Abstract
The Chernobyl nuclear disaster has caused a remarkable increase in radiation-induced papillary thyroid carcinoma in children and young adults. In this issue of the JCI, Ricarte-Filho and colleagues demonstrate that chromosomal rearrangements are the oncogenic "drivers" in most post-Chernobyl carcinomas and that they often lead to unscheduled activation of the MAPK signaling pathway. These findings represent a major step forward in our understanding of radiation-induced carcinogenesis and suggest various hypotheses about the mechanisms underlying the formation and selection of gene rearrangements during cancer cell evolution.