities viz. reduced renal GSH, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, catalase, superoxide dismutase and renal toxicity markers (BUN, Creatinine, KIM-1). Administration of Fe-NTA significantly depleted antioxidant renal armory, enhanced renal lipid peroxidation as well as the levels of BUN, creatinine and KIM-1. However, simultaneous pretreatment of hesperidin restored their levels in a dose dependent manner. Expression of apoptotic markers caspase-3, caspase-9, bax, bcl-2 and proliferative marker PCNA along with inflammatory markers (NFκB, iNOS, TNF-α) were also analysed to assess the chemopreventive potential of hesperidin in two-stage renal carcinogenesis model. Hesperidin was found to induce caspase-3, caspase-9, bax expression and downregulate bcl-2, NFκB, iNOS, TNF-α, PCNA expression. Histopathological findings further revealed hesperidin's chemopreventive efficacy by restoring the renal morphology. Our results provide a powerful evidence suggesting hesperidin to be a potent chemopreventive agent against renal carcinogenesis possibly by virtue of its antioxidant properties and by modulation of multiple molecular pathways.

Aristolochic acid-associated urothelial cancer in Taiwan.

Aristolochic acid, a potent human carcinogen produced by Aristolochia plants, is associated with urothelial carcinoma of the upper urinary tract (UUC). Following metabolic activation, aristolochic acid reacts with DNA to form aristolactam (AL)-DNA adducts. These lesions concentrate in the renal cortex, where they serve as a sensitive and specific biomarker of exposure, and are found also in the urothelium, where they give rise to a unique mutational signature in the TP53 tumor-suppressor gene. Using AL-DNA adducts and TP53 mutation spectra as biomarkers, we conducted a molecular epidemiologic study of UUC in Taiwan, where the incidence of UUC is the highest reported anywhere in the world and where Aristolochia herbal remedies have been used extensively for many years. Our study involves 151 UUC patients, with 25 patients with renal cell carcinomas serving as a control group. The TP53 mutational signature in patients with UUC, dominated by otherwise rare A:T to T:A transversions, is identical to that observed in UUC associated with Balkan endemic nephropathy, an environmental disease. Prominent TP53 mutational hotspots include the adenine bases of (5')AG (acceptor) splice sites located almost exclusively on the nontranscribed strand. A:T to T:A mutations also were detected at activating positions in the FGFR3 and HRAS oncogenes. AL-DNA adducts were present in the renal cortex of 83% of patients with A:T to T:A mutations in TP53, FGFR3, or HRAS. We conclude that exposure to aristolochic acid contributes significantly to the incidence of UUC in Taiwan, a finding with significant implications for global public health.