Kim et al. [26] found that in DCIS, the high infiltration of CD4 +, CD8 + and FOXP3 + T cells and the presence of PD-L1 + immune cells were related to clinicopathological features of worse biological behavior, such as high nuclear grade, comedo-type necrosis, and high Ki-67 proliferation index. Here, MKI67 is linked to ductal breast carcinoma in situ.