FOXP3 and neoplasm: Stratifying regions by MSH6 labeling revealed a clear increase in infiltrating CD8-positive cytotoxic T cells (Fig. 5d), CD20-positive B cells (Fig. 5e), CD4-positive T cells (Fig. 5f) and FoxP3-positive Treg cells (Fig. 5g) in MSH6-deficient tumor regions.