NR4A1 and esophageal squamous cell carcinoma: A lower Nur77 expression level was associated with distant metastasis (P = 0.012) and advanced tumor/node/metastases (TNM) stage (P = 0.017), whereas a higher IRF1 expression was associated with lymphatic metastasis (P = 0.013) and advanced TNM stage (P = 0.029) in ESCC patients.