Immunohistochemical detection of ras p21 in oral papilloma

Twenty-four oral papillomas were fixed in a 10% formalin solution, and 5 mu paraffin sections were prepared by normal procedure. Using monoclonal antibody NCC-RAS-001 as the primary antibody, the expression of ras p21 in the oral papilloma was searched immunohistochemically by the Histostain SP kit. The ras p21 was detected in 10 (41.7%) of 24 oral papillomas. In the histologic expression, it was less frequently detected in keratinized cell layer and basal cell layer, and it was most often detected in the cytoplasm of the cells in the spinous cell layer. These findings suggested the close relation between the expression of ras p21 and the epithelial proliferation and differentiation in the oral papilloma.