The univariate analysis indicated that tumor diameter, degree of tumor differentiation, TNM stage, depth of tumor invasion, lymph node metastasis, and the expression levels of PD-1, PD-L1, FOXP3, CD25, CD4, and CD8 were factors significantly influencing EC prognosis (P < 0.05) (Table 1). This evidence concerns the gene PDCD1 and metastasis.