Fig. 2

Spatial distribution of tumor-infiltrating lymphocytes in CCA. In CCA, CD8+ T lymphocytes represent the majority of T lymphocytes, whereas CD4+ T lymphocytes were also common. B lymphocytes are only seen occasionally. The total number of NK cells is also modest, though higher than B cells. While CD8+ and CD4+ cells are mainly distributed around the cancer, while Foxp3 cells infiltrate into the tumor. CCA, cholangiocarcinoma; CD; cluster of differentiation; Foxp3, forkhead box p3; NK, natural killer; TGF, transforming growth factor