PDCD1 and neoplasm: By comparing the prognostic models with a likelihood ratio test, using the increment in the log-likelihood of the models (∆LRχ2), we demonstrated that a combination of PD-1+ immune infiltrates and PDCD1 gene expression offered the highest additional prognostic value for both OS and DFS, compared with traditionally used clinicopathological parameters (Table 4), including patient age, tumor size, tumor grade and lymph node status.