CAR represents a type of engineered receptors that is composed of a single-chain variable fragment (scFv) targeting tumor-associated-antigens (TAAs) or specific antigens for certain types of cells (e.g. CD19 on B cells), a transmembrane domain (TMD), and an intracellular signaling domain (ISD) (9) (Figure 1). The gene discussed is CD19; the disease is neoplasm.