We discovered that 24 h after carbon ion irradiation of two ESCC cell lines with different degrees of differentiation, CDH1 expression was upregulated, while that of MMP2 and STAT3 was downregulated at the transcriptional level in ECA109 cells; these changes consequently inhibited the metastasis of tumor cells. The gene discussed is STAT3; the disease is esophageal squamous cell carcinoma.