For example, preclinical observations (Lopes de Menezes et al, 2007; Reddy et al, 2007) have described a synergistic effect of IL-2 in combination with rituximab in both retuximab-sensitive and retuximab-insensitive non-Hodgkin lymphoma (NHL) xenograft models. This evidence concerns the gene IL2 and non-Hodgkin lymphoma.