Validating CD69 expression in a CT26 syngeneic tumor immunotherapy model using ex vivo autoradiography and IHC. A, Representative autoradiography images of whole tumor sections from responders, nonresponders, and untreated control groups. B, 20x magnified histological and IHC images of CD69 expression (NovaRED) on tumors sections from responders, nonresponders, and untreated control groups. Scale bar, 100 μmol/L.