A variety of mouse studies have identified additional Rai1 features, including upregulation of Rai1 in mouse carcinoma cells following retinoic acid treatment [20], localization of the Rai1 mRNA transcript and protein to neurons suggesting a role in neuronal differentiation [20], and a dosage-dependent role for Rai1 in the serotonin pathway [21]. Here, RAI1 is linked to carcinoma.