Abstract: Objective To investigate the effects of proto-oncogene c-myc, tumor suppressor gene p53 and apoptosis protection gene bcl-2 on abnormal apoptosis of keratinocytes in psoriatic lesions. Methods Expression of c-myc, p53, bcl-2 was analysed by both immunohistochemical methods and nucleic acid in situ hybridization in a total of thirty six lesional skin samples from patients with psoriasis vulgaris. Results c-myc, p53 and PCNA-positive keratinocytes increased significantly in psoriatic lesions in comparison with the controls,especially in the lower and basal layers of epidermis. bcl-2-positive cells decreased in basal layers of psoriatic skin. In lesions with more than 30 PCNA-positive cells, there were a significant increase of c-myc protein (P<0.01) and p53 protein (P<0.01), a significant decline of bcl-2 protein (P<0.02), and a significantly high rate of apoptosis (P<0.01). Conclusions The increased expression of c-myc, p53 and the decreased expression of bcl-2 may play a role in coordinated activation of apoptotic pathways in psoriatic skin. The abnormal apoptosis of keratinocytes is likely to relate to hyperplasia of keratinocytes in the psoriatic lesions.

Key words: Genes,c-myc, Genes,p53, Genes,bcl-2, Psoriasis, Apoptosis