While IDO protein is expressed in malignant B-cells of NHL [53], and intratumoral levels are higher in lymphoma than in reactive lymph nodes, associated to poor outcome [54,55,56], in CLL IDO is produced by microenvironment cells, such as dendritic cells, macrophages and nurse-like cells [57]. The gene discussed is IDO1; the disease is B-cell chronic lymphocytic leukemia.