CD8A and neoplasm: An initial case report published in 2009 66 used CD8+ CTLs that had been genetically modified to express chimeric antigen receptor (CAR) interleukin-13 receptor alpha 2 for tumor targeting as well as herpes simplex virus type 1 thymidine kinase for dual suicide gene therapy and PET imaging of the CAR cells using 9-[4-[18F]fluoro-3-(hydroxymethyl)butyl]guanine.