In the present study, we found that miR-621 manifested a negative and significant correlation with PYCR1 mRNA expression in ESCC tissues, miR-621 over-expression decreased PYCR1 expression, and miR-621 inhibition increased PYCR1 expression in ESCC cells. The gene discussed is PYCR1; the disease is esophageal squamous cell carcinoma.