Moreover, DCIS mixed with synchronous IBC harboured more dense stromal TILs, PD1, PDL1 and various subpopulation of lymphocytes within the stroma than pure DCIS, with the highest difference observed with stromal PD1+ (Z = 5.8, p < 0.0001) followed by stromal CD8+ (Z = 5.5, p < 0.0001). Here, CD274 is linked to ductal breast carcinoma in situ.