Analysis of various TILs subsets in DCIS with and without microinvasion showed that CD8+PD1+ TILs were more frequent in DCIS with microinvasion regardless of the ER status, whereas CD8+PD1- TILs were the only subset whose density differed between HER2-positive and HER2-negative patients [39]. Here, CD8A is linked to ductal breast carcinoma in situ.