The initial efforts to introduce CARs into macrophages were pioneered by Biglari and colleagues in 2006, in which a chimeric CD64 molecule was developed, comprising a single-chain variable fragment (scFv) designed to target the human carcinoembryonic antigen (CEA), along with the transmembrane and cytoplasmic domains of human CD64, resulting a significant reduction in the tumor growth rate in a xenotransplantation model [140]. The gene discussed is CEACAM5; the disease is neoplasm.