Previous studies have shown that macrophages can bind to cancer cells through specific ligand interactions (α4 integrins and vascular cell adhesion molecule-1 (VCAM-1), and NPs camouflaged with macrophage membranes can enhance the targeting of NPs in lung metastasis of breast cancer treatment [42, 43], owing to the inflammatory tendency of macrophages and the retention of membrane proteins [42, 44]. The gene discussed is VCAM1; the disease is breast cancer.