In the present study, we further extended this model to investigate whether cytotoxic T cells can access brain metastases in the brain parenchyma, and whether and how anti-PD-L1 antibody has antitumor effects on established brain metastases using a xenograft mouse model of hematogenous brain metastases with adoptive transfer of immune cells from tumor-immunized immuno-competent mice. The gene discussed is CD274; the disease is neoplasm.