In 1995, a GPI-anchored variant of the costimulatory molecule, B7.1 (CD80) (see also Table 1), was introduced to different tumor cell lines, including the human breast cell carcinoma cell line T47D (ATCC® HTB-133TM), the human melanoma cell line SKMEL28 (ATCC® HTB-72TM), and the human lymphoblastic leukemia cell line MOLT4 (ATCC® CRL-1582TM). This evidence concerns the gene CD80 and acute lymphoblastic leukemia.