Increased expression of the epidermal growth factor receptor gene in psoriasis

Choi, Yoon Yae; Lee, Kyu Suk; Lee, Sang Sook; Chang, Eun Sook; Song, Jun Young

Abstract

Psoriasis is characterized by disregulation of keratinocyte growth with profound epidermal hyperplasia. Keratinocyte hyperplasia in psoriasis may be expained in part by overproduction of growth factor, and by altered metabolism of the epidemal growth factor receptors (EGFR) in affected skin. The expression of epidermal growth f ictor receptor was investigated by Northern blot and slot-blot analysis of total RNA extrated from biopsies of normal skin and psoriatic lesions. In Northern blot analysis, EGFR-specific mRNA transcripts from psoriatic tissues demonstrated the specificity of hybridizarion with a EGFR mDNA probe. The size of EGFR mRNA transcript was 6.7kb in psoriasis lesions which showed no change of quality. In slot-blot analysis, the levels of EGFR mRNA in poriasis revealed a 1.2 fold to 4.1 fold elevation when compared to normal skin. EGFR were present in all epidermal layers by immunoperoxidase staining, whereas in normal skin they were primarily present in the stratum basalis. These results indicate that the increased expresion of the EGFR gene may be, in part, responsible for the hyperproliferation of the epider nis and that retained EGFR may reflect incomplet; abnormal differentiation in active porasis. This altered process of EGFR metabolism may be involved in the pathogenesis of psoriasis.