Despite no relevant association of PD-1 expression with tumor size (data not shown), patients with lymph node metastasis (N+) had significantly higher PD-1 expression on CD4+ Tconv, Treg cells and CD8+ T cells compared to patients without lymph node metastasis (N-; Figure 5A–C). This evidence concerns the gene PDCD1 and metastatic malignant neoplasm in the lymph nodes.