PDCD1 and breast carcinoma: As shown in Table 2, compared with that in patients with benign tumors, the proportion of CD4+Tn cells in patients with breast cancer decreased (mean: 27.9 vs. 33.5, P = 0.011), while the absolute number and proportion of CD4+CD57+T and CD4+PD-1+T cells significantly increased (P < 0.05).