gms | German Medical Science

102. Jahrestagung der DOG

Deutsche Ophthalmologische Gesellschaft e. V.

23. bis 26.09.2004, Berlin

Microphthalmia transcription factor (Mitf) expression in melanocytic tumours of the conjunctiva

Meeting Abstract

  • corresponding author F. Mackensen - Universitäts-Augenklinik Heidelberg
  • B. Helmke - Pathologisches Institut der Universität Heidelberg
  • M. Pfirrmann - Universitäts-Augenklinik Heidelberg
  • H. E. Völcker - Universitäts-Augenklinik Heidelberg
  • S. Dithmar - Universitäts-Augenklinik Heidelberg

Evidenzbasierte Medizin - Anspruch und Wirklichkeit. 102. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft. Berlin, 23.-26.09.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04dogP 012

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dog2004/04dog503.shtml

Veröffentlicht: 22. September 2004

© 2004 Mackensen et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

In a histologically unclear, especially in an unpigmented, possibly malign melanocytic process of the conjunctiva immunhistochemical staining is used. Common markers are S-100- , HMB-45- and also Melan A-Antibodies. Microphthalmia transcription factor (Mitf) is a nuclear protein whose isoform Mitf-M shows expression exclusively in melanocytes and melanomacells. It seems to have an important role in development and survival of melanocytes. Mitf expression was shown in cutaneous and uveal melanoma and dermal nevi. We examined Mitf expression in nevi and melanoma of the conjunctiva and compared with common markers.

Methods

Formalin-fixed, paraffin-embeded conjunctival nevi (n = 10) and melanoma of the conjunctiva (n = 5) were immunolabeled with S100, HMB-45, Melan A and Mitf. The results were rated on the basis of pervasiveness of the labeling regarding the percentage of positive cells by two authors.

Results

All specimens were strongly immunolabeled by S100, Melan A and Mitf. Also the scores of pervasiveness showed good correlation.HMB-45 showed only weak staining. Semiquantitative scoring was dificult in the specimens with broad cytoplasmatic S100 and Melan-A labeling, Mitf with the intense nuclear signal was clearer. In contrast to staining with the other markers, in the specimens immunolabeled with Mitf it was easier to distinguish unpigmented melanocytic cells from other cell types.

Conclusions

Mitf-M is a reliable, specific marker for melanocytic processes. In a histologically unclear process it can be helpful to distinguish melanocytic cell populations. Mitf was the only antibody used showing an intense nuclear signal owing to its binding specifically to nuclear proteins. This could be useful in additional staining for cytological characterisation.