Interpretation of the margin of exposure for genotoxic carcinogens – Elicitation of expert knowledge about the form of the dose response curve at human relevant exposures

•Experts are reluctant to express views on the dose–response curve for genotoxic carcinogens.•The POD can be extrapolated first from high to low dose in animals and then to humans, or vice versa.•Expert judgment was that the dose–response curve is likely to be non-linear at human relevant exposures.•Stochastic events and the distribution of susceptibilities will contribute, to an unknown extent.•Interpretation of the MOE requires consideration of MOA, species differences and human variability.