Human leukocyte antigen G is associated with esophageal squamous cell carcinoma progression and poor prognosis.

•HLA-G positive rates are significantly higher in patients with ESCC than controls.•HLA-G1 and HLA-G5 were the main isoforms in ESCC tissues.•The plasma sHLA-G and IL-10 level was higher in ESCC patients than the controls.•HLA-G expression correlated with cancer cell differentiation and metastasis.•HLA-G positive expression and sHLA-G>15.04U/mL showed poorer prognosis of ESCC.