Circulating and tissue expression levels of YKL-40 in renal cell cancer

Abstract

PURPOSE: Blood levels of YKL-40 are elevated in various malignancies and other inflammatory diseases. Moreover, higher YKL-40 levels, have consequently been shown to correlate with poor prognosis in several cancers. The aim of this study was to investigate the prognostic value of circulating and tissue levels of YKL-40 in renal cell cancer (RCC). PATIENTS AND METHODS: Preoperative YKL-40 serum/plasma levels were determined in 222 surgically treated RCC patients, as well as in 35 controls. Postoperative serum samples were analysed in 19 of the 222 RCC cases. Moreover, gene expression levels were assessed in 101 RCC frozen tissue samples using quantitative RT real-time PCR. Finally, immunohistochemical analysis was done in 37 RCC cases to assess the tissue localization of YKL-40. Results were correlated with clinicopathological and follow-up data. RESULTS: YKL-40 serum but not tissue gene expression levels were higher in RCC patients compared to controls (p= 0.050). Serum YKL-40 levels significantly increased following nephrectomy (p< 0.001). High circulating YKL-40 concentrations were independently associated with shorter survival in both serum and plasma cohorts. YKL-40 gene expression was not correlated with patients' prognosis. CONCLUSIONS: Preoperative elevated circulating levels of YKL-40 predict survival in patients treated with nephrectomy for RCC independently of determining from serum or plasma. Tumour cells do not seem to be the main source of elevated serum/plasma YKL-40 levels in RCC patients.