Association of serum level of YKL-40 in patients with squamous cell carcinoma of the head and neck with survival

Abstract

5551 Background: High serum YKL-40 is associated with poor prognosis in breast-, colorectal-, ovarian-, prostate-, small cell lung carcinoma and malignant melanoma. YKL-40 is secreted by cancer cells, macrophages and neutrophils. Its function in cancer is unknown. It may be a growth factor, play a role in angiogenesis or protect against apoptosis. The aim was to examine serum YKL-40 in patients with squamous cell carcinoma of the head and neck (SCCHN). Methods: YKL-40 was determined by ELISA (Quidel, Santa Clara, CA) in serum samples from 138 patients with SCCHN (median age 60, range 44–92 years) before surgery and/or fractionated radiotherapy (total dose of 60–68 Gy, 2-Gy fractions). 42 patients had stage 1, 28 stage 2, 22 stage 3, and 46 stage 4 disease. The median follow-up time was 4.0 years (range 15 days–8.5 years). 91 patients had died. Results: Serum YKL-40 was increased (p < 0.001) in patients with SCCHN (median 120 μg/l, range 25–1848 μg/l) compared to healthy controls (43 μg/l, 20–184 μg/l, n = 245). Serum YKL-40 was elevated in 52% of the patients. Patients with stage 1 disease had lower, but non-significant, serum YKL-40 compared to patients with stage 2–4 disease (median 113 μg/l, range 25–1000 μg/l vs. 139 μg/l, 29–1848 μg/l, p = 0.06). Patients with high serum YKL-40 had significantly shorter survival than patients with normal serum YKL-40 (33 months vs. 74 months, p = 0.01 logrank test). Univariate analysis of serum YKL-40 (log transformed and treated as a continuous covariate) showed significant association with overall survival after start of therapy (HR = 1.4, 95% CI: 1.2–1.7, p = 0.0004). Multivariate Cox analysis including age, stage and serum YKL-40 (log transformed and treated as a continuous variable) showed that stage (stage 3–4 vs. stage 1–2, HR = 3.0, 95% CI: 1.9–4.6, p < 0.0001) and serum YKL-40 (HR = 1.5, 95% CI: 1.2–1.8, p = 0.0003) were independent prognostic variables of overall survival. Conclusions: Serum YKL-40 is a prognostic biomarker of overall survival in SCCHN patients. No significant financial relationships to disclose.