Relationship between Serum Levels of Interleukin 6, Various Disease Parameters, and Malnutrition in Patients with Esophageal Squamous Cell Carcinoma

Abstract

Serum levels of interleukin 6 (IL-6) are correlated with the disease status and prognosis in cancer patients. IL-6 is also an important mediator of experimental cancer cachexia. We investigated the production of IL-6 and IL-6 receptors and expression of IL-6 mRNA by esophageal squamous carcinoma cells using immunohistochemical staining and in situ reverse transcription-PCR. We also measured levels of serum IL-6 using an ELISA in 50 patients with esophageal squamous cell carcinoma (ESCC) to determine the correlation between serum levels of IL-6 and clinicopathological factors. IL-6 mRNA was expressed in the primary tumor. Esophageal squamous carcinoma cells produced both IL-6 and IL-6 receptor. IL-6 concentrations were significantly higher in the primary tumor than in the normal epithelium. The incidences of weight loss, tumor invasion to adjacent organs, and noncurative resection were significantly higher in ESCC patients with serum levels of IL-6 ≥ 7 pg/ml (n = 13, group C) compared with patients with serum levels <7 pg/ml and ≥3 pg/ml (n = 14, group B) and <3 pg/ml (n = 23, group A). Tumor size and C-reactive protein levels were significantly higher and albumin levels were significantly lower in group C. Results suggest that IL-6, which is produced by tumor cells, may be related to various disease parameters as well as to the nutritional status in patients with ESCC.