Heat shock protein 27 is expressed in normal and malignant human melanocytes in vivo.
BACKGROUND
Heat shock proteins (HSPs) are a family of highly conserved proteins found ubiquitously in mammalian cells, believed to be regulators of normal cell physiology and the cellular stress response. In addition, the small 27-kDa heat shock protein (HSP27) has previously been found to be a differentiation marker for keratinocytes and a prognostic marker associated with increased survival in certain cancerous tumors.


METHODS
Using immunohistochemistry on routinely processed paraffin sections, we examined skin biopsies from 15 invasive melanomas, 13 intradermal nevi, and two compound nevi immunostained with a mouse monoclonal antibody to HSP27. In addition, cultured melanocytes were heat stressed at 45 degrees C for 1 h and then fixed and immunostained in order to localize HSP27 expression intracellularly.


RESULTS
We found cytoplasmic and strong perinuclear staining of HSP27 in melanocytes in normal skin, in melanomas, and in nevi. Nuclear reactivity was absent. In addition, in cultured non-malignant melanocytes, HSP27 expression relocated from the cytoplasm to the nucleus with heat stress.


CONCLUSIONS
To our knowledge, this investigation is the first to demonstrate that HSP27 is expressed in melanocytes in normal skin, in nevi, and in non-malignant cultured melanocytes.
Kang
Steven H
SH
Department of Dermatology, University of California Davis, School of Medicine, One Shields Avenue Davis, CA 95616, USA.
Fung
Maxwell A
MA
Gandour-Edwards
Regina
R
Reilly
Debra
D
Dizon
Teresa
T
Grahn
Jennifer
J
Isseroff
R Rivkah
RR
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D055551:HSP27 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008544:Melanocytes / Q000378:metabolism* / Q000473:pathology; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000378:metabolism*; D018330:Nevus, Intradermal / Q000378:metabolism* / Q000473:pathology; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins