title: Immunohistochemically demonstrated metallothionein expression in malignant melanoma.
abstract: Metallothioneins are ubiquitous proteins with a high affinity for heavy metal ions, e.g. zinc, copper and cadmium. Experimentally, metallothionein over-expression in cell lines derived from a variety of cancers has been associated with resistance to anticancer drugs and irradiation therapy. Using a monoclonal antibody (E9) to metallothionein we investigated immunoreactive expression in routinely fixed and paraffin-embedded tissue from 63 cases of malignant melanoma and 13 secondary deposits. Whereas a variety of cells in normal skin showed metallothionein expression, all forms of benign naevi studied were uniformly negative. In contrast 13/30 'thin' (< or = 1.5 mm; 0.7 +/- 0.4), 25/29 'thick' malignant melanoma (> 1.5 mm; 5.5 +/- 3.9) and 12/13 metastases were positive. Six patients with thin and 19 with thick melanoma with metallothionein expression died during a mean observation period of 6.4 +/- 1.8 and 3.6 +/- 2.5 years, respectively, their survival distribution function analyses giving statistically significant results for both the vertical tumour thickness (P < 0.0001) and metallothionein expression (P < 0.0001). These immunohistochemical results, based on routinely processed paraffin-embedded tissue, suggest that metallothionein expression in malignant melanoma is significantly associated with progressive disease and might therefore be a useful prognostic indicator.
authors.affiliation: Department of Dermatology, University of Innsbruck, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Zelger
authors.forename: A
authors.initials: A
authors.lastname: Hittmair
authors.forename: M
authors.initials: M
authors.lastname: Schir
authors.forename: C
authors.initials: C
authors.lastname: Ofner
authors.forename: D
authors.initials: D
authors.lastname: Ofner
authors.forename: P O
authors.initials: PO
authors.lastname: Fritsch
authors.forename: W
authors.initials: W
authors.lastname: Böcker
authors.forename: B
authors.initials: B
authors.lastname: Jasani
authors.forename: K W
authors.initials: KW
authors.lastname: Schmid
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000737:chemistry* / Q000401:mortality / Q000473:pathology; D008668:Metallothionein / Q000032:analysis*; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D009506:Nevus / Q000737:chemistry; D012878:Skin Neoplasms / Q000737:chemistry; D016019:Survival Analysis
chemical_list: D009363:Neoplasm Proteins; D008668:Metallothionein