1. ^*Department of Dermatology, Helsinki University Central Hospital and Biomedicum Helsinki, Helsinki, Finland
2. ^†Departments of Genetics, Pediatrics and Medicine, Washington University School of Medicine, St Louis, Missouri, USA
3. ^‡Department of Dermatology, Karolinska Institute at Söder Hospital, Stockholm, Sweden

Correspondence: Ulpu Saarialho-Kere, MD, PhD, Department of Dermatology, Helsinki University Central Hospital, Meilahdentie 2, 00250 Helsinki, Finland. Email: ulpu.saarialho-kere@helsinki.fi

Received 18 June 2003; Revised 16 October 2003; Accepted 20 October 2003.

Abstract

IFI27 is an interferon -inducible protein found to be upregulated in lesional and non-lesional psoriatic skin in a gene array study. To further characterize its function, we studied by in situ hybridization whether IFI27 is expressed in psoriasis, other inflammatory skin diseases, and wound repair in vivo. We also examined its regulation by different growth factors and anti-psoriatic agents using quantitative RT-PCR (TaqMan). IFI27 mRNA expression was highly upregulated in lesional psoriatic epidermis and also detected in non-lesional keratinocytes. It was also expressed in lichen planus, chronic eczema, cutaneous squamous cell cancers, and during normal wound repair when IFI27 was found in the proliferating subpopulation of keratinocytes. A 3–17-fold upregulation of IFI27 mRNA expression was observed when keratinocytes were stimulated with IFN-, TNF-, or TGF-1 while retinoids and vitamin D downregulated its expression. Our results suggest that IFI27 is a novel marker of epithelial proliferation and cancer.