Tyrosinase immunoreactivity in formalin-fixed, paraffin-embedded primary and metastatic melanoma: frequency and distribution.
Monoclonal antibody T311 specifically detects tyrosinase protein expression. Tyrosinase-derived peptides are recognized by CD8+ T-cells and applied in immunotherapy. We examined formalin-fixed paraffin-embedded tissue of 50 melanoma (primary n=31, metastatic n=19) and 41 control cases (junctional, dermal, compound, Spitz, Reed, balloon-cell nevi) by immunochemistry using the alkaline phosphatase-anti-alkaline phosphatase method after antigen retrieval. Staining with mAb T311 showed a sensitivity of 94% for melanoma with a very high specificity for melanocytic cells. Immunopositivity (94% of melanomas overall) correlated inversely with clinical stage: clinical stage I and stage II showed 100%, stage III and stage IV 86% immunoreactivity each. Staining changed from an exclusively homogeneous pattern in early stages to a more heterogeneous pattern in later stages. Melanocytic control tissue like nevi of different subtypes all showed weak to moderate, homogeneous immunoreactivity with polarity towards the epidermis. RT-PCR ELISA analysis of short-term melanoma cell cultures displayed mRNA expression in only half of the originally immunopositive tumors only, suggesting rapid mRNA expression loss in culture. mAb T311 allows detection of melanoma-associated tyrosinase protein expression and thus profiling of melanomas using routine archival tissue suited for immunotherapy approaches involving tyrosinase derived epitopes.
Hofbauer
G F
GF
Department of Dermatology, University Hospital, Zürich, Switzerland.
Kamarashev
J
J
Geertsen
R
R
Böni
R
R
Dummer
R
R
D000911:Antibodies, Monoclonal; D017931:DNA Primers / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D005557:Formaldehyde; D006801:Humans; D018327:Hutchinson's Melanotic Freckle / Q000201:enzymology / Q000473:pathology; D007124:Immunoenzyme Techniques; D008545:Melanoma / Q000201:enzymology* / Q000556:secondary; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000378:metabolism*; D009506:Nevus / Q000201:enzymology / Q000473:pathology; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D012878:Skin Neoplasms / Q000201:enzymology* / Q000473:pathology; D016707:Tissue Fixation / Q000379:methods
D000911:Antibodies, Monoclonal; D017931:DNA Primers; D012333:RNA, Messenger; D005557:Formaldehyde; D014442:Monophenol Monooxygenase