Background: Disturbances in adipokine secretion are associated with the risk of cancer growth and progression.
Objectives: The aim of the study was to evaluate the mRNA expression and protein levels of apelin, the apelin receptor, resistin, and adiponectin in the tumor tissues of surgically treated esophageal squamous cell carcinoma (ESCC) patients. Concentrations of serum adipokines were assessed in relation to ESCC progression.
Material and methods: The study group consisted of 53 patients with ESCC and 27 controls. In the ESCC group, 27 patients were surgically treated and 26 were treated with palliative procedures. RT-PCR and ELISA tests were used to measure the mRNA expression and protein level of adipokines in tissues and their concentration in serum.
Results: We found that mRNA expression and protein concentrations of apelin, the apelin receptor and resistin were significantly higher in tumor tissue than in control tissue. The protein concentration of apelin were significantly increased in the tumors of patients with lymph node metastasis (p < 0.005). Circulating levels of apelin, the apelin receptor and resistin were significantly higher in the cancer patients than in controls (p < 0.05 for all). The concentration of serum apelin receptor significantly decreased in patients with stage IV cancer, the presence of lymph node or distant metastasis (p < 0.05).
Conclusions: Apelin may participate in lymphangiogenesis and the progression of ESCC. The apelin receptor is intensely produced in the early stage of cancer development and it may take part in the carcinogenic processes of ESCC.
Keywords: adipokines; apelin; apelin receptor; esophageal squamous cell carcinoma.