In lung cancer, Fpr2 can inhibit tumor growth in mice subcutaneously transplanted with Lewis lung cancer (LLC) cells by limiting the macrophage response to the tumor-derived chemokine C-C motif chemokine ligand 2 (CCL2) and inhibiting the polarization of macrophage M2 (Liu et al., 2013). The gene discussed is FPR2; the disease is neoplasm.