Apoptotic DNA fragments in serum of patients with muscle invasive bladder cancer: a prognostic entity.

Patients with malignancies often possess increased concentrations of cell-free serum DNA. In this study, we investigated serum DNA levels in each 45 patients with bladder cancer (BCA) undergoing radical cystectomy and with benign prostate hyperplasia. A quantitative real-time PCR was used to amplify a 124 bp (PTGS2; mostly apoptotic origin) and a 271 bp (Reprimo; mostly necrotic origin) DNA fragment. Changes in the origin of DNA fragments were specified as the Apoptosis Index (AI, ratio of 124 bp/271 bp fragments). Small and large fragments were increased (p<0.001 and p=0.041) in BCA patients. The AI increase suggests that DNA fragmentation was mostly (p<0.001) caused by apoptosis. High levels of small DNA fragments distinguished between BCA and BPH with high sensitivity (96%) and moderate specificity (62%). DNA levels and the AI were not correlated with clinicopathological parameters. However, an increased AI was correlated with BCA-specific mortality in a multivariate analysis (p=0.011) indicating that the AI is an independent prognostic factor. Thus, cell-free DNA seems to be a useful prognostic marker in patients with BCA.

Systematic Expression Analysis of Mitochondrial Complex I Identifies NDUFS1 as a Biomarker in Clear-Cell Renal-Cell Carcinoma.

INTRODUCTION: Mitochondrial dysfunction is common in cancer, and the mitochondrial electron transport chain is often affected in carcinogenesis. So far, little is known about the expression of the mitochondrial complex I (NADH:ubiquinone oxidoreductase) subunits in clear-cell renal-cell carcinoma (ccRCC). MATERIALS AND METHODS: An expression profile of the mitochondrial complex I subunits was determined using the NextBio database. Subsequently, the expression of selected subunits was experimentally validated on mRNA (quantitative real-time polymerase chain reaction) and protein (Western blot analysis, immunohistochemistry) level. RESULTS: We observed that 7 subunits of the complex I were down-regulated in at least 3 microarray studies. Deregulated mRNA expression was confirmed for NDUFA3, NDUFA, NDUFB1, NDUFB9, NDUFS1, NDUFS8, and NDUFV1. Low NDUFS1 mRNA expression was a significant and independent adverse predictor of a shorter overall survival in our mRNA cohort and the ccRCC cohort of The Cancer Genome Atlas project. NDUFS1 expression was furthermore analyzed on the protein level, and a distinct down-regulation was observed in ccRCC as well as in the chromophobe and the sarcomatoid subtype compared to normal renal tissue. CONCLUSION: Expression alterations occur in only a few subunits of the mitochondrial complex I subunits in ccRCC, and altered mRNA and protein expression levels of NDUFS1 may be useful to distinguish between renal-cell carcinoma and normal renal tissue.

Systematic expression analysis of the mitochondrial complex III subunits identifies UQCRC1 as biomarker in clear cell renal cell carcinoma.

Mitochondrial dysfunction is common in cancer, and the mitochondrial electron transport chain is often affected in carcinogenesis. So far, few is known about the expression of the mitochondrial complex III (ubiquinol-cytochrome c reductase complex) subunits in clear cell renal cell carcinoma (ccRCC). In this study, the NextBio database was used to determine an expression profile of the mitochondrial complex III subunits based on published microarray studies. We observed that five out of 11 subunits of the complex III were downregulated in at least three microarray studies. The decreased mRNA expression level of UQCRFS1 and UQCRC1 in ccRCC was confirmed using PCR. Low mRNA levels UQCRC1 were also correlated with a shorter period of cancer-specific and overall survival. Furthermore, UQCRFS1 and UQCRC1 were also decreased in ccRCC on the protein level as determined using Western blotting and immunohistochemistry. UQCRC1 protein expression was also lower in ccRCC than in papillary and chromophobe subtypes. Analyzing gene expression and DNA methylation in The Cancer Genome Atlas cohort revealed an inverse correlation of gene expression and DNA methylation, suggesting that DNA hypermethylation is regulating the expression of UQCRC1 and UQCRFS1. Taken together, our data implicate that dysregulated UQCRC1 and UQCRFS1 are involved in impaired mitochondrial electron transport chain function.