The REL/NF-kappaB/IkappaB superfamily of signal transducers and transcription factors are paradigmatic of molecular mechanisms by which rapid responses in the immune system can be achieved. NF-kappaB proteins have been implicated in diverse processes such as the ontogeny of the immune system, immune responses to pathogens and, importantly, in contributions to the multistage processes of oncogenesis, as described in this review. NF-kappaB and its regulators, the IkappaBs, are linked to pro- and anti-apoptotic events as well as signaling systems contributing to cellular transformation. How are these disparate events controlled to effect normal and abnormal processes in cells? Here we explore a few of the many events in which NF-kappaB appears to participate and processes that integrate signals to control important stages of oncogenesis.