Kidney cancer: the new landscape

Sensing Dying Cells in Health and Disease: The Importance of Kidney Injury Molecule-1

Kidney injury molecule-1 (KIM-1), also known as T-cell Ig and mucin domain-1 (TIM-1), is a widely recognized biomarker for AKI, but its biological function is less appreciated. KIM-1/TIM-1 belongs to the T-cell Ig and mucin domain family of conserved transmembrane proteins, which bear the characteristic six-cysteine Ig-like variable domain. The latter enables binding of KIM-1/TIM-1 to its natural ligand, phosphatidylserine, expressed on the surface of apoptotic cells and necrotic cells. KIM-1/TIM-1 is expressed in a variety of tissues and plays fundamental roles in regulating sterile inflammation and adaptive immune responses. In the kidney, KIM-1 is upregulated on injured renal proximal tubule cells, which transforms them into phagocytes for clearance of dying cells and helps to dampen sterile inflammation. TIM-1, expressed in T cells, B cells, and natural killer T cells, is essential for cell activation and immune regulatory functions in the host. Functional polymorphisms in the gene for KIM-1/TIM-1, HAVCR1 , have been associated with susceptibility to immunoinflammatory conditions and hepatitis A virus-induced liver failure, which is thought to be due to a differential ability of KIM-1/TIM-1 variants to bind phosphatidylserine. This review will summarize the role of KIM-1/TIM-1 in health and disease and its potential clinical applications as a biomarker and therapeutic target in humans.

Kidney cancer trends and risk factors in Lebanon: a 12-year epidemiological study

PURPOSE

Lebanon has witnessed an increase in the rates of several cancer subtypes over the last years. The aim of this study is to examine the incidence rates of kidney cancer in Lebanon over 12 years and to compare them to other countries.

METHODS

Data were collected from the Lebanese National Cancer Registry (NCR) for the time period 2005-2016 (inclusive). Data from other countries were retrieved from an online database "Cancer Incidence in Five Continents." The age specific and age-standardized rates (ASR) were calculated and analyzed using Joinpoint regression.

RESULTS

Kidney cancer ranked as the 10th commonest cancer among men and the 19th among women. An age-standardized rate of 3.54 (per 100,000) was obtained. The average ASR was 4.80 for men and 2.27 for women. Kidney cancer showed a significantly rising trend for both genders. Lebanon had the highest ASR for kidney cancer in men and the third highest in women among regional countries.

CONCLUSION

Lebanon presented an average-to-high ASR for kidney cancer compared to regional countries. However, compared to countries worldwide, Lebanon had a below-average ASR. Nonetheless, with the rising kidney cancer trends, it is important to study the associated risk factors in order to develop proper preventive and screening measures and therefore decrease the incidence rates.

Iron-Bound Lipocalin-2 Protects Renal Cell Carcinoma from Ferroptosis

While the importance of the iron-load of lipocalin-2 (Lcn-2) in promoting tumor progression is widely appreciated, underlying molecular mechanisms largely remain elusive. Considering its role as an iron-transporter, we aimed at clarifying iron-loaded, holo-Lcn-2 (hLcn-2)-dependent signaling pathways in affecting renal cancer cell viability. Applying RNA sequencing analysis in renal CAKI1 tumor cells to explore highly upregulated molecular signatures in response to hLcn-2, we identified a cluster of genes (SLC7A11, GCLM, GLS), which are implicated in regulating ferroptosis. Indeed, hLcn-2-stimulated cells are protected from erastin-induced ferroptosis. We also noticed a rapid increase in reactive oxygen species (ROS) with subsequent activation of the antioxidant Nrf2 pathway. However, knocking down Nrf2 by siRNA was not sufficient to induce erastin-dependent ferroptotic cell death in hLcn-2-stimulated tumor cells. In contrast, preventing oxidative stress through N-acetyl-l-cysteine (NAC) supplementation was still able to induce erastin-dependent ferroptotic cell death in hLcn-2-stimulated tumor cells. Besides an oxidative stress response, we noticed activation of the integrated stress response (ISR), shown by enhanced phosphorylation of eIF-2α and induction of ATF4 after hLcn-2 addition. ATF4 knockdown as well as inhibition of the ISR sensitized hLcn-2-treated renal tumor cells to ferroptosis, thus linking the ISR to pro-tumor characteristics of hLcn-2. Our study provides mechanistic details to better understand tumor pro-survival pathways initiated by iron-loaded Lcn-2.

Increasing trends in kidney cancer over the last 2 decades in Saudi Arabia

Objectives:

To examine the trends of kidney cancer over the last 2 decades in a subset of a Saudi Arabian population.

Methods:

We conducted a retrospective study in a tertiary care center including all adult patients with primary kidney cancer who presented and were managed between 1990 and 2010. The time period was split into 4 quartiles, and variables tested and compared using chi-square, T-test, and Kaplan-Meier curves for survival.

Results:

The total was 215 patients with a mean age of 57.8 years. There was an increase in the number of kidney cancer cases over the last 2 decades. There was no significant difference in the mode of presentation or stage distribution between quartiles. A significant change was observed in the management towards minimally invasive and nephron-sparing surgeries (p<0.001). There was no change in recurrence-free and disease-specific survival over the last 20 years.

Conclusions:

There have been an increasing number of kidney cancer patients over the last 2 decades with no observed migration towards more incidental and low stage tumors as compared with developed countries.

A nonrandomized prospective comparison of robotic-assisted partial nephrectomy in the elderly to a younger cohort: an analysis of 339 patients with intermediate-term follow-up

OBJECTIVE

To assess the role of robotic-assisted partial nephrectomy (RAPN) in elderly patients focusing on perioperative, functional, and oncologic outcomes in comparison with a younger cohort.

MATERIALS AND METHODS

From a prospectively maintained institutional review board-approved database, 339 patients were divided into 2 groups defined by age ≥ 70 (n = 71) or <70 years (n = 268) at the time of RAPN. They were compared for perioperative outcomes and complications, including risk of chronic kidney disease (CKD) stage progression. The standard t test and chi square test were used for continuous and categorical variables, respectively. Logistic regression identified risk factors for progression of renal dysfunction. Kaplan-Meier estimates modeled tumor recurrence at 368 and 462 days in the elderly and young, respectively.

RESULTS

Elderly patients were more likely to have hypertension (86% vs 60%; P < .001) or coronary artery disease (27% vs 9%; P < .001), and rates of chronic obstructive pulmonary disorder and diabetes were also higher. Preoperative estimated glomerular filtration rate was significantly lower in the elderly (70 vs 82 mL/min/1.73 m2; P < .001). Twenty-four percent of elderly patients progressed in CKD stage as compared to 14% in the younger cohort (P = .08). Elderly age was not a statistically significant risk factor for CKD progression (relative risk, 2.34; 95% confidence interval, 0.81-6.05; P = .11). Surgical and medical complication rates were similar between the cohorts (P = .75 and .80, respectively) as were Kaplan-Meier estimates of risk of tumor recurrence (P = .47). Limitations include nonrandomized, single-center study, and intermediate-term follow-up for oncologic outcomes.

CONCLUSION

Elderly patients undergoing RAPN had no increased risk of perioperative complications. CKD progression and risk of oncologic recurrence were similar to younger patients at intermediate-term follow-up.

Reproductive factors and kidney cancer risk in 2 US cohort studies, 1993-2010

Clinical and experimental findings suggest that female hormonal and reproductive factors could influence kidney cancer development. To evaluate this association, we conducted analyses in 2 large prospective cohorts (the National Institutes of Health-AARP Diet and Health Study (NIH-AARP), 1995-2006, and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO), 1993-2010). Cohort-specific and aggregated hazard ratios and 95% confidence intervals relating reproductive factors and kidney cancer risk were computed by Cox regression. The analysis included 792 incident kidney cancer cases among 283,952 postmenopausal women. Women who had undergone a hysterectomy were at a significantly elevated kidney cancer risk in both NIH-AARP (hazard ratio = 1.28, 95% confidence interval: 1.09, 1.50) and PLCO (hazard ratio = 1.41, 95% confidence interval: 1.06, 1.88). Similar results were observed for both cohorts after analyses were restricted to women who had undergone a hysterectomy with or without an oophorectomy. For the NIH-AARP cohort, an inverse association was observed with increasing age at menarche (P for trend = 0.02) and increasing years of oral contraceptive use (P for trend = 0.02). No clear evidence of an association with parity or other reproductive factors was found. Our results suggest that hysterectomy is associated with increased risk of kidney cancer. The observed associations with age at menarche and oral contraceptive use warrant further investigation.

Sensitivity and specificity of urinary neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 for the diagnosis of renal cell carcinoma

BACKGROUND/AIMS

Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) are urinary biomarkers of diagnostic relevance in a wide variety of acute and chronic kidney diseases. Their diagnostic sensitivity and specificity for kidney cancer are largely unknown and therefore the subject of this investigation.

METHODS

A prospective cohort study was performed to evaluate urine biomarkers for clear-cell and papillary subtypes of renal cancer (67 patients undergoing nephrectomy) and 55 control patients undergoing non-kidney surgery. Urinary KIM-1 and NGAL concentrations were determined by sensitive and specific ELISAs.

RESULTS

In renal cancer patients, median NGAL excretion was 0.52 (1st to 3rd quartiles: 0.28-0.82) ng/mg urinary creatinine (U(Cr)) before nephrectomy compared to 0.15 (0.04-0.31) ng/mg U(Cr) in controls (p < 0.001), and there was a modest decrease of 30% after nephrectomy (p < 0.008). NGAL was not correlated to tumor size (r = 0.19, p = 0.27) or stage. Before nephrectomy, KIM-1 excretion was 0.68 (0.40-1.12) ng/mg U(Cr) compared to 0.03 (0.01-0.06) in controls (p < 0.001). There was a linear correlation between KIM-1 excretion before nephrectomy and tumor size (Spearman's r = 0.66, p < 0.001), tumor stage, and a 50% decrease in median KIM-1 concentration 1 month following tumor excision (p < 0.01). Biomarker concentration ranges for renal cancer patients and controls overlapped substantially for NGAL but not KIM-1.

CONCLUSION

NGAL is not a sensitive or specific urinary biomarker of kidney cancer. Although KIM-1 had diagnostic sensitivity for kidney cancer, it is well known to reflect many types of kidney injuries, thus limiting its specificity as a diagnostic biomarker for renal cancer.

Concurrent robotic renal and prostatic surgery: initial case series and safety data of a new surgical technique

INTRODUCTION

In the era of prostate-specific antigen screening and frequent cross-sectional abdominal imaging, concurrent prostate cancer and renal masses are being identified and treated. Minimizing patient morbidity and cost by avoiding separate surgical procedures is advantageous, provided technical feasibility, and safety data. Our goal was to assess the feasibility and safety of single-setting robotic renal surgery and prostatectomy. We present our initial experience.

PURPOSE

To assess the feasibility and safety of single-setting concurrent robot-assisted renal surgery and radical prostatectomy utilizing the same port access scheme.

PATIENTS AND METHODS

From February 2009 to June 2009, we performed single-setting concurrent robot-assisted radical nephrectomy/partial nephrectomy and radical prostatectomy on two patients with synchronous kidney tumors and prostate cancer. Identical port sites were used during both aspects of the procedure with the exception of one additional port during prostatectomy. Prostate cancer clinical stage and Gleason scores were T1c and 6 and T2a and 7, respectively. Corresponding renal tumors were 5 cm, respectively.

RESULTS

Both operations were performed, with no conversion to open surgery. There were no intraoperative complications and the postoperative course was uneventful in both patients. Discharge was on postoperative day 2 and 3, respectively. Patient 2 had an episode of delayed bleeding on postoperative day 9, treated by selective angio-embolization. Mean operative time for nephrectomy and prostatectomy (135 and 139 minutes, respectively) and estimated blood loss (75 and 100 mL, respectively) were reasonable. We began with the renal portion utilizing a lateral decubitus position before re-positioning into the lithotomy position for the prostatic portion. Clamping time was 34 minutes during partial nephrectomy.

CONCLUSION

Single-setting robotic radical/partial nephrectomy and radical prostatectomy is technically feasible and safe in properly selected patients who present with synchronous primary renal and prostate malignancies.

Urinary biomarkers for the early diagnosis of kidney cancer

OBJECTIVE

To test the hypothesis that increased tumor expression of proteins such as aquaporin-1 (AQP1) and adipophilin (ADFP) in patients with renal cancer would result in increased urine AQP1 and ADFP excretion.

PATIENTS AND METHODS

Prenephrectomy and postnephrectomy (pseudocontrol) urine samples were collected from 42 patients with an incidental radiographically discovered renal mass and presurgical presumptive diagnosis of kidney cancer from July 8, 2008, through March 10, 2009. Also enrolled were 15 control patients who underwent nonrenal surgery and 19 healthy volunteers. Urine AQP1 and ADFP concentrations normalized to urine creatinine were determined by sensitive and specific Western blot assays.

RESULTS

Mean +/- SD preexcision urine AQP1 and ADFP concentrations (76+/-29 and 117+/-74 arbitrary units, respectively) in patients with a pathologic diagnosis of clear cell (n=22) or papillary (n=10) cancer were significantly greater than in patients with renal cancer of nonproximal tubule origin, control surgical patients, and healthy volunteers (combined values of 0.1+/-0.1 and 1.0+/-1.6 arbitrary units, respectively; n=44; P<.001). The AQP1 and ADFP concentrations decreased 88% to 97% in the 25 patients with clear cell or papillary cancer who provided postnephrectomy follow-up urine samples. In patients with clear cell and papillary carcinoma, a linear correlation (Spearman) was found between tumor size and preexcision urine AQP1 or ADFP concentration (r=0.82 and 0.76, respectively; P<.001 for each).

CONCLUSION

Urine AQP1 and ADFP concentrations appear to be sensitive and specific biomarkers of kidney cancers of proximal tubule origin. These biomarkers may be useful to diagnose an imaged renal mass and screen for kidney cancer at an early stage.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00851994.