The epidemiology of renal cell carcinoma. Eur Urol. 2011;60:615-621. [PMID: 21741761 DOI: 10.1016/j.eururo.2011.06.049]

Axitinib: in advanced, treatment-experienced renal cell carcinoma

Axitinib is a new inhibitor of vascular endothelial growth factor (VEGF) receptors 1-3, with greater inhibition potency than existing VEGF receptor inhibitors sunitinib, sorafenib and pazopanib. In a pivotal phase III trial in patients with advanced renal cell carcinoma that had progressed despite first-line therapy, axitinib 5 mg twice daily significantly prolonged median progression-free survival (primary endpoint) compared with sorafenib 400 mg twice daily. A significant between-group difference favouring axitinib over sorafenib in terms of progression-free survival was maintained in the subgroups of patients who had previously received cytokine or sunitinib therapy. However, median overall survival was not significantly different between the treatment groups. Significantly more axitinib than sorafenib recipients achieved an objective response, and axitinib therapy significantly prolonged time to deterioration (a composite endpoint of death, disease progression and symptom worsening) relative to sorafenib therapy. While its tolerability profile was generally consistent with that of other VEGF receptor inhibitors, axitinib was associated with a numerically lower incidence of palmar-plantar erythrodysaesthesia, cutaneous toxicity and anaemia than sorafenib in the phase III trial.

Development of interferon γ-based immunocytokines targeting renal cancer

Advanced renal cancer is an incurable malignancy in need of novel therapeutic avenues. We have generated interferon γ (IFNγ)-based fusion antibodies (immunocytokines) that target CD70, a putative biomarker of renal cancer. These immunocytokines efficiently labeled renal cancer cells, and, when combined with the proteasome inhibitor bortezomib, killed them by activating a RIP1-dependent necrotic pathway.

NF-κB inhibition by bortezomib permits IFN-γ-activated RIP1 kinase-dependent necrosis in renal cell carcinoma

Advanced renal cell carcinoma (RCC) is an invariably fatal cancer. Currently, small-molecule inhibitors that target cell growth, angiogenesis, or nutrient-sensing pathways represent the primary pharmacologic interventions for this disease, but these inhibitors only delay tumor progression and are not curative. The cytokine IFN-γ showed the potential to provide lasting remission in several phase I/II trials for advanced RCCs, but subsequent trials, including a multicenter phase III study using IFN-γ as a monotherapy for RCCs, were less promising. Notably, these trials were designed to exploit the indirect immunomodulatory effects of IFN-γ, whereas its direct antitumor properties--including its ability to trigger programmed cell death in tumors-remain mostly untapped. Here, we show that the proteasome inhibitor bortezomib (PS-341, Velcade) sensitizes otherwise resistant RCC cells to direct necrotic death by IFN-γ. Mechanistically, we show that bortezomib functions, at least in part, by inhibiting prosurvival NF-κB signaling. In the absence of this signal, IFN-γ triggers programmed necrosis (or "necroptosis") dependent on the kinase RIP1. When taken together with the observation that NF-κB signaling is elevated in RCCs, these results provide rationale for the combined use of IFN-γ and bortezomib in the treatment of metastatic RCCs.

Robotic partial nephrectomy: current technique and outcomes

Over the past decade, management of the T1 renal mass has focused on nephron-sparing surgery. Robotic partial nephrectomy has played an increasing role in the technique of preserving renal function by decreasing warm ischemia time, as well as optimizing outcomes of hemorrhage and fistula. Robot-assisted partial nephrectomy is designed to provide a minimally-invasive nephron-sparing surgical option utilizing reconstructive capability, decreasing intracorporeal suturing time, technical feasibility and safety. Ultimately, its benefits are resulting in its dissemination across institutions. Articulated instrumentation and three-dimensional vision facilitate resection, collecting system reconstruction and renorrhaphy, leading to decreased warm ischemia time while preserving oncological outcomes. The aim of the present review was to present our surgical sequence and technique, as well as review the current status of robot-assisted partial nephrectomy.

Expression of the Na+/K+-transporting ATPase gamma subunit FXYD2 in renal tumors

Chromophobe renal cell carcinoma (RCC) is a form of renal cancer that may be confused with other eosinophilic renal tumors, including oncocytoma, type 2 papillary RCC, and clear-cell RCC with eosinophilic features. There are currently no robust markers to distinguish these neoplasms. Chromophobe RCC and renal oncocytoma are presumably derived from the distal nephron. FXYD2 is a distal tubule regulator of the trimeric Na(+/)K(+)-transporting ATPase that is enriched in kidney tissue. In this study, we investigated the expression of FXYD2 in normal human kidney, 27 chromophobe RCCs, 30 oncocytomas, 15 clear-cell RCCs, and 11 papillary RCCs. Immunohistochemical staining for FXYD2 showed diffuse, strong immunoreactivity in the basolateral membrane of distal tubules of normal human kidney. Ninety-six percent (26/27) of chromophobe RCCs were immunoreactive for FXYD2 in a distinctly membranous pattern. Twenty-five of these tumors showed at least focal 2+ staining. In contrast, only 17% (5/30) of renal oncocytomas, 11% (2/15) of clear-cell RCCs, and 0% (0/11) of papillary RCCs displayed FXYD2 immunoreactivity. None of these cases showed ≥2+ FXYD2 staining. A subset of cases was confirmed as oncocytoma or chromophobe RCC using cytokeratin 7, colloidal iron, and interphase fluorescence in situ hybridization analysis of chromosomes 1, 2, 6, 10, and 17. Among this subset, 100% (7/7) of chromophobe RCCs were FXYD2 positive, whereas 17% (2/12) of oncocytomas were stained with FXYD2. The oncocytomas that stained with FXYD2 did so in a weak (1+), patchy manner. In contrast, chromophobe RCCs showed ≥2+ staining in 86% (6/7) of these tumors. For comparison, this subset was also stained for kidney-specific cadherin (Ksp-cadherin). Ksp-cadherin showed positive staining in 100% (7/7) of chromophobe RCCs and 33% (4/12) of oncocytomas. This is the first report demonstrating the potential utility of FXYD2 immunohistochemistry in the diagnosis of chromophobe RCC.

[Active surveillance: concept for renal cell carcinoma?]

More than 80% of renal cell carcinomas are currently being detected incidentally by ultrasonic imaging and often affect elderly patients with substantial comorbidities. Surgical options cannot be applied in this cohort as routinely as in younger patients, as in some cases the perioperative risk factors may outweigh the risk of tumor-related death. In this context the concept of active surveillance for localized renal cell cancer in elderly patients is becoming increasingly important. The aim of active surveillance is to avoid surgery-related adverse effects and to achieve a controlled observation of tumor behavior with an option of delayed intervention in cases of aggressive clinical tumor features. This review sheds light on the current status of this strategy.

Anti-CD70 immunocytokines for exploitation of interferon-γ-induced RIP1-dependent necrosis in renal cell carcinoma

Metastatic renal cell carcinoma (RCC) is an incurable disease in clear need of new therapeutic interventions. In early-phase clinical trials, the cytokine IFN-γ showed promise as a biotherapeutic for advanced RCC, but subsequent trials were less promising. These trials, however, focused on the indirect immunomodulatory properties of IFN-γ, and its direct anti-tumor effects, including its ability to kill tumor cells, remains mostly unexploited. We have previously shown that IFN-γ induces RIP1 kinase-dependent necrosis in cells lacking NF-κB survival signaling. RCC cells display basally-elevated NF-κB activity, and inhibiting NF-κB in these cells, for example by using the small-molecule proteasome blocker bortezomib, sensitizes them to RIP1-dependent necrotic death following exposure to IFN-γ. While these observations suggest that IFN-γ-mediated direct tumoricidal activity will have therapeutic benefit in RCC, they cannot be effectively exploited unless IFN-γ is targeted to tumor cells in vivo. Here, we describe the generation and characterization of two novel ‘immunocytokine’ chimeric proteins, in which either human or murine IFN-γ is fused to an antibody targeting the putative metastatic RCC biomarker CD70. These immunocytokines display high levels of species-specific IFN-γ activity and selective binding to CD70 on human RCC cells. Importantly, the IFN-γ immunocytokines function as well as native IFN-γ in inducing RIP1-dependent necrosis in RCC cells, when deployed in the presence of bortezomib. These results provide a foundation for the in vivo exploitation of IFN-γ-driven tumoricidal activity in RCC.

Treatment of patients with metastatic renal cell carcinoma undergoing hemodialysis: case report of two patients and short literature review

Background

Renal cell carcinoma (RCC) may involve both kidneys. When bilateral nephrectomy is necessary renal replacement therapy is mandatory. Treating such patients with sequential therapy based on cytokines, antiangiogenic factors and mammalian target of rapamycin (mTOR) inhibitors is challenging.

Case presentation

The first case, a 50-year-old Caucasian female, underwent a radical right nephrectomy for RCC. Twelve years later she underwent a radical left nephrectomy along with total hysterectomy including bilateral salpingo-oophorectomy for RCC involving the right kidney and ovary. Hemodialysis was necessary because of bilateral nephrectomy. She relapsed with pulmonary metastases and enlarged mediastinal lymph nodes and received cytokine based therapy along with bevacizumab. Therapy was discontinued despite the partial response because of hemorrhagic gastritis. Therapy was switched to an antiangiogenic factor but the patient manifested a parietal brain hematoma and stopped therapy. Subsequently disease relapsed with malignant pleural effusion and pulmonary nodules and a mammalian target of rapamycin inhibitor was administered which was withdrawn only at patient’s deteriorating performance status. The patient died of the disease 13 years after the initial diagnosis of RCC.

The second case, a 51-year-old, Caucasian male, underwent a radical right nephrectomy for a chromophobe RCC. Six months later he underwent a radical left nephrectomy for RCC that proved to be a clear cell RCC. Due to bilateral nephrectomy hemodialysis was obligatory. Following disease recurrence at the anatomical bed of the right kidney therapy with antiangiogenic factor was administered which led to disease regression. However the patient experienced a left temporal-occipital brain hematoma. A radical excision of the recurrence which histologically proved to be a chromophobe RCC was not achieved and the patient received mTOR inhibitor which led to disease complete response. Nine years after the initial diagnosis of RCC he is disease free and leads an active life.

Conclusion

Patients with RCC are in significant risk to manifest bilateral disease. Renal insufficiency requiring hemodialysis poses therapeutic challenges. Clinicians must be aware of the antiangiogenic factors’ adverse effects, especially bleeding, that may manifest in higher frequency and more severe in this setting.

Potential biofluid markers and treatment targets for renal cell carcinoma

Renal cell carcinoma (RCC) is the 13th most common cancer in the world and one of the few cancers for which incidence is increasing. This disease is generally asymptomatic at an early stage and is highly metastatic. Frequently discovered by physicians in the process of working up other diseases such as acute kidney injury, RCC is often discovered in an advanced form and many patients have metastases at the time of diagnosis. Given that life expectancy with currently approved therapies for metastatic RCC is approximately 1-2 years, biomarkers for RCC that will enable early detection are urgently needed. Although it is unlikely that highly sensitive and specific biomarkers will be identified in the near future that are useful for screening the general population, a noninvasive marker or set of markers could soon be used in general medicine, nephrology, and urology clinics to screen patients at increased risk of RCC. In addition to the ongoing need for RCC biomarkers, the frequent resistance reported with currently available targeted therapies makes the identification of new therapeutic targets similarly important. Many promising leads for new targeted therapies have come to light; some of these therapies are in clinical trials and others are still being evaluated in the laboratory.

Patient and caregiver knowledge and utilization of partial versus radical nephrectomy: results of a national kidney foundation survey to assess educational needs of kidney cancer patients and caregivers

BACKGROUND

In response to requests from patients, caregivers, and physicians for information on kidney cancer, the National Kidney Foundation (NKF) conducted a survey to assess the educational needs of the kidney cancer community. Key areas of assessment were patient and caregiver knowledge of risk factors for chronic kidney disease (CKD), including kidney cancer and nephrectomy, and of kidney-sparing surgical options.

STUDY DESIGN

Survey to assess educational needs of patients with kidney cancer and caregivers.

SETTING & PARTICIPANTS

Respondents were invited through physician referrals and online sources and included 365 adult patients with kidney cancer and 52 caregivers.

PREDICTOR

Age, geographic region, and cancer stages 1-2 versus 3-4.

OUTCOMES & MEASUREMENTS

Survey responses were descriptively analyzed, with data compared and weighted to the population age and geographic characteristics of the general kidney cancer population.

RESULTS

83% of 181 early-stage patients, 92% of 123 late-stage patients, and 86% of 113 patients who did not know their stage received radical nephrectomy. Although 62% agreed that radical nephrectomy for cancer treatment is a risk factor for CKD, only 40% agreed that losing part or all of 1 kidney from injury or a disease other than cancer is a risk factor for CKD. 56% agreed that kidney cancer can be related to CKD.

LIMITATIONS

We did not have patient medical records to validate responses and we do not know the number of people who were invited to take the survey but declined.

CONCLUSIONS

There is a lack of patient awareness that kidney cancer and radical nephrectomy are risk factors for CKD. Only a minority of patients underwent partial nephrectomy or were given it as an option for their early-stage kidney cancer. This suggests a knowledge deficit among physicians, surgeons, patients, and caregivers alike that there is a bidirectional relationship between kidney cancer and CKD and that kidney-sparing surgery is preferable when feasible.

Establishment and characterization of clear cell renal cell carcinoma cell lines with different metastatic potential from Chinese patients

Abstracts

[Partial nephrectomy. Rationale and limitations of an organ-preserving approach]

The rising incidence of renal cell cancer in recent decades has led to a revision in the therapy of this malignancy. For small renal masses, partial nephrectomy has become the standard surgical treatment instead of radical nephrectomy. This approach can lead to a higher overall survival due to preservation of renal function. Avoiding chronic kidney disease is mandatory for patients with benign or small non-aggressive tumors; however, partial nephrectomy correlates with higher complication rates and is conditioned by operator skills. The role of partial nephrectomy compared to radical nephrectomy is still to be established particularly for larger tumors. The results of studies so far are mostly based on non-randomized retrospective data. This article will present the pros and cons of partial nephrectomy and will focus on the steps required to promulgate the indications of nephron-sparing surgery.

Vasoactive intestinal peptide induces oxidative stress and suppresses metastatic potential in human clear cell renal cell carcinoma

Molecular mechanisms involved in progression of clear-cell renal-cell carcinomas (ccRCCs) are poorly understood. A common genetic mutation found in ccRCC is the loss of the von Hippel-Lindau (VHL) gene, which contributes to cancer progression and metastasis. We investigated VIP effects on metastatic and angiogenic factors in human VHL-null A498 ccRCC and HK2 renal cells. VIP increased adhesion but decreased expression of metalloproteinases, MMP2 and MMP9, as well as cell migration and VEGF expression and secretion in A498 but not in HK2 cells. VIP enhanced ROS levels and decreased nuclear levels of β-catenin and NFκB p50-subunit in A498 cells, suggesting neuropeptide involvement in the observed decrease of metastatic ability in clear-cell carcinoma. VIP effects in A498 cells were blocked by the VPAC(1/2)-receptor antagonist JV-1-53. In conclusion, present data point to a role of VIP in preventing invasion and metastasis in ccRCCs and support its potential therapeutic usefulness in this disease.

[Renal cell carcinoma: A 12-year retrospective study of epidemiologic, therapeutic and follow-up data]

OBJECTIVE

To describe the evolution of epidemiology and management of renal cell carcinoma and their impact on overall and progression-free survivals.

PATIENTS AND METHODS

We reviewed the files of consecutive patients with renal cell carcinoma in our center between January 2000 and December 2011. Patients with confirmed diagnosis on histology who underwent radical nephrectomy, partial nephrectomy or thermoablation were included. Benign tumors were excluded. Epidemiologic and therapeutic data during the period of study were compared. Overall and progression-free survivals divided in three periods were compared by Kaplan-Meier curves.

RESULTS

Four hundred and forty-nine patients were included with a median age of 60 years old [21; 89], and median follow-up of 39 months. Tumor histology was clear cell carcinoma in 75.9% of cases. During the period of study, patients with ASA score upper than 3 increased from 20.4% to 47.8%, tumor size decreased from 58.4mm to 49.5mm and incidental tumor discovery increased from 59.1% to 71.6%. Nephron-sparing surgery increased from 19.7% to 44%. Overall survival and progression-free survival was not different during this period (P=0.071 and P=0.582).

CONCLUSION

The increase in early incidental discovery of renal cell carcinoma allowed nephron-sparing surgery in spite of patients with more comorbidities, with stable overall and progression-free survivals in our series.

Down-regulation of CD74 inhibits growth and invasion in clear cell renal cell carcinoma through HIF-1α pathway

OBJECTIVES

To investigate the expression and function of CD74 in normal renal tissue and clear cell-renal cell carcinoma (ccRCC), as well as related renal tubule epithelial lines. We also analyzed the association between clinicopathological characteristics of ccRCCs and the expression levels of CD74.

METHODS

Immunostaining of CD74 was performed in 107 patients' renal tissue and cell lines. We evaluated the association between clinicopathological characteristics of ccRCC and CD74 levels using image analysis. CD74 expression levels were also analyzed by Western blot. Lentivirus-mediated CD74 knockdown inhibited the growth and invasion, of ccRCC cell lines 786-O in vitro and in vivo. Cell proliferation, apoptosis, and invasion as well as HIF-1α pathway-related proteins, were estimated by Western blot. All experiments were repeated at least 3 times.

RESULTS

Immunostaining and image analysis showed strong immunoreactions of CD74 in all patients' ccRCC tissue and malignant cell lines, while CD74 expression levels were associated with tumor grade (P = 0.013). Western blot indicated that ccRCC tissue and malignant cell lines expressed higher levels of CD74 and hypoxia inducible factor 1α (HIF-1α) than adjacent normal renal tissue and normal cell HK-2. Vitro and vivo tests demonstrated that lentivirus-mediated CD74 knockdown inhibited the proliferation of ccRCC cell lines, induced G1/S arrest and apoptosis, and inhibited invasion. Inhibition of CD74 resulted in down-regulation of HIF-1α pathway proteins.

CONCLUSIONS

CD74 was overexpressed in human ccRCCs and associated with tumor grade, and inhibition of CD74 produced ccRCC proliferation arrest, induced apoptosis, and inhibited invasion, which impinged on HIF-1α pathway-related proteins. It might represent a potential therapeutic target for ccRCC.

A functional variant in the MTOR promoter modulates its expression and is associated with renal cell cancer risk

BACKGROUND

The mTOR signaling pathway plays a crucial role in the carcinogenesis of renal cell cancer (RCC). We sought to investigate the influence of genetic variations in the mTOR pathway-related genes on the risk of RCC.

METHODS

We genotyped 8 potentially functional polymorphisms in AKT1, AKT2, PTEN and MTOR genes using the TaqMan method in a case-control study of 710 RCC patients and 760 cancer-free subjects. Unconditional logistic regression, adjusted for potential confounding factors, was used to assess the risk associations. We then examined the functionality of the important polymorphisms.

RESULTS

Of the 8 polymorphisms, after adjusting for multiple comparisons, we found a significant association between one variant (rs2295080) in the promoter of MTOR and reduced RCC risk (P = 0.005, OR = 0.74, 95%CI = 0.59-0.91, TG/GG vs. TT). Another variant (rs701848) in the 3'UTR region of PTEN was associated with increased RCC risk (P = 0.014, OR = 1.45, 95%CI = 1.08-1.96, CC vs. TT); however, the association was not significant after adjusting for multiple comparisons. Furthermore, we observed lower MTOR mRNA levels in the presence of the rs2295080G allele in normal renal tissues. The luciferase reporter assay showed that the rs2295080G allele significantly decreased luciferase activity. No other significant association between the selected polymorphisms and RCC risk was observed.

CONCLUSIONS

Our results suggest that the functional MTOR promoter rs2295080 variant affects RCC susceptibility by modulating the endogenous MTOR expression level. The risk effects and the functional impact of the MTOR rs2295080 variant need further validation.

Malignant tumors in patients with end stage renal failure undergoing renal replacement therapy

In 1975 Matas and co-workers were the first in the world literature to show an increased risk of malignant tumor occurrence in the group of hemodialyzed patients and kidney transplant recipients. The report is an analysis of world literature from the last 35 years in reference to epidemiology as well as the profile of screening tests and diagnostic methods related to malignant tumors in the population with end stage renal disease, especially hemodialyzed patients.

Constitutional genetic variants as predictors of antiangiogenic therapy outcome in renal cell carcinoma

The development of specific angiogenesis inhibitors has drastically improved renal cancer treatment in recent years. Currently, four VEGF receptor inhibitors (sorafenib, sunitinib, pazopanib and axitinib), one anti-VEGF monoclonal antibody (bevacizumab) and two inhibitors of the mTOR pathway (temsirolimus and everolimus) have been approved to treat renal cell carcinoma (RCC), and several other molecules are under investigation. However, lack of response to antiangiogenic drugs and adverse drug reactions leading to treatment suspension are critical clinical problems that need to be solved. Because antiangiogenic drugs act on nonmalignant endothelial cells, the genetic background of the patient may play a crucial role determining the efficacy of these drugs. This article focuses on the identification of polymorphisms associated with antiangiogenic drugs outcome in RCC patients. It reviews and summarizes our current knowledge on this area and discusses future strategies to identify new biomarkers that could be used to personalize RCC management.

WNT10A plays an oncogenic role in renal cell carcinoma by activating WNT/β-catenin pathway

Renal cell carcinoma (RCC) is a malignancy with poor prognosis. WNT/β-catenin signaling dysregulation, especially β-catenin overactivation and WNT antagonist silencing, is associated with RCC carcinogenesis and progression. However, the role of WNT ligands in RCC has not yet been determined. We screened 19 WNT ligands from normal kidney and RCC cell lines and tissues and found that WNT10A was significantly increased in RCC cell lines and tissues as compared to that in normal controls. The clinical significance of increase in WNT10A was evaluated by performing an immunohistochemical association study in a 19-year follow-up cohort comprising 284 RCC and 267 benign renal disease (BRD) patients. The results of this study showed that WNT10A was dramatically upregulated in RCC tissues as compared to that in BRD tissues. This result suggests that WNT10A, nuclear β-catenin, and nuclear cyclin D1 act as independent risk factors for RCC carcinogenesis and progression, with accumulative risk effects. Molecular validation of cell line models with gain- or loss-of-function designs showed that forced WNT10A expression induced RCC cell proliferation and aggressiveness, including higher chemoresistance, cell migration, invasiveness, and cell transformation, due to the activation of β-catenin-dependent signaling. Conversely, WNT10A siRNA knockdown decreased cell proliferation and aggressiveness of RCC cells. In conclusion, we showed that WNT10A acts as an autocrine oncogene both in RCC carcinogenesis and progression by activating WNT/β-catenin signaling.

Inverse correlation of intracellular calcium and cyclic AMP levels in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common renal tumour in adults. Altered levels of secondary messengers, that is, intracellular calcium and cyclic AMP (cAMP), have been implicated in the pathogenesis of various malignancies. In the present study, we measured levels of intracellular calcium and cAMP in RCC. The intracellular calcium level was significantly reduced, whereas the cAMP level was significantly augmented in RCC as compared with adjacent grossly normal renal parenchyma.

[Incidence, prevalence and mortality of kidney cancer in Spain: estimates and projections for the 1998-2022 period]

OBJECTIVE

To estimate kidney cancer incidence and prevalence in Spain, based on mortality and survival data from the period 1998-2007, and to provide projections of incidence, prevalence and mortality until the year 2022.

MATERIAL AND METHODS

All-cause and kidney-cancer mortality rates were obtained from the National Statistics Institute and survival data were obtained from the EUROCARE study. Estimations were carried out using the MIAMOD program. The Joinpoint program was used to quantify the expected annual change in the projections.

RESULTS

An increase in the incidence rate is expected in men from, this going from 11.92 (Adjusted Rate - AR=8.66) per 100,000 inhabitants/year to 15.7 (AR=9.55). Prevalence would increase from 72.84 (AR=51.62) to 94.47 (AR=59.57), and mortality would increase from 5.77 (AR=7.29) to 7.29 (AR=4.56). The incidence rate in women would increase from 5.56 (AR=3.86) to 26.77 (AR=16.4). Prevalence would increase from 24.6 (AR=17.28) to 133.69 (81.37), and for mortality, the expected increase would be from 2.46 (AR=1.54) to 11.65 (AR=6.56) cases per 100.000 inhabitants/year.

CONCLUSION

The projections indicate that kidney cancer in Spain follows an increasing trend in incidence, mortality and prevalence. This needs to be considered in order to plan more effective prevention and treatment measures.

Cholesterol and the development of clear-cell renal carcinoma

The majority of kidney cancers are clear-cell carcinomas (ccRCC), characterized by the accumulation of cholesterol, cholesterol esters, other neutral lipids and glycogen. Rather than being a passive bystander, the clear-cell phenotype is suggested to be a biomarker of deregulated cholesterol and lipid biosynthesis, which plays an important role in development of the disease. One clue to this relationship has come from the elucidation of the hereditary kidney cancer gene, TRC8, which functions partly to degrade key regulators of endogenous cholesterol and lipid biosynthesis. In addition, deregulation of the mevalonate pathway has been shown to play a key role in cellular transformation and invasion. These findings are supported by considerable epidemiologic data linking obesity and the deregulation of lipid biosynthesis to ccRCC.

Determination of the nonlethal margin inside the visible "ice-ball" during percutaneous cryoablation of renal tissue

OBJECTIVE

The study was designed to determine the distance between the visible "ice-ball" and the lethal temperature isotherm for normal renal tissue during cryoablation.

METHODS

The Animal Care Committee approved the study. Nine adult swine were used: three to determine the optimum tissue stain and six to test the hypotheses. They were anesthetized and the left renal artery was catheterized under fluoroscopy. Under MR guidance, the kidney was ablated and (at end of a complete ablation) the nonfrozen renal tissue (surrounding the "ice-ball") was stained via renal artery catheter. Kidneys were explanted and sent for slide preparation and examination. From each slide, we measured the maximum, minimum, and an in-between distance from the stained to the lethal tissue boundaries (margin). We examined each slide for evidence of "heat pump" effect.

RESULTS

A total of 126 measurements of the margin (visible "ice-ball"-lethal margin) were made. These measurements were obtained from 29 slides prepared from the 6 test animals. Mean width was 0.75 ± 0.44 mm (maximum 1.15 ± 0.51 mm). It was found to increase adjacent to large blood vessels. No "heat pump" effect was noted within the lethal zone. Data are limited to normal swine renal tissue.

CONCLUSIONS

Considering the effects of the "heat pump" phenomenon for normal renal tissue, the margin was measured to be 1.15 ± 0.51 mm. To approximate the efficacy of the "gold standard" (partial nephrectomy, ~98 %), a minimum margin of 3 mm is recommended (3 × SD). Given these assumptions and extrapolating for renal cancer, which reportedly is more cryoresistant with a lethal temperature of -40 °C, the recommended margin is 6 mm.

New tools for assessing the individual risk of metastasis in renal cell carcinoma

Localized renal cell carcinoma (RCC) progresses to metastatic disease in 20-40 % after surgical resection. Affected patients might benefit from adjuvant treatment and have to be reliably identified for treatment indication. However, existing molecular markers and classification nomograms lack sufficient validity for clinical application so far. Therefore, in order to improve diagnostic tools for the identification of patients at risk, we tested invasiveness and the capability to activate vascular endothelium of primary RCC cells as tumor specific functional parameters. As a parameter for cell invasiveness the ability of RCC cells to break-down transepithelial electrical resistance (TEER) of an epithelial cell monolayer was tested. Loss of resistance, calculated as invasivity index, resembled the degree of cell invasiveness. In addition, secretion of Von Willebrand Factor by endothelial cells incubated with RCC cell supernatant was measured as a surrogate marker for endothelial cell activation. TEER-assay results matched clinical status of disease in 9 out of 12 cases. Metastatic tumors and less differentiated tumors had a significant increase of invasivity index (p = 0.007; p = 0.034). Endothelial cell activation and clinical outcome matched in 5 out of 9 samples. In addition, tumor cell induced endothelial cell activation significantly correlated to the pathologic T classification status of RCC tumors (p = 0.009). Taken together, our study validated endothelial cell activation analysis and cell invasiveness as solitary prognostic markers for tumor dissemination. TEER-analysis has proven to be a useful functional assay giving highly relevant individual information on functional tumor cell characteristics that add to pathologic evaluation.

Does preoperative platelet count and thrombocytosis play a prognostic role in patients undergoing nephrectomy for renal cell carcinoma? Results of a comprehensive retrospective series

PURPOSE

To evaluate the still controversially discussed prognostic role of preoperative platelet level (PPL) and thrombocytosis (TC) in patients who undergo surgery for renal cell carcinoma (RCC) based on the largest patient series reported to date.

METHODS

A total of 3,139 patients, who underwent radical or nephron-sparing nephrectomy at four centres, were subdivided based on a threshold for preoperative platelets of 400 × 10(9) cells/L. Univariate and multivariable Cox regression analyses were applied to determine the prognostic influence of PPL and TC on cancer-specific survival (CSS) for patients with localized and metastatic disease at presentation.

RESULTS

Group 1 (PPL ≤ 400/nl) and Group 2 (PPL > 400/nl) included 2,862 (91 %) and 277 patients (9 %), respectively. With a median follow-up (FU) of 69.5 months (IQR: 35-105), CSS of all patients after 5 years was 84.6 % in Group 1 versus 53.4 % in Group 2 (p < 0.001). At multivariable analysis, TC (HR:1.337; p = 0.007) and continuous PPL (HR:1.001; p = 0.002) independently predicted a decreased survival. However, integration of these parameters into multivariable models for the entire study group and for patients with localized tumours did only result in marginal improvement of the model quality (0.66 and 1.04 %, respectively). Interestingly, neither TC (p = 0.257) nor PPL (p = 0.132) significantly influenced survival in M1 patients.

CONCLUSIONS

Preoperative TC turned out an independent predictor for decreased CSS in patients undergoing surgery for localized RCC. However, significant improvement of multivariable models comprising standard clinical and pathological parameters by the inclusion of TC is not achieved. In metastatic disease, TC did not reveal an independent influence on CSS.

Reduced expression of vasohibin-1 is associated with clinicopathological features in renal cell carcinoma

Vasohibin-1(VASH1) has recently been isolated as a novel negative feedback inhibitor of angiogenesis. Several studies have demonstrated that VASH1 plays important roles in tumor angiogenesis but the role of this angiogenic inhibitor in renal cell carcinoma (RCC) has not been elucidated until now. In this study, we investigated the expression pattern of VASH1 and the association with clinicopathological features in RCC. Expression of VASH1, hypoxia-inducible factor-1α (HIF-1α), and microvessel density (MVD, labeled by CD34) was assessed by immunohistochemistry in 46 RCC specimens and 20 adjacent nontumorous renal tissues (ANRTs). Correlation between vasohibin-1 and HIF-1α, MVD, and clinicopathological features was then investigated. In RCC, VASH1 was expressed mainly in the cytoplasm and membrane of tumor cells and partly in vascular endothelial cells. In ANRT, it was mainly expressed in the cytoplasm and membrane of renal tubular epithelial cells and partly in vascular endothelial cells and glomerular mesangial cells. The expression level of VASH1 in RCC tissue was significantly lower than that in ANRT and was significantly reduced with the increased degree of malignancy in RCC tissues. In addition, a significantly negative correlation was noted between VASH1 expression and HIF-1α expression and a significantly negative correlation was noted between VASH1 expression and MVD in RCC. Therefore, VASH1 expression is reduced and it associates with clinicopathological features in RCC. Based on our findings and the knowledge of other angiogenesis inhibitors, we postulate that VASH1 would potentially be a biomarker and a candidate for molecular targeted therapy for patients with RCC in the future.

Vitamin D3 triggers antitumor activity through targeting hedgehog signaling in human renal cell carcinoma

Human clear cell renal cell carcinoma (CCC) remains resistant to treatments despite the progress in targeted therapies. Several signaling pathways acting during renal development are reactivated during kidney tumorigenesis; this is the case of the sonic hedgehog (SHH)-Gli. Interestingly, the precursor of active vitamin D3 (VD3), cholecalciferol, has been demonstrated to be a strong inhibitor of SHH-Gli signaling. Here, we show the preclinical efficacy of cholecalciferol in CCC both in vitro and in vivo. A panel of CCC cell lines, tumors and normal corresponding tissues from CCC patients were used to evaluate the expression of the VD3 receptor and metabolizing enzymes and the effects of cholecalciferol treatment. Subsequently, xenografted mice were treated with cholecalciferol in a prophylactic or therapeutic manner; their response and the adverse effects were evaluated on the basis of weekly monitoring, followed by blood collection procedures and X-ray micro-computed tomography. VD3 receptor and metabolizing enzymes are dramatically decreased in human cell lines and tumors. Cholecalciferol decreases cell proliferation and increases cell death by inhibition of the SHH-Gli pathway. Xenografted mice treated with cholecalciferol exhibit absence of tumor development or substantial growth inhibition. The treatment was shown to be safe; it did not induce calcification or calcium reabsorption. These findings establish that, although VD3 receptors and metabolizing enzymes are absent in CCC, cholecalciferol supplementation is a strong tool to block the reactivation of SHH-Gli pathway in this pathology, leading ultimately to tumor regression. Cholecalciferol may have highly therapeutic potential in CCC.

De novo renal cell carcinoma of native kidneys in renal transplant recipients: a single-center experience

OBJECTIVES

Our study aimed to determine the incidence of de novo renal cell carcinoma in the native kidneys of patients transplanted at our center and to identify possible risk factors.

MATERIALS AND METHODS

We performed a retrospective, single-center cohort study, which included patients transplanted at the District Hospital in Poznan, Poland, during 1994-2011, among whom 836 were selected. Sixty-three patients with confirmed de novo cancer were found. Of those, 11 had renal cell carcinoma in the native kidney (1.3%) and 2 in the transplanted kidney (0.2%).

RESULTS

Mean follow-up was 10 ± 3.2 years. Mean age at renal cell carcinoma diagnosis was 52 ± 9.4 years, and mean time from transplant was 3 ± 2.6 years. A statistical analysis showed no significant differences in demographic or clinical characteristics between renal cell carcinoma and noncancer group, except for the prevalence of male sex and smoking in the cancer group (P < .05).

CONCLUSIONS

Renal cell carcinoma development in the native kidney seems to be an early event, frequently observed within 4 to 5 years after transplant. We believe that kidneys in renal transplant recipients should be routinely screened by ultrasound for early diagnosis.

Heparanase expression and glycosaminoglycans profile in renal cell carcinoma

A better understanding of the molecular mechanisms of renal cell carcinogenesis could contribute to a decrease in the mortality rate of this disease. The aim of this study was to evaluate the glycosaminoglycans profile and heparanase expression in renal cell carcinoma. The study included 24 patients submitted to nephrectomy with confirmed pathological diagnosis of renal cell carcinoma. The majority of the samples (87.5%) were classified in the initial stage of renal cell carcinoma (clinical stages I and II). Heparanase messenger ribonucleic acid expression was evaluated by quantitative real-time reverse transcription polymerase chain reaction, and sulfated glycosaminoglycans were identified and quantified by agarose gel electrophoresis of renal cell carcinoma samples or non-neoplastic tissues obtained from the same patients (control group). The sulfated glycosaminoglycans and hyaluronic acid were analyzed in urine samples of the patients before and after surgery. The data showed a significant statistical increase in chondroitin sulfate, and a decrease in heparan sulfate and dermatan sulfate present in neoplastic tissues compared with non-neoplastic tissues. Higher heparanase messenger ribonucleic acid expression in the neoplastic tissues was also shown, compared with the non-neoplastic tissues. The urine glycosaminoglycans profile showed no significant difference between renal cell carcinoma and control samples. Extracellular matrix changes observed in the present study clarify that heparanase is possibly involved with heparan sulfate turnover, and that heparanase and the glycosaminoglycans can modulate initial events of renal cell carcinoma development.

Vasoactive intestinal peptide (VIP) inhibits human renal cell carcinoma proliferation

Clear renal cell carcinoma (cRCC) is an aggressive and fatal neoplasm. The present work was undertaken to investigate the antiproliferative potential of vasoactive intestinal peptide (VIP) exposure on non-tumoral (HK2) and tumoral (A498, cRCC) human proximal tubular epithelial cell lines. Reverse transcription and semiquantitative PCR was used at the VIP mRNA level whereas enzyme immunoanalysis was performed at the protein level. Both renal cell lines expressed VIP as well as VIP/pituitary adenylate cyclase-activating peptide (VPAC) receptors whereas only HK2 cells expressed formyl peptide receptor-like 1 (FPRL-1). Receptors were functional, as shown by VIP stimulation of adenylyl cyclase activity. Treatment with 0.1μM VIP (24h) inhibited proliferation of A498 but not HK2 cells as based on a reduction in the incorporation of [(3)H]-thymidine and BrdU (5'-Br-2'-deoxyuridine), PCNA (proliferating-cell nuclear antigen) expression and STAT3 (signal transducer and activator of transcription 3) expression and activation. VPAC(1)-receptor participation was established using JV-1-53 antagonist and siRNA transfection. Growth-inhibitory response to VIP was related to the cyclic adenosine monophosphate (cAMP)/exchange protein directly activated by cAMP (EPAC)/phosphoinositide 3-kinase (PI3-K) signaling systems as shown by studies on adenylate cyclase stimulation, and using the EPAC-specific compound 8CPT-2Me-cAMP and specific kinase inhibitors such as H89, wortmannin and PD98059. The efficacy of VIP on the prevention of tumor progression was confirmed in vivo using xenografted athymic mouse. These actions support a potential role of this peptide and its agonists in new therapies for cRCC.

Quantitative structure-activity relationship studies on indenoisoquinoline topoisomerase I inhibitors as anticancer agents in human renal cell carcinoma cell line SN12C

Topoisomerase I is important for DNA replication and cell division, making it an attractive drug target for anticancer therapy. A series of indenoisoquinolines displaying potent Top1 inhibitory activity in human renal cell carcinoma cell line SN12C were selected to establish 3D-QSAR models using CoMFA and CoMSIA methods. Internal and external cross-validation techniques were investigated, as well as some measures taken, including region focusing, bootstrapping and the “leave-group-out” cross-validation method. The satisfactory CoMFA model predicted a q² value of 0.659 and an r² value of 0.949, indicating that electrostatic and steric properties play a significant role in potency. The best CoMSIA model, based on a combination of steric, electrostatic and H-bond acceptor descriptors, predicted a q² value of 0.523 and an r² value of 0.902. The models were graphically interpreted by contour plots which provided insight into the structural requirements for increasing the activity of a compound, providing a solid basis for future rational design of more active anticancer agents.

Single-CpG-resolution methylome analysis identifies clinicopathologically aggressive CpG island methylator phenotype clear cell renal cell carcinomas

To clarify the significance of DNA methylation alterations during renal carcinogenesis, methylome analysis using single-CpG-resolution Infinium array was performed on 29 normal renal cortex tissue (C) samples, 107 non-cancerous renal cortex tissue (N) samples obtained from patients with clear cell renal cell carcinomas (RCCs) and 109 tumorous tissue (T) samples. DNA methylation levels at 4830 CpG sites were already altered in N samples compared with C samples. Unsupervised hierarchical clustering analysis based on DNA methylation levels at the 801 CpG sites, where DNA methylation alterations had occurred in N samples and were inherited by and strengthened in T samples, clustered clear cell RCCs into Cluster A (n = 90) and Cluster B (n = 14). Clinicopathologically aggressive tumors were accumulated in Cluster B, and the cancer-free and overall survival rates of patients in this cluster were significantly lower than those of patients in Cluster A. Clear cell RCCs in Cluster B were characterized by accumulation of DNA hypermethylation on CpG islands and considered to be CpG island methylator phenotype (CIMP)-positive cancers. DNA hypermethylation of the CpG sites on the FAM150A, GRM6, ZNF540, ZFP42, ZNF154, RIMS4, PCDHAC1, KHDRBS2, ASCL2, KCNQ1, PRAC, WNT3A, TRH, FAM78A, ZNF671, SLC13A5 and NKX6-2 genes became hallmarks of CIMP in RCCs. On the other hand, Cluster A was characterized by genome-wide DNA hypomethylation. These data indicated that DNA methylation alterations at precancerous stages may determine tumor aggressiveness and patient outcome. Accumulation of DNA hypermethylation on CpG islands and genome-wide DNA hypomethylation may each underlie distinct pathways of renal carcinogenesis.

Abbreviations:

BAMCA

bacterial artificial chromosome array-based methylated CpG island amplification

C

normal renal cortex tissue obtained from patients without any primary renal tumor

CIMP

CpG island methylator phenotype

HCC

hepatocellular carcinoma

N

non-cancerous renal cortex tissue obtained from patients with clear cell renal cell carcinomas

NCBI

National Center for Biotechnology Information

RCC

renal cell carcinoma

T

tumorous tissue

TNM

Tumor-Node-Metastasis

MicroRNA target site polymorphisms in the VHL-HIF1α pathway predict renal cell carcinoma risk

Renal cell carcinoma (RCC) accounts for ∼4% of all human malignancies and is the 9th leading cause of male cancer death in the United States. The purpose of this study was to determine the effect of variation within microRNA (miRNA)-binding sites of genes in the VHL-HIF1α pathway on RCC risk. We identified 429 miRNA-binding site single-nucleotide polymorphisms (SNPs) in 102 pathway genes and assessed 53 tagging-SNPs for 31 of these genes for risk in a case-control study consisting of 894 RCC cases and 1,516 controls. Results showed that five SNPs were significantly associated with RCC risk. The most significant finding was rs743409 in MAPK1. Under the additive model, the variant was associated with a 10% risk reduction (OR: 0.90, 95% CI, 0.77-0.98). Other significant findings were for SNPs in CDCP1, TFRC, and DEC1. Cumulative effects analysis showed that subjects carrying four or five unfavorable genotypes had a 2.14-fold increase in risk (95% CI, 1.03-4.43, P = 0.04) than those with no unfavorable genotypes. Potential higher-order gene-gene interactions were identified and categorized subjects into different risk groups. The OR of the high-risk group defined by two SNPs: CDCP1:rs6773576 (GG) and DEC1:rs10982724 (GG) was 4.46 times higher than that of low-risk reference group (95% CI, 1.31-15.08). Overall, our study provides the first evidence supporting a connection between miRNA-binding site SNPs within the VHL-HIF1α pathway and RCC risk. These novel genetic risk factors might help identify individuals at high risk to enable detection of tumors at an early, curable stage.

End stage and chronic kidney disease: associations with renal cancer

There is a well known association between end stage renal disease and the development of kidney cancer in the native kidney of patients requiring renal replacement therapy. There is now emerging evidence that lesser degrees of renal insufficiency (chronic kidney disease, CKD) are also associated with an increased likelihood of cancer in general and kidney cancer in particular. Nephropathological changes are commonly observed in the non-tumor bearing portions of kidney resected at the time of partial and radical nephrectomy (RN). In addition, patients with renal cancer are more likely to have CKD at the time of diagnosis and treatment than the general population. The exact mechanism by which renal insufficiency transforms normal kidney cells into tumor cells is not known. Possible mechanisms include uremic immune inhibition or increased exposure to circulating toxins not adequately cleared by the kidneys. Surgeons managing kidney tumors must have an increased awareness of their patient's renal functional status as they plan their resection. Kidney sparing approaches, including partial nephrectomy (PN) or active surveillance in older and morbidly ill patients, can prevent CKD or delay the further decline in renal function which is well documented with RN. Despite emerging evidence that PN provides equivalent local tumor control to RN while at the same time preventing CKD, this operation remains under utilized in the United States and abroad. Increased awareness of the bi directional relationship between kidney function and kidney cancer is essential in the contemporary management of kidney cancer.

Knockdown of the nucleosome binding protein 1 inhibits the growth and invasion of clear cell renal cell carcinoma cells in vitro and in vivo

BACKGROUND

The nucleosome binding protein 1 (HMGN5/NSBP1) is a member of the HMGN protein family and is highly expressed in several kinds of cancer. Nevertheless, the role of NSBP1 in clear cell renal cell carcinoma (ccRCC) remains unclear. This study aimed to confirm the oncogenic role of NSBP1 in ccRCC using in vitro and in vivo models and explore the mechanism by which NSBP1 contributes to ccRCC tumorigenesis.

METHODS

NSBP1 expression was detected in renal tissues from 152 ccRCC patients by immunohistochemistry, and examined in ccRCC cell lines by RT-PCR and Western blot analysis. ccRCC cells were transfected by NSBP1 RNAi and cell viability, apoptosis and invasion were detected by cell vitality test, flow cytometry and transwell assay in vitro. Xenograft in nude mice was also employed to examine the tumorigenesis of ccRCC cells depleted of NSBP1.

RESULTS

Immunohistostaining showed strong immunoreactivity of NSBP1 in all ccRCC tissues and NSBP1 expression level was associated with tumor grade (p = 0.04). NSBP1 expression at mRNA and protein levels was high in ccRCC cell lines. Knockdown of NSBP1 induced cell cycle arrest and apoptosis, and inhibited invasion in 786-O cells. Western blot analysis demonstrated increased expression of Bax and decreased expression of Bcl-2, CyclinB1, VEGF, VEGFR-2, MMP-2, MMP-9, c-fos and c-jun in 786-O cells depleted of NSBP1. In vivo study further showed that knockdown of NSBP1 affected the tumorigenesis of ccRCC cells in nude mice.

CONCLUSIONS

NSBP1 plays oncogenic role in ccRCCs by promoting cell proliferation and invasion, and could be exploited as a target for ccRCC treatment.

Modest improvement in 20 years of kidney cancer care in the Netherlands

AIM

For an evaluation of the progress achieved in the field of kidney cancer care in the Netherlands in the last decades, we described trends in incidence, treatment, mortality and relative survival.

METHODS

All adult patients newly diagnosed with kidney cancer between 1989 and 2009 (N=32,545) were selected from the Netherlands Cancer Registry. Age-standardised incidence and mortality rates were calculated. Follow-up was completed until January 2010. In order to assess trends estimated annual percentages of change (EAPC) were estimated.

RESULTS

The incidence of kidney cancer has been fairly stable between 1989 and 2001 with a European Standardised Rate of approximately 11 per 100,000 person years (PY). Since 2001 the incidence increased to 13 per 100,000 PY in 2009 (EAPC: 2.4%; 95%confidence interval (CI): 1.5 to 3.4%). The mortality rate decreased slightly over time, from 6.2 per 100,000 PY in 1989 to 5.6 in 2010. No changes in treatment were observed, except for the introduction of targeted therapies for stage IV disease, since 2005. The 5-year relative survival improved from 51% in 1989-1994 to 58% in 2005-2009 (EAPC: 0.9%; 95%CI 0.7 to 1.2%). Improvement in survival was especially seen in males, younger age groups and low stages.

CONCLUSIONS

The incidence of kidney cancer has increased slightly, and survival improved modestly, resulting in a decreasing mortality. A positive effect of the introduction of targeted therapies for metastatic kidney cancer was observed in 1-year relative survival. For progress in kidney cancer care, effective prevention strategies and new therapies remain warranted.

Functional promoter -31G>C variant in survivin gene is associated with risk and progression of renal cell cancer in a Chinese population

Background

Survivin is an inhibitor of apoptosis protein and is involved in the occurrence and progression of human malignancies. Recently, a functional polymorphism (−31G>C, rs9904341) in the promoter of survivin has been shown to influence its expression and confer susceptibility to different types of cancer. The present study was aimed to investigate whether the polymorphism also influences susceptibility and progression of renal cell cancer (RCC) in a Chinese population.

Methods

We genotyped this polymorphism using the TaqMan assay in a case-control study comprised of 710 RCC patients and 760 controls. The logistic regression was used to assess the genetic association with occurrence and progression of RCC.

Results

Compared with the genotypes containing G allele (GG and GC), we found a statistically significant increased occurrence of RCC associated with the CC genotype [P = 0.006, adjusted odds ratio (OR) = 1.38, 95% confidence interval (CI) = 1.08–1.76]. The polymorphism was associated with risk of developing advanced stage (OR = 2.02, 95%CI = 1.34–3.07) and moderately differentiated (OR = 1.75; 95%CI = 1.20–2.54) RCC. Furthermore, the patients carrying the CC genotype had a significantly greater prevalence of high clinical stage disease (P_trend = 0.003). Similar results were also observed when we restricted the analysis to clear cell RCC, a major histological type of RCC.

Conclusions

Our results suggest that the functional −31G>C polymorphism in the promoter of survivin may influence the susceptibility and progression of RCC in the Chinese population. Large population-based prospective studies are required to validate our findings.

Risk of renal cell carcinoma and polymorphism in phase I xenobiotic metabolizing CYP1A1 and CYP2D6 enzymes

The progressive increase in sporadic renal cell carcinoma (RCC) observed in industrialized countries supports the opinion that certain carcinogens present in the environment (tobacco smoke, drugs, pollutants, and dietary constituents) may affect the occurrence and progression of this disease in developing countries like India. The polymorphism of the enzymes involved in metabolism of such environmental factors may, therefore, confer variable propensity to RCC. The possible association between RCC and a polymorphism of the CYP1A1 and CYP2D6 genes specific to the Indian population was examined using peripheral blood DNA from 196 RCC cases and 250 population controls with detailed data of clinicopathologic characteristics for the disease. The CYP1A1 (val) "variant" genotype, which contains at least 1 copy of the CYP1A1 variant alleles, was found to be associated with a 2.03-fold [GG ver. AA/AG, unadjusted OR = 2.03; 95%CI = 1.233-3.342; P = 0.005] increase in the risk of RCC. There was also a significant association (p(trend) = 0.034) between higher frequency of RCC subjects containing at least of copy of the CYP1A1 (val) "variant" genotype with III or IV Fuhrman's grade. Whereas, the CYP2D6 polymorphism did not show any association with RCC risk [TT ver. CT/CC, unadjusted OR = 95%CI = 1.233-3.342; P = 0.005]. There was a significant association (p(trend) = 0.001) between the poor metabolizer CYP2D6 (TT) and progression towards higher pathological stage of RCC. Our data demonstrate for the first time a significant association between pharmacogenetic polymorphisms of CYP1A1 and risk of RCC development in the Indian population. The findings suggest that inter-individual variation in the phase I metabolic enzymes involved in the fictionalization and detoxification of specific xenobiotics is an important susceptibility factor for development and progression of RCC in Indians.

Role of VHL gene mutation in human renal cell carcinoma

The Von Hippel-Lindau (VHL) is an inherited neoplasia syndrome caused by the inactivation of VHL tumor suppressor gene, and somatic mutation of this gene has been related to the development of sporadic clear cell renal carcinoma. The affected individuals are at higher risk for the development of tumor in other organs, which include pheochromocytomas, retinal angioma, pancreatic cysts, and CNS hemangioblastomas. The VHL mRNA encodes a protein (pVHL) that contains 213 amino acid residues which migrate with an apparent molecular weight of 24 to 30 kDa. The VHL gene protein has multiple functions that are linked to tumor suppression, but the best recognized and evidently linked to the development of renal cell carcinoma (RCC) is inhibition of hypoxia-inducible factor (HIF), as well as plays a role in targeting HIF for ubiquitin-mediated degradation. Aberrations in VHL's function, either through mutation or promoter hypermethylation, lead to the accumulation of HIF, which will transcriptionally upregulate a sequence of hypoxia responsive genes, including epidermal growth factor, vascular endothelial growth factor, platelet-derived growth factor, and other proangiogenic factors, resulting in upregulated blood vessel growth, one of the prerequisites of a tumor. HIF plays a critical role in pVHL-defective tumor formation, raising the possibility that drugs directed against HIF or its downstream targets (such as vascular endothelial growth factor) may one day play a role in the treatment of RCC. Moreover, a number of drugs have been developed that target HIF-responsive gene products, many of these targeted therapies have demonstrated significant activity in kidney cancer clinical trials and signify substantive advances in the treatment of this disease.