miR-22 is down-expressed in ESCC tissues. (A) The relative levels of miR-22 in thirty paired of ESCC samples were measured by real-time quantitative RT–PCR, and the U6 small nuclear RNA was used as an internal control. Student’s t test was used to analyze the significant differences between the tumor and normal tissues. (B) and (C) The expression of miR-22 in metastasis tumors and advanced histologic grades. Student’s t-test was used to analyze the significant differences.