CD8A and neoplasm: CAR is a chimeric recombinant molecule consisting of an extracellular tumor antigen-binding domain typically represented by a single-chain fragment variable (scFv), a transmembrane (CD3, CD8, CD28 and FcεRI) and an intracytoplasmic region composed of CD8, CD28 or CD137 and CD3ζ as an intracellular signaling domain [25,26].