Fibrinogen-like protein 2 (Fgl2), a pleiotropic cytokine affecting multiple cellular functions, was found to be able to increase the aggregation of MDSCs through CXCL12 in lung cancer, and also induced the activation and pro-tumorigenic phenotype of CAFs, which are the main source of CXCL12 in TME [147]. The gene discussed is CXCL12; the disease is lung cancer.