TNF and psoriasis: Now, a new generation of biologics,cytokine blockers targeting key cytokines or pathways, have shown positive efficacyfor psoriasis in clinical trials [75].Etanercept, a typical biologic for psoriasis, targets TNF-α (+489 GGand + 489 GA genotypes) and is effective in treating psoriasis,especially psoriasis arthropathica [41,76,77].