Urinary and circulatory netrin-1 as biomarker in diabetes and its related complications: a systematic review and meta-analysis

BACKGROUND

Novel biomarkers have been suggested for the diagnosis and prognosis of diabetes mellitus. The biomarker utility of netrin-1 in diabetes as an extracellular protein has been investigated. In this systematic review and meta-analysis, we reviewed the role of netrin-1 as a biomarker in prediabetes, diabetes, and complications of diabetes.

METHODS

PubMed, Embase, Scopus, and Web of Science were systematically searched for studies that measured circulatory and/or urinary netrin-1 levels in diabetes and compared them with non-diabetic patients or evaluated the prognostic role of this marker. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated using random-effect meta-analysis to compare netrin-1 levels between groups. The impact of mean age, male sex percentage, sample size, mean body mass index, and publication year on the overall heterogeneity was assessed using meta-regression.

RESULTS

Among 413 records from international databases, 19 original studies were included with 2061 cases (1137 diabetics, 196 prediabetics, and 728 healthy controls). Meta-analysis of eight studies measuring netrin-1 in patients with diabetes and comparing it with healthy controls showed no significant difference between the two groups (SMD 0.69, 95% CI -0.78 to 2.16, I2 = 98%, p-value = 0.36). On the other hand, a meta-analysis of netrin-1 levels in patients with prediabetes in comparison with healthy controls revealed that they had lower levels (SMD -0.51, 95% CI -0.81 to -0.21, p-value < 0.01). Diabetic patients with microalbuminuria and macroalbuminuria had significantly higher circulatory netrin-1 levels compared to normoalbuminuric group SMD 1.18, 95% CI 0.83 to 1.53, p-value < 0.01 and SMD 1.67, 95% CI 0.76 to 2.58, p-value < 0.01, respectively). Moreover, no difference in urinary netrin-1 levels was found between micro-, macro-, and normoalbuminuric groups (p-value > 0.05).

CONCLUSION

Netrin-1 showed promising results as a biomarker in diabetes prognosis. However, more studies are required to confirm our findings, and higher sample size studies are needed to evaluate the diagnostic utility of this marker.

Screening of urine identifies PLA2G16 as a field defect methylation biomarker for prostate cancer detection

BACKGROUND

Prostate cancer (PC) is a multifocal disease. DNA methylation alterations are not restricted to the immediate peritumor environment, but spatially widespread in the adjacent and distant histologically normal prostate tissues. In the current study, we utilized high-throughput methylation arrays to identify epigenetic changes in the urine from men with and without cancer.

DESIGN, SETTING, AND PARTICIPANTS

DNA urine samples were enriched for methylated fragments using MBD methyl-binding antibodies and applied to high density CytoScanHD arrays. Significant loci were validated using quantitative pyrosequencing and binary logistic regression modeling applied to urine sample analyses in a training (n = 83) and validation approach (n = 84). Methylation alterations in prostate tissues using pyrosequencing at the PLA2G16 locus were examined in 38 histologically normal specimens from men with (TA, n = 26) and without (NTA, n = 12) cancer and correlated to gene expression.

RESULTS

Methylation microarrays identified 3,986 loci showing significantly altered methylation in the urine samples from patients with PC compared to those without (TA vs NTA; p<0.01). These loci were then compared against subjects with their prostates removed to exclude non-prostate cell markers yielding 196 significant regions. Multiple CpGs adjacent to PLA2G16 CpG island showed increased methylation in TA compared to NTA (p<0.01) in a large validation study of urine samples. The predictive accuracy of PLA2G16 methylation at CG2 showed the highest predictive value at 0.8 (odds ratio, 1.37; 95% confidence interval, 1.16-1.62; p<0.001). Using a probability cutoff of 0.065, the sensitivity and specificity of the multivariate model was 92% and 35%. When histologically normal prostate tissues/biopsies from patients with PC (TA) were compared to subjects without cancer, significant hypermethylation of PLA2G16 was noted (odds ratio, 1.35; 95% confidence interval, 1.07-1.71; p = 0.01).

CONCLUSION

PLA2G16 methylation defines an extensive field defect in histologically normal prostate tissue associated with PC. PLA2G16 methylation in urine and prostate tissues can detect the presence of PC.

[Diagnostic values of urinary netrin-1 and kidney injury molecule-1 for acute kidney injury induced by neonatal asphyxia]

OBJECTIVE

To investigate the values of urinary netrin-1 and kidney injury molecule-1 (KIM-1) in the early diagnosis of acute kidney injury (AKI) induced by neonatal asphyxia.

METHODS

A total of 80 full-term neonates with asphyxia were enrolled (mild asphyxia: 34 neonates; severe asphyxia: 46 neonates). Forty normal full-term neonates were selected as the control group. Urinary samples were collected from the neonates in the three groups within 12 hours and 13-48 hours after birth. ELISA was applied to measure urinary levels of netrin-1 and KIM-1. Peripheral venous blood samples were also collected to measure serum creatinine (Scr) level.

RESULTS

Compared with the control group, the asphyxia group had significantly higher urinary levels of netrin-1 and KIM-1 within 48 hours after birth and a significantly higher Scr level within 13-48 hours after birth (P<0.05). The neonates in the AKI group had significantly higher urinary levels of netrin-1 and KIM-1 and Scr level within 48 hours after birth than those in the non-AKI group (P<0.05). The areas under the receiver operating characteristic curve for urinary netrin-1 and KIM-1 levels within 12 hours after birth to predict AKI after asphyxia were 0.878 (95% CI: 0.775-0.981; P<0.01) and 0.899 (95% CI: 0.829-0.969; P<0.01), respectively. Any two indicators of urinary netrin-1 level, urinary KIM-1 level, and Scr level within 12 hours after neonatal asphyxia had a positive correlation (P<0.05).

CONCLUSIONS

Urinary netrin-1 and KIM-1 levels increase significantly when neonates with asphyxia develop AKI. Urinary netrin-1 and KIM-1 can be used as indicators for the early diagnosis of AKI after asphyxia.

[Diagnostic values of urinary netrin-1 and kidney injury molecule-1 for acute kidney injury induced by neonatal asphyxia]

OBJECTIVE

To investigate the values of urinary netrin-1 and kidney injury molecule-1 (KIM-1) in the early diagnosis of acute kidney injury (AKI) induced by neonatal asphyxia.

METHODS

A total of 80 full-term neonates with asphyxia were enrolled (mild asphyxia: 34 neonates; severe asphyxia: 46 neonates). Forty normal full-term neonates were selected as the control group. Urinary samples were collected from the neonates in the three groups within 12 hours and 13-48 hours after birth. ELISA was applied to measure urinary levels of netrin-1 and KIM-1. Peripheral venous blood samples were also collected to measure serum creatinine (Scr) level.

RESULTS

Compared with the control group, the asphyxia group had significantly higher urinary levels of netrin-1 and KIM-1 within 48 hours after birth and a significantly higher Scr level within 13-48 hours after birth (P<0.05). The neonates in the AKI group had significantly higher urinary levels of netrin-1 and KIM-1 and Scr level within 48 hours after birth than those in the non-AKI group (P<0.05). The areas under the receiver operating characteristic curve for urinary netrin-1 and KIM-1 levels within 12 hours after birth to predict AKI after asphyxia were 0.878 (95% CI: 0.775-0.981; P<0.01) and 0.899 (95% CI: 0.829-0.969; P<0.01), respectively. Any two indicators of urinary netrin-1 level, urinary KIM-1 level, and Scr level within 12 hours after neonatal asphyxia had a positive correlation (P<0.05).

CONCLUSIONS

Urinary netrin-1 and KIM-1 levels increase significantly when neonates with asphyxia develop AKI. Urinary netrin-1 and KIM-1 can be used as indicators for the early diagnosis of AKI after asphyxia.

Trefoil Factor 1 Excretion Is Increased in Early Stages of Chronic Kidney Disease

Chronic kidney disease (CKD) is associated with high morbidity and mortality. In many patients CKD is diagnosed late during disease progression. Therefore, the implementation of potential biomarkers may facilitate the early identification of individuals at risk. Trefoil factor family (TFF) peptides promote restitution processes of mucous epithelia and are abundant in the urinary tract. We therefore sought to investigate the TFF peptide levels in patients suffering from CKD and their potential as biomarkers for CKD. We analysed TFF1 and TFF3 in serum and urine of 115 patients with CKD stages 1–5 without dialysis by ELISA. 20 healthy volunteers served as controls. Our results showed, that urinary TFF1 levels were significantly increased with the onset of CKD in stages 1–4 as compared to controls and declined during disease progression (p = 0.003, < 0.001, 0.005, and 0.007. median concentrations: 3.5 pg/mL in controls vs 165.2, 61.1, 17.2, and 15.8 pg/mL in CKD 1–4). TFF1 and TFF3 serum levels were significantly elevated in stages 3–5 as compared to controls (TFF1: p < 0.01; median concentrations: 12.1, 39.7, and 34.5 pg/mL in CKD 3–5. TFF3: p < 0.001; median concentrations: 7.1 ng/mL in controls vs 26.1, 52.8, and 78.8 ng/mL in CKD 3–5). TFF3 excretion was increased in stages 4 and 5 (p < 0.001; median urinary levels: 65.2 ng/mL in controls vs 231.5 and 382.6 ng/mL in CKD 4/5; fractional TFF3 excretion: 6.4 in controls vs 19.6 and 44.1 in CKD 4/5). ROC curve analyses showed, that monitoring TFF peptide levels can predict various CKD stages (AUC urinary/serum TFF > 0.8). In conclusion our results show increased levels of TFF1 and TFF3 in CKD patients with a pronounced elevation of urinary TFF1 in lower CKD stages. Furthermore, TFF1 and TFF3 seems to be differently regulated and show potential to predict various CKD stages, as shown by ROC curve analysis.

Identification of a Three-Biomarker Panel in Urine for Early Detection of Pancreatic Adenocarcinoma

PURPOSE

Noninvasive biomarkers for early detection of pancreatic ductal adenocarcinoma (PDAC) are currently not available. Here, we aimed to identify a set of urine proteins able to distinguish patients with early-stage PDAC from healthy individuals.

EXPERIMENTAL DESIGN

Proteomes of 18 urine samples from healthy controls, chronic pancreatitis, and patients with PDAC (six/group) were assayed using GeLC/MS/MS analysis. The selected biomarkers were subsequently validated with ELISA assays using multiple logistic regression applied to a training dataset in a multicenter cohort comprising 488 urine samples.

RESULTS

LYVE-1, REG1A, and TFF1 were selected as candidate biomarkers. When comparing PDAC (n = 192) with healthy (n = 87) urine specimens, the resulting areas under the receiver-operating characteristic curves (AUC) of the panel were 0.89 [95% confidence interval (CI), 0.84-0.94] in the training (70% of the data) and 0.92 (95% CI, 0.86-0.98) in the validation (30% of the data) datasets. When comparing PDAC stage I-II (n = 71) with healthy urine specimens, the panel achieved AUCs of 0.90 (95% CI, 0.84-0.96) and 0.93 (95% CI, 0.84-1.00) in the training and validation datasets, respectively. In PDAC stage I-II and healthy samples with matching plasma CA19.9, the panel achieved a higher AUC of 0.97 (95% CI, 0.94-0.99) than CA19.9 (AUC = 0.88; 95% CI, 0.81-0.95, P = 0.005). Adding plasma CA19.9 to the panel increased the AUC from 0.97 (95% CI, 0.94-0.99) to 0.99 (95% CI, 0.97-1.00, P = 0.04), but did not improve the comparison of stage I-IIA PDAC (n = 17) with healthy urine.

CONCLUSIONS

We have established a novel, three-protein biomarker panel that is able to detect patients with early-stage pancreatic cancer in urine specimens.

Netrin-1 and semaphorin 3A predict the development of acute kidney injury in liver transplant patients

Acute kidney injury (AKI) is a serious complication after liver transplantation. Currently there are no validated biomarkers available for early diagnosis of AKI. The current study was carried out to determine the usefulness of the recently identified biomarkers netrin-1 and semaphorin 3A in predicting AKI in liver transplant patients. A total of 63 patients’ samples were collected and analyzed. AKI was detected at 48 hours after liver transplantation using serum creatinine as a marker. In contrast, urine netrin-1 (897.8±112.4 pg/mg creatinine), semaphorin 3A (847.9±93.3 pg/mg creatinine) and NGAL (2172.2±378.1 ng/mg creatinine) levels were increased significantly and peaked at 2 hours after liver transplantation but were no longer significantly elevated at 6 hours after transplantation. The predictive power of netrin-1, as demonstrated by the area under the receiver-operating characteristic curve for diagnosis of AKI at 2, 6, and 24 hours after liver transplantation was 0.66, 0.57 and 0.59, respectively. The area under the curve for diagnosis of AKI was 0.63 and 0.65 for semaphorin 3A and NGAL at 2 hr respectively. Combined analysis of two or more biomarkers for simultaneous occurrence in urine did not improve the AUC for the prediction of AKI whereas the AUC was improved significantly (0.732) only when at least 1 of the 3 biomarkers in urine was positive for predicting AKI. Adjusting for BMI, all three biomarkers at 2 hours remained independent predictors of AKI with an odds ratio of 1.003 (95% confidence interval: 1.000 to 1.006; P = 0.0364). These studies demonstrate that semaphorin 3A and netrin-1 can be useful early diagnostic biomarkers of AKI after liver transplantation.

Age-related differences in kidney injury biomarkers induced by cisplatin

Acute kidney injury (AKI) occurs in a half of cisplatin (CDDP)-treated patients. Traditional biomarkers including blood urea nitrogen (BUN) and serum creatinine (SCr) are still used for detection of CDDP-induced AKI, but these biomarkers are not specific or sensitive. The aim of this study was to identify the specific and sensitive biomarkers against CDDP-induced renal injury between young (3-week-old) and old (20-week-old) rats. All animals were intraperitoneally injected once with CDDP (6 mg/kg). After 3 days, all animals were sacrificed and serum, urine, and kidney tissues were collected. Urinary and serum biomarkers as well as histological changes were measured. CDDP-induced proximal tubular damage was apparent from histopathological examination, being more severe in 3-week-old rats accompanied by increased number of TUNEL-positive apoptotic cells. This was associated with elevated urinary kidney injury molecule-1 (KIM-1), glutathione-S-transferase alpha (GST-α), vascular endothelial growth factor (VEGF), and tissue inhibitor of metalloproteinases-1 (TIMP-1). In contrast, the levels of neutrophil gelatinase-associated lipocalin (NGAL) and osteopontin were significantly increased in 20-week-old rats after CDDP treatment. These results indicate that the use of age-specific urinary biomarkers is necessary to diagnosis of CDDP-induced AKI. Especially, urinary KIM-1, GST-α, TIMP-1, and VEGF levels may help in the early diagnosis of young patients with CDDP-induced AKI.

Tubular injury marker netrin-1 is elevated early in experimental diabetes

BACKGROUND

Netrin-1 was recently identified as an early diagnostic biomarker of acute kidney injury. However, its usefulness for early diagnosis of chronic kidney disease (CKD) is unknown. The current study evaluated whether these proteins are increased in urine from experimental animals with diabetes.

METHODS

The current study evaluated whether netrin-1 is increased in urine from diabetic rats and mice, and whether netrin-1 correlated with development of nephropathy.

RESULTS

In rats, urinary netrin-1 excretion was significantly (p<0.001) higher in the diabetic group at 4 and 10 weeks after induction of diabetes as compared with the control group. Similarly, netrin-1 was increased significantly (p<0.001) in urine from hypertensive rats at 4 weeks as compared with controls. Likewise, urinary albumin excretion rates were increased in diabetic rats at 4 and 10 weeks as compared with controls and were increased in hypertensive rats at 4 weeks. Consistent with the diabetic model in rats, netrin-1 excretion was also increased early in diabetic mice's urine, and peak levels correlated with disease severity.

CONCLUSION

Netrin-1 can be detected in urine from diabetic and hypertensive rats and may serve as a useful early diagnostic biomarker for development of CKD.

Current developments in early diagnosis of acute kidney injury

Acute kidney injury (AKI) is a very frequent and serious clinical problem, accounting for overall high morbidity and mortality. Up to date, mortality due to AKI is virtually unchanged over the past 50 years. This may partly be explained due to a delay in initiating renal protective and appropriate therapeutic measures since until now there are no reliable early-detecting biomarkers. The gold standard, serum creatinine, displays poor specificity and sensitivity with regard to identification of the incipient phase of AKI, and this is also true for cystatin C. We aimed to review novel biomarkers of AKI in urine and serum which have now progressed to the clinical phase. The main focus refers to their diagnostic and prognostic value. For this purpose, a web-based literature search using PubMed was performed comprising the following terms: renal failure, acute kidney injury and biomarkers. New molecules such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), N-acetyl-β-D-glucosaminidase (NAG), monocyte chemotactic peptide (MCP-1), Il-18, liver-type fatty acid-binding protein (L-FABP) and Netrin-1 are available and represent promising new markers that, however, need to be further evaluated in the clinical setting for suitability. In clinical settings with incipient AKI, not only the development and the implementation of more sensitive, practicable and accurate biomarkers are required for well-timed treatment initiation. Just as important is a substantial improvement of refined and applicable prophylactic therapeutic options in these situations. Before full adoption in clinical practice can be accomplished, adequately powered clinical trials testing a row of biomarkers are strongly warranted.

The association of retinoic acid receptor beta2(RARβ2) methylation status and prostate cancer risk: a systematic review and meta-analysis

The retinoic acid receptor beta2(RARβ2) is a type of nuclear receptor that is activated by both all-trans retinoic acid and 9-cis retinoic acid, which has been shown to function as a tumor suppressor gene in different types of human tumors. Previous reports demonstrated that the frequency of RARβ2 methylation was significantly higher in prostate cancer patients compared with controls, but the relationship between RARβ2 promoter methylation and pathological stage or Gleason score of prostate cancer remained controversial. Therefore, a meta-analysis of published studies investigating the effects of RARβ2 methylation status in prostate cancer occurrence and association with both pathological stage and Gleason score in prostate cancer was performed in the study. A total of 12 eligible studies involving 777 cases and 404 controls were included in the pooled analyses. Under the random-effects model, the pooled OR of RARβ2 methylation in prostate cancer patients, compared to non-cancer controls, was 17.62 with 95%CI = 6.30-49.28. The pooled OR with the fixed-effects model of pathological stage in RASSF1A methylated patients, compared to unmethylated patients, was 0.67 (95%CI = 0.40-1.09) and the pooled OR of low-GS in RARβ2 methylated patients by the random-effect model, compared to high-GS RARβ2 methylated patients, was 0.54 (95%CI = 0.28-1.04). This study showed that RARβ2 might be a potential biomarker in prostate cancer prevention and diagnosis. The detection of RARβ2 methylation in urine or serum is a potential non-invasive diagnostic tool in prostate cancer. The present findings also require confirmation through adequately designed prospective studies.

Study of genetic and epigenetic alterations in urine samples as diagnostic markers for prostate cancer

BACKGROUND

Early diagnosis of prostate cancer and identification of new prognostic factors remain main issues in prostate cancer research. In this study, we sought to test a panel of cancer-specific markers in urine samples as an aid for early cancer diagnosis.

MATERIALS AND METHODS

Sedimented urine samples of 66 candidates for needle biopsy were tested. Real time-polymerase chain reaction (RT-PCR) was applied to detect the expression of transmembrane protease serine-2 and Ets-related gene fusion (TMPRSS2-ERG), Ets-related gene (ERG), prostate cancer antigen-3 (PCA3), and serine peptidase inhibitor kazal type-1 (SPINK1) transcripts. For testing of the methylation status of Glutahione S-tranferase P (GSTP1) and Ras association domain family member-1(RASSF1A) promoter region, methylation-specific PCR (MSP-PCR) was applied.

RESULTS

Among the tested parameters, the presence of TMPRSS2-ERG (OR=9.044, 95% CI=2.207-37.066, p=0.002), as well as a positive test result for PCA3 (OR=7.549, 95% CI=1,858-30,672, p=0.005) were associated with the subsequent diagnosis of prostate cancer. A multivariable logistic regression including all the significantly associated variables [prostate-specific antigen (PSA), digital rectal examination (DRE), TMPRSS2-ERG and PCA3], yielded a model with area under the receiver-operating characteristic curve (AUC) =0.894 (95% CI=0.772-1.00).

CONCLUSION

A multiplexed quantitative PCR analysis on sedimented urine, in conjunction with the results of serum PSA levels and DRE, has the potential to accurately foresee subsequent needle biopsy outcomes. On the basis of the above, algorithms may be designed to guide decisions for needle biopsy.

Acute Kidney Injury (AKI) biomarker

The kidney has a remarkable capacity to withstand insults for an extended period of time. The sensitivities of individual renal cells to injury vary depending on their type, position in the nephron, local vascularization, and the nature of injury. The resulting kidney injury is a product of the interplay between cell dysfunction, cell death, proliferation, inflammation, and recovery. The Acute Kidney Injury Network (AKIN) defined Acute Kidney Injury (AKI) as "functional and structural disorder or signs of renal damage including any defect from blood and urine test, or tissue imaging that is less than 3 months". RIFLE (Risk, Injury, Failure, Loss, End-Stage Kidney Disease) criteria is the most frequently used system. Ideal biomarker for AKI should be affordable, quick and measurable, precise and accurate, with prognostic ability to define severity of renal dysfunction, specific for renal, increase in the early stage dysfunction, with high sensitivity and specificity. Efforts to detect AKI in the earlier stage has resulted in some promising biomarkers such as KIM-1, NGAL, IL-18, Clusterin, etc. Cystatin C is a biomarker for glomerular filtration function, while 2-microglobulin, 1-microglobulin, NAG, RBP, IL-18, NGAL, Netrin-1, KIM-1, Clusterin, Sodium Hydrogen Exchanger Isoform and Fetuin A are biomarkers for tubular reabsorption function.

Frequent methylation of RASSF1 and RARB in urine sediments from patients with early stage prostate cancer

BACKGROUND. Prostate cancer (PCa) is the second most prevalent malignancy among males, characterized by high mortality rates. Aberrant DNA methylation in promoters of tumor suppressor genes is an early and frequent event during prostate carcinogenesis. Modern techniques allow a sensitive detection of DNA methylation biomarkers in bodily fluids from cancer patients offering a noninvasive tool for PCa monitoring. Our study aimed at the analysis of DNA methylation in urine sediments from PCa patients for the selection of most informative noninvasive biomarkers. MATERIAL AND METHODS. Real-time methylation-specific polymerase chain reaction was used for the detection of methylated RASSF1, RARB, and GSTP1 genes in catheterized urine specimens from 34 patients with biopsy-proven early or medium stage PCa. RESULTS. At least one gene was methylated in urine sediments from 28 cases with PCa, with a sensitivity of the test reaching 82%. RASSF1 was methylated in 71% (24 of 34), RARB in 44% (15 of 34), and GSTP1 in 3% (1 of 34) of the specimens. High level of methylation (≥50%) in RARB and RASSF1 genes was detected in 40% and 20% of cases, respectively. A significant association was observed between high level of RARB methylation and Gleason score (P=0.01), while methylation of at least one gene occurred more frequently in urine DNA of older patients (P=0.02). CONCLUSIONS. Results of our study show a high sensitivity of DNA methylation biomarkers, especially RASSF1 and RARB, for the early and noninvasive detection of PCa.

DNA methylation biomarkers of prostate cancer: confirmation of candidates and evidence urine is the most sensitive body fluid for non-invasive detection

BACKGROUND

A prostate cancer (PCa) biomarker with improved specificity relative to PSA is a public health priority. Hypermethylated DNA can be detected in body fluids from PCa patients and may be a useful biomarker, although clinical performance varies between studies. We investigated the performance of candidate PCa DNA methylation biomarkers identified through a genome-wide search.

METHODS

Real-time PCR was used to measure four DNA methylation biomarkers: GSTP1 and three previously unreported candidates associated with the genes RASSF2, HIST1H4K, and TFAP2E in sodium bisulfite-modified DNA. Matched plasma and urine collected prospectively from 142 patients referred for prostate biopsy and 50 young asymptomatic males were analyzed.

RESULTS

Analysis of all biomarkers in urine DNA significantly discriminated PCa from biopsy negative patients. The biomarkers discriminated PCa from biopsy negative patients with AUCs ranging from 0.64 for HIST1H4K (95% CI 0.55-0.72, P < 0.00001) to 0.69 for GSTP1 (95% CI 0.60-0.77, P < 0.00001). All biomarkers showed minimal correlation with PSA. Multivariate analysis did not yield a panel that significantly improved performance over that of single biomarkers. All biomarkers showed greater sensitivity for PCa in urine than in plasma DNA.

CONCLUSIONS

Analysis of the biomarkers in urine DNA significantly discriminated PCa from biopsy negative patients. The biomarkers provided information independent of PSA and may warrant inclusion in nomograms for predicting prostate biopsy outcome. The biomarkers' PCa sensitivity was greater for urine than plasma DNA. The biomarker performances in urine DNA should next be validated in formal training and test studies.

Isolation and comparative study of cell-free nucleic acids from human urine

Cell-free nucleic acids (NA) from human urine were investigated. Concentrations of DNA and RNA in the urine of healthy people were independent of gender and were in the range of 6 ng/mL to 50 ng/mL and 24 ng/mL to 140 ng/mL, respectively. DNA fragments of 150-400 bp represent the main part of cell-free DNA, along with DNA fragments up to 1,300 bp, which were found in male urine, and DNA fragments up to 19 kbp, which were found in female urine. Analysis of circulating DNA, isolated from blood of breast cancer patients and cell-free DNA isolated from their urine by methylation-specific PCR, demonstrates that the presence of methylated promoters of RASSF1A and RARbeta2 genes in plasma was accompanied by the detection of the same methylated markers in urine. The data obtained demonstrate applicability of cell-free urine DNA in cancer diagnostics.

[Circulating proteinic biomarkers and breast cancer]

Circulating proteinic biomarkers are secreted by tumor cells or by their environmental cells and they have a variable specificity. In case of breast cancer, carcino-embryonic antigen (CEA) was for a long time the only circulating biomarker used. Nowadays, the most useful biomarkers measure circulating levels of fragments of MUC1-polymorphic epithelial mucin (MUC1-PEM): cancer antigen (CA) 15.3, mucin-like carcinoma-associated antigen (MCA), CA 27-29, CA 549... They are useful for general disease follow-up. Other circulating markers belonging to keratins (tissue polypeptide antigen, TPA, TPS or Cyfra 21.1) are correlated with proliferative activity of breast tumors. More recently, the measure of the c-erb B2 circulating part (extra cellular domain, ECD) was proposed as a prognostic biomarker for breast tumors with c-erb B2 overexpression. Moreover, the determination of urinary level of trefoil factor1 (PS2-TFF1) might be useful for the follow-up of hormonodependent breast cancers. The present review describes the clinical interest of these different circulating biomarkers in case of breast cancer, emphasizing their biological characteristics.

Identification of human urinary trefoil factor 1 as a novel calcium oxalate crystal growth inhibitor

Previous research on proteins that inhibit kidney stone formation has identified a relatively small number of well-characterized inhibitors. Identification of additional stone inhibitors would increase understanding of the pathogenesis and pathophysiology of nephrolithiasis. We have combined conventional biochemical methods with recent advances in mass spectrometry (MS) to identify a novel calcium oxalate (CaOx) crystal growth inhibitor in normal human urine. Anionic proteins were isolated by DEAE adsorption and separated by HiLoad 16/60 Superdex 75 gel filtration. A fraction with potent inhibitory activity against CaOx crystal growth was isolated and purified by anion exchange chromatography. The protein in 2 subfractions that retained inhibitory activity was identified by matrix-assisted laser desorption/ionization-time-of-flight MS and electrospray ionization-quadrupole-time-of-flight tandem MS as human trefoil factor 1 (TFF1). Western blot analysis confirmed the mass spectrometric protein identification. Functional studies of urinary TFF1 demonstrated that its inhibitory potency was similar to that of nephrocalcin. The inhibitory activity of urinary TFF1 was dose dependent and was inhibited by TFF1 antisera. Anti-C-terminal antibody was particularly effective, consistent with our proposed model in which the 4 C-terminal glutamic residues of TFF1 interact with calcium ions to prevent CaOx crystal growth. Concentrations and relative amounts of TFF1 in the urine of patients with idiopathic CaOx kidney stone were significantly less (2.5-fold for the concentrations and 5- to 22-fold for the relative amounts) than those found in controls. These data indicate that TFF1 is a novel potent CaOx crystal growth inhibitor with a potential pathophysiological role in nephrolithiasis.