SiRNA was employed to downregulate the expression of PIGU in MCF7 and MDA-MB-231 cells, and the ability of PIGU to effectively retard proliferation of MCF7 and MDA-MB-231 cells was confirmed by CCK8 assay (Figure 8E).We also employed a multiplex immunofluorescence staining technique to detect the expression levels of GPAA1 and PIGU molecules, as well as the degree of CD8 T cell infiltration in 25 local breast cancer tissues. The gene discussed is CD8A; the disease is breast cancer.