They are retinoic acid receptor alpha (RARA), retinoic acid receptor beta (RARB), retinoid X receptor beta (RXRB), NR3C2, vitamin D3 receptor (VDR), aldo-keto reductase (AKR1C1) and phosphodiesterase-4D(PDE4D), which meant that these targets might be the key targets for STT treating psoriasis (Fig. 8B). This evidence concerns the gene PDE4D and psoriasis.