TNF and neoplasm: The reduction of the intra-medullary pressure does not account for the rapid pain relief that may occur a few days after the radionuclide administration, since the absorbed radiation dose delivered has not yet destroyed a sufficient quantity of tumor cells.2 One possible explanation would be that tumor necrosis induced by radiation would result in the death of cells that participate in the inflammatory and immuno-logical processes, consequently reducing the release of bradykinins, tumor necrosis factor, prostaglandins and interleukins, substances that are known to increase pain.2,3