The most investigated genes were those implicated in neuroendocrine stress responses; dopamine, norepinephrine, and serotonin signalling; apoptosis; insulin secretion; neuroplasticity; reproduction; foetal growth; and cancer (e.g. MAOA, BRSK2, ADCYAP1, BDNF, DRD2, IGF2, H19). Here, DRD2 is linked to cancer.