It has been postulated that Treg are implicated in myeloma progression based on their contribution to the complex immunosuppressive environment via secretion of the cytokines interleukin (IL)-10 and transforming growth factor β (TGF-β) by APRIL/TACI dependent mechanisms (24), the CD39/CD73 adenosine pathway (25) and direct inhibition of effector T cell responses (26). This evidence concerns the gene NT5E and plasma cell myeloma.