ObjectiveTo investigate the expression of MicroRNA 155 (miR-155) in esophageal squamous cell carcinoma (ESCC) and analyze its correlation with clinicopathological features of ESCC. MethodsThis study included 54 patients with primary ESCC who underwent radical esophagectomy in Department of Thoracic Surgery, Henan Cancer Hospital of Zhengzhou University between January 2010 and November 2012. There were 47 males and 7 females with median age of 61 years (range, 45 to 82 years). Forty patients were in stage Ⅰ or Ⅱ and 14 patients in stage Ⅲ a+b. Expression of miR-155 was determined by SYBR Green qRT-PCR in ESCC tissue and corresponding adjacent normal mucosa in surgical samples from the 54 patients, and its correlation with clinicopathological features was analyzed. ResultsExpression of miR-155 was significantly lower in ESCC tissue than that in adjacent normal mucosa (Z=-4.258, P=0.000).Expression level of miR-155 was significantly correlated with lymph node metastasis (P=0.040), but not significantly correlated with smoking (P=0.430), drinking (P=0.429), age (P=0.769), gender (P=0.671), depth of invasion (P=0.230), differentiation degree (P=0.896) or pTNM (P=0.407) of ESCC. ConclusionUnder-regulation of miR- 155 expression in ESCC tissue may lead to disorders of inflammation response, immune response and relevant tumor suppressor, and may play a significant role in carcinogenesis and progression of ESCC.