These authors suggest a possibile physiopathological role of this receptor: the expression of CTLA-4 in leukemias (as well as in a number of human malignant solid tumors including carcinoma, melanoma, neuroblastoma, rhabdomyosarcoma and osteosarcoma) might indicate the ability to interact with the CD80/CD86 ligands on antigen-presenting cells, and to transduce a relevant immunosuppressive signal [11], [12]. The gene discussed is CTLA4; the disease is leukemia.