Abstract:

Objective To investigate the expression of psoriasin in actinic keratosis （AK）, Bowen′s disease and squamous cell carcinoma （SCC） tissues. Methods Immunohistochemistry was carried out to quantify the expression of psoriasin protein in tissue specimens from the lesions of 20 patients with AK, 25 patients with Bowen′s disease, 21 patients with well differentiated SCC, and 16 patients with poorly differentiated SCC, as well as from the skin of 18 normal human controls. Results The expression rate of psoriasin was 11.1% in the control specimens, significantly different from that in the AK （95.0%）, Bowen′s disease （88.0%）, well differentiated SCC （95.2%）, and poorly differentiated SCC （92.3%） specimens （all P < 0.01）. Psoriasin was expressed in the cytoplasm of keratinocytes and dyskeratotic keratinocytes in stratum corneum and upper 1 to 3 layers of stratum spinosums in AK tissue, in the cytoplasm of keratinocytes as well as the membrane and cytoplasm of vacuolated cells in all layers of the epidermis in Bowen′s disease tissue. In well differentiated SCC, cornified pearl and dyskeratotic keratinocytes located in the stratum corneum and all layers of the stratum spinosums stained positive for psoriasin, and in poorly differentiated SCC, psoriasin was distributed in the stratum corneum and upper 1 to 5 layers of the stratum spinosums, but absent in poorly differentiated squamous cells. The expression intensity of psoriasin in tissues sequentially increased from AK, Bowen′s disease to well differentiated SCC. Though the expression intensity of psoriasin in poorly differentiated SCC decreased, but was still higher than that in normal skin tissue （P < 0.05）. Conclusion Psoriasin is abnormally expressed in skin disorders with dysdifferentiation of squamous cells.

Key words: psoriasin