This antibody reacts with the TGF alpha and shows no cross-reaction with EGF and the neuropeptide synenkephalin. The staining with this MAb is completely blocked by the peptide used for raising this antibody. TGF? ? (aa50) is a growth factor with 33% homology to EGF, binds to EGFR, activates tyrosine phosphorylation of the receptor, and stimulates cell proliferation. It plays a role in tumor initiation by inducing the reversible transformed phenotype.