CC49-ζ-modified CD4 and CD8 T cells were capable of killing TAG-72-expressing tumor cells with equivalent efficiency, but only CD4 CAR-T cells were capable of IL-2 secretion and proliferation following CD3 and CD28 co-stimulation, suggesting that both populations were necessary for optimal in vivo proliferation and tumor killing [23]. This evidence concerns the gene CD4 and neoplasm.