Diabetes and risk of renal cell carcinoma

Prevalence of diabetes and hospitalization due to poor glycemic control in people with bladder cancer or renal cell carcinoma in Sweden

BACKGROUND

Bladder cancer (BC) and Renal cell carcinoma (RCC) are the most common urogenital cancers among both sexes, with a yearly global incidence of around 500 000 each. Both BC and RCC have been linked to diabetes. Poor glycemic control (malglycemia) is a serious consequence of diabetes and a possible consequence of systemic treatments used in BC and RCC. The objective of this study was to investigate the prevalence of diabetes and use of hospital-based care for malglycemia in people with BC or RCC.

METHODS

This Swedish retrospective population-based register study used national health-data registers for longitudinal data on cancer incidence covering 15 years, use of hospital-based health care, and filled prescriptions of outpatient medications. Study endpoints included co-prevalence of diabetes in individuals with BC/RCC, healthcare resource utilization due to malglycemia, use of systemic corticosteroids, and changes in diabetes management for people with concomitant type 2 diabetes.

RESULTS

We identified 36,620 and 15,581 individuals diagnosed with BC and RCC, respectively, between 2006 and 2019. The proportion of individuals registered with diabetes was 24% in BC and 23% in RCC. An association between BC/RCC and poor glycemic control was found, although the number of malglycemic events in hospital-based care were few (65/59 per 1000 individuals with diabetes and BC/RCC respectively with at least one event). An earlier switch to insulin-based diabetes management was observed in BC/RCC compared to matched individuals with type 2 diabetes but no cancer. The results also indicated an association between steroid treatment and poor glycemic control, and that systemic corticosteroids were more common among people with BC/RCC compared to diabetes controls.

CONCLUSION

The high prevalence of diabetes and increased use of systemic corticosteroid treatment observed in this large national study highlights the need for specific clinical management, risk-assessment, and monitoring of individuals with BC/RCC and diabetes.

Associations between Diabetes Mellitus and Selected Cancers

Cancer is one of the major causes of mortality and is the second leading cause of death. Diabetes mellitus is a serious and growing problem worldwide, and its prevalence continues to grow; it is the 12th leading cause of death. An association between diabetes mellitus and cancer has been suggested for more than 100 years. Diabetes is a common disease diagnosed among patients with cancer, and evidence indicates that approximately 8-18% of patients with cancer have diabetes, with investigations suggesting an association between diabetes and some particular cancers, increasing the risk for developing cancers such as pancreatic, liver, colon, breast, stomach, and a few others. Breast and colorectal cancers have increased from 20% to 30% and there is a 97% increased risk of intrahepatic cholangiocarcinoma or endometrial cancer. On the other hand, a number of cancers and cancer therapies increase the risk of diabetes mellitus. Complications due to diabetes in patients with cancer may influence the choice of cancer therapy. Unfortunately, the mechanisms of the associations between diabetes mellitus and cancer are still unknown. The aim of this review is to summarize the association of diabetes mellitus with selected cancers and update the evidence on the underlying mechanisms of this association.

Global epidemiology of kidney cancer

Kidney cancer (KC) is a disease with a rising worldwide incidence estimated at 400 000 new cases annually, and a worldwide mortality rate approaching 175 000 deaths per year. Current projections suggest incidence continuing to increase over the next decade, emphasizing the urgency of addressing this significant global health trend. Despite the overall increases in incidence and mortality, striking social disparities are evident. Low- and middle-income countries bear a disproportionate burden of the disease, with higher mortality rates and later-stage diagnoses, underscoring the critical role of socioeconomic factors in disease prevalence and outcomes. The major risk factors for KC, including smoking, obesity, hypertension and occupational exposure to harmful substances, must be taken into account. Importantly, these risk factors also often contribute to kidney injury, a condition that the review identifies as a significant, yet under-recognized, precursor to KC. Finally, the indispensable role of nephrologists is underscored in managing this complex disease landscape. Nephrologists are at the forefront of detecting and managing kidney injuries, and their role in mitigating the risk of KC is becoming increasingly apparent. Through this comprehensive analysis, we aim to facilitate a more nuanced understanding of KC's epidemiology and determinants providing valuable insights for researchers, clinicians and policymakers alike.

Genomic and epigenomic integrative subtypes of renal cell carcinoma in a Japanese cohort

Renal cell carcinoma (RCC) comprises several histological types characterised by different genomic and epigenomic aberrations; however, the molecular pathogenesis of each type still requires further exploration. We perform whole-genome sequencing of 128 Japanese RCC cases of different histology to elucidate the significant somatic alterations and mutagenesis processes. We also perform transcriptomic and epigenomic sequencing to identify distinguishing features, including assay for transposase-accessible chromatin sequencing (ATAC-seq) and methyl sequencing. Genomic analysis reveals that the mutational signature differs among the histological types, suggesting that different carcinogenic factors drive each histology. From the ATAC-seq results, master transcription factors are identified for each histology. Furthermore, clear cell RCC is classified into three epi-subtypes, one of which expresses highly immune checkpoint molecules with frequent loss of chromosome 14q. These genomic and epigenomic features may lead to the development of effective therapeutic strategies for RCC.

Effect of smoking, hypertension and lifestyle factors on kidney cancer - perspectives for prevention and screening programmes

Renal cell carcinoma (RCC) incidence has doubled over the past few decades. However, death rates have remained stable as the number of incidental renal mass diagnoses peaked. RCC has been recognized as a European health care issue, but to date, no screening programmes have been introduced. Well-known modifiable risk factors for RCC are smoking, obesity and hypertension. A direct association between cigarette consumption and increased RCC incidence and RCC-related death has been reported, but the underlying mechanistic pathways for this association are still unclear. Obesity is associated with an increased risk of RCC, but interestingly, improved survival outcomes have been reported in obese patients, a phenomenon known as the obesity paradox. Data on the association between other modifiable risk factors such as diet, dyslipidaemia and physical activity with RCC incidence are conflicting, and potential mechanisms underlying these associations remain to be elucidated.

Importance of metabolic and immune profile as a prognostic indicator in patients with diabetic clear cell renal cell carcinoma

Background

ccRCC, also known as clear cell renal cell carcinoma, is a cancer that is highly metabolically active and has a strong connection with the immune system. The objective of this research was to investigate the correlation between pathways associated with metabolism, diabetes, immune infiltration, and their impact on the prognosis of ccRCC.

Method

We conducted an extensive examination utilizing ssGSEA, ESTIMATE algorithm, WGCNA, and GSVA for gene set enrichment analysis, gene co-expression network analysis, and gene set variation analysis. An established prognostic model, utilizing immune-related WGCNA findings, was evaluated for its association with clinical characteristics and the tumor microenvironment (TME).

Result

The ssGSEA effectively categorized ccRCC into groups based on low and high metabolism. Strong associations were observed between scores related to metabolism and immune scores, ESTIMATE scores, stromal scores, and gene expression related to HLA. The analysis conducted by WGCNA revealed a module called the 'yellow module' that exhibited a significant correlation with the infiltration of immune cells and the survival rates of patients. A risk model was developed, demonstrating reliable predictive performance for patient survival outcomes. The risk model also correlated significantly with immune scores and HLA-related gene expressions, suggesting potential immune evasion mechanisms. The analysis of mutations in TCGA data revealed the mutational patterns of ccRCC, and there was a significant correlation between the risk score and clinical characteristics. The GSVA analysis revealed a notable enrichment of pathways associated with cancer in patients at high risk. Finally, in order to evaluate the role of CX3CL1 in renal cell carcinoma cells, we then performed the cell proliferation assays. The results demonstrated that the over expression of CXCL1 could promote the cell proliferation ability in renal cell carcinoma cells.

Conclusion

Our findings provide a novel perspective on the interactions between diabetes, metabolic pathways, and the immune landscape in ccRCC. The predictive value of the prognostic model established in this research has the potential to guide the development of new therapeutic and prognostic approaches for patients with ccRCC.

Gene expression profile analysis unravelled the systems level association of renal cell carcinoma with diabetic nephropathy and Matrix-metalloproteinase-9 as a potential therapeutic target

Type 2 diabetes (T2D) and cancer share many common risk factors. However, the potential biological link that connects the two at the molecular level is still unclear. The experimental evidence suggests that several genes and their pathways may be involved in developing cancerous conditions associated with diabetes. In this study, we identified the protein-protein interaction (PPI) networks and the hub protein(s) that interlink T2D and cancer using genome-scale differential gene expression profiles. Further, the PPI network of AMP-activated protein kinase (AMPK) in cancer was analyzed to explore novel insights into the molecular association between the two conditions. The densely connected regions were analyzed by constructing the backbone and subnetworks with key nodes and shortest pathways, respectively. The PPI network studies identified Matrix-metalloproteinase-9 (MMP-9) as a hub protein playing a vital role in glomerulonephritis tubular diseases and some genetic kidney diseases. MMP-9 was also associated with different growth factors, like tumor necrosis factor (TNF-α), transforming growth factor 1 (TGF-1), and pathways like chemokine signaling, NOD-like receptor signaling, etc. Further, the molecular docking and molecular dynamic simulation studies supported the druggability of MMP-9, suggesting it as a potential therapeutic target in treating renal cell carcinoma linked with diabetic kidney disease.Communicated by Ramaswamy H. Sarma.

Primary and Immortalized Cultures of Human Proximal Tubule Cells Possess Both Progenitor and Non-Progenitor Cells That Can Impact Experimental Results

Studies have reported the presence of renal proximal tubule specific progenitor cells which co-express PROM1 and CD24 markers on the cell surface. The RPTEC/TERT cell line is a telomerase-immortalized proximal tubule cell line that expresses two populations of cells, one co-expressing PROM1 and CD24 and another expressing only CD24, identical to primary cultures of human proximal tubule cells (HPT). The RPTEC/TERT cell line was used by the authors to generate two new cell lines, HRTPT co-expressing PROM1 and CD24 and HREC24T expressing only CD24. The HRTPT cell line has been shown to express properties expected of renal progenitor cells while HREC24T expresses none of these properties. The HPT cells were used in a previous study to determine the effects of elevated glucose concentrations on global gene expression. This study showed the alteration of expression of lysosomal and mTOR associated genes. In the present study, this gene set was used to determine if pure populations of cells expressing both PROM1 and CD24 had different patterns of expression than those expressing only CD24 when exposed to elevated glucose concentrations. In addition, experiments were performed to determine whether cross-talk might occur between the two cell lines based on their expression of PROM1 and CD24. It was shown that the expression of the mTOR and lysosomal genes was altered in expression between the HRTPT and HREC24T cell lines based on their PROM1 and CD24 expression. Using metallothionein (MT) expression as a marker demonstrated that both cell lines produced condition media that could alter the expression of the MT genes. It was also determined that PROM1 and CD24 co-expression was limited in renal cell carcinoma (RCC) cell lines.

Associations of Renal Cell Carcinoma Subtype with Patient Demographics, Comorbidities, and Neighborhood Socioeconomic Status in the California Population

BACKGROUND

Renal cell carcinoma (RCC) subtypes differ in molecular characteristics and prognosis. We investigated the associations of RCC subtype with patient demographics, comorbidity, and neighborhood socioeconomic status (nSES).

METHODS

Using linked California Cancer Registry and Office of Statewide Health Planning and Development data, we identified history of hypertension, diabetes, and kidney disease prior to RCC diagnosis in Asian/Pacific Islander, non-Latino Black, Latino, and non-Latino White adults diagnosed with their first pathologically confirmed RCC from 2005 through 2015. We used multinomial multivariable logistic regression to model the association of demographics, comorbidity, and nSES with clear-cell, papillary, and chromophobe RCC subtype.

RESULTS

Of the 40,016 RCC cases included, 62.6% were clear cell, 10.9% papillary, and 5.9% chromophobe. The distribution of subtypes differed strikingly by race and ethnicity, ranging from 40.4% clear cell and 30.4% papillary in non-Latino Black adults to 70.7% clear cell and 4.5% papillary in Latino adults. In multivariable analysis, non-Latino Black individuals had a higher likelihood of presenting with papillary (OR, 3.99; 95% confidence interval, 3.61-4.42) and chromophobe (OR, 1.81; 1.54-2.13) versus clear-cell subtype compared with non-Latino White individuals. Both hypertension (OR, 1.19; 1.10-1.29) and kidney disease (OR, 2.38; 2.04-2.77 end-stage disease; OR, 1.52; 1.33-1.72 non-end-stage disease) were associated with papillary subtype. Diabetes was inversely associated with both papillary (OR, 0.63; 0.58-0.69) and chromophobe (OR, 0.61; 0.54-0.70) subtypes.

CONCLUSIONS

RCC subtype is independently associated with patient demographics, and comorbidity.

IMPACT

Targeted RCC treatments or RCC prevention efforts may have differential impact across population subgroups.

Metabolic Syndrome is an Independent Risk Factor for Fuhrman Grade and TNM Stage of Renal Clear Cell Carcinoma

Background

More and more evidences show that metabolic syndrome (MS) is closely related to clear cell renal cell carcinoma (ccRCC), but the impact of MS on Fuhrman grade and TNM stage of ccRCC is rarely reported.

Purpose

To explore the relationship between MS and its components of Fuhrman grade and TNM stage in ccRCC.

Objective

The clinical data of 247 patients with ccRCC diagnosed in our hospital from January 2016 to November 2020 were retrospectively collected and analyzed. Based on diagnostic criteria of MS, the patients were divided into MS and non-MS group. Logistic regression analysis was used to analyze the independent risk factors of ccRCC.

Results

The incidence of MS was 32.79% (81/247). There was no significant difference in age, gender, smoking and drinking between MS group and non-MS group (P > 0.05). In MS group, BMI ≥25kg/m², hypertension, diabetes, hyperlipidemia, tumor diameter, poorly differentiated renal cancer, high-stage renal cancer, triglyceride, fasting blood glucose, glycated hemoglobin, fasting insulin and homeostasis model assessment index were significantly higher than those in non-MS group (P < 0.001), while in high density lipoprotein cholesterol (p < 0.005), islet beta cell secretory index (P < 0.001), well-differentiated renal cell carcinoma (P= 0.009), and low-stage renal cell carcinoma (P = 0.019) were significantly lower than that of non-MS group. Logistic regression analysis showed that hypertension (P = 0.005), diabetes (P = 0.012), hyperlipidemia (P = 0.021) are independent risk factors for Fuhrman grade of ccRCC, while diabetes (P = 0.002), hyperlipidemia (P = 0.007) are independent risk factors for TNM staging of ccRCC.

Conclusion

The patients with ccRCC and MS had higher Fuhrman grade and TNM stage. MS is an independent risk factor for Fuhrman grade and TNM stage of ccRCC.

Relationship Between Pre-operative Blood Glucose Level and Length of Hospital Stay in Patients With Renal Cell Carcinoma Undergoing Laparoscopic Nephrectomy

Purpose: The aim of this study was to assess the effect of pre-operative blood glucose (POBG) levels on the length of stay (LOS) in patients with renal cell carcinoma (RCC) undergoing laparoscopic nephrectomy.

Methods: We collected clinical data on 338 patients with RCC who underwent laparoscopic nephrectomy between 2014 and 2019. Univariate and multivariate logistic regression and dose-response analysis curves of restricted cubic spline function were used to investigate the relationship between POBG and LOS.

Results: According to the level of POBG, we divided the patients into three groups: <4.94 mmol/L group, 4.94 to <7.11 mmol/L group, and ≥7.11 mmol/L group. According to the dose-response analysis curves, we found that the adjusted risk of LOS > 2 weeks and LOS > 3 weeks gradually increased with increasing POBG. In addition, we found that among all patients, patients with POBG levels ≥ 7.11 mmol/L had a 115% higher risk of LOS > 2 weeks than patients with POBG levels <4.94 mmol/L [adjusted odds risk (aOR) 2.15; 95% CI 1.11-4.20; p = 0.024] and patients with POBG levels ≥ 7.11 mmol/L had a 129% higher risk of LOS > 3 weeks than patients with POBG levels <4.94 mmol/L (aOR 2.29; 95% CI 1.16-4.52; p = 0.017). Moreover, similar results were observed in the most subgroups analysis.

Conclusion: We found that in patients with RCC undergoing laparoscopic nephrectomy, higher POBG levels were significantly associated with prolonged LOS.

The Importance of Nephropathology in Kidney Cancer

As early detection and advances in the treatment for renal cell carcinoma continue to lead to excellent oncologic outcomes, the preservation of renal function in kidney cancer patients has emerged as an increasingly important clinical objective. Given that diabetes, hypertension, obesity, cigarette smoking, and aging are independent risk factors for renal cell carcinoma, the corresponding non-neoplastic kidney diseases frequently are present, but often undiagnosed. In addition, the subsequent clinical management of the ensuing chronic kidney disease historically has not included nephrologists. Awareness of these practice gaps remain low among nephrologists, surgeons, and pathologists. This article discusses the common non-neoplastic kidney diseases that are encountered in cancer nephrectomy specimens. The accurate and timely diagnosis of these disorders will result in additional gains in clinical outcomes. There is a unique opportunity for the nephrology community to play a central role in the management of chronic kidney disease that often is present in kidney cancer patients.

Bioinformatic gene analysis for potential biomarkers and therapeutic targets of diabetic nephropathy associated renal cell carcinoma

Background

Numerous epidemiological studies have confirmed that diabetes can promote the development of malignant tumors. However, the relationship between renal cell carcinoma (RCC) and diabetic nephropathy (DN) is still controversial. This study aimed to investigate the genes that are co-expressed in DN and RCC in order to gain a better understanding of the relationship between these diseases, and to identify potential biomarkers and targets for the treatment of DN-related RCC.

Methods

We evaluated the differentially expressed genes (DEGs) that are co-expressed in DN and RCC using a wide range of target prediction and analysis methods. Twenty-four genes were identified by intersecting the differential genes of 3 DN datasets and 2 RCC datasets. We predicted the micro-ribonucleic acids (miRNAs) of these genes that may be controlled using the miRNA Data Integration Portal (mirDIP) database, and rated them according to each data forecast based on the Comparative Toxicogenomics Database (CTD) and the StarBase database.

Results

Four genes were associated with DN and RCC patients: the predicted miRNAs hsa-miR-200b-3p and hsa-miR-429 of fibronectin 1 (FN1); the predicted miRNA hsa-miR-29c-3p of collagen type 1 alpha 2 (COL1A2); the predicted miRNA hsa-miR-29c-3p of collagen type 3 alpha 1 (COL3A1); and the predicted miRNA hsa-miR-29a-3p and hsa-miR-200c-3p of glucose-6-phosphatase catalytic subunit (G6PC). These genes may serve as potential biomarkers or specific targets in the treatment of DN-related RCC.

Conclusions

A significant correlation was identified between DN and RCC. The FN1, COL1A2, COL3A1, and G6PC genes could be novel biomarkers of DN-related RCC.

The Role of Metabolic Factors in Renal Cancers

An increasing number of evidence indicates that metabolic factors may play an important role in the development and progression of certain types of cancers, including renal cell carcinoma (RCC). This tumour is the most common kidney cancer which accounts for approximately 3–5% of malignant tumours in adults. Numerous studies indicated that concomitant diseases, including diabetes mellitus (DM) and hypertension, as well as obesity, insulin resistance, and lipid disorders, may also influence the prognosis and cancer-specific overall survival. However, the results of studies concerning the impact of metabolic factors on RCC are controversial. It appears that obesity increases the risk of RCC development; however, it may be a favourable factor in terms of prognosis. Obesity is closely related to insulin resistance and the development of diabetes mellitus type 2 (DM2T) since the adipocytes in visceral tissue secrete substances responsible for insulin resistance, e.g., free fatty acids. Interactions between insulin and insulin-like growth factor (IGF) system appear to be of key importance in the development and progression of RCC; however, the exact role of insulin and IGFs in RCC pathophysiology remains elusive. Studies indicated that diabetes increased the risk of RCC, but it might not alter cancer-related survival. The risk associated with a lipid profile is most mysterious, as numerous studies provided conflicting results. Even though large studies unravelling pathomechanisms involved in cancer growth are required to finally establish the impact of metabolic factors on the development, progression, and prognosis of renal cancers, it seems that the monitoring of health conditions, such as diabetes, low body mass index (BMI), and lipid disorders is of high importance in clear-cell RCC.

The oxidation and hypoglycaemic effect of sorafenib in streptozotocin-induced diabetic rats

Background

Diabetes reduces the activity of CYP3A4 and may increase the exposure for the drugs metabolized by the isoenzyme. Sorafenib is a multi-targeted tyrosine kinase inhibitor (TKI), used for the treatment of advanced renal cell carcinoma, hepatocellular carcinoma and radioactive iodine resistant thyroid carcinoma. The TKI undergoes CYP3A4-dependent oxidative transformation, which may be influenced by hyperglycaemia. The aim of the study was to compare the oxidation for sorafenib between healthy and streptozotocin-induced diabetic rats. Additionally, the effect of sorafenib on glucose levels was investigated.

Methods

The rats were assigned to the groups: streptozotocin-induced diabetic (DG, n = 8) or healthy (HG, n = 8). The rats received sorafenib orally as a single dose of 100 mg/kg. The plasma concentrations of sorafenib and its metabolite N-oxide were measured with the validated high-performance liquid chromatography with ultraviolet detection.

Results

The difference between groups in C_max and AUC_0−t values for sorafenib were significant (p = 0.0004, p = 0.0104), and similarly for the metabolite (p = 0.0008, p = 0.0011). Greater exposure for the parent drug and analysed metabolite was achieved in diabetic group. However, the C_max, AUC_0−t, and AUC_0−∞ ratios between the metabolite and sorafenib were similar in both groups. The significant reduction of glycaemia was observed only in the diabetic animals.

Conclusion

The findings of the study provide evidence that diabetes significantly influence on the exposition for sorafenib and its metabolite, but similar ratios N-oxide/sorafenib for AUC and C_max in healthy and diabetic animals suggest that oxidation of the TKI is rather unchanged. Additionally, sorafenib-associated hypoglycaemia was confirmed in diabetic animals.

Pre-existing type 2 diabetes is an adverse prognostic factor in patients with renal cell carcinoma

BACKGROUND

Diabetes is a risk factor for various cancers, but its prognostic role in renal cell carcinoma (RCC) is controversial and understudied. This study investigated the prognostic value of type 2 diabetes (T2D) in RCC patients.

METHODS

The clinicopathological and follow-up data of 451 RCC patients undergoing radical or partial nephrectomy at the First Hospital of Shanxi Medical University from 2013 to 2018 were reviewed. Associations of T2D with clinicopathological parameters of RCC were evaluated using the Kaplan-Meier method for survival estimates and Cox regression univariate and multivariate analyses.

RESULTS

Of 451 patients, 74 (16.4%) had T2D. These patients were older, had a higher body mass index, higher incidence rates of hypertension and cardiovascular morbidity, a higher rate of laparoscopic surgery, and smaller neoplasms (all P < .05). Patients with T2D exhibited shorter overall survival (OS; P = .009), cancer-specific survival (CSS; P = .043), and recurrence-free survival (RFS; P = .008) than patients without T2D. Fuhrman grade (hazard ratio [HR] 2.542, 95% confidence interval [CI] 1.115-5.795, P = .026) and T2D (HR 3.391, CI 1.458-7.886, P = .005) were independent predictors of OS; T2D was an independent predictor of CSS (HR = 4.637, 95% CI 1.420-15.139, P = .011) and RFS (HR 3.492, 95% CI 1.516-8.044, P = .003).

CONCLUSIONS

Renal cell carcinoma patients with T2D have a shorter OS and higher recurrence rate and mortality risk than those without T2D.

The long-term rapid increase in incidence of adenocarcinoma of the kidney in the USA, especially among younger ages

BACKGROUND

We previously observed a rapid increase in the incidence of renal cell carcinoma (RCC) in men and women between 1935 and 1989 in the USA, using data from the Connecticut Tumor Registry. This increase appeared to be largely explained by a positive cohort effect, but no population-based study has been conducted to comprehensively examine age-period-cohort effects by histologic types for the past decade.

METHODS

We calculated age-adjusted and age-specific incidence rates of the two major kidney-cancer subtypes RCC and renal urothelial carcinoma, and conducted an age-period-cohort analysis of 114 138 incident cases of kidney cancer reported between 1992 and 2014 to the Surveillance, Epidemiology, and End Results programme.

RESULTS

The age-adjusted incidence rates of RCC have been increasing consistently in the USA among both men and women (from 12.18/100 000 in 1992-1994 to 18.35/100 000 in 2010-2014 among men; from 5.77/100 000 in 1992-1994 to 8.63/100 000 in 2010-2014 among women). Incidence rates generally increased in successive birth cohorts, with a continuing increase in rates among the younger age groups (ages 0-54 years) in both men and women and among both Whites and Blacks. These observations were confirmed by age-period-cohort modelling, which suggested an increasing birth-cohort trend for RCC beginning with 1955 birth cohorts, regardless of the assumed value for the period effect for both men and women and for Whites and Blacks.

CONCLUSIONS

Known risk factors for kidney cancer may not fully account for the observed increasing rates or the birth-cohort pattern for RCC, prompting the need for additional etiologic hypotheses (such as environmental exposures) to investigate these descriptive patterns.

Racial/ethnic disparities in renal cell carcinoma: Increased risk of early-onset and variation in histologic subtypes

Background

Racial/ethnic minority groups have a higher burden of renal cell carcinoma (RCC), but RCC among Hispanic Americans (HAs) and American Indians and Alaska Natives (AIs/ANs) are clinically not well characterized. We explored variations in age at diagnosis and frequencies of RCC histologic subtypes across racial/ethnic groups and Hispanic subgroups using National Cancer Database (NCDB) and Arizona Cancer Registry Data.

Methods

Adult RCC cases with known race/ethnicity were included. Logistic regression analysis was performed to estimate odds and 95% confidence interval (CI) of early‐onset (age at diagnosis <50 years) and diagnosis with clear cell RCC (ccRCC) or papillary RCC.

Results

A total of 405 073 RCC cases from NCDB and 9751 cases from ACR were identified and included. In both datasets, patients from racial/ethnic minority groups had a younger age at diagnosis than non‐Hispanic White (NHW) patients. In the NCDB, AIs/ANs had twofold increased odds (OR, 2.21; 95% CI, 1.88‐2.59) of early‐onset RCC compared with NHWs. HAs also had twofold increased odds of early‐onset RCC (OR, 2.14; 95% CI, 1.79‐2.55) in the ACR. In NCDB, ccRCC was more prevalent in AIs (86.3%) and Mexican Americans (83.5%) than NHWs (72.5%). AIs/ANs had twofold increased odds of diagnosis with ccRCC (OR, 2.18; 95% CI, 1.85‐2.58) in the NCDB, but the association was stronger in the ACR (OR, 2.83; 95% CI, 2.08‐3.85). Similarly, Mexican Americans had significantly increased odds of diagnosis with ccRCC (OR, 2.00; 95% CI, 1.78‐2.23) in the NCDB.

Conclusions

This study reports younger age at diagnosis and higher frequencies of ccRCC histologic subtype in AIs/ANs and Hispanic subgroups. These variations across racial/ethnic groups and Hispanic subgroups may have potential clinical implications.

Activation of AMPK by metformin promotes renal cancer cell proliferation under glucose deprivation through its interaction with PKM2

Metformin, a common therapeutics for type 2 diabetics, was recently demonstrated to possess antitumor activity in various cancer types. However, its therapy effect in renal cell carcinoma (RCC) still remains controversial. In this study, we found that metformin treatment in RCC cells lead to activation of AMPK, which suppressed the cell proliferation under normal condition, but enhanced cell proliferation under glucose deprivation (GD) condition. Depletion of AMPK by siRNA abolished the proliferation effect of MF under GD condition. Mechanistic investigations revealed that the effect of AMPK on cell proliferation under GD condition is dependent on its nuclear translocation. Moreover, the nuclear AMPK recruits PKM2 and β-Catenin to form a complex, which promotes the transcription of cell proliferation related genes, including CCND1 and c-Myc. Furthermore, depletion of PKM2 or β-Catenin abrogated the proliferative effects of metformin under GD condition. And inhibition of PKM2 also re-sensitized the A498 xenograft in response to metformin treatment. Together, our results suggested that combined of AMPK activation and PKM2 depletion or inhibition can achieve better therapeutic effect for RCC patients.

Racial and Ethnic Disparities in Renal Cell Carcinoma: An Analysis of Clinical Characteristics

BACKGROUND

Racial/ethnic minority groups, including Hispanic Americans (HAs) and Native Americans (NAs), have a heavier burden of kidney cancer than European Americans (EAs). We investigated variations in clinical characteristics of HA and NA patients with renal cell carcinoma (RCC) who were previously underrepresented.

MATERIALS AND METHODS

Clinical records of 294 patients with RCC (151 EAs, 95 HAs, 22 NAs, and 26 others) without prior diagnosis of cancer were reviewed. Logistic regression analysis was performed to understand patients' clinical characteristics.

RESULTS

HAs had about 5 years younger average age at diagnosis than EAs (55.8 vs. 60.5 years) and an almost 3-fold increased odds of diagnosis before age 50 years (odds ratio [OR], 2.77; 95% confidence interval [CI], 1.39-5.54). The mean age of diagnosis among NAs was 49.7 years, and NAs had an over 6-fold higher odds of diagnosis at a younger age (OR, 6.23; 95% CI, 2.00-19.46). Clear-cell RCC (ccRCC) was more common in HAs and NAs than EAs. Over 90% of HA patients had ccRCC, whereas only 78.8% of EA patients had ccRCC. HAs had increased odds of diagnosis with ccRCC compared with EAs (OR, 2.79; 95% CI, 1.15-6.80). Among HAs, older patients and patients who spoke Spanish as their primary language were more likely to have advanced stage RCC at diagnosis (OR, 10.48; 95% CI, 1.69-64.89 and OR, 4.61; 95% CI, 1.38-15.40).

CONCLUSION

HA and NA patients with RCC had different clinical characteristics than EA patients. It is necessary to better understand the clinical characteristics of these underserved HA and NA populations with high kidney cancer burden.

Effects of Resveratrol, Lovastatin and the mTOR-Inhibitor RAD-001 on Insulin-Induced Genomic Damage In Vitro

Diabetes mellitus (DM) is one of the major current health problems due to lifestyle changes. Before diagnosis and in the early years of disease, insulin blood levels are elevated. However, insulin generates low levels of reactive oxygen species (ROS) which are integral to the regulation of a variety of intracellular signaling pathways, but excess levels of insulin may also lead to DNA oxidation and DNA damage. Three pharmaceutical compounds, resveratrol, lovastatin and the mTOR-inhibitor RAD-001, were investigated due to their known beneficial effects. They showed protective properties against genotoxic damage and significantly reduced ROS after in vitro treatment of cultured cells with insulin. Therefore, the selected pharmaceuticals may be attractive candidates to be considered for support of DM therapy.

Identification of candidate drugs using tensor-decomposition-based unsupervised feature extraction in integrated analysis of gene expression between diseases and DrugMatrix datasets

Identifying drug target genes in gene expression profiles is not straightforward. Because a drug targets proteins and not mRNAs, the mRNA expression of drug target genes is not always altered. In addition, the interaction between a drug and protein can be context dependent; this means that simple drug incubation experiments on cell lines do not always reflect the real situation during active disease. In this paper, I applied tensor-decomposition-based unsupervised feature extraction to the integrated analysis using a mathematical product of gene expression in various diseases and gene expression in the DrugMatrix dataset, where comprehensive data on gene expression during various drug treatments of rats are reported. I found that this strategy, in a fully unsupervised manner, enables researchers to identify a combined set of genes and compounds that significantly overlap with gene and drug interactions identified in the past. As an example illustrating the usefulness of this strategy in drug discovery experiments, I considered cirrhosis, for which no effective drugs have ever been proposed. The present strategy identified two promising therapeutic-target genes, CYPOR and HNFA4; for their protein products, bezafibrate was identified as a promising candidate drug, supported by in silico docking analysis.

Renal cell carcinoma: a critical analysis of metabolomic biomarkers emerging from current model systems

Metabolomics, an emerging field of "omics" sciences, has caught wide scientific attention in the area of biomarker research for cancers in which early diagnostic biomarkers have the potential to greatly improve patient outcome, such as renal cell carcinoma (RCC). Metabolomic approaches have been successfully applied to various human RCC model systems, mostly ex vivo neoplastic renal tissues and biofluids (urine and serum) from patients with RCC. Importantly, in contrast to other cancers, only a few studies have addressed the RCC metabolome using cancer cell culture-based in vitro models. Herein, we first carried out a comprehensive review of current metabolomic data in RCC, with emphasis on metabolite disturbances and dysregulated metabolic pathways identified in each of these experimental models. We then critically analyzed the consistency of evidence in this field and whether metabolites found altered in tumor cell and tissue microenvironment are reflected in biofluids, which constitute the rationale underlying the translation of discovered metabolic biomarkers into noninvasive diagnostic tools. Finally, dominant metabolic pathways and promising metabolites as biomarkers for diagnosis and prognosis of RCC are outlined.

Renal cell carcinoma: links and risks

This review provides an overview of the incidence of renal cell carcinoma (RCC) and a summary of the most commonly associated risk factors. A literature review was performed with a focus on recent studies with a high level of evidence (large prospective cohort studies and meta-analyses). The incidence rate of RCC varies globally, with the rate rising rapidly in more developed regions, demonstrating the effects of increased use of diagnostic imaging and prevalence of modifiable risk factors. Based on the current evidence, cigarette smoking, obesity, and hypertension are the most well-established risk factors for sporadic RCC worldwide. Acquired cystic kidney disease is also a significant risk factor, specifically in dialysis patients. There is increasing evidence for an inverse association between RCC risk and moderate alcohol consumption. Certain analgesics and occupational exposure have been linked to an increased risk of RCC, although data are limited. Diets rich in fruits and vegetables may provide a protective effect.

Metformin Protects Kidney Cells From Insulin-Mediated Genotoxicity In Vitro and in Male Zucker Diabetic Fatty Rats

Hyperinsulinemia is thought to enhance cancer risk. A possible mechanism is induction of oxidative stress and DNA damage by insulin, Here, the effect of a combination of metformin with insulin was investigated in vitro and in vivo. The rationales for this were the reported antioxidative properties of metformin and the aim to gain further insights into the mechanisms responsible for protecting the genome from insulin-mediated oxidative stress and damage. The comet assay, a micronucleus frequency test, and a mammalian gene mutation assay were used to evaluate the DNA damage produced by insulin alone or in combination with metformin. For analysis of antioxidant activity, oxidative stress, and mitochondrial disturbances, the cell-free ferric reducing antioxidant power assay, the superoxide-sensitive dye dihydroethidium, and the mitochondrial membrane potential-sensitive dye 5,5',6,6'tetrachloro-1,1',3,3'-tetraethylbenzimidazol-carbocyanine iodide were applied. Accumulation of p53 and pAKT were analyzed. As an in vivo model, hyperinsulinemic Zucker diabetic fatty rats, additionally exposed to insulin during a hyperinsulinemic-euglycemic clamp, were treated with metformin. In the rat kidney samples, dihydroethidium staining, p53 and pAKT analysis, and quantification of the oxidized DNA base 8-oxo-7,8-dihydro-2'-deoxyguanosine were performed. Metformin did not show intrinsic antioxidant activity in the cell-free assay, but protected cultured cells from insulin-mediated oxidative stress, DNA damage, and mutation. Treatment of the rats with metformin protected their kidneys from oxidative stress and genomic damage induced by hyperinsulinemia. Metformin may protect patients from genomic damage induced by elevated insulin levels. This may support efforts to reduce the elevated cancer risk that is associated with hyperinsulinemia.

Microarray profile of human kidney from diabetes, renal cell carcinoma and renal cell carcinoma with diabetes

Recent study from our laboratory showed that patients with diabetes are at a higher risk of developing kidney cancer. In the current study, we have screened whole human DNA genome from healthy control, patients with diabetes or renal cell carcinoma (RCC) or RCC+diabetes. We found that 883 genes gain/163 genes loss of copy number in RCC+diabetes group, 669 genes gain/307 genes loss in RCC group and 458 genes gain/38 genes loss of copy number in diabetes group, after removing gain/loss genes obtained from healthy control group. Data analyzed for functional annotation enrichment pathways showed that control group had the highest number (280) of enriched pathways, 191 in diabetes+RCC group, 148 in RCC group, and 81 in diabetes group. The overlap GO pathways between RCC+diabetes and RCC groups showed that nine were enriched, between RCC+diabetes and diabetes groups was four and between diabetes and RCC groups was eight GO pathways. Overall, we observed majority of DNA alterations in patients from RCC+diabetes group. Interestingly, insulin receptor (INSR) is highly expressed and had gains in copy number in RCC+diabetes and diabetes groups. The changes in INSR copy number may use as a biomarker for predicting RCC development in diabetic patients.

Hyperactivation of Akt/mTOR and deficiency in tuberin increased the oxidative DNA damage in kidney cancer patients with diabetes

Recent study from our laboratory showed that patients with diabetes are at a higher risk of developing kidney cancer. In the current study, we have explored one of the mechanisms by which diabetes accelerates tumorigenesis in the kidney. Kidney cancer tissue from patients with diabetes showed a higher activity of Akt and decreased in total protein of tuberin compared to kidney cancer patient without diabetes or diabetes alone. In addition, a significant increase in phospho-Akt/tuberin expression was associated with an increase in Ki67 expression and activation of mTOR in kidney tumor with or without diabetes compared to diabetes alone. In addition, decrease in tuberin expression resulted in a significant decrease in protein expression of OGG1 and increased in oxidative DNA damage, 8-oxodG in kidney tissues from patients with cancer or cancer+diabetes. Importantly, these data showed that the majority of the staining of Akt/tuberin/p70S6K phosphorylation was more prominently in the tubular cells. In addition, accumulation of oxidative DNA damage is localized only in the nucleus of tubular cells within the cortex region. These data suggest that Akt/tuberin/mTOR pathway plays an important role in the regulation DNA damage and repair pathways that may predispose diabetic kidneys to pathogenesis of renal cell carcinoma.

The association between metformin use and oncologic outcomes among surgically treated diabetic patients with localized renal cell carcinoma

INTRODUCTION

Metformin inhibits renal cell carcinoma (RCC) cell proliferation both in vitro and in vivo; however, clinical data regarding the effect of metformin in patients with RCC are lacking. We evaluated the association of metformin use with outcomes among patients with surgically treated localized RCC.

MATERIALS AND METHODS

We identified 283 consecutive diabetic patients treated surgically for localized RCC between January 1, 1994 and December 31, 2008. Clinicopathologic features were compared between patients exposed to metformin (n = 83, 29%) and those who were not (n = 200, 71%). Progression-free, cancer-specific, and overall survival rates were estimated with the Kaplan-Meier analysis, and Cox models were used to evaluate the association of metformin use with outcomes.

RESULTS AND CONCLUSIONS

Patients receiving metformin had a better renal function (median estimated glomerular filtration rate = 65 vs. 55 ml/min/1.73 m(2), P<0.001), performance status (Eastern Cooperative Oncology Group<1: 89% vs. 71%, P = 0.001), and lower Charlson comorbidity index (median = 2 vs. 3, P = 0.02) compared with those who did not, but were otherwise similar across other clinicopathologic features (P>0.05 for all). At a median postoperative follow-up of 8.1 years, patients exposed to metformin had similar 5-year progression-free (80% vs. 75%, P = 0.6) and cancer-specific survival rates (91% vs. 81%, P = 0.16), but significantly improved overall survival rate (79% vs. 62%, P = 0.01). However, metformin was not independently associated with the risks of progression, RCC-specific mortality, or all-cause mortality on multivariable analyses. In this surgical cohort of diabetic patients with M0 RCC, preoperative metformin exposure was associated with improved overall survival on unadjusted analysis. Although metformin was not independently associated with oncologic or survival outcomes, future studies appear warranted.

Type 2 diabetes mellitus and risk of malignant melanoma: a systematic review and meta-analysis of cohort studies

BACKGROUND

Epidemiology studies have demonstrated inconsistent associations between type 2 diabetes mellitus and the risk of malignant melanoma. To this end, the aim was to perform a meta-analysis of cohort studies.

METHOD

Medline, PubMed, Embase and the Cochrane Library were searched up to February 2014. Cohort studies addressing the relative risk of type 2 diabetes mellitus on malignant melanoma were included in this meta-analysis. The Newcastle-Ottawa Scale was applied for quality evaluation. The pooled relative risks with the corresponding 95% confidence intervals (95% CIs) were calculated by using random-effects or random-effects model. Heterogeneity and publication bias were evaluated by I (2) and funnel plot analysis, respectively. Data was analyzed using STATA 11.0.

RESULTS

A total of 9 independent cohorts from 8 manuscripts were entered this meta-analysis. Type 2 diabetes mellitus was slightly associated with an increased risk of malignant melanoma, and the pooled relative risk was 1.15 (95% CI, 1.00-1.32) in diabetes compared with non-diabetes with significant evidence of heterogeneity among these studies (P=0.016, I (2) =57.6%). For the studies adjusted for age, gender and obesity, the relative risks were 1.21 (95% CI, 1.03-1.42), 1.17 (95% CI, 1.01-1.35) and 1.11 (95% CI, 1.00-1.24), respectively. For the population-based studies in which case cohort established, the relative risk was 1.85 (95% CI, 1.31-2.62).

CONCLUSION

Type 2 diabetes might be an independent risk factor for malignant melanoma. Further studies are needed to specifically test the effect, and fully elucidate the underlying pathophysiologic mechanisms.

The impact of type 2 diabetes on the outcome of localized renal cell carcinoma

PURPOSE

To evaluate the influence of type 2 diabetes on cancer-specific outcome in patients undergoing surgery for localized renal cell carcinoma (RCC).

METHODS

A total of 1,140 patients with localized RCC undergoing radical or partial nephrectomy were enrolled into this retrospective case-control study. Primary outcome was the cancer-specific survival comparing patients with and without type 2 diabetes at the time of surgery. Secondary outcomes were recurrence-free survival and metastases-free survival comparing the same groups. Additionally, the influence of accompanying factors on cancer-specific survival and overall survival of patients was evaluated in a multivariate analysis. Among 1,140 patients included in the analyses, 202 had diabetes at the time of surgery and 938 patients without diabetes served as control.

RESULTS

The univariate comparisons between patients with and without diabetes regarding recurrence-free, metastases-free, and cancer-specific survival revealed no significant differences. Multivariate results demonstrate that age, BMI, and diabetes had no significant effect on cancer-specific hazard among participants. After adjustment of the factors in terms of overall survival, however, increased age, increased BMI, and type 2 diabetes at the time of surgery were independent risk factors for the occurrence of the event death.

CONCLUSIONS

Type 2 diabetes and obesity at the time of surgery have no significant impact on cancer-specific and recurrence-free survival in patients with localized renal cancer.

Renal histologic parameters influencing postoperative renal function in renal cell carcinoma patients

BACKGROUND

Pre-existing non-neoplastic renal diseases or lesions may influence patient renal function after tumor removal. However, its description is often neglected or omitted in pathologic reports. To determine the incidence and clinical significance of non-neoplastic lesions, we retrospectively examined renal tissues obtained during 85 radical nephrectomies for renal cell carcinoma.

METHODS

One paraffin-embedded tissue block from each case containing a sufficient amount of non-tumorous renal parenchyma was cut and processed with hematoxylin and eosin and periodic acid-Schiff methods. Non-neoplastic lesions of each histological compartment were semi-quantitatively and quantitatively evaluated.

RESULTS

Among the various histologic lesions found, tubular atrophy, arterial intimal thickening, and glomerulosclerosis were the most common (94.1%, 91.8%, and 88.2%, respectively). Glomerulosclerosis correlated with estimated glomerular filtration rate at the time of surgery, as well as at 1- and 5-years post-surgery (p=.0071), but tubulointerstitial fibrosis or arterial fibrous intimal thickening did not. Post-hoc analysis revealed that glomerulosclerosis of more than 20% predicted post-operative renal function. However, its significance disappeared when gender and age were considered.

CONCLUSIONS

In conclusion, non-neoplastic lesions, especially with regard to glomerulosclerosis percentage, should be described in pathology reports to provide additional information on renal function decline.

Patient approach in advanced/metastatic renal cell carcinoma: focus on the elderly population and treatment-related toxicity

Recent therapeutic advances have changed the treatment landscape of metastatic renal cell carcinoma. Unfortunately, the seven agents now available are not based on biomarkers that would indicate which one could provide the best benefit for every patient. We have reviewed the available information concerning the impact of each treatment on comorbidities or status that are frequently seen before commencing treatment for the advanced disease: elderly and patients with cardiovascular complications, metabolic and endocrinology disorders, and infections, as well as impaired organ function (kidney, liver and heart). Additional new drugs will be launched, but no predictive biomarkers are available. Head-to-head studies to evaluate the safety of the different drugs are rare. In this quite complex scenario, we believe that a decision-making approach focused on the patient may represent a suitable strategy.

Effect of type 2 diabetes mellitus on prognosis of nonmetastatic renal cell cancer

Purpose

We evaluated the prognostic value of type 2 diabetes mellitus (DM) in patients treated surgically for localized renal cell carcinoma (RCC).

Materials and Methods

Between 1995 and 2011, 588 patients with renal tumor diagnoses were treated surgically and 492 patients with pathologically confirmed nonmetastatic RCC diagnoses were included in the study. The associations of clinical and pathologic parameters with a type 2 DM diagnosis were evaluated. Kaplan-Meier estimations for disease-specific survival (DSS) and overall survival (OS) were generated according to type 2 DM diagnosis, and the log-rank test was used to compare survival according to the variables.

Results

The mean age of the patients was 56.7±12 years (range, 15 to 84 years; median, 58 years) and the mean length of follow-up was 35.9±28 months (range, 1 to 145 months; median, 34.3 months). Of the 492 patients, 62 (12.6%) had a diagnosis of DM at the time of surgery (group I) and 430 did not have DM (group II). The mean age and the incidence of clear cell RCC histological subtype were significantly higher in group I than in group II (p<0.001 and p=0.036, respectively). Although DSS and OS were lower in group I, this difference was not significant. Type 2 DM was not detected as an independent prognostic factor for DSS and OS.

Conclusions

This study investigated the role and effect of DM on the prognosis of localized RCC that was treated surgically. The present study did not detect DM as an independent prognostic factor for RCC.

Insulin-mediated oxidative stress and DNA damage in LLC-PK1 pig kidney cell line, female rat primary kidney cells, and male ZDF rat kidneys in vivo

Hyperinsulinemia, a condition with excessively high insulin blood levels, is related to an increased cancer incidence. Diabetes mellitus is the most common of several diseases accompanied by hyperinsulinemia. Because an elevated kidney cancer risk was reported for diabetic patients, we investigated the induction of genomic damage by insulin in LLC-PK1 pig kidney cells, rat primary kidney cells, and ZDF rat kidneys. Insulin at a concentration of 5nM caused a significant increase in DNA damage in vitro. This was associated with the formation of reactive oxygen species (ROS). In the presence of antioxidants, blockers of the insulin, and IGF-I receptors, and a phosphatidylinositol 3-kinase inhibitor, the insulin-mediated DNA damage was reduced. Phosphorylation of protein kinase B (PKB or AKT) was increased and p53 accumulated. Inhibition of the mitochondrial and nicotinamide adenine dinucleotide phosphatase oxidase-related ROS production reduced the insulin-mediated damage. In primary rat cells, insulin also induced genomic damage. In kidneys from healthy, lean ZDF rats, which were infused with insulin to yield normal or high blood insulin levels, while keeping blood glucose levels constant, the amounts of ROS and the tumor protein (p53) were elevated in the high-insulin group compared with the control level group. ROS and p53 were also elevated in diabetic obese ZDF rats. Overall, insulin-induced oxidative stress resulted in genomic damage. If the same mechanisms are active in patients, hyperinsulinemia might cause genomic damage through the induction of ROS contributing to the increased cancer risk, against which the use of antioxidants and/or ROS production inhibitors might exert protective effects.

Diabetes and risk of cancer

Diabetes and cancer represent two complex, diverse, chronic, and potentially fatal diseases. Cancer is the second leading cause of death, while diabetes is the seventh leading cause of death with the latter still likely underreported. There is a growing body of evidence published in recent years that suggest substantial increase in cancer incidence in diabetic patients. The worldwide prevalence of diabetes was estimated to rise from 171 million in 2000 to 366 million in 2030. About 26.9% of all people over 65 have diabetes and 60% have cancer. Overall, 8–18% of cancer patients have diabetes. In the context of epidemiology, the burden of both diseases, small association between diabetes and cancer will be clinically relevant and should translate into significant consequences for future health care solutions. This paper summarizes most of the epidemiological association studies between diabetes and cancer including studies relating to the general all-site increase of malignancies in diabetes and elevated organ-specific cancer rate in diabetes as comorbidity. Additionally, we have discussed the possible pathophysiological mechanisms that likely may be involved in promoting carcinogenesis in diabetes and the potential of different antidiabetic therapies to influence cancer incidence.

Effects of oleic acid on cell proliferation through an integrin-linked kinase signaling pathway in 786-O renal cell carcinoma cells

An increased risk of renal cell carcinoma (RCC) has been linked with obesity and metabolic syndrome. However, the mechanisms by which lipid metabolic disorders affect the development of RCC remain unclear and highly controversial. Integrin-linked kinase (ILK) is a serine/threonine protein kinase involved in the regulation of tumor cell growth and angiogenesis. In the present study, the effect of free fatty acids in the promotion of RCC progression was investigated by upregulating ILK. Results of the MTT assay indicated that treatment of 786-O cells with oleic acid induced a concentration-dependent increase in cell viability. Flow cytometry analysis revealed that the effect of oleic acid on cell apoptosis was not significant. Following treatment with oleic acid, the expression of ILK, phospho-Akt and G protein-coupled receptor 40 (GPR40) was increased in 786-O cells. These effects were reversed when the expression of ILK was downregulated using specific small interfering RNA. These results indicate that free fatty acids are associated with the development of renal cell carcinoma via activation of the GPR40/ILK/Akt pathway, revealing a novel mechanism for the correlation between metabolic disturbance and renal carcinoma.

Metabolism of kidney cancer: from the lab to clinical practice

CONTEXT

There is increasing evidence for the role of altered metabolism in the pathogenesis of renal cancer.

OBJECTIVE

This review characterizes the metabolic effects of genes and signaling pathways commonly implicated in renal cancer.

EVIDENCE ACQUISITION

A systematic review of the literature was performed using PubMed. The search strategy included the following terms: renal cancer, metabolism, HIF, VHL.

EVIDENCE SYNTHESIS

Significant progress has been made in the understanding of the metabolic derangements present in renal cancer. These findings have been derived through translational, in vitro, and in vivo studies. To date, the most well-characterized metabolic features of renal cancer are linked to von Hippel-Lindau (VHL) loss. VHL loss and the ensuing increase in the expression of hypoxia-inducible factor affect several metabolic pathways, including glycolysis and oxidative phosphorylation. Collectively, these changes promote a glycolytic metabolic phenotype in renal cancer. In addition, other histologic subtypes of renal cancer are also notable for metabolic derangements that are directly related to the causative genes.

CONCLUSIONS

Current knowledge of the genetics of renal cancer has led to significant understanding of the metabolism of this malignancy. Further studies of the metabolic basis of renal cell carcinoma should provide the foundation for the development of new treatment approaches and development of novel biomarkers.