1 5 6 7 8 9 10 11 13 14 15 16 Drosophila melanogaster 17 18 19 20 21 22 23 24 25 11 . 12 13 . 9 10 2 9 10 26 33 28 31 31 28 28 31 26 27 30 29 30 26 27 29 29 32 33 The disparity between our findings in humans after caloric restriction during a short and severe famine and the abundant literature on sustained caloric restriction and cancer risk in rodents may be ascribed to differences in exposure duration, as is corroborated by the abovementioned animal studies on transient caloric restriction that are in line with the famine observations. 3 5 34 36 37 38 39 18 19 40 41 42 43 In conclusion, the general notion that caloric restriction prevents cancer needs some amendment, even for rodents. Evidence is strong that during caloric restriction, cancer risk is decreased proportionally to the amount of restriction, and such interventions can be effective whether started in early life or later. However, a short and transient period of restriction followed by a “normal” diet does not show such effects and could actually be detrimental. 44 45 46 47 48 Currently, the relation between famine exposure in early life and risk of other types of cancer than that of the breast is largely unknown. It would be valuable to further investigate these relations to see whether associations are different between cancer types, e.g. comparing hormone to non-hormone associated cancer types. This would give further insight into whether general mechanisms in human cancer aetiology are involved or whether adaptation of hormonal axes leading to harmful hormone concentrations is the potential culprit.