Notably, p53 promotes the expression of the cell cycle inhibitor p21 (CDKN1A) [71] and the pro-apoptotic proteins FoxO1 [23], FoxO3a [23, 25], and TRAIL [26] and inhibits anti-apoptotic pro-survival effectors such as IGF1R [28], AR [27] and survivin (BIRC5) [72], all known p53 target genes involved in acne pathogenesis. This evidence concerns the gene CDKN1A and acne.