Molecular Mechanisms of Radiation-Induced Second Cancers

Abstract

Second primary cancers are a rare but relevant late effect of radiotherapy. However few studies have looked into the molecular mechanisms. In this work, basic mechanisms of carcinogenesis, DNA repair and radiation-induced genetic changes are reviewed. Ionizing radiation does not induce changes in specific genes but can inactivate tumor suppressor genes and, more rarely, activate oncogenes in a stochastic fashion. Radiation-induced genomic instability is likely to play a major role, too. A single mechanism is unlikely to explain all second cancers.