MTOR and psoriasis: Studies have reported hyperactivity of AKT/mTOR and its downstream molecular target ribosomal protein S6 kinase 1 (S6K1) in the skin lesions of patients with psoriasis [49,50], and the highly active PI3K/AKT/mTOR pathway can lead to the abnormal differentiation of keratinocytes, which is generally recognized as a main pathological feature of psoriasis [16,46].