Serum Amyloid A (SAA), C-reactive protein (CRP) and IL-6 as prognostic indicators in Renal Cell Carcinoma and Prostate Cancer

Abstract

9711 Background: IL-6, CRP and SAA are three biomarkers whose expressions have been shown to correlate with prognosis in select tumor models. We have evaluated these three biomarkers and their potential use as prognostic indicators in renal cell carcinoma (RCC) and prostate cancer in a retrospective study. Methods: Serum samples from patients with RCC or prostate cancer were obtained from IMPATH-BCP, Inc. (New York, NY). Healthy control subjects were also included. Serum levels of IL-6, CRP and SAA were measured using commercially available ELISA kits. Summary statistics were calculated and associations between variables were evaluated using linear regression analysis and Pearson correlation coefficient. Results: Serum levels of IL-6 (range <0.78 - 175 pg/mL), CRP (range 0.74 - 144.98 μg/mL) and SAA (<9.40 - 1530.84 ng/mL) were measured. All three biomarkers were found to be significantly higher in patients with RCC, while only SAA and CRP were found to be significantly higher in PC patients when compared to normal donors. Significant correlations between IL-6, CRP, and SAA were revealed by statistical analysis of the RCC serum data (IL-6/CRP r2=0.752; SAA/CRP r2=0.596; SAA/IL-6 r2=0.635). Correlation of these markers with patient survival (defined as the number of days between date of diagnosis and date of death) was found using Pearson correlation coefficients for RCC data analysis (IL-6 -0.4151, p=0.0063; CRP –0.4129, p=0.0059; SAA –0.3793, p=0.0158). In prostate cancer patients, no correlations between PSA and SAA, or CRP and IL-6 were found. Additionally, no significant correlation was observed between the investigated markers and survival (IL-6 0.0996, p=0.4650; CRP −0.0354, p=0.8219; SAA –0.0670, p=0.6207). Conclusions: Based on these results, it appears that there may be mild to moderate association between survival time and the inflammatory markers in RCC but not in PC. However, other clinical variables may affect these conclusions in these heterogeneous populations. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Centocor, Inc. Centocor, Inc. Centocor, Inc.