Expression of BMI-1 in normal skin and inflammatory and neoplastic skin lesions.
BACKGROUND
BMI-1 is involved in the maintenance of stem cells and functions as an oncogene in both lymphomas and solid carcinomas, acting by downregulation of p16ink4a. We have investigated the expression profile of BMI-1 in normal and inflamed skin as well as in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs).


METHODS
BMI-1 expression was determined by immunohistochemistry and immunofluorescence, and evaluated semiquantitatively.


RESULTS
BMI-1 was weakly expressed in nuclei of basal and sometimes suprabasal keratinocytes, in basal cells of sebaceous glands, weakly to moderately in the bulge area and the external root sheath of hair follicles, and strongly in sweat glands. Whereas BCCs showed strong and diffuse BMI-1 expression, SCCs expressed BMI-1 heterogeneously. Strong cytoplasmic expression of BMI-1 was found in dividing cells.


CONCLUSIONS
BMI-1 expression marks stem cells within the hair follicle. As BMI-1 was also found in suprabasal keratinocytes and a variety of specialized cells, the distribution of BMI-1 only partly reflects the known distribution of stem cell compartments. BMI-1 is strongly overexpressed in BCCs, tumors linked to dysregulation of the sonic hedgehog pathway, which has been shown to upregulate BMI-1, suggesting a contribution of the BMI-1 oncogene in their pathogenesis.
Reinisch
Christina M
CM
Department of Dermatology, Medical University of Vienna, Vienna, Austria.
Uthman
Aumaid
A
Erovic
Boban M
BM
Pammer
Johannes
J
D015415:Biomarkers / Q000378:metabolism; D002280:Basal Cell Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002467:Cell Nucleus / Q000378:metabolism / Q000473:pathology; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D004730:Endothelium, Vascular / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D005402:Fistula / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D063150:Polycomb Repressive Complex 1; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D011565:Psoriasis / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012867:Skin / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D012883:Skin Ulcer / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism / Q000473:pathology
C069077:BMI1 protein, human; D015415:Biomarkers; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1