CD8A and breast cancer: Mechanically, in both advanced breast cancer patients and breast tumor-bearing mice, STAT3 directly decreased the PKCβII protein and PRKCB2 expression by binding to negative regulatory elements of the PRKCB promoter [98], eventually leading to the suppression of DCs formation and this subtle change can delay the T cells activity, namely CD8+ CTLs (Fig. 2c) [99, 100].