In vivo therapeutic results the knockout of PD-L1 in BMFs distinctly reduced the tumor-promoting capacity compared to the unmodified BMFs as well as rescued the inhibitory effects of BMFs on the anti-tumor immune responses, indicating that the BMFs induced facilitated-tumor growth and repressed-anti-tumor immune responses was, to some extent at least, caused by the upregulation of PD-L1 in BMFs. The gene discussed is CD274; the disease is neoplasm.