These models possess the capacity to reproduce a variety of phenotypes, and the format of the model itself (i.e., its ability to fit into a test tube) provides a wide range of opportunities for researching the characteristics of cancer development, metastasis, treatment, and resistance to therapy The hypothesis is proposed that the cytokines LIF, SDF-1, HGF, and SCGF-β may be associated with a regulatory role in PD-L1 expression by tumor cells, thereby opening up potential avenues for investigating mechanisms of immune evasion. The gene discussed is HGF; the disease is cancer.