Author(s): Hofbauer GF, Kamarashev J, Geertsen R, Bni R, Dummer R, Hofbauer GF, Kamarashev J, Geertsen R, Bni R, Dummer R
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Abstract 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.
This article was published in J Cutan Pathol
and referenced in Journal of Pigmentary Disorders