Urine epigenomics: a promising path for bladder cancer diagnostics

Detection of multiple mutations in urinary exfoliated cells from male bladder cancer patients at diagnosis and during follow-up

Most bladder cancer (BC) patients need life-long, invasive and expensive monitoring and treatment, making it a serious burden on the health system. Thus, there is a pressing need for an accurate test to assist diagnosis and surveillance of BC as an alternative to cystoscopy. Mutations in human TERT, FGFR3, PIK3CA, and RAS genes have been proposed as potential molecular markers in bladder tumor. Their concomitant presence in urine samples has not been fully explored.

We investigated a panel of mutations in DNA from exfoliated urinary cells of 255 BC patients at diagnosis. Forty-one mutations in TERT, FGFR3, PIK3CA, and RAS were analyzed by SNaPshot assay in relation to clinical outcome. In 81 of these patients under surveillance, the same set of mutations was screened in additional 324 samples prospectively collected.

The most common mutations detected in urine at diagnosis were in the TERT promoter. In non-invasive BC, these mutations were related to high risk and grade (p<0.0001) as well as progression to muscle-invasive disease (p=0.01), whereas FGFR3 mutations were observed in low-grade BC (p=0.02) and patients with recurrences (p=0.05). Stronger associations were observed for combined TERT and FGFR3 mutations and number of recurrences (OR: 4.54 95% CI: 1.23-16.79, p=0.02). Analyses of the area under the curve for combinations of mutations detected at diagnosis and follow-up showed an accuracy of prediction of recurrence of 0.80 (95% CI: 0.71-0.89).

Mutations in urine of BC patients may represent reliable biomarkers. In particular, TERT and FGFR3 mutations have a good accuracy of recurrence prediction.

Circulating microRNAs, miR-92a, miR-100 and miR-143, as non-invasive biomarkers for bladder cancer diagnosis

The application of microRNAs (miRNAs) as potential biomarkers and therapy targets has been widely investigated in many kinds of cancers. Recent advantages of serum miRNAs open a new realm of possibilities for non-invasive diagnosis and prognosis of bladder cancer (BC). The aim of our study was to identify plasma miR-92a, miR-100 and miR-143 expression signatures in patients with BC to introduce new markers for establishing BC diagnosis and prognosis. Blood samples were collected from 70 BC patients and 62 controls. An expression of three target miRNAs (miR-92a, miR-100 and miR-143) was measured using quantitative real-time PCR method. Results were correlated with clinicopathological data and analysed. Plasma levels of miR-92a, miR-100 and miR-143 were significantly lower in BC patients than in control group. Receiver operator characteristic analysis revealed that the sensitivity and specificity values of miR-92a were 97·1% and 76·7%, respectively, with a cut-off value of 0·573. The sensitivity and specificity values of miR-100 were 90% and 66·7%, respectively, with a cut-off value of 0·644. The sensitivity and specificity values of miR-143 were 78·6% and 93·3%, respectively, with a cut-off value of 0·164. This study explores the existence of specific plasma miRNAs as early diagnostic biomarkers for BC in Egyptian patients; and these findings suggest that plasma miR-92a, miR-100 and miR-143 could be promising novel circulating biomarkers in clinical detection of BC.

MicroRNA-137 upregulation increases bladder cancer cell proliferation and invasion by targeting PAQR3

There is increasing evidence suggesting that dysregulation of some microRNAs (miRNAs) may contribute to tumor progression and metastasis and have been proposed to be key regulators of diverse biological processes such as transcriptional regulation, cell growth and tumorigenesis. Previous studies have shown that miR-137 is dysregulated in some malignancies, but its role in bladder cancer is still unknown. In our study, we find that miR-137 is up-regulated in human bladder cancer tissues and cell lines. Moreover, the higher level of miR-137 was associated with pM or pTNM stage in clinical bladder cancer patients. Enforced expression of miR-137 in bladder cancer cells significantly enhanced their proliferation, migration and invasion. Bioinformatics analysis identified the tumor suppressor gene PAQR3 as a potential miR-137 target gene. Further studies indicated that miR-137 suppressed the expression of PAQR3 by binding to its 3′-untranslated region. Silencing of PAQR3 by small interfering RNAs phenocopied the effects of miR-137 overexpression, whereas restoration of PAQR3 in bladder cancer cells bladder cancer cells overexpressing miR-137, partially reversed the suppressive effects of miR-137. These findings indicate that miR-137 could be a potential oncogene in bladder cancer.

Serum secreted frizzled-related protein 5 levels differentially decrease in patients with hepatitis B virus-associated chronic infection and hepatocellular carcinoma

The aim of this study was to investigate the characteristics of serum secreted frizzled-related protein 5 (SFRP5), an inhibitor of Wnt signaling, in hepatitis B virus (HBV)-associated infections and hepatocellular carcinoma (HCC) patients. Serum SFRP5 levels were detected in 147 patients with HBV-associated chronic infection or HCC. Compared with the non-HBV-infected and non-HCC group, the HBV-associated chronic infection and HCC groups exhibited decreased serum SFRP5 levels. A significant inverse correlation between serum SFRP5 levels and HBV DNA levels was identified in the HBV-associated chronic infection and HCC groups. Furthermore, SFRP5 levels differentially decreased in patients with HBV-associated diseases, in a manner which was dependent on liver disease status. Compared with patients exhibiting HBV-associated chronic infection, patients with HCC were found to exhibit lower serum SFRP5 levels. The results of the present study indicated that patients with HBV-associated liver infection and HCC exhibited significantly deceased serum SFRP5 levels, which were found to negatively correlate with HBV DNA levels. Serum SFRP5 levels may present a biomarker for the severity of HBV-associated liver infection, and the risk of HCC initiation and progression.

Methylation of a novel panel of tumor suppressor genes in urine moves forward noninvasive diagnosis and prognosis of bladder cancer: a 2-center prospective study

PURPOSE

Changes in DNA methylation of tumor suppressor genes early in carcinogenesis represent potential indicators of cancer detection and disease evolution. We examined the diagnostic, stratification and prognostic biomarker roles in urine of the methylation of a novel panel of tumor suppressor genes in bladder cancer.

MATERIAL AND METHODS

We evaluated the methylation of 18 tumor suppressor genes in 2 prospective, independent sets of urine samples (training set of 120 preparations and validation set of 128) from patients with bladder cancer (170) and controls (78) using methylation specific multiplex ligation-dependent probe amplification. Diagnostic performance was evaluated with ROC curves. Recurrence, progression and disease specific survival were analyzed using univariate and multivariate Cox models.

RESULTS

PRDM2, HLTF, ID4, DLC1, BNIP3, H2AFX, CACNA1G, TGIF and CACNA1A were methylated in bladder cancer. CCND2, SCGB3A1, BNIP3, ID4 and RUNX3 were the most frequently methylated tumor suppressor genes in each urine set. Methylation of several tumor suppressor genes correlated with clinicopathological variables, such as stage, tumor grade, focality or age. ROC analysis revealed significant diagnostic accuracy for RUNX3 and CACNA1A in the training set, and for RUNX3 and ID4 in the validation set. On univariate and multivariate analysis CACNA1A methylation correlated with recurrence in the training set, while in the validation set PRDM2 and BNIP3 were significantly associated with recurrence and disease specific survival, respectively.

CONCLUSIONS

Tumor suppressor gene methylation allowed for histopathological and clinical stratification. Urine methylation has noninvasive usefulness not only for diagnostic assessment but also as independent bladder cancer prognosticators.