In order to further examine how PGRN affects tumor immune cells, by using immunohistochemical staining, we observed that the infiltration of CD4+ cells, CD8+ cells, and granzyme B+ cells in breast cancer tumor tissues in PGRN−/− group was more than those in WT group, especially CD8+ cells and Granzyme B+ cells. The gene discussed is CD8A; the disease is neoplasm.