PDCD1LG2 and invasive ductal breast carcinoma: Lindh et al. [41] found 10/34 (29%) ductal adenocarcinomas showing PD-L1+ tumor-infiltrating cells (positivity in 1–20% of cells), including the case with PD-L1+ tumor cells, while PD-L2 was negative in both tumor cells and tumor-infiltrating immune cells in all cases.