FOXO3 and acne: In accordance, upregulated TRAIL expression has been observed in the basal and suprabasal layers of SG during isotretinoin treatment of acne patients [120], which allows the conclusion that isotretinoin-ATRA-p53/FoxO3a-induced TRAIL signalling explains isotretinoin-induced sebocyte apoptosis resulting in the involution of SGs (Fig. 1).