Abstract: Objective  To investigate the expression levels of serum microRNA-33a-5p (miR-33a-5p) and Sirtuin6 (SIRT6) in patients with esophageal cancer,and their relationship with clinical pathological characteristics and prognosis.Methods  From March 2018 to March 2020,123 newly diagnosed patients with esophageal cancer (esophageal cancer group) and 94 patients with esophagitis (benign lesion group) admitted to our hospital were collected as the research subjects,another 72 healthy individuals who underwent physical examination were regarded as the health control group;the clinical and pathological characteristics of esophageal cancer patients were collected.Real-time fluorescence quantitative PCR method was applied to detect the expression of miR-33a-5p and SIRT6 mRNA in three groups of serum,the relationship between the expression levels of serum miR-33a-5p and SIRT6 mRNA in esophageal cancer patients and clinical pathological characteristics was analyzed;TargetScanHuman website was applied to predict the targeting relationship between miR-33a-5p and SIRT6;Pearson method was applied to analyze the correlation between serum miR-33a-5p and SIRT6 mRNA expression levels in esophageal cancer patients;Kaplan-Meier method was applied to analyze the relationship between the expression levels of serum miR-33a-5p and SIRT6 mRNA in esophageal cancer patients and their prognosis;Cox regression was applied to analyze the prognostic factors of esophageal cancer patients.Results  The expression level of serum miR-33a-5p in the esophageal cancer group was greatly higher than that in the benign lesion group and healthy control group (P＜0.05),the expression level of serum SIRT6 mRNA was greatly lower than that of the benign lesion group and healthy control group (P＜0.05);TargetScanHuman website predicts that there was a targeted binding site between miR-33a-5p and SIRT6,and there was a negative correlation between serum miR-33a-5p and SIRT6 mRNA expression levels in esophageal cancer patients (r=-0.468,P＜0.05);the expression levels of serum miR-33a-5p and SIRT6 mRNA in esophageal cancer patients were related to TNM staging,lymph node metastasis,and degree of differentiation;the 3-year survival rate of esophageal cancer patients with low expression of serum miR-33a-5p and high expression of SIRT6 mRNA was greatly higher than that of esophageal cancer patients with high expression of miR-33a-5p and low expression of SIRT6 mRNA (P＜0.05);Cox- regression analysis showed that high expression of miR-33a-5p and low expression of SIRT6 mRNA were independent risk factors for death in esophageal cancer patients (P＜0.05).Conclusion  The expression level of serum miR-33a-5p in esophageal cancer patients is greatly increased,while the expression level of SIRT6 mRNA is greatly reduced;the expression levels of both are closely related to the clinical pathological characteristics and prognosis of esophageal cancer patients.

Key words: esophageal cancer, micro RNA-33a-5p, sirtuin6, clinical pathological characteristics, prognosis