Psoriasin (S100A7) is significantly up-regulated in human epithelial skin tumours.
OBJECTIVE
Psoriasin (S100A7) has originally been described to be expressed by psoriatic keratinocytes possibly as a result of altered differentiation and inflammation. As psoriasin was found to be overexpressed in human breast and bladder cancer suggesting a role in tumour progression, we investigated the expression of psoriasin in human epithelial skin tumours.


METHODS
Realtime reverse transcription-polymerase chain reaction experiments were performed to analyse the mRNA-expression levels of psoriasin together with involucrin as a marker for epithelial differentiation and interleukin-8 (IL-8) as a marker for inflammation in skin biopsy samples from patients with precancerous skin lesions (PSL, n = 6), squamous cell carcinoma (SCC, n = 11), basal cell carcinoma (BCC, n = 17), and healthy controls (n = 10).


RESULTS
Unexpectedly, mRNA expression levels for Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) revealed a variation of up to 600-fold in all cDNA-samples under investigation, indicating that GAPDH is not suitable as a housekeeping gene in human skin samples. Psoriasin mRNA expression was significantly up-regulated in samples of PSL, SCC and BCC. In situ hybridisation and immunohistochemical examinations identified psoriasin mRNA and protein expression in the differentiated layers of the epidermis. IL-8 mRNA expression was significantly up-regulated in SCC, however, there was no correlation between elevated levels of psoriasin and the expression of IL-8.


CONCLUSIONS
Similar to the findings in breast and bladder cancer, the up-regulation of psoriasin might play a role in the progression of skin cancer. The expression of psoriasin in human skin tumours seems to be independent from differentiation and inflammation.
Moubayed
Noemi
N
Department of Dermatology, Allergology and Venerology, University Hospital of Schleswig-Holstein, Campus Kiel, Schittenhelmstr. 7, 24105 Kiel, Germany.
Weichenthal
Michael
M
Harder
Jürgen
J
Wandel
Elke
E
Sticherling
Michael
M
Gläser
Regine
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002280:Basal Cell Carcinoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002648:Child; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D016209:Interleukin-8 / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; D012878:Skin Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D015854:Up-Regulation
D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins; D016209:Interleukin-8; D012334:RNA, Neoplasm; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; C089242:S100A7 protein, human; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases