Immunohistochemical expression of discoidin domain receptor 1 in keloid scar

Objectives To assess the role of discoidin domain receptor 1 (DDR1) in keloid scar. Background Keloid scars are formed of inert masses of collagen. Therefore, expression of collagen and DDR1 may determine the nature and extent of tissue scarring. Patients and methods This case–control study was carried out on 20 patients presented with keloid and 40 age-matched, sex-matched, and site-matched apparently normal skin from apparently healthy volunteers. Skin biopsies were sent to the Pathology Department of Faculty of Medicine, Menoufia University, for histopathological assessment and immunohistochemical staining of DDR1. Results Epidermal expression of DDR1 was positive in all keloid cases (lesional and perilesional). Its intensity was mild in all lesional biopsies and in only 20% of perilesional ones. Dermal expression was positive in all perilesional cases and in only 30% of lesional biopsies. A significant difference was found between lesional and perilesional keloid regarding DDR1 expression intensity in the epidermis and dermis (P < 0.001). A significant difference was found between lesional and perilesional keloid regarding DDR1 expression H-score in the epidermis and dermis (P < 0.001). A significant positive correlation was found between lesional epidermal and lesional dermal groups regarding keloid H-score (r = 0.552; P = 0.012). In control group, positive epidermal expression of DDR1 was found in all biopsies, with cytoplasmic localization and basal topography. Mild intensity was seen in 52.5% and moderate intensity was seen in 47.5%. The mean ± SD values of H-score were 81.50 ± 39.52. Positive dermal expression of DDR1 was found in all biopsies, with cytoplasmic localization and basal topography. Mild intensity was seen in 50% and moderate intensity was seen in 50%. The mean ± SD values of H-score were 82 ± 27.38. Conclusion DDR1 expression in keloid scar is suspected in early pathogenesis.