Serum amyloid A as indicator of distant metastases but not as early tumor marker in patients with renal cell carcinoma.

The aim of the present study was to evaluate the clinical significance of the concentration of serum amyloid A (SAA) in patients with renal cell carcinoma (RCC). SAA protein was determined with enzyme-linked immunosorbent assay in serum samples of 55 healthy controls and 98 RCC patients subdivided into groups with localized tumor (N0M0, n=40), with lymph node metastases (N1M0, n=13), and distant metastases (M1, n=45). SAA concentrations in controls and N0M0 group of RCC were not different while SAA concentrations were significantly elevated in M1 patients compared to the N1M0 and N0M0 patients. In this respect, SAA provided an accurate detection of distant metastases with the area under the ROC curve of 0.86. SAA was identified as a significant independent factor of survival in RCC patients using the multivariate Cox proportional hazards regression model. SAA could be a useful analyte in predicting the survival outcome of RCC patients.

Plasma matrix metalloproteinase-7 as a metastatic marker and survival predictor in patients with renal cell carcinomas.

We evaluated the clinical usefulness of plasma matrix metalloproteinase-7 (MMP-7) as a diagnostic and prognostic biomarker in patients with renal cell carcinoma (RCC). MMP-7 was quantified in plasma of 50 healthy subjects and 97 RCC patients using a Fluorokine MultiAnalyte Profiling assay. RCC patients were stratified into the following groups: without metastases (N0M0; n = 39), with lymph nodes (N1M0; n = 13), and with distant metastases (M1; n = 45). Diagnostic performance of MMP-7 was analyzed by the receiver operating characteristics (ROC) curve. Kaplan-Meier analysis and the Cox regression model were used to estimate the impact of MMP-7 on the cancer-specific survival outcome of RCC patients. MMP-7 was significantly higher in both metastatic groups N1M0 and M1 (medians, 3.82 and 3.34 microg/L) compared to N0M0 group or controls (medians, 1.85 and 1.64 microg/L; all P < 0.001). In ROC analysis, the area under the ROC curve of MMP-7 was 0.80 in the detection of metastases in RCC (P < 0.0001). In the Kaplan-Meier analysis, patients with MMP-7 above the 95th percentile of controls showed less favorable survival rates compared to those with normal MMP-7 (log-rank test, 15.7; P < 0.0001). High MMP-7 was associated with cancer-related mortality estimated by univariate Cox regression (risk ratio, 4.34, 95% CI, 1.12-10.6; P = 0.032). The multivariate Cox regression model determined MMP-7 (risk ratio, 2.70, 95% CI, 1.39-5.24; P = 0.003) and metastases (risk ratio, 5.81, 95% CI, 2.77-12.2; P < 0.0001) as independent determinants of cancer-related survival outcomes. In conclusion, increased plasma MMP-7 could be related to metastatic disease and poor prognosis in patients with RCC.

In search of suitable reference genes for gene expression studies of human renal cell carcinoma by real-time PCR.

BACKGROUND: Housekeeping genes are commonly used as endogenous reference genes for the relative quantification of target genes in gene expression studies. No conclusive systematic study comparing the suitability of different candidate reference genes in clear cell renal cell carcinoma has been published to date. To remedy this situation, 10 housekeeping genes for normalizing purposes of RT-PCR measurements already recommended in various studies were examined with regard to their usefulness as reference genes. RESULTS: The expression of the potential reference genes was examined in matched malignant and non-malignant tissue specimens from 25 patients with clear cell renal cell carcinoma. Quality assessment of isolated RNA performed with a 2100 Agilent Bioanalyzer showed a mean RNA integrity number of 8.7 for all samples. The between-run variations related to the crossing points of PCR reactions of a control material ranged from 0.17% to 0.38%. The expression of all genes did not depend on age, sex, and tumour stage. Except the genes TATA box binding protein (TBP) and peptidylprolyl isomerase A (PPIA), all genes showed significant differences in expression between malignant and non-malignant pairs. The expression stability of the candidate reference genes was additionally controlled using the software programs geNorm and NormFinder. TBP and PPIA were validated as suitable reference genes by normalizing the target gene ADAM9 using these two most stably expressed genes in comparison with up- and down-regulated housekeeping genes of the panel. CONCLUSION: Our study demonstrated the suitability of the two housekeeping genes PPIA and TBP as endogenous reference genes when comparing malignant tissue samples with adjacent normal tissue samples from clear cell renal cell carcinoma. Both genes are recommended as reference genes for relative gene quantification in gene profiling studies either as single gene or preferably in combination.

Elevated plasma osteopontin as marker for distant metastases and poor survival in patients with renal cell carcinoma.

PURPOSE: To evaluate diagnostic and prognostic significance of plasma osteopontin (OPN) in patients with renal cell carcinoma (RCC). METHODS: The retrospective study included 80 patients with RCC (pN0M0, n = 32; pN1M0, n = 11; M1, and n = 37), and 52 healthy controls (27 females and 25 males). OPN, the bone marker bone-specific alkaline phosphatase (bALP) and carboxyterminal telopetide of type-I collagen (ICTP), and the enzymes alanine aminotransferase (ALAT), and gamma-glutamyltransferase (GGT) were evaluated together with Memorial Sloan-Kettering Cancer Center (MSKCC) laboratory parameters. Data were analyzed by receiver-operating characteristics (ROC), survival analysis, and Cox proportional hazards regression model. RESULTS: OPN and ICTP levels in RCC patients with distant metastases were significantly elevated (medians 115 and 4.7 microg/l, P < 0.001) compared to those without metastases (31.1 and 2.5 microg/l) and controls (28.9 and 2.1 microg/l) but did not differ between patients with bone or non-bone metastases. Both bALP and ALAT were not different between all study groups, while GGT was only increased in patients with non-bone metastases. In ROC analysis, OPN showed the best discrimination between patients with and without metastases (area under the curve: 0.888). High OPN values were associated with poor survival (Kaplan-Meier analysis, log-rank test, P = 0.002). Multivariate Cox regression with forward and backward stepwise elimination confirmed plasma OPN as independent predictive survival factor in RCC patients. CONCLUSIONS: Our results show that high plasma OPN levels are associated with distant metastases and poor survival in RCC patients. The use of OPN as potential marker to monitor new treatment strategies in patients with advanced RCC should be evaluated in prospective studies.

Plasma osteopontin in comparison with bone markers as indicator of bone metastasis and survival outcome in patients with prostate cancer.

BACKGROUND: The study was undertaken to evaluate the diagnostic and prognostic value of plasma osteopontin (OPN) in comparison to bone markers as well as the relationships between the markers and clinico-pathological factors in prostate cancer (PCa) patients. METHODS: OPN and the bone markers carboxyterminal-telopeptide of type I collagen, bone-specific alkaline phosphatase (bALP), and aminoterminal-propeptide of type I procollagen (PINP) were measured in 90 PCa patients with and without bone metastases, 35 patients with benign prostatic hyperplasia, and 29 healthy men. RESULTS: OPN and bone markers were significantly elevated in patients with bone metastases compared to the other groups. Significant correlations were found between all four-bone markers (r(s) = 0.43-0.79, all P < 0.01). OPN correlated with tumor grade (r(s) = 0.23, P < 0.05). In receiver-operating characteristics (ROC) analyses, OPN and bone markers were effective in distinguishing PCa patients with and without bone metastases showing areas under the curve (AUC) between 0.80 and 0.88 (all P < 0.001). OPN had an AUC of 0.85 that increased in combination with bALP up to 0.93 providing at the point with the highest diagnostic accuracy both a sensitivity and specificity of about 90%. Kaplan-Meier analyses and Cox proportional hazards regression models showed decreased survival of patients with high OPN and bone marker levels, while only high OPN and PINP were independent negative prognostic factors for PCa-related death. CONCLUSIONS: OPN alone or in combination with bone markers is useful as diagnostic marker in the detection of bone metastases and as prognosticator in the survival prediction in PCa patients.