RESUMEN
BACKGROUND: Psoriasis is an immune-related disease with dermal inflammation and epidermal hyperplasia. Cornulin has a significant role in keratinocyte proliferation and stimulates inflammation in psoriasis. AIM OF THE WORK: This work aims to evaluate Cornulin expression values in lesional and perilesional psoriatic skin compared with the control group's skin through immunohistochemistry. METHODS: This case-control study included 30 cases with plaque psoriasis and another 30 as controls. Patient samples were collected, and immunohistochemical staining of Cornulin was conducted. RESULTS: In the epidermis, there was a stepwise pattern of significant Cornulin overexpression in keratinocytes starting from controls (34.00 ± 23.65) to lesional (62.59 ± 23.93) passing through perilesional skin (36.52 ± 18.49) (p < 0.001). Moreover, there was also a stepwise pattern of the significance of Cornulin starting from 4 in controls (13.3% for both) to 28 lesional cases (93.3%) and 18 (60.0%) passing through 17 perilesional skin cases (56.7%) and 5 (16.7%) (p < 0.001 for both) for inflammatory cells and adnexa, respectively. A significant relationship between lesional epidermal Cornulin's strong intensity and a higher H-score and both hyperkeratosis and parakeratosis was found (p = 0.008 for both intensity and 0.028 for both H-scores). CONCLUSION: Cornulin might be implicated in keratinocyte hyperproliferation and inflammation in plaque psoriasis and may be valuable as therapeutic target.