Modern PsV therapy includes topical treatments (such as corticosteroids and vitamin D analogs); phototherapy (especially narrow-band UV-B for various forms of psoriasis); and systemic therapies for moderate to severe cases, including methotrexate (MTX) and newer biologics targeting tumor necrosis factor alpha (TNF-α), interleukin (IL)–17, and IL-23. This evidence concerns the gene TNF and psoriasis.