High YKL-40 is associated with poor survival in patients with renal cell carcinoma: a novel independent prognostic marker

Abstract

Objective: YKL-40 is an inflammation-associated glycoprotein supposed to have a role in cell survival and angiogenesis. Renal cell carcinoma (RCC) is characterized by varying prognosis and risk of relapse after a disease-free period of years. Prognostic markers are critically needed. This study investigated whether YKL-40 could be a useful biomarker in RCC patients.

Materials and methods: Blood samples from 82 patients with RCC were collected at the time of diagnosis and 3, 5 and 9 months and 2 and 3 years after nephrectomy. YKL-40 levels were determined by enzyme-linked immunosorbent assay. Survival of patients and relapse of RCC were followed up to 15 years.

Results: Circulating YKL-40 levels were increased in patients with metastatic RCC at the time of diagnosis (median 115.7 ng/ml, interquartile range 61.0–221.6 ng/ml). Among patients primarily diagnosed with non-metastatic RCC, baseline YKL-40 levels were significantly higher in patients who experienced a relapse during follow-up (103.7, 59.3–242.0 ng/ml) than in patients without relapse (50.6, 33.8–97.1 ng/ml). High baseline YKL-40 was highly associated with poor prognosis in RCC: in age-adjusted univariate analysis, YKL-40 over 120 ng/ml (highest tertile) predicted over five-fold mortality in 5 years, and in multivariate analysis high YKL-40 remained a statistically significant independent risk factor for 5 and 15 year survival.

Conclusions: Increased circulating YKL-40 levels were significantly associated with poor survival in patients with RCC. The results suggest YKL-40 as a useful novel biomarker in evaluating prognosis and relapse risk in RCC, being especially beneficial in patients primarily diagnosed with non-metastatic RCC.

Keywords:

• Prognosis
• renal cell carcinoma
• YKL-40

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

The study was financially supported by the Competitive State Research Financing of the Expert Responsibility area of Tampere University Hospital and the Research Fund of E.K. Savolainen.