Hu et al. screened out a CD133-directed 64Cu PET tracer 64Cu CM-2 and tested its imaging performance and specificity in human hepatoma, melanoma, glioblastoma, breast cancer (Huh-7, Bowes, U87MG, MDA-MB231) and murine melanoma B16F10 allografts [54]. This evidence concerns the gene PROM1 and glioblastoma.