Psoriasin (S100A7) expression is altered during skin tumorigenesis.
BACKGROUND
Psoriasin (S100A7) expression has previously been associated with psoriasiform hyperplasia as well as with tumor progression in breast cancer. Its expression profile for different stages of skin lesions is unknown. The aim of this study was to determine the relationship between psoriasin (S100A7) and tumor progression in skin.


METHODS
Psoriasin was assessed by immunohistochemistry and levels of expression determined by semi-quantitative scoring in skin biopsies from 50 patients. The cohort included normal skin, actinic keratosis, squamous carcinoma in-situ, invasive squamous cell carcinoma, and basal cell carcinoma.


RESULTS
In normal skin, psoriasin was rarely detected in epidermis but was expressed in underlying adnexae. In abnormal epidermis psoriasin was frequently expressed in abnormal keratinocytes in actinic keratosis, in-situ and invasive squamous cell carcinoma, but was rarely observed in the basal epidermal layer or in superficial or invasive basal cell carcinoma. The highest levels of expression were seen within squamous carcinoma in-situ. Significantly reduced levels of expression were observed in both unmatched (p = 0.0001) and matched (p < 0.004) invasive squamous cell carcinoma. Psoriasin expression within abnormal squamous lesions correlated with mitotic count (r = 0.54, p = 0.0036), however no significant relation was found with the intensity of dermal inflammatory cell infiltrates assessed within each pathology.


CONCLUSIONS
These results suggest that altered psoriasin expression occurs in abnormal epidermis and that downregulation may be related to the onset of invasion in squamous cell carcinoma in skin.
Alowami
Salem
S
Department of Pathology, University of Manitoba, Faculty of Medicine, Winnipeg, Manitoba, Canada, R3E OW3. alowami@hotmail.com
Qing
Gefei
G
Emberley
Ethan
E
Snell
Linda
L
Watson
Peter H
PH
D014408:Biomarkers, Tumor / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D006801:Humans; D009361:Neoplasm Invasiveness; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology
D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; C089242:S100A7 protein, human