As presented in Fig. 3c, HepG2 cells incubated with F12+-ANP-Gal showed a much brighter afterglow image compared to that of F12+-ANP, β-Gal-pre-treated HepG2 cells, or β-Gal receptor-deficient human lung cancer A549 cells incubated with F12+-ANP-Gal. The gene discussed is NPPA; the disease is lung cancer.