CD3 is a multimeric (CD3ε, CD3γ, CD3δ, CD3ζ) protein complex widely expressed at variable intensity levels on the cell surface of mature T-cell lymphomas and mature T-ALLs [149], whereas cytoplasmic CD3 expression is a mandatory diagnostic marker for immature T-ALL subtypes. This evidence concerns the gene CD3E and T-cell non-Hodgkin lymphoma.