CD34 and non-Hodgkin lymphoma: TAR (TAT response element) and RRE (Rev-response element) are 2 such cis-acting factors that are necessary for proper function of the key HIV-1 regulatory proteins, Tat and Rev. These elements have been evaluated in clinical trials, 1 in transduced and transplanted marrow-derived hematopoietic stem cells in HIV-1 infected children [21] and 1 in CD34+ HSPC transduced and transplanted in HIV-1 infected patients with Non-Hodgkin’s Lymphoma (NHL) who required autologous transplantation [25••].