HDAC9 and psoriasis: At the same time, there are many common therapeutic agents for psoriasis and tumors, and the efficacy of these drugs is usually achieved through the same target protein—for example, calcipotriol, the topical gold standard drug for psoriasis, activates vitamin D receptor-sensitizing chemotherapeutic drugs and immunotherapy in some tumors, and topical HDAC inhibitors, which are antineoplastic drugs, have the effect of treating psoriasis.