Epidemiologic characteristics and risk factors for renal cell cancer

Gut microbiota and immunotherapy of renal cell carcinoma

The gut microbiome has recently been proposed as a key player in cancer development and progression. Several studies have reported that the composition of the gut microbiome plays a role in the response to immune checkpoint inhibitors (ICIs). The gut microbiome modulation has been investigated as a potential therapeutic strategy for cancer, mainly in patients undergoing therapy with ICIs. In particular, modulation through probiotics, FMT or other microbiome-related approaches have proven effective to improve the response to ICIs. In this review, we examine the role of the gut microbiome in enhancing clinical responses to ICIs in the treatment of renal cancer.

Kidney Tumor Semantic Segmentation Using Deep Learning: A Survey of State-of-the-Art

Cure rates for kidney cancer vary according to stage and grade; hence, accurate diagnostic procedures for early detection and diagnosis are crucial. Some difficulties with manual segmentation have necessitated the use of deep learning models to assist clinicians in effectively recognizing and segmenting tumors. Deep learning (DL), particularly convolutional neural networks, has produced outstanding success in classifying and segmenting images. Simultaneously, researchers in the field of medical image segmentation employ DL approaches to solve problems such as tumor segmentation, cell segmentation, and organ segmentation. Segmentation of tumors semantically is critical in radiation and therapeutic practice. This article discusses current advances in kidney tumor segmentation systems based on DL. We discuss the various types of medical images and segmentation techniques and the assessment criteria for segmentation outcomes in kidney tumor segmentation, highlighting their building blocks and various strategies.

Occupational Asbestos Exposure and Kidney Cancer: Systematic Review and Meta-analysis of Cohort Studies

OBJECTIVES

An estimated 125 million workers are exposed to asbestos worldwide. Asbestos is classified by the International Agency for Research on Cancer as a Group 1 carcinogen. The association between occupational asbestos exposure and kidney cancer is not well established however. This study aimed to determine the mortality and incidence of kidney cancer in workers who have been exposed to asbestos. We performed a systematic review and meta-analysis to evaluate the association between occupational asbestos exposure and kidney cancer.

METHODS

Medline, EMBASE, and Web of Science were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for articles on occupational asbestos exposure and kidney cancer. The studies reported the standardized mortality ratio (SMR) or standardized incidence ratio (SIR) of kidney cancer in workers exposed to asbestos. SMRs or SIRs with its 95% confidence interval (CI) were pooled using a fixed-effect model.

RESULTS

Forty-nine cohort studies involving 335 492 workers were selected for analysis. These studies included 468 kidney cancer deaths and 160 incident cases. The overall pooled-SMR of kidney cancer was 0.95 (95% CI: 0.86-1.05), with no significant heterogeneity (PQ = 0.09, I2 = 24.87%). The overall pooled-SIR of kidney cancer was 0.95 (95% CI: 0.79-1.11), with no significant heterogeneity (PQ = 0.68, I2 = 0.00%). Subgroup analysis did not find any increased association with occupational asbestos exposure. There was no evidence of publication bias with Egger's test P values of 0.08 for mortality studies and 0.99 for incidence studies.

CONCLUSIONS

This systematic review and meta-analysis did not show evidence of association between occupational asbestos exposure and kidney cancer mortality or incidence.

Cellular and physical microenvironments regulate the aggressiveness and sunitinib chemosensitivity of clear cell renal cell carcinoma

Renal cell carcinoma (RCC) is the most predominant type of kidney cancer in adults and is responsible for approximately 85% of clinical cases. The tumor‐specific microenvironment includes both cellular and physical factors, and it regulates the homeostasis and function of cancer cells. Perirenal adipose tissue and tumor‐associated macrophages are the major cellular components of the RCC microenvironment. The RCC microvasculature network generates interstitial fluid flow, which is the movement of fluid through the extracellular compartments of tissues. This fluid flow is a specific physical characteristic of the microenvironment of RCC. We hypothesized that there may be an interaction between the cellular and physical microenvironments and that these two factors may play an important role in regulating the behavior of RCC. To elucidate the effects of adipose tissue, macrophages, and fluid flow stimulation on RCC and to investigate the relationships between these factors, we used a collagen gel culture method to generate cancer–stroma interactions and a gyratory shaker to create fluid flow stimulation. Adipose‐related cells, monocytes, and fluid flow influenced the proliferative potential and invasive capacity of RCC cells. Extracellular signal‐regulated kinase and p38 signaling were regulated either synergistically or independently by both fluid flow and cellular interactions between RCC and adipose tissue fragments or macrophages. Fluid flow stimulation synergistically enhanced the anti‐proliferative effect of sunitinib on RCC cells, but macrophages abolished the synergistic anti‐proliferative effect related to fluid flow stimulation. In conclusion, we established a reconstructed model to investigate the cellular and physical microenvironments of RCC in vitro. Our alternative culture model may provide a promising tool for further therapeutic investigations into many types of cancer. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Ursolic acid inhibits the invasiveness of A498 cells via NLRP3 inflammasome activation

Renal cell cancer is a common malignant tumor of the urinary system. Ursolic acid (UA) serves an important antitumor role in certain types of cancer, such as lung cancer, breast cancer and hepatocellular carcinoma; however, to the best of our knowledge, the effect of UA on renal cancer has not yet been investigated. In the present study, A498 cells were treated with different concentrations of UA for 12, 24 and 48 h, and then MCC950, an inhibitor of the NLR family pyrin domain-containing 3 (NLRP3) receptor, was added to block NLRP3 signaling. The proliferation of A498 cells was analyzed using an MTS assay and invasiveness was analyzed using a Transwell assay. The expression levels of NLRP3, cleaved caspase-1, IL-1β and MMP-2 were detected using western blotting. The present results demonstrated that the invasiveness of A498 cells was significantly decreased following UA treatment (P<0.05), while expression levels of NLRP3, cleaved caspase-1 and IL-1β were significantly increased, and MMP-2 expression was decreased following UA stimulation (P<0.05). This was reversed by MCC950 treatment (P<0.05), with the exception of NLRP3. In conclusion, the present results indicated that UA exposure decreased the proliferation and invasiveness of A498 cells. Additionally, UA exposure significantly decreased MMP-2 production and induced the activation of NLRP3 inflammasome, which was reversed by MCC950 treatment, indicating that NLRP3 activation may be involved in UA inhibition of A498 cell invasiveness.

The Relationship Between Hormone Replacement Therapy and Risk of Kidney Cancer in Women: A Meta-Analysis

Results from the epidemiologic studies on the relationship between hormone replacement therapy (HRT) and the risk of kidney cancer in women were not completely consistent. This meta-analysis aimed to evaluate the relationship between HRT and risk of kidney cancer in women. We performed a meta-analysis of observational studies to assess this association. The PubMed and Embase databases were searched from their inception to January 29, 2020, to identify relevant studies that fit the pre-stated inclusion criteria; reference lists from the retrieved articles were also been reviewed. Relative risks (RRs) with corresponding 95% CIs were extracted and combined using random effects models. Furthermore, dose-response, sensitivity analyses, publication bias, and subgroup analysis by study design, regional location, and exposure assessment method were conducted. Thirteen articles involving 6 cohort studies and 8 case-control studies were included in our meta-analysis. Overall, 4194 women were diagnosed with kidney cancer among 648 107 participants. The pooled RR for kidney cancer was 1.08 (95% CI: 0.96-1.22) in those who were administered HRT compared to those who had not. Subgroup analysis indicated the overall result was not influenced by study type, regional location, or adjusted variables. Dose-response analysis showed a nonlinear relationship between HRT and kidney cancer (P = .0021) and the risk of kidney cancer decreased by 15% to 28% with 12 to 18 years of HRT use. No evidence of publication bias was found (P for Egger =.111). Our meta-analysis showed that HRT use is inversely associated with kidney cancer risk in a dose-dependent fashion.

Expression of PD-1 and CTLA-4 Are Negative Prognostic Markers in Renal Cell Carcinoma

Immuno-oncological therapy with checkpoint inhibition (CI) has become a new standard treatment in metastatic renal cell carcinoma (RCC), but the prognostic value of the expression of CI therapy target molecules is still controversial. 342 unselected consecutive RCC tumor samples were analyzed regarding their PD-1, PD-L1, and CTLA-4 expression by immunohistochemistry (IHC). The prognostic values for cancer-specific survival (CSS) and overall survival (OS) were analyzed for those not exposed to CI therapy. The expression of PD-1 in tumor-infiltrating mononuclear cells (TIMC) and PD-L1 in tumor cells was detected in 9.4% and 12.3%, respectively (Immune reactive score (IRS) > 0). Furthermore, PD-L1 expression in TIMC (IRS > 0) and CTLA-4 expression in TIMC (>1% positive cells) was detected in 4.8% and 6.3%. PD-1 expression and CTLA-4 expression were significantly associated with a worse OS and CSS in log rank survival analysis and univariate Cox regression analysis. CTLA-4 expression is a prognostic marker that is independently associated with a worse outcome in multivariate Cox regression analysis in the whole cohort (OS: p = 0.013; CSS: p = 0.048) as well as in a non-metastatic subgroup analysis (OS: p = 0.028; CSS: p = 0.022). Patients with combined CTLA-4 expression and PD-1-expression are at highest risk in OS and CSS. In RCC patients, PD-1 expression in TIMC and CTLA-4 expression in TIMC are associated with a worse OS and CSS. The combination of PD-1 expression in TIMC and CTLA-4 expression in TIMC might identify high risk patients. This is, to our knowledge, the first description of CTLA-4 expression to be a prognostic marker in RCC.

Renal Cell Carcinoma Presenting as an Ampullary Mass: A Case Report and Review of Literature

We present a case of a 60-year-old female patient who has significant medical history of renal cell carcinoma diagnosed 2 years back and had undergone right nephrectomy and chemotherapy. She presented to the hospital with complaints of abdominal pain and jaundice of 2 weeks duration and was found to have periampullary mass lesion causing compression of distal common bile duct on imaging with computed tomography of abdomen. Endoscopic retrograde cholangiography and endoscopic ultrasound showed ampullary mass lesion causing biliary obstruction along with abdominal lymphadenopathy. A temporary plastic stent was placed to relieve obstruction. Fine needle aspiration cytology of the periampullary mass along with immunohistochemical staining confirmed the diagnosis of metastatic renal cell carcinoma.

Transferrin receptor 1 upregulation in primary tumor and downregulation in benign kidney is associated with progression and mortality in renal cell carcinoma patients

The central dysregulated pathway of clear cell (cc) renal cell carcinoma (RCC), the von Hippel Lindau/hypoxia inducible factor-α axis, is a key regulator of intracellular iron levels, however the role of iron uptake in human RCC tumorigenesis and progression remains unknown. We conducted a thorough, large-scale investigation of the expression and prognostic significance of the primary iron uptake protein, transferrin receptor 1 (TfR1/CD71/TFRC), in RCC patients. TfR1 immunohistochemistry was performed in over 1500 cores from 574 renal cell tumor patient tissues (primary tumors, matched benign kidneys, metastases) and non-neoplastic tissues from 36 different body sites. TfR1 levels in RCC tumors, particularly ccRCC, were significantly associated with adverse clinical prognostic features (anemia, lower body mass index, smoking), worse tumor pathology (size, stage, grade, multifocality, sarcomatoid dedifferentiation) and worse survival outcomes, including after adjustments for tumor pathology. Highest TfR1 tissue levels in the non-gravid body were detected in benign renal tubule epithelium. Opposite to TfR1 changes in the primary tumor, TfR1 levels in benign kidney dropped during tumor progression and were inversely associated with worse survival outcomes, independent of tumor pathology. Quantitative measurement of TfR1 subcellular localization in cell lines demonstrated mixed cytoplasmic and membranous expression with increased TfR1 in clusters in ccRCC versus benign renal cell lines. Results of this study support an important role for TfR1 in RCC progression and identify TfR1 as a novel RCC biomarker and therapeutic target.

Metabesity and urological cancers

Metabolic syndrome is one of today's most important health problems. Due to increased prevalence of metabolic syndrome in society, studies done on this topic have increased in number. Although metabolic syndrome was previously considered to be important only for cardiovascular health, it has been learned that with new data, human health is compromised more thoroughly by metabolic syndrome and is also a danger to malignancy. As a result, a new definition in the form of metabesity has been introduced. In this review, available information on metabesity and urological cancers is presented.

Renal cell carcinoma histological subtype distribution differs by age, gender, and tumor size in coastal Chinese patients

The distribution pattern of renal cell carcinoma (RCC) histological subtypes according to age, gender and tumor size has not been well illustrated in RCC patients living in fast-developing regions of China. We recruited 2941 patients with clear cell renal cell carcinoma (ccRCC), papillary renal cell carcinoma (PCC) or chromophobe from two hospitals in coastal China (2004−2012) consecutively and draw 538 American Chinese RCC patients’ data with time matched from the Surveillance, Epidemiology, and End Results database. We found that compared with ccRCC patients, chromophobe patients were more likely to be female (OR: 2.538, 95% CI: 1.923−3.350), younger (OR for 51−60 years old: 0.686; OR for over 60 years old: 0.478; reference: age < 50) and to have a larger maximal diameter (Dmax) (OR for Dmax > 7 cm: 1.883; reference: Dmax ≤ 4 cm). Besides, in comparison with coastal Chinese patients, American Chinese individuals had lower Fuhrman grades (P < 0.001) and had an onset age 10 years delay. In conclusion, we were the first to observe marked gender, age and tumor size differences in the proportional subtype distribution of RCCs in coastal Chinese patients, and also the first to compare coastal Chinese with American Chinese data.

Systemic therapy in metastatic renal cell carcinoma

PURPOSE

Current systemic treatment of targeted therapies, namely the vascular endothelial growth factor-antibody (VEGF-AB), VEGF receptor tyrosine kinase inhibitor (TKI) and mammalian target of rapamycin (mTOR) inhibitors, have improved progression-free survival and replaced non-specific immunotherapy with cytokines in metastatic renal cell carcinoma (mRCC).

METHODS

A panel of experts convened to review currently available phase 3 data for mRCC treatment of approved agents, in addition to available EAU guideline data for a collaborative review as the plurality of substances offers different options of first-, second- and third-line treatment with potential sequencing.

RESULTS

Sunitinib and pazopanib are approved treatments in first-line therapy for patients with favorable- or intermediate-risk clear cell RCC (ccRCC). Temsirolimus has proven benefit over interferon-alfa (IFN-α) in patients with non-clear cell RCC (non-ccRCC). In the second-line treatment TKIs or mTOR inhibitors are treatment choices. Therapy options after TKI failure consist of everolimus and axitinib. Available third-line options consist of everolimus and sorafenib. Recently, nivolumab, a programmed death-1 (PD1) checkpoint inhibitor, improved overall survival benefit compared to everolimus after failure of one or two VEGFR-targeted therapies, which is likely to become the first established checkpoint inhibitor in mRCC. Data for the sequencing of agents remain limited.

CONCLUSIONS

Despite the high level of evidence for first and second-line treatment in mRCC, data for third-line therapy are limited. Possible sequences include TKI-mTOR-TKI or TKI-TKI-mTOR with the upcoming checkpoint inhibitors in perspective, which might settle a new standard of care after previous TKI therapy.

Anti-PD-L1 treatment enhances antitumor effect of everolimus in a mouse model of renal cell carcinoma

Immunotherapy based on blockade of the programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis has shown promising clinical activity for renal cell carcinoma (RCC) patients; however, the most effective use of these agents in combination with conventional targeted therapy remains to be resolved. Here we evaluated the therapeutic efficacy of the combination of the mTOR inhibitor everolimus (EVE) and anti-PD-L1 using an immunocompetent mouse model of RCC. We first assessed the in vitro effect of EVE on PD-L1 expression in the human 786-O and mouse RENCA RCC cell lines and found that EVE upregulated PD-L1 expression in these RCC cell lines. We then treated RENCA tumor-bearing mice with EVE and found that PD-L1 expression was also increased in tumor cells after EVE treatment. To determine the antitumor effects of EVE alone, anti-PD-L1 alone, and EVE in combination with anti-PD-L1, we evaluated their antitumor effects on RENCA tumor-bearing mice. A significant decrease in the tumor burden was observed in the EVE alone but not in the anti-PD-L1 alone treatment group compared with the control group. Importantly, the combination of EVE with anti-PD-L1 significantly reduced tumor burden compared with the EVE alone treatment, increasing tumor infiltrating lymphocytes (TILs) and the ratio of cytotoxic CD8⁺ T cells to TILs. The results of the present study demonstrated that anti-PD-L1 treatment enhanced the antitumor effect of EVE in a mouse model, supporting a direct translation of this combination strategy to the clinic for the treatment of RCC.

Current status of robotic partial nephrectomy in Japan

The safety and efficacy of robot-assisted partial nephrectomy (RAPN) has been reported in Western countries. However, there are no similar reported studies of RAPN in Japan. Although common medical services are covered by public health insurance in Japan, RAPN had not been approved as a listed treatment for public insurance. We conducted a prospective clinical trial to confirm the efficacy and safety of RAPN in Japan. The aim of the present review article is to describe current status of RAPN in Japan and to introduce a part of clinical results obtained from the clinical trial. Based on the favorable results obtained in this clinical trial, RAPN was approved in April 2016 by the Japanese Ministry of Health, Labour and Welfare to be covered by public health insurance. This change allows access to RAPN to everyone in Japan, regardless of wealth. The RAPN techniques used in Japan are also reviewed.

Association of leptin, visfatin, apelin, resistin and adiponectin with clear cell renal cell carcinoma

Although an association between obesity and the occurrence of renal cell carcinoma (RCC) has been identified, the mechanism by which obesity functions to increase this risk of cancer remains unclear. Leptin, visfatin, apelin, resistin and adiponectin are peptide hormones secreted by adipocytes; it is considered that these may affect RCC development by exerting effects on proliferation, cell growth and inflammation. The aim of the present study was to investigate the association between the aforementioned adipokine genes and clear cell RCC (CC-RCC). The GSE6344 dataset was downloaded from the Gene Expression Omnibus database, and the relative expression levels of the adipokine genes were analyzed. To verify the results of the mRNA microarray, 77 paired samples of CC-RCC and corresponding adjacent normal tissue were allocated into two groups. The extraction of total RNA was conducted, and the mRNA expression of adipokine genes was analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The data from the GSE6344 dataset indicated that the expression of visfatin and apelin was upregulated (P<0.0001 and P<0.01, respectively), and adiponectin was downregulated (P<0.001) in the CC-RCC tissues compared with the adjacent normal tissues. The data from RT-qPCR demonstrated that visfatin and resistin gene expression was increased (P<0.01 and P<0.05, respectively) in the CC-RCC tissues. Furthermore, the mRNA expression level of leptin and adiponectin in the adjacent normal tissue was higher than those in the cancer tissue (P<0.01). The current study verifies that visfatin and adiponectin are associated with an increased risk of CC-RCC, which presents further insights into the molecular mechanisms of CC-RCC tumorigenesis.

Incidence and mortality of kidney cancers, and human development index in Asia; a matter of concern

Background

The incidence and mortality of kidney cancer have steadily increased by 2%- 3% per decade worldwide, and an increased risk of kidney cancer has been observed in many Asian countries. The information on the incidence and mortality of a disease and its distribution is essential for better planning for prevention and further studies.

Objectives

This study aimed to assess the incidence and mortality of kidney cancer and their correlation with the human development index (HDI) in Asia.

Materials and Methods

This ecological study was based on GLOBOCAN data Asia for assessment the correlation between age-specific incidence rate (ASIR) and age-specific mortality rate (ASMR) with HDI and its details that include life expectancy at birth, mean years of schooling and gross national income (GNI) per capita. We use of correlation bivariate method for assessment the correlation between ASIR and ASMR with HDI and its components.

Results

A total of 121 099 kidney cancer cases were recorded in Asian countries in 2012.Overall, 80 080 cases (66.12%) were males. Sex ratio was 1.95. The three countries with the highest number of new patients were china (66 466 cases), Japan (16 830 cases), India(9658 cases), respectively. Positive correlation were seen between HDI and ASIR of kidney cancer 0.655 (P = 0.001), and HDI and ASMR of kidney cancer 0.285 (P = 0.055).

Conclusions

A positive relationship between ASIR and the HDI was seen. The relationship is due to risk factors in countries with high development such as older age, smoking, hypertension, obesity, and diet. However, ASMR showed no significant relationship with HDI.

Recurrence of renal cell carcinoma diagnosed using contralateral adrenal biopsy with endoscopic ultrasound-guided fine-needle aspiration

A 76-year-old female in whom a renal cell carcinoma (RCC) lesion was resected 19 years previously presented to our hospital with cognitive dysfunction. Magnetic resonance imaging and computed tomography revealed nodules in the brain, lung, adrenal gland and a pelvic osteolytic lesion. To identify the primary cancer site, the present study performed endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of the left adrenal lesion. Consequently, the pathological findings of the tissue obtained by EUS-FNA were similar to those of the previous nephrectomy specimen, revealing that the adrenal lesion was the recurrence of RCC. The majority of the metastatic lesions in the patient were reduced in size by the multiple kinase inhibitor, pazopanib. Contralateral adrenal metastasis of RCC is rare and the use of EUS-FNA in the diagnosis of adrenal lesions remains to be elucidated. This is a rare case of adrenal lesion, diagnosed by EUS-FNA. Therefore, EUS-FNA is considered to be a useful diagnostic modality of adrenal metastases from unidentified primary tumor types.

Analgesic use and risk of renal cell carcinoma: A case-control, cohort and meta-analytic assessment

Analgesics are the most commonly consumed drugs worldwide. Evidence that analgesics increase kidney cancer risk has been mixed. We investigated the association between renal cell carcinoma (RCC) and analgesic use in a large population-based case-control study and a post-trial observational cohort study. Findings were used to update a recent meta-analytic review. We analyzed data from 1,217 RCC cases and 1,235 controls in the US Kidney Cancer Study and 98,807 participants in the US Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO: n = 137 RCCs). Self-reported acetaminophen, aspirin and nonsteroid anti-inflammatory drug (NSAID) use and duration information was assessed in relation to RCC. For the US Kidney Cancer Study, we calculated odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression. For PLCO, we computed hazard ratios (HRs) and 95%CIs using Cox regression. Among case-control participants, RCC risk was associated with over-the-counter acetaminophen use (OR = 1.35, 95%CI = 1.01-1.83). There was a positive trend with increasing duration (p-trend = 0.01), with a two-fold risk for use ≥10 years (OR = 2.01, 95%CI = 1.30-3.12). No association with prescription acetaminophen use was detected. In PLCO, acetaminophen use was also associated with increased RCC risk (HR = 1.68, 95%CI = 1.19-2.39), although elevated risk was absent among the few long-term users. No association with RCC risk was detected for aspirin or NSAIDs use in either study. An association between acetaminophen use and kidney cancer was supported by meta-analytic cohort (n = 4; summary relative risk = 1.34; 95%CI = 1.13-1.59; p-heterogeneity  = 0.40) and case-control (n = 9, summary OR = 1.20; 95%CI = 1.01-1.42; p-heterogeneity  = 0.05) findings. In brief, acetaminophen use may increase the risk of developing RCC.

Oral contraceptive use and kidney cancer risk among women: evidence from a meta-analysis

Previous studies have investigated the relationship between oral contraceptives (OCs) use and kidney cancer risk. However, they yielded inconsistent results. To our knowledge, a comprehensive assessment of the association between OC and kidney cancer risk has not been reported. Hence, we conducted a meta-analysis to quantify the association. We identified all relevant studies up to July 2014 through a literature search of using PubMed and EMBASE, and by reviewing the references from the retrieved articles. Fixed-effect and random-effect models were used to estimate summary relative risks (SRRs) and the corresponding 95% confidence intervals (CIs). A total of 12 studies were eligible and included in this meta-analysis, involving 4,206 kidney cancer cases and 638,677 participants. The SRR of kidney cancer for ever versus never OC use was 0.89 (95% CI: 0.82-0.98). The protection became stronger when compared the longest duration of OC use with never use (RR = 0.80; 95% CI: 0.68-0.94). In dose-response analysis, we found that the kidney cancer risk decreased by 2% for per 1 year increment in OC use (RR = 0.98; 95% CI: 0.96-0.99). No apparent heterogeneity was observed across studies included in this analysis. Egger's and Begg's test also indicated no publication bias. The present study suggested that OC may reduce the risk of kidney cancer, especially for long-term users. More well-conducted and large-scale prospective studies are warranted to confirm the effects of OC use on kidney cancer.

Angiogenic and signalling proteins correlate with sensitivity to sequential treatment in renal cell cancer

BACKGROUND

We aimed to study key signalling proteins involved in angiogenesis and proliferation on the response to inhibitors of tyrosine kinases and mammalian target of rapamycin in first- and in second-line treatment of renal cell carcinoma (RCC).

METHODS

In a panel of human RCC tumours, in vitro and in nude mice, we evaluated the effect of sunitinib, sorafenib and everolimus, alone and in sequence, on tumour growth and expression of signalling proteins involved in proliferation and resistance to treatment.

RESULTS

We demonstrated that, as single agents, sunitinib, sorafenib and everolimus share similar activity in inhibiting cell proliferation, signal transduction and vascular endothelial growth factor (VEGF) secretion in different RCC models, both in vitro and in tumour xenografts. Pre-treatment with sunitinib reduced the response to subsequent sunitinib and sorafenib but not to everolimus. Inability by sunitinib to persistently inhibit HIF-1, VEGF and pMAPK anticipated treatment resistance in xenografted tumours. After first-line sunitinib, second-line treatment with everolimus was more effective than either sorafenib or rechallenge with sunitinib in interfering with signalling proteins, VEGF and interleukin-8, translating into a significant advantage in tumour growth inhibition and mice survival.

CONCLUSION

We demonstrated that a panel of angiogenic and signalling proteins can correlate with the onset of resistance to sunitinib and the activity of everolimus in second line.

Risk of cancer in patients exposed to gabapentin in two electronic medical record systems

PURPOSE

High doses of gabapentin were associated with pancreatic acinar cell tumors in male Wistar rats, but there is little published epidemiological data regarding gabapentin and carcinogenicity. We explored the association between gabapentin and cancer in a US medical care program and followed up nominally significant associations in a UK primary care database.

METHODS

In the US Kaiser Permanente Northern California (KPNC) health system, we performed nested case-control analyses of gabapentin and 55 cancer sites and all cancers combined using conditional logistic regression. Up to 10 controls were matched to each case on year of birth, sex, and year of cohort entry. No other covariates were included in models. Only dispensings for gabapentin 2 years or more before index date were considered. Nominally significant associations with an OR > 1.00 and p < 0.05 for three or more dispensings versus no dispensings were followed up by similar nested case-control analyses in the UK General Practice Research Database (GPRD), adjusting for potential indications for gabapentin and risk factors for the specific cancers.

RESULTS

The following analyses had OR > 1.00 and p < 0.05 for three or more dispensings of gabapentin versus no dispensing (2-year lag) in KPNC and were also examined in the GPRD: all cancers, breast, lung and bronchus, urinary bladder, kidney/renal pelvis, stomach, anus/anal canal/anorectum, penis, and other nervous system. These cancers were not statistically significantly associated with gabapentin in the GPRD case-control studies (2-year lag). The GPRD and KPNC studies did not identify a statistically significant increased risk of pancreatic cancer with more than two prescriptions of gabapentin in the 2-year lagged analyses.

CONCLUSIONS

The epidemiological data in a US cohort with up to 12 years of follow-up and a UK cohort with up to 15 years of follow-up do not support a carcinogenic effect of gabapentin use. However, the confidence intervals for some analyses were wide, and an important effect cannot be confidently excluded.

Renal cell cancer among African Americans: an epidemiologic review

Incidence rates for renal cell cancer, which accounts for 85% of kidney cancers, have been rising more rapidly among blacks than whites, almost entirely accounted for by an excess of localized disease. This excess dates back to the 1970s, despite less access among blacks to imaging procedures in the past. In contrast, mortality rates for this cancer have been virtually identical among blacks and whites since the early 1990s, despite the fact that nephrectomy rates, regardless of stage, are lower among blacks than among whites. These observations suggest that renal cell cancer may be a less aggressive tumor in blacks. We have reviewed the epidemiology of renal cell cancer, with emphasis on factors which may potentially play a role in the observed differences in incidence and mortality patterns of renal cell cancer among blacks and whites. To date, the factors most consistently, albeit modestly, associated with increased renal cell cancer risk in epidemiologic studies among whites--obesity, hypertension, cigarette smoking--likely account for less than half of these cancers, and there is virtually no epidemiologic evidence in the literature pertaining to their association with renal cell cancer among blacks. There is a long overdue need for detailed etiologic cohort and case-control studies of renal cell cancer among blacks, as they now represent the population at highest risk in the United States. In particular, investigation of the influence on renal cell cancer development of hypertension and chronic kidney disease, both of which occur substantially more frequently among blacks, is warranted, as well as investigations into the biology and natural history of this cancer among blacks.