Background:Whether methylation of the microRNA (mir)-124-3 CpG island is of relevance for the clinical course of a solid cancer and whether it shows association with clinicopathology or survival of patients with renal cell cancer (RCC) is not known as yet.Methods:In a cross-sectional study, relative methylation of mir-124-3 was measured in 111 RCC samples and 77 paired normal appearing tissues using quantitative methyl-specific PCR. Results were statistically compared with tumour histology, clinicopathological parameters and disease recurrence.Results:We found tumour-specific hypermethylation of mir-124-3 in samples of RCCs with clear cell histology (ccRCC) compared with paired normal appearing tissues (P<0.0001). Methylation was significantly increased in tumours with state of advanced disease (P<0.0001). Higher relative methylation was associated with worse recurrence-free survival in both univariate (hazard ratio=9.37; P=0.0005) as well as bivariate Cox regression analyses considering age, sex, diameter of tumours and state of advanced disease, metastasis and lymph node metastases as covariates (hazard ratios=5.9–18.2; P-values of 0.0003–0.008).Conclusion:We identified mir-124-3 CpG islands (CGI) methylation as a relevant epigenetic mark for ccRCC thus underlining the need for functional studies of potentially affected signalling pathways in kidney tumour models. Methylation of mir-124-3 is suggested as an independent prognosticator for ccRCC.

Neurofilament Heavy polypeptid (NEFH) belongs to the group of type IV intermediate filament proteins. DNA methylation of the NEFH promoter and loss of expression have previously been shown to activate the AKT/β-catenin pathway in tumor cells. When identifying hypermethylation of the NEFH CpG island (CGI) in renal cell cancer (RCC) we asked whether methylation could provide clinical or prognostic information for RCC and/or predict therapy response in patients with metastatic RCC (mRCC) undergoing antiangiogenic therapy. Relative methylation of the NEFH CGI was analyzed in 132 RCC samples and 83 paired normal tissues using quantitative methylation-specific PCR. Results were statistically compared with tumor histology, clinicopathological parameters, progression-free survival (PFS) as well as with overall survival (OS) in a subset of 18 mRCC patients following antiangiogenic therapy regimens. The NEFH CGI methylation demonstrated a tumor-specific increase (P < 0.001), association with advanced disease (P < 0.001), and distant metastasis (P = 0.005). Higher relative methylation was also significantly associated with a poor PFS (HR = 8.6, P < 0.001) independent from the covariates age, gender, diameter of tumors, state of advanced disease, and local and distant metastasis. Median OS following targeted therapy was 29.8 months for patients with low methylation versus 9.8 months for the group with high methylation (P = 0.028). We identified NEFH methylation as a candidate epigenetic marker for prognosis of RCC patients as well as prediction of anti-vascular endothelial growth factor-based therapy response.

VEGF-targeted therapy increases both the progression-free (PFS) and overall survival (OS) of patients with metastasized renal cell cancer (mRCC). Identification of molecular phenotypes of RCC could improve risk-stratification and the prediction of the clinical disease course. We investigated whether gene-specific DNA hypermethylation can predict PFS and OS among patients undergoing anti-VEGF-based therapy. Primary tumor tissues from 18 patients receiving targeted therapy were examined retrospectively using quantitative methylation-specific PCR analysis of CST6, LAD1, hsa-miR-124-3, and hsa-miR-9-1 CpG islands. PFS and OS were analyzed for first-line and sequential antiangiogenic therapies using the log rank statistics. Sensitivity and specificity were determined for predicting first-line therapy failure. Hypermethylation of CST6 and LAD1 was associated with both a shortened PFS (log rank p = 0.009 and p = 0.004) and OS (p = 0.011 and p = 0.043). The median PFS observed for the high and low methylation groups of CST6 and LAD1 was 2.0 vs.11.4 months. LAD1 methylation had a specificity of 1.0 (95% CI 0.65–1.0) and a sensitivity of 0.73 (95% CI 0.43–0.90) for the prediction of first-line therapy. CST6 and LAD1 methylation are candidate epigenetic biomarkers showing unprecedented association with PFS and OS as well as specificity for the prediction of the response to therapy. DNA methylation markers should be considered for the prospective evaluation of larger patient cohorts in future studies.

Transcriptional inactivation and CpG island (CGI) methylation of GATA transcription factor family members GATA3 and GATA5 have been reported for a few types of human cancer. Whether high-density CGI methylation of GATA3 or GATA5 is associated with the clinical course of patients with renal cell cancer (RCC) has not been clarified. Quantitative methylation-specific PCR assays were carried out to analyze 25 tumor cell lines including 6 RCC lines and 119 RCC and 87 adjacent normal tissues for the presence of densely methylated sequences. Methylation values were statistically compared with clinicopathological and recurrence-free survival (RFS) data for patients. Comparison of GATA3 and GATA5 methylation in different tumor cell lines revealed a marker-specific methylation characteristic with high and frequent signals for both methylation marks in RCC lines. GATA3 and GATA5 CGI relative methylation levels were found to be strongly associated with the state of metastasis (P=0.003 and P<0.001, respectively) and advanced disease (P=0.024 and P<0.001, respectively). Moreover, an independent decrease in RFS in Cox proportional hazard analysis was found for tumors exhibiting high GATA5 methylation (P<0.001, hazard ratio, 19.3; 95% confidence interval, 4.58–81.6). Epigenetic alterations in GATA family members may be associated with aggressive tumor phenotypes in RCC, and in the case of GATA5, may serve as a new independent molecular marker for aggressiveness and disease progression.

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459 Background: Antiangiogenic therapy has demonstrated to increase progression-free (PFS) as well as overall survival (OS) in RCC patients. Clinical scoring systems like the Memorial Sloan Kettering Cancer Center (MSKCC) help to stratify patients for treatment options. However, identification of molecular phenotypes of RCC patients would improve stratification of specific targeted therapies. We investigated whether DNA hypermethylation based markers can predict the PFS following first-line therapy. Methods: We examined primary tumors from formalin-fixed paraffin embedded tissue specimens obtained from 18 patients receiving anti-VEGF based targeted therapy. Quantitative methylation-specific PCRs were carried out following bisulphite conversion of DNA for CpG island methylation analysis of the five candidate genes, CST6, GATA5, LAD1, hsa-miR124-3 and hsa-miR9.1 identified in advance as potential prognosticators for RCC. For Kaplan Meier survival analysis relative methylation values were uniformly dichotomized and logrank statistics calculated. The analyses of sensitivity and specificity were carried out using a cutoff of 6 months for PFS to categorize for therapy failure and response, as described in the literature. Results: Hypermethylation of CST6 and LAD1 shows a highly significant association with a shortened PFS following first-line therapy (p=0.009, p=0.004, logrank test). The median survival observed for the high and low methylation group was 2.0 and 11.4 months for CST6 and LAD1. Moreover, LAD1 methylation showed a specificity of 1.0 (0.65-1.0, 95%CI) and a sensitivity of 0.73 (0.43-0.90, 95%CI) for detection of therapy failure. For CST6 methylation analysis a specificity of 0.86 (0.49-0.97, 95%CI) and a sensitivity of 0.82 (0.52-0.95, 95%CI) was detected. Conclusions: The analysis of our discovery cohort revealed that CGI methylation of CST6 and LAD1 predicts a shortened PFS of patients after anti-VEGF therapy. Provided, these results can be confirmed in an independent larger evaluation cohort, detection of hypermethylated loci in primary RCC would allow, to our knowledge for the first time, a molecular-based clinical management of patients.

e22076 Background: Kidney Cancer (RCC) is one of the top ten causes of cancer dependent death. Anti-VEGF targeted therapy has demonstrated increased progression-free (PFS) and overall survival in RCC patients, though the clinical outcome is still poor overall. Stratification of patient treatment currently depends on different clinical scoring systems such as the Memorial Sloan Kettering Cancer Center score. However, identification of molecular phenotypes of RCC patients could improve stratification of targeted therapies and prediction of clinical course. We investigated whether DNA hypermethylation-based markers can predict the PFS following first-line therapy. Methods: We examined primary tumor tissues obtained from 18 patients receiving anti-VEGF targeted therapy. Quantitative methylation-specific PCRs were carried out for CpG island (CGI) methylation analysis of 5 candidate genes CST6, GATA5, LAD1, hsa-miR124-3 and hsa-miR9.1 identified in advance as potential prognosticators for RCC. For Kaplan Meier survival analysis relative methylation values were uniformly dichotomized and logrank statistics calculated. The analyses of sensitivity and specificity were carried out using a cutoff of 6 months for PFS to categorize for therapy failure and response. Results: Hypermethylation of CST6 and LAD1 shows a highly significant association with a shortened PFS following first-line therapy (p=0.009, p=0.004, logrank test). The median survival observed for the high and low methylation group was 2.0 and 11.4 months for CST6 and LAD1. Moreover, LAD1 methylation showed a specificity of 1.0 (0.65-1.0, 95%CI) and a sensitivity of 0.73 (0.43-0.90, 95%CI) for detection of therapy failure. For CST6a specificity of 0.86 (0.49-0.97, 95%CI) and a sensitivity of 0.82 (0.52-0.95, 95%CI) was detected. Conclusions: The analysis of our discovery cohort revealed that CGI methylation of CST6 and LAD1 predicts a shortened PFS of patients after anti-VEGF therapy. Provided, these results can be confirmed in an independent larger evaluation cohort, detection of hypermethylated loci in primary RCC would allow, to our knowledge for the first time, a molecular-based clinical management of patients.

370 Background: Transcriptional inactivation and CGI methylation of GATA3 and −5 has been reported to be involved in mammary carcinoma, pancreatic cancer, colorectal and gastric carcinogenesis. A recent study demonstrated that a loss of GATA-3 expression due to partially methylation silencing in several renal cell carcinoma (RCC) patients. We quantitatively investigated GATA3 and −5 CGI methylation in RCC and analyzed its association with clinical characteristics as well as progression free survival of patients. Methods: Methylation data were obtained from a quantitative methylation-specific polymerase chain reaction assay (QMSP) for both genes. We investigated 108 RCC and 77 paired tissue samples as well as six RCC cell lines. Statistical analyses were carried out using the paired t-test for matched tumor (TU) and adjacent normal (adN) samples, logistic regression for comparisons of independent samples and cox regression for survival analysis. Results: In paired samples we found a significant higher methylation in TU compared to adN for GATA3 (P=0.007) and for GATA5 (P=3.6*10−9) for all RCCs. GATA5 showed also strong correlations between methylation and status of metastasis (P=0.05) and advanced (pT≥3 and/or N+, M+) tumor samples compared to localized (pT≤2, N0, M0) tumors (P=4.7*10−9). A decreased progression free survival in cox proportional hazard model analysis could be demonstrated for patients with a high GATA5 methylation (P=0.0006, HR=6.5) and a trend could also be seen for GATA3 methylated patients (P=0.06). Conclusions: GATA3 and −5 were identified to demonstrate tumor-specific CGI hypermethylation in renal cell cancer patients. The association of GATA5 CGI methylation with metastasis, advanced disease and progression free survival of patients indicates that epigenetic alterations of both genes are involved in renal cell carcinogenesis. GATA5 methylation could serve as a biomarker for tumor progression. Further prospective and functional investigations are necessary to clarify whether CGI methylation of GATA family members can provide independent information for future clinical management of patients with RCC.