Fig. 4

Tumor-infiltrating lymphocytes and EBV status. The invasive front is highlighted by a yellow dashed line, which separates the tumor part (T) from the nontumor part (NT). Few CD3(+) tumor-infiltrating lymphocytes (brown spot) (a). The infiltrating CD3(+) cells were composed mainly of CD4(+) cells (brown spot) (b) and a few CD8(+) cells (brown spot) (c). The invasive front had only a few lymphocytes. Most of the lymphocytes were scattered between tumor nests rather than within tumor nests. EBER in situ hybridization revealed no evidence of EBV infection in the tumor cells (positive is denoted by a dark blue spot in nuclei) (d); original magnification: ×100