Non-invasive urine markers for the differentiation between RCCs and oncocytoma.

BACKGROUND: Recently, our group showed that Vim3 is overexpressed in tissue samples of renal oncocytomas and Mxi-2 in clear cell renal carcinoma (ccRCC). The mechanism leading to the truncation of both proteins is known and involves with two miRs, both detectable in urine. Since the analysis of miRs is time-consuming, our aim was to identify the truncated proteins in urine instead. Furthermore, urine samples from small renal masses (SRMs) (n = 45, <4 cm) were analyzed to get a pre-surgical differentiation of the cancer subtypes. METHODS: Urines were accessed from the urological biobank (n = 350). Proteins were isolated from urine samples, and Western blots were performed. Each sample was analyzed with ELISA for the expression of Vim3 and Mxi-2. A lateral flow assay was established. For the detection of SRMs, the miRs were isolated and qRT-PCR was performed. RESULTS: A significant increase of Vim3 in urines from patients with oncocytoma (n = 20) was detectable with ELISA compared to all other subtypes of RCCs (chromophobe (n = 50), papillary (n = 40), ccRCC (n = 200), and controls (n = 40) (***p < 0.0001)). Mxi-2 was predominantly overexpressed in ccRCCs (***p < 0.0001). Lateral flow assay of Vim3 and Mxi-2 shows two bands in the case of oncocytoma and ccRCC indicating the specificity of this test. For SRMs, an overexpression of miR-15a/Mxi2 was detectable in urine samples from ccRCC and chromoRCC patients. In contrast to that, miR-498/Vim3 were predominantly overexpressed in oncocytoma patients. CONCLUSION: Both proteins (Vim3 and Mxi-2) were detectable in patients' urines and can be used for the non-invasive differentiation of kidney cancers.

Searching for prognostic biomarkers for small renal masses in the urinary proteome.

Renal cell carcinoma (RCC) is frequently diagnosed incidentally as an early-stage small renal mass (SRM; pT1a, ≤4 cm). Overtreatment of patients with benign or clinically indolent SRMs is increasingly common and has resulted in a recent shift in treatment recommendations. There are currently no available biomarkers that can accurately predict clinical behavior. Therefore, we set out to identify early biomarkers of RCC progression. We employed a quantitative label-free liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) proteomics approach and targeted parallel-reaction monitoring to identify and validate early, noninvasive urinary biomarkers for RCC-SRMs. In total, we evaluated 115 urine samples, including 33 renal oncocytoma (≤4 cm) cases, 30 progressive and 26 nonprogressive clear cell RCC (ccRCC)-SRM cases, in addition to 26 healthy controls. We identified six proteins, which displayed significantly elevated expression in clear cell RCC-SRMs (ccRCC-SRMs) relative to healthy controls. Proteins C12ORF49 and EHD4 showed significantly elevated expression in ccRCC-SRMs compared to renal oncocytoma (≤4 cm). Additionally, proteins EPS8L2, CHMP2A, PDCD6IP, CNDP2 and CEACAM1 displayed significantly elevated expression in progressive relative to nonprogressive ccRCC-SRMs. A two-protein signature (EPS8L2 and CCT6A) showed significant discriminatory ability (areas under the curve: 0.81, 95% CI: 0.70-0.93) in distinguishing progressive from nonprogressive ccRCC-SRMs. Patients (Stage I-IV) with EPS8L2 and CCT6A mRNA alterations showed significantly shorter overall survival (p = 1.407 × 10-6 ) compared to patients with no alterations. Our in-depth proteomic analysis identified novel biomarkers for early-stage RCC-SRMs. Pretreatment characterization of urinary proteins may provide insight into early RCC progression and could potentially help assign patients to appropriate management strategies.

Identification of Prognostic Biomarkers in the Urinary Peptidome of the Small Renal Mass.

Renal cell carcinoma (RCC) is often diagnosed incidentally as a small renal mass (SRM; pT1a, ≤4 cm). Increasing concerns surrounding the overtreatment of patients with benign or clinically silent SRMs has resulted in a recent shift in treatment recommendations, especially in elderly and infirm patients. There are currently no biomarkers that can predict progression. We used a quantitative label-free liquid chromatography-tandem mass spectrometry peptidomics approach and targeted parallel-reaction monitoring to identify early, noninvasive diagnostic and prognostic biomarkers for early-stage RCC-SRMs. In total, 115 urine samples, including 33 renal oncocytoma (≤4 cm) cases, 30 progressive and 26 nonprogressive clear cell RCC-SRM cases, and 26 healthy controls were evaluated. Nine endogenous peptides that displayed significantly elevated expression in clear cell RCC-SRMs relative to healthy controls were identified. Peptides NVINGGSHAGNKLAMQEF, VNVDEVGGEALGRL, and VVAGVANALAHKYH showed significantly elevated expression in clear cell RCC-SRMs relative to renal oncocytoma. Additionally, peptides SHTSDSDVPSGVTEVVVKL and IVDNNILFLGKVNRP displayed significantly elevated expression in progressive relative to nonprogressive clear cell RCC-SRMs. Peptide SHTSDSDVPSGVTEVVVKL showed the most significant discriminatory utility (area under the curve, 0.76; 95% CI, 0.62-0.90; P = 0.0027). Patients with elevated SHTSDSDVPSGVTEVVVKL expression had significantly shorter overall survival (hazard ratio, 4.13; 95% CI, 1.09-15.65; P = 0.024) compared to patients with low expression. Pretreatment characterization of urinary peptides can provide insight into early RCC progression and may aid clinical decision-making and improve disease management.

MicroRNAs as Urinary Biomarker for Oncocytoma.

The identification of benign renal oncocytoma, its differentiation from malignant renal tumors, and their eosinophilic variants are a continuous challenge, influencing preoperative planning and being an unnecessary stress factor for patients. Regressive changes enhance the diagnostic dilemma, making evaluations by frozen sections or by immunohistology (on biopsies) unreliable. MicroRNAs (miRs) have been proposed as novel biomarkers to differentiate renal tumor subtypes. However, their value as a diagnostic biomarker of oncocytoma in urines based on mechanisms known in oncocytomas has not been exploited. We used urines from patients with renal tumors (oncocytoma, renal cell carcinoma: clear cell, papillary, chromophobe) and with other urogenital lesions. miRs were extracted and detected via qRT-PCR, the respective tumors analyzed by immunohistology. We found isocitrate dehydrogenase 2 upregulated in oncocytoma and oncocytic chromophobe carcinoma, indicating an increased Krebs cycle metabolism. Since we had shown that all renal tumors are stimulated by endothelin-1, we analyzed miRs preidentified by microarray after endothelin-1 stimulation of renal epithelial cells. Four miRs are proposed as presurgical urinary biomarkers due to their known regulatory mechanism in oncocytoma: miR-498 (formation of the oncocytoma-specific slice-form of vimentin, Vim3), miR-183 (associated with increased CO2 levels), miR-205, and miR-31 (signaling through downregulation of PKC epsilon, shown previously).

MicroRNA-15a expression measured in urine samples as a potential biomarker of renal cell carcinoma.

INTRODUCTION: Currently, there is no accurate diagnostic molecular biomarker for renal cell carcinoma (RCC). The aim of this study was to assess the expression of microRNA-15a (miR-15a) in urine of patients with RCC and to evaluate its potential as a diagnostic molecular biomarker. MATERIALS AND METHODS: In total, 67 patients with solid renal tumors were enrolled: clear-cell RCC (ccRCC, n = 22), papillary RCC (pRCC, n = 16), chromophobe RCC (chRCC, n = 14), oncocytoma (n = 8), papillary adenoma (n = 2) and angiomyolipoma (n = 5). MiRNA-15a expression levels measurement in urine were performed using qPCR. Urine of 15 healthy volunteers without kidney pathology was used as control. RESULTS: We observed a difference in mean miR-15a expression values in groups of pre-operative patients with RCC, benign renal tumors and healthy persons (2.50E-01 ± 2.72E-01 vs 1.32E-03 ± 3.90E-03 vs 3.36E-07 ± 1.04E-07 RFU, respectively, p < 0.01). There was no difference in miR-15a expression between ccRCC, pRCC and chRCC (p > 0.05). Direct association between RCC size and miR-15a expression values was obtained (Pearson correlation coefficient-0.873). On the 8th day after nephrectomy, mean expression value in patients with RCC decreased by 99.53% (p < 0.01). MiR-15a expression differentiated RCC from benign renal tumors with 98.1% specificity, 100% sensitivity at a cut-off value of 5.00E-06 RFU, with AUC-0.955. CONCLUSIONS: MiR-15a expression measured in urine may be used as diagnostic molecular biomarker for RCC.

Matrix metalloproteinase-2 and -9 in the sera and in the urine of human oncocytoma and renal cell carcinoma.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases, capable of degrading all the molecular components of extracellular matrix. MMPs have been shown to play critical roles in tumor cell invasion and metastasis. We verified the activity of MMPs in the sera and in the urine of patients with kidney carcinoma by gelatin zymography. Of these patients, 16 had clear cell renal carcinoma (ccRCC) and 4 patients had oncocytoma. The sera and the urine of 16 healthy subjects were used as controls. In the sera, zymography analysis showed gelatinolytic bands at 72 kDa (gelatinase A) at 92, 130 and 240 kDa (gelatinase B). MMP-9 activity was slightly enhanced in sera from ccRCC compared with oncocytoma patients. Serum MMP-2 activity was similar in ccRCC and in oncocytoma patients. In the urine, 2 oncocytoma patients and 3 (33%) of the ccRCC patients showed gelatinolytic activity, whereas MMPs could not be detected in the concentrated urine of healthy subjects. The most abundant lytic activity was at 92 kDa, whereas MMP-2 was present in lesser quantities. However, there was broad overlap of the data and we did not find any correlation to type, stage or grade. Therefore, despite previous evidence, MMP-2 and -9 activity in serum and urine may not be useful biomarker for kidney carcinomas.

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.