A study by Higashikawa et al. synthesized a CTLA4-targeting PET probe by using an anti-CTLA4 monoclonal antibody (mAb) conjugated with 64Cu-1,4,7,10-tetraazacyclododecane-N,N′,N′′,N′′′-tetraacetic acid (DOTA), and found a high accumulation of the probe in the CT26 tumor of the BALB/c mice [87]. The gene discussed is CTLA4; the disease is neoplasm.