Thresholds of Genotoxic Carcinogens: From Mechanisms to Regulation brings together current opinion and research activities from Japan, the US, and Europe on the subject of genotoxic thresholds. In regulation, it is an adage that genotoxic carcinogens have no thresholds for action, and that they impose cancer risk on humans even at very low levels. This policy is frequently called into question as humans possess a number of defense mechanisms including detoxication, DNA repair, and apoptosis, meaning there is a threshold at which these genotoxic carcinogens take action.

The...