It is a potent mitogenic stimulus that acts on epidermal keratinocytes to induce hyper proliferation, an inducer of epidermal VEGF expression (responsible for much of the inflammatory vascular changes associated with psoriasis), and an inducer of other proinflammatory cytokines such as IL-1, IL-6, IL-8, and TNF-α. This evidence concerns the gene TNF and psoriasis.