FOXP3 and pancreatic neoplasm: Infiltration of lymphocytes was also analyzed in PKF and PKF2h mice, which revealed that infiltration of cytotoxic CD8+ T cells and regulatory T cell-specific FoxP3+ cells decreased in the pancreatic tumor nest in PKF2h mice, whereas no significant difference of CD4+ suppressor T cells and CD45R+ B lymphocytes was detected between PKF and PKF2h mice (Fig. 5a, b).