Acquired Cystic Disease-Associated Renal Cell Carcinoma: A Systematic Review and Meta-analysis

Acquired cystic disease-associated renal cell carcinoma (ACD-RCC) is a common subtype of renal cell carcinoma (RCC) in end-stage renal disease (ESRD) patients. The current systematic review and meta-analysis was performed to evaluate the clinicopathological, and genetic characteristics of patients with ACD-RCC. A systematic search on three electronic databases including the Pubmed, Scopus, and Web of Science databases were performed until December 31, 2022. A meta-analysis was performed following the PRISMA 2020 Guidelines. Of 888 identified articles, full-text screening in 69 articles, there were 26 articles analyzed, with a total of 2314 tumors in 2199 patients, including 418 ACD-RCC tumors in 363 patients, 1340 clear cell RCC (ccRCC) tumors, 308 papillary RCC (pRCC) tumors. Most ACD-RCC patients were male (80.2%). All the ACD-RCC patients underwent prior dialysis with 148.2 months of mean dialysis duration. There were 8.7%, 3.4%, and 5.8% tumors at the T3-4 stage, N1 stage, and M1 stage, respectively. The mean overall survival of ACD-RCC patients was 39.6 months (95% CI, 26.6-52.5). Compared to ccRCC and pRCC, ACD-RCC patients had a longer duration of dialysis (MD: 103.5 and 31.77 months, respectively; 95% CI: [75.48; 131.53] and [0.95; 62.58], respectively), and a higher rate of multifocal tumors (MD: 3.46 and 2.45 tumors, respectively; 95% CI [1.71; 6.98] and [1.26; 4.79], respectively). Regarding genetic characteristics, chromosomes 3 and 16 were the 2 most frequent chromosomal aberrations. The missense mutation in KMT2C (25%) and TSC2 (18.75%) were the 2 most common gene mutations in ACD-RCC. In conclusion, the ACD-RCC subtype exhibited several distinct clinicopathological and genetic characteristics compared to others RCC subtypes. Further researchs are needed to assess the survival outcome and the genetic characteristics of this subtype.

Targeting mTOR and Survivin Concurrently Potentiates Radiation Therapy in Renal Cell Carcinoma by Suppressing DNA Damage Repair and Amplifying Mitotic Catastrophe

Background

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

Experimental Design

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

Results

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

Conclusion

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

Dry and wet experiments reveal the significant role of FUT11 in clear cell renal cell carcinoma

BACKGROUND

Renal cancer is one of the most common urogenital tumors worldwide. Although numerous traditional and relatively new therapeutic strategies have been adopted for clear cell renal cell carcinoma (ccRCC) patients, their effects are not satisfactory enough for the improvement of patients. The pathogenesis and progression of ccRCC requires further investigations.

METHODS

Using a series of bioinformatic analyses, the expression levels, clinical relevance, and prognostic potential of FUT11 as well as its correlations with immune cells in ccRCC were investigated. The mRNA and protein expression levels of FUT11 in renal cancer cell lines and human tissues were determined using quantitative real-time-polymerase chain reaction (RT-PCR) and Western blot analyses. MTT, colony formation, Edu, and wound healing assays were performed to explore the function of FUT11 in renal cancer cell lines. The immunohistochemical staining of human and mouse tissues was performed to reveal the correlations between the expression levels of FUT11 and the infiltration level of immune cell subtypes. Using mouse xenograft models, the role of FUT11 was further investigated in-vivo.

RESULTS

The data mining and corresponding analyses indicated that the expression levels of FUT11 were elevated in renal cancer and independently correlated with the prognosis of ccRCC patients. The cibersort and ssGSEA algorithms revealed differential infiltration levels of immune cells between the patients with distinct expression levels of FUT11; these results were verified by the consequent human renal cancer tissues and animal models. The MTT, colony formation, EdU, and wound healing assays showed that the decreased expression level of FUT11 could promote the proliferation and migration of renal cancer cell lines. The animal models-based analysis showed similar results.

CONCLUSIONS

In conclusion, this study identified a novel important molecule correlated with the prognosis of ccRCC patients and revealed its immune-related role and its function in the proliferation and migration of renal cancer cells. This study might provide a novel basis for the treatment of renal cancer.

Sodium selenite inhibits proliferation and metastasis through ROS-mediated NF-κB signaling in renal cell carcinoma

Background

Sodium selenite (SSE) has been reported to exert anti-tumor effects in several cancer cells. However, the underlying mechanisms in renal cancer are yet to be elucidated. The effects of SSE on the proliferation, metastasis, and apoptosis of renal cancer cells, as well as its mechanism, were investigated in this study.

Methods

ACHN and 786-O renal cancer cells were treated with different concentrations of SSE, MTT, and colony formation assays were used to detect the proliferation ability of cells. The migration of cells was detected using scratch-wound-healing and transwell-migration assays. The effect of SSE on apoptosis was assessed by AnnexinV-FITC/PI double staining. Besides, Western blotting was employed to detect the protein-expression level and elucidate the underlying pathways. We also made subcutaneous xenografts in athymic mice to verify the effect of SSE on tumor growth in vivo.

Results

Our results demonstrated that treatment with SSE resulted in significant inhibition of cell proliferation and migration. Flow cytometry and Western blot confirmed that SSE induced apoptosis via the endogenous apoptotic pathway. We also confirmed that SSE treatment causes an increase in intracellular reactive oxygen species (ROS) levels, resulting in the inhibition of nuclear transcription factor-κB (NF-κB) signaling. Modulation of the ROS level by the chemical inhibitor N-acetyl-cysteine reversed the effect of SSE on cells. Similarly, subcutaneous xenografts in athymic mice models showed that SSE inhibits tumor growth in vivo.

Conclusion

These results indicate that SSE inhibits proliferation and migration and induces apoptosis via ROS mediated inhibition of NF-κB signaling in renal cancer cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09965-8.

The renal cancer risk allele at 14q24.2 activates a novel hypoxia-inducible transcription factor-binding enhancer of DPF3 expression

Evolution of clear cell renal cell carcinoma is guided by dysregulation of hypoxia-inducible transcription factor (HIF) pathways following loss of the von Hippel-Lindau tumor suppressor protein. Renal cell carcinoma (RCC)-associated polymorphisms influence HIF–DNA interactions at enhancers of important oncogenes thereby modulating the risk of developing renal cancer. A strong signal of genome-wide association with RCC was determined for the single nucleotide polymorphism (SNP) rs4903064, located on chr14q.24.2 within an intron of DPF3, encoding for Double PHD Fingers 3, a member of chromatin remodeling complexes; however, it is unclear how the risk allele operates in renal cells. In this study, we used tissue specimens and primary renal cells from a large cohort of RCC patients to examine the function of this polymorphism. In clear cell renal cell carcinoma tissue, isolated tumor cells as well as in primary renal tubular cells, in which HIF was stabilized, we determined genotype-specific increases of DPF3 mRNA levels and identified that the risk SNP resides in an active enhancer region, creating a novel HIF-binding motif. We then confirmed allele-specific HIF binding to this locus using chromatin immunoprecipitation of HIF subunits. Consequentially, HIF-mediated DPF3 regulation was dependent on the presence of the risk allele. Finally, we show that DPF3 deletion in proximal tubular cells retarded cell growth, indicating potential roles for DPF3 in cell proliferation. Our analyses suggest that the HIF pathway differentially operates on a SNP-induced hypoxia-response element at 14q24.2, thereby affecting DPF3 expression, which increases the risk of developing renal cancer.

Rapidly Progressive Paraneoplastic Neuropathy Associated with Renal Cell Carcinoma: A Case Report

Background

Paraneoplastic neurological disorders are rare syndromes that occur with various malignancies including renal cell carcinoma. Symptoms of paraneoplastic neurological disorders are diverse and involve either the central nervous system, peripheral nervous system, or both.

Case Presentation

We present a patient with diffuse limb pain, rapidly progressive asymmetric motor and sensory symptoms and distal upper limb atrophy. Electrodiagnostic testing was suggestive of mononeuritis multiplex. Initial empiric treatment with corticosteroids did not lead to improvement. Further diagnostic studies revealed bilateral clear cell renal carcinoma. Treatment with plasmapheresis led to significant and rapid improvement in pain and limb strength.

Conclusions

This case highlights the rare occurrence of paraneoplastic neuropathy in renal cancer and emphasizes the importance of screening for malignancy in patients presenting with rapidly progressive multifocal neuropathy.

Volume-outcome relationships for kidney cancer may be driven by disparities and patient risk

PURPOSE

Provider and hospital factors influence healthcare quality, but data are lacking to assess their impact on renal cancer surgery. We aimed to assess factors related to surgeon and hospital volume and study their impact on 30-day outcomes after radical nephrectomy.

MATERIALS AND METHODS

Renal surgery data were abstracted from Maryland's Health Service Cost Review Commission from 2000 to 2018. Patients ≤18 years old, without a diagnosis of renal cancer, and concurrently receiving another major surgery were excluded. Volume categories were derived from the mean annual cases distribution. Multivariable logistic and linear regression models assessed the association of volume on length of stay, intensive care days, cost, 30-day mortality, readmission, and complications.

RESULTS

7,950 surgeries, completed by 573 surgeons at 48 hospitals, were included. Demographic, surgical, and admission characteristics differed between groups. Radical nephrectomies performed by low volume surgeons demonstrated increased post-operative complication frequency, mortality frequency, length of stay, and days spent in intensive care relative to other groups. However, after logistic regression adjusting for clinical risk and socioeconomic factors, only increased length of stay and ICU days remained associated with lower surgeon volume. Similarly, after adjusted logistic regression, hospital volume was not associated with the studied outcomes.

CONCLUSIONS

Surgeons and hospitals differ in regards to patient demographic and clinical factors. Barriers exist regarding access to high-volume care, and thus some volume-outcome trends may be driven predominantly by disparities and case mix.

Claudin-2 inhibits renal clear cell carcinoma progression by inhibiting YAP-activation

Background

Claudin-2 expression is upregulated in multiple cancers and promotes cancer malignancy. Remarkably, the regulation of claudin-2 expression in kidney cell lines contrasts its reported regulation in other organs. However, claudin-2 role in renal clear cell carcinoma (RCC) remains unknown despite its predominant expression in the proximal tubular epithelium (PTE), the site of RCC origin.

Methods

Publicly available and independent patient databases were examined for claudin-2 association with RCC. The novel protein function was validated in vitro and in vivo by gain or loss of function assays. Mechanistic results were concluded by Mass spectroscopy, immunoprecipitation and mutational studies, and functional evaluations.

Results

We show that the significant decrease in claudin-2 expression characterized PTE cells and Ex-vivo cultured mouse kidney subjected to dedifferentiation. Inhibition of claudin-2 was enough to induce mesenchymal plasticity and invasive mobility in these models. Further, a progressive loss of claudin-2 expression associated with the RCC progression and poor patient survival. Overexpression of claudin-2 in RCC-derived cancer cells inhibited tumorigenic abilities and xenograft tumor growth. These data supported a novel tumor-suppressive role of claudin-2 in RCC. Mechanistic insights further revealed that claudin-2 associates with YAP-protein and modulates its phosphorylation (S127) and nuclear expression. The tumor suppressive effects of claudin-2 expression were lost upon deletion of its PDZ-binding motif emphasizing the critical role of the PDZ-domain in claudin-2 interaction with YAP in regulating RCC malignancy.

Conclusions

Our results demonstrate a novel kidney specific tumor suppressive role for claudin-2 protein and further demonstrate that claudin-2 co-operates with the YAP signaling in regulating the RCC malignancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01870-5.

Treatment patterns and health outcomes in metastatic renal cell carcinoma patients treated with targeted systemic therapies in the UK

BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) treated with targeted systemic therapies have demonstrated favourable outcomes in randomised controlled trials, however real-world evidence is limited. Thus, this study aimed to determine the effectiveness of targeted systemic therapies for patients with mRCC in routine clinical practice in the UK.

METHODS

A retrospective, observational, longitudinal study based on chart review of newly diagnosed adult mRCC patients treated at two UK hospitals from 2008 to 2015 was conducted. Targeted systemic therapies recommended for use in mRCC patients were evaluated across first to third lines of therapy (1LOT-3LOT). Important exclusions were treatment with cytokine therapy and within non-standard of care clinical trials. Primary outcome measure was overall survival (OS); data were analysed descriptively and using Kaplan-Meyer analysis.

RESULTS

652 patients (65.3% male, 35.0% ≥70 years) were included. In 1LOT, 98.5% of patients received sunitinib or pazopanib. In 2LOT and 3LOT, 99.0 and 94.4% received axitinib or everolimus. Median OS was 12.9, 6.5 and 5.9 months at 1LOT, 2LOT and 3LOT respectively. Estimated OS at 1-year was 52.4% (95% CI: 48.6-56.4%) in 1LOT, 31.5% (25.2-39.5%) in 2LOT and 23.8% (10.1-55.9%) in 3LOT. Median OS from 1LOT in favourable, intermediate and poor MSKCC were 39.7, 15.8 and 6.1 months respectively.

CONCLUSIONS

In this study, treatment was consistent with current National Institute for Health and Care Excellence (NICE) guidelines for mRCC patients. Although the study population favoured poorer prognosis patients, outcomes were more favourable than those for England at the same time. However, overall survival in this 'real-world' population remains poor and indicates significant unmet need for effective and safe treatment options to improve survival among mRCC patients.

[Concordances and predictors of biopsies in renal tumors]

AIM

Evaluate the concordance between the renal lesions biopsy's histology and the final histology of the surgical specimen according to histological subtype, and search for predictive factors of non-concordance.

MATERIAL

We performed a monocentric retrospective study that included 156 patients suffering from a renal tumor that benefited a lesion biopsy before surgical treatment. Sensibility and specificity of the renal lesion's biopsy for histological diagnostic of the different renal tumors where calculated.

RESULTS

One hundred and fifty-eight renal tumor biopsies were realized between 2001 and 2016. One hundred and forty-three renal cell carcinoma were found on the surgical piece, 135 were diagnosed on prior biopsy. Global concordance rate was 88%. For the establishment of the nuclear Fuhrmann grade, the concordance rate (low vs. high grade) was 72.9%. The cohort was divided into 2 groups according to the existence (group 1, n=139) or the absence (group 2, n=19) of concordance. Group 1 and 2 differed by the predominance of men in group 1 (66% vs. 37%, P=0.013), distance between the sinus and the tumor above 4mm (65% vs. 42%, P=0.05).

CONCLUSION

In renal tumor care, renal biopsy is a reliable testing. However, some factors most likely linked to the tumor anatomy (intra-sinusal tumor) and their histological composition were involved in the lack of non-contribution to the diagnosis.

LEVEL OF EVIDENCE

4.

Radiosurgery or hypofractionated stereotactic radiotherapy for brain metastases from radioresistant primaries (melanoma and renal cancer)

Background

Until 50% of patients with renal cancer or melanoma, develop brain metastases during the course of their disease. Stereotactic radiotherapy has become a standard of care for patients with a limited number of brain metastases. Given the radioresistant nature of melanoma and renal cancer, optimization of the fractionation of stereotactic radiotherapy is needed. The purpose of this retrospective study was to elucidate if hypofractionated stereotactic radiotherapy (HFSRT) impacts local control of brain metastases from radioresistant tumors such as melanoma and renal cancer, in comparison with radiosurgery (SRS).

Methods

Between 2012 and 2016, 193 metastases, smaller than 3 cm, from patients suffering from radioresistant primaries (melanoma and renal cancer) were treated with HFSRT or SRS. The primary outcome was local progression free survival (LPFS) at 6, 12 and 18 months. Overall survival (OS) and cerebral progression free survival (CPFS) were secondary outcomes, and were evaluated per patient. Objective response rate and radionecrosis incidence were also reported. The statistical analysis included a supplementary propensity score analysis to deal with bias induced by non-randomized data.

Results

After a median follow-up of 7.4 months, LPFS rates at 6, 12 and 18 months for the whole population were 83, 74 and 70%, respectively. With respect to fractionation, LPFS rates at 6, 12 and 18 months were 89, 79 and 73% for the SRS group and 80, 72 and 68% for the HFSRT group. The fractionation schedule was not statistically associated with LPFS (HR = 1.39, CI95% [0.65–2.96], p = 0.38). Time from planning MRI to first irradiation session longer than 14 days was associated with a poorer local control rate. Over this time, LPFS at 12 months was reduced from 86 to 70% (p = 0.009). Radionecrosis occurred in 7.1% for HFSRT treated metastases to 9.6% to SRS treated metastases, without any difference according to fractionation (p = 0.55). The median OS was 9.6 months. Six, 12 and 18 months CPFS rates were 54, 24 and 17%, respectively.

Conclusion

Fractionation does not decrease LPFS. Even for small radioresistant brain metastases (< 3 cm), HFSRT, with 3 or 6 fractions, leads to an excellent local control rate of 72% at 1 year with a rate of 7.1% of radionecrosis. HFSRT is a safe and efficient alternative treatment to SRS.

Electronic supplementary material

The online version of this article (10.1186/s13014-018-1083-1) contains supplementary material, which is available to authorized users.

Humeral metastasis of renal cancer: Surgical options and review of literature

INTRODUCTION

The humerus is the second most common long bone site of metastatic disease from renal cell carcinomas (RCC) after femur. Surgery has an important role in the treatment of these lesions due to renal cell tumor's resistance to chemotherapy and radiotherapy.

HYPOTHESIS

Prosthetic replacement is an effective and safe solution in treatment of renal humeral metastasis.

MATERIAL AND METHODS

Fifty-six patients affected by RCC bone metastases of the humerus that underwent a surgical reconstruction were rewised. Thirty-five lesions were localized on proximal third, 12 on the shaft, 9 on distal third. Among proximal 29 were treated with resection and endoprosthetic replacement and 6 with plate and cement. Six diaphyseal lesions were stabilized with intramedullary nailing, 5 with plate and cement and 1 with an intercalary prosthesis. Regarding distal lesions, 7 elbow prostheses and 2 plates and cement were used.

RESULTS

The average age was 63years. Metastasis was single in 55% of cases, and in 45% metachronous. A pathologic fracture (PF) occurred in 64% of cases. Only 9% of patients had a mechanical complication, 7% an infection and 5% neurological deficit. A local recurrence occurred in 14% of patients. An implant failure has been observed in 10 patients, 5 for mechanical complications, 2 for infections and 3 for local recurrence; of these 7 were treated with a prosthesis and 3 with plate and cement. The mean value of MSTS score was 64%, 63% and 59% respectively in patients with proximal, diaphyseal and distal humerus metastases.

DISCUSSION

Solitary and metachronous bone metastases have a longer survival. Disease-free interval>2years is another important prognostic factor. Reconstruction with a modular prosthesis is recommended in proximal and distal third. Instead in diaphyseal lesions a closed reduction and fixation with intramedullary locked nailing are preferred. When surgical indications are correctly followed, good oncologic and functional outcomes are obtained, leading to markedly improvement of patients' quality of life.

RETROSPECTIVE STUDY

Level of evidence: IV.

Fuzzy-FishNET: a highly reproducible protein complex-based approach for feature selection in comparative proteomics

Background

The hypergeometric enrichment analysis approach typically fares poorly in feature-selection stability due to its upstream reliance on the t-test to generate differential protein lists before testing for enrichment on a protein complex, subnetwork or gene group.

Methods

Swapping the t-test in favour of a fuzzy rank-based weight system similar to that used in network-based methods like Quantitative Proteomics Signature Profiling (QPSP), Fuzzy SubNets (FSNET) and paired FSNET (PFSNET) produces dramatic improvements.

Results

This approach, Fuzzy-FishNET, exhibits high precision-recall over three sets of simulated data (with simulated protein complexes) while excelling in feature-selection reproducibility on real data (based on evaluation with real protein complexes). Overlap comparisons with PFSNET shows Fuzzy-FishNET selects the most significant complexes, which are also strongly class-discriminative. Cross-validation further demonstrates Fuzzy-FishNET selects class-relevant protein complexes.

Conclusions

Based on evaluation with simulated and real datasets, Fuzzy-FishNET is a significant upgrade of the traditional hypergeometric enrichment approach and a powerful new entrant amongst comparative proteomics analysis methods.

Electronic supplementary material

The online version of this article (doi:10.1186/s12920-016-0228-z) contains supplementary material, which is available to authorized users.

Translational research will fail without surgical leadership: SCOTRRCC a successful surgeon-led Nationwide translational research infrastructure in renal cancer

BACKGROUND

High quality human biosamples with associated high quality clinical data are essential for successful translational research. Despite this, the traditional approach is for the surgeon to act as a technician in the tissue collection act. Biomarker research presents multiple challenges and the field is littered with failures. Tissue quality, poor clinical information, small sample numbers and lack of validation cohorts are just a few reasons for failure. It is clear that the surgeon involved in tissue acquisition must be fully engaged in the process of biosampling for a specific condition, as this will negate many of the issues for translational research failure due to an inadequate bioresource.

APPROACH

In this Matter for Debate paper, the Scottish Collaboration On Translational Research into Renal Cell Cancer (SCOTRRCC) is discussed as an example of a urological surgery lead bioresource which has resulted in a National collection of renal cancer tissue and blood (from over 900 patients to date), negating all of the traditional issues with biobanks because of close enagagement and acknowledgement of urologists and uropathologists from seven centres around Scotland. SCOTRRCC has leveraged renal cancer research in Scotland resulting in several high impact publications and providing a springboard for future research in this disease in Scotland and beyond.

CONCLUSIONS

The SCOTRRCC model presented here can be transferred to other surgical disciplines for success in translational research.

Malignant priapism due to renal cancer: a case report of first manifestation of systemic spread

Introduction:

Malignant priapism due to cancers is a rare condition that only 30 cases of kidney cancers were reported.

Case Presentation:

We report on the first case of simultaneous penile, renal vein, vena cava, liver and ipslateral adrenal gland metastases from primary renal cancer in a 56-year-old man. The only complain of the patient was a history of painful priapism for one month. Corporoglanular shunt surgery was useless. Postoperative imaging showed extensive regional and distal metastases and tumor embolus in vena cava as well as renal and hepatic vein.

Conclusions:

Review of literature showed priapism being the first presentation in 20% to 50% of cases, almost all cases have shown very poor prognosis. This case report underscored the importance of investigation of primary tumors for patients with malignant priapism.

The hypoxia-inducible factor renders cancer cells more sensitive to vitamin C-induced toxicity

Megadose vitamin C (Vc) is one of the most enduring alternative treatments for diverse human diseases and is deeply engrafted in popular culture. Preliminary studies in the 1970s described potent effects of Vc on prolonging the survival of patients with terminal cancer, but these claims were later criticized. An improved knowledge of the pharmacokinetics of Vc and recent reports using cancer cell lines have renewed the interest in this subject. Despite these findings, using Vc as an adjuvant for anticancer therapy remains questionable, among other things because there is no proper mechanistic understanding. Here, we show that a Warburg effect triggered by activation of the hypoxia-inducible factor (HIF) pathway greatly enhances Vc-induced toxicity in multiple cancer cell lines, including von Hippel-Lindau (VHL)-defective renal cancer cells. HIF increases the intracellular uptake of oxidized Vc through its transcriptional target glucose transporter 1 (GLUT1), synergizing with the uptake of its reduced form through sodium-dependent Vc transporters. The resulting high levels of intracellular Vc induce oxidative stress and massive DNA damage, which then causes metabolic exhaustion by depleting cellular ATP reserves. HIF-positive cells are particularly sensitive to Vc-induced ATP reduction because they mostly rely on the rather inefficient glycolytic pathway for energy production. Thus, our experiments link Vc-induced toxicity and cancer metabolism, providing a new explanation for the preferential effect of Vc on cancer cells.

Differentiation of oncocytoma from chromophobe renal cell carcinoma (RCC): can novel molecular biomarkers help solve an old problem?

Standard treatment of renal neoplasms remains surgical resection, and nephrectomy for localised renal cell carcinoma (RCC) still has the best chance of cure with excellent long-term results. For smaller renal masses, especially stage T1a tumours less than 4 cm, nephron-sparing surgery is often employed. However, small incidentally detected renal masses pose an important diagnostic dilemma as a proportion of them may be benign and could be managed conservatively. Renal oncocytoma is one such lesion that may pose little risk to a patient if managed with routine surveillance rather than surgery. Additionally, lower-risk RCC, such as small chromophobe RCC, may be managed in a similar way, although with more caution than the renal oncocytomas (RO). The ability to differentiate ROs from chromophobe RCCs, and from other RCCs with a greater chance of metastasis, would guide the physician and patient towards the most appropriate management, whether nephron-sparing surgical resection or conservative surveillance. Consistent accurate diagnosis of ROs is likely to remain elusive until modern molecular biomarkers are identified and applied routinely. This review focuses on the differentiation of renal oncocytomas and chromophobe RCCs. It summarises the history, epidemiology and clinical presentation of the renal neoplasms, explains the diagnostic dilemma, and describes the value, or not, of current molecular markers that are in development to assist in diagnosis of the renal neoplasms.