Immunocytochemical detection of MART-1 in fresh and paraffin-embedded malignant melanomas.
MART-1 is a transmembrane protein that appears to be melanocyte specific. This study evaluated the use of a new monoclonal antibody, directed against MART-1, in fresh and paraffin-embedded specimens. Twenty-three paraffin-embedded tumors were evaluated for MART-1 immunoreactivity both before and after microwave-based antigen retrieval. After this comparison, 53 fine-needle aspirates from 43 patients with malignant melanoma were assessed for MART-1 immunoreactivity. Immunocytochemistry was performed on both cytospins and paraffin-embedded tissues that were pretreated with antigen retrieval. Seventeen (74%) of 23 tumors evaluated for immunoreactivity before and after antigen retrieval showed a significant increase in both staining intensity and the number of cells stained. When cytospins and antigen-retrieved cell blocks from 53 fine-needle aspirates were compared. 38 (72%) showed good correlation. In 13 (25%) of 53 tumors, MART-1 immunoreactivity was more intense in the cytospins, although the differences were marked in only two cases: Microwave-based antigen retrieval renders paraffin-embedded tissues nearly as sensitive as fresh material for use in the immunocytochemical detection of MART-1. This technique will allow the evaluation of MART-1 immunoreactivity in archival malignant melanomas.
Fetsch
P A
PA
Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1500, USA.
Cormier
J
J
Hijazi
Y M
YM
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D058965:MART-1 Antigen; D008545:Melanoma / Q000276:immunology*; D009363:Neoplasm Proteins / Q000032:analysis*; D016612:Paraffin Embedding; D013048:Specimen Handling / Q000379:methods
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins