Fig. 1.

TILs and expression of MHC class I antigen in representative UC tumor samples. (A) An intratumoral CD8 TIL (arrow) accompanied by stromal CD8 lymphocyte infiltration (arrowheads). (B) Abundant CD8 TILs (arrows) infiltrating a solid tumor with no stromal component. (C) Muscle-invasive case showing heterogeneous expression of class I MHC. (D) Homogeneous expression of class I MHC in another tumor. (E) Class I MHC are not expressed by cancer cells, but are expressed by endothelial cells (arrow). (F) Down-regulation of class I MHC expression associated with cancer invasion. Class I MHC is expressed in the mucosal component (arrow), but not in the invasive component (arrowheads). (Scale bar, 50 μm.)