However, autoradiography experiments performed after the incubation of either [<sup>11</sup>C]<b>CP31398</b> or [<sup>18</sup>F]<b>FG-CP31398</b> on H358 (p53 positive) and A549 (p53 negative) tumor slices derived from human lung cancer cells revealed that both tracers were not able to bind the p53-positive cells. The gene discussed is TP53; the disease is lung cancer.