Henri P, Prevel C, Pellerano M, et al. - In order to gain insight into the molecular implication of CDK2 and CDK4 kinases in psoriasis, researchers characterized the expression of these kinases and associated cyclins, as well as of CKIs, and addressed the status of CDK2 and CDK4 activity in human psoriatic epidermis. The study sample consisted of 24 patients with psoriasis. By immunoblotting, immunohistochemistry and immunofluorescence, CDK2, CDK4, cyclin D1, cyclin E and CKI protein expression were evaluated. By real-time polymerase chain reaction, CDK4 and CDK2 mRNA expression were determined. In the psoriatic epidermis, epidermal CDK2 activity is increased while CDK4 activity is completely inhibited. These modifications are not linked to changes in CDK transcription and instead involve posttranslational control mediated by reduced expression of p27 and p16 overexpression, respectively.