The CAR protein is composed of two domains: (a) The extracellular tumour-antigen receptor that specifically recognises tumour-associated antigens (TAA) on the cell-surface membrane of cancer cells (e.g., CD19 on B-cells); and (b) the intracellular signal transduction domain, which stimulates the engineered cell’s proliferation and function [1,9]. The gene discussed is CD19; the disease is cancer.