AIM To identify whether chitinase 3-like 1(CHI3 L1) serves as a suitable biomarker for the prognosis of esophageal squamous cell carcinoma(ESCC) and to analyze this protein’s cellular source.METHODS An ELISA was conducted to detect the concentration of CHI3 L1 in the serum of 150 ESCC patients diagnosed between January 2001 and February 2005. The prognostic relevance of CHI3 L1 was evaluated by a Kaplan-Meier and Cox regression analysis. The immunohistochemistry was reanalyzed,and fluorescent staining was utilized to explore the cellular origins of CHI3 L1. We stimulated monocyte-derived macrophages(MDMs) with either IL-6 or the supernatant of the ESCC cell line Eca-109 and later investigated the level of CHI3 L1 by q PCR and ELISA.RESULTS The level of serum CHI3 L1 was higher in older patients(≥ 60) than in patients under the age of 60(P = 0.001). The patients with higher levels of CHI3 L1 had a significantly shorter overall survival,whereas the traditional markers,carcinoembryonic antigen and squamous cell carcinoma antigen,were less effective(P > 0.05). A multivariate Cox analysis(P = 0.001) indicated that CHI3 L1 was an independent prognostic factor for ESCC patients. Peritumoral macrophages in ESCC exhibited high levels of CHI3 L1. Interleukin-6(IL-6) and the supernatant of Eca-109 containing IL-6 stimulated MDMs to secrete CHI3 L1. The serum concentration of CHI3 L1 in the ESCC patients showed a weak correlation with the laboratory inflammatory parameters neutrophil(NEU,P = 0.045),neutrophil/lymphocyte rate(NLR,P = 0.016),and C-reactive protein(CRP,P < 0.001).CONCLUSION Our study first established a connection between the pretreated CHI3 L1 and patients with ESCC,and the serum CHI3 L1 was primarily secreted by ESCC-surrounded macrophages. AIM To identify whether chitinase 3-like 1 (CHI3 L1) serves as a suitable biomarker for the prognosis of esophageal squamous cell carcinoma (ESCC) and to analyze this protein’s cellular source. METHODS An ELISA was conducted to detect the concentration of CHI3 L1 in the serum of 150 ESCC patients diagnosed between January 2001 and February 2005. The prognostic relevance of CHI3 L1 was evaluated by a Kaplan-Meier and Cox regression analysis. The immunohistochemistry was reanalyzed, and fluorescent staining was utilized to explore the cellular origins of CHI3 L1 . We stimulated monocyte-derived macrophages (MDMs) with either supernatant of the ESCC cell line Eca-109 and later investigated the level of CHI3 L1 by q PCR and ELISA. RESULTS The level of serum CHI3 L1 was higher in older patients (≥ 60) than in patients under the age of 60 (P = 0.001). The patients with higher levels of CHI3 L1 had a significantly shorter overall survival, while the traditional markers, carcinoembryonic A multivariate Cox analysis (P = 0.001) indicated that CHI3 L1 was an independent prognostic factor for ESCC patients. Peritumoral macrophages in ESCC exhibited high levels of CHI3 L1. Interleukin -6 (IL-6) and the supernatant of Eca-109 containing IL-6 stimulated MDMs to secrete CHI3 L1. The serum concentration of CHI3 L1 in the ESCC patients showed a weak correlation with the laboratory inflammatory parameters neutrophil (NEU, P = 0.045), neutrophil / lymphocyte rate (NLR, P = 0.016), and C-reactive protein (CRP, P <0.001) .CONCLUSION Our study first established a connection between the pretreated CHI3 L1 and patients with ESCC, and the serum CHI3 L1 was was secreted by ESCC-surrounded macrophages.