Microphthalmia transcription factor: a sensitive and specific marker for malignant melanoma in cytologic specimens.

Abstract

BACKGROUND:

The diagnosis of melanoma can be difficult because of shared cytomorphology with other malignant neoplasms. The most commonly used melanocytic markers, anti-S-100 protein and HMB-45 antigen, have limited specificity and sensitivity, respectively. Microphthalmia transcription factor (Mitf) is a nuclear transcription factor critical for the development and survival of melanocytes and has been shown as a sensitive and specific marker for melanoma in histologic specimens.

METHODS:

To evaluate the efficacy of Mitf as a marker for melanoma in cytologic preparations, 81 cell blocks from 44 patients with melanoma and 37 patients with nonmelanoma malignancies (29 patients with carcinoma, 4 patients with mesotheliomas, 2 patients with lymphoma, and 2 patients with islet cell tumors) were stained with monoclonal antibodies against Mitf (clone D5), S-100 protein, and HMB-45 antigen. The staining was evaluated blindly by three independent observers. The presence of nuclear staining for Mitf and cytoplasmic staining for S-100 protein or HMB-45 antigen in > 10% of tumor cells was considered positive staining for each antigen.

RESULTS:

Forty-four melanomas (100%), including all 3 spindle-cell melanomas, were positive for Mitf. All nonmelanoma neoplasms were negative with only one exception: One mammary carcinoma showed rare (< 10%), weak nuclear staining with Mitf. The sensitivity and specificity of Mitf as a marker for melanoma were both 100%, whereas the sensitivity of HMB-45 antigen was 90.4%, and the specificity of S-100 protein was 70.3%.

CONCLUSIONS:

Mitf is a sensitive and specific marker for malignant melanoma, including the spindle-cell variant, in cytologic specimens and may be superior to the current standard melanocytic markers, S-100 protein and HMB-45 antigen.

• Authors: C C Dorvault, K N Weilbaecher, H Yee, D E Fisher, L A Chiriboga, Y Xu, D C Chhieng
• Journal: Cancer (Cancer) Vol. 93 Issue 5 Pg. 337-43 (Oct 25 2001) ISSN: 0008-543X [Print] United States
• PMID: 11668469 (Publication Type: Comparative Study, Journal Article)
• Copyright: Copyright 2001 American Cancer Society.

Chemical References

• Antibodies, Monoclonal
• Antigens, Neoplasm
• Biomarkers, Tumor
• DNA-Binding Proteins
• MITF protein, human
• Melanoma-Specific Antigens
• Microphthalmia-Associated Transcription Factor
• Neoplasm Proteins
• S100 Proteins
• Transcription Factors

Topics

• Antibodies, Monoclonal
• Antigens, Neoplasm
• Biomarkers, Tumor (analysis)
• DNA-Binding Proteins (analysis)
• Humans
• Immunohistochemistry (standards)
• Melanoma (pathology, secondary)
• Melanoma-Specific Antigens
• Microphthalmia-Associated Transcription Factor
• Neoplasm Proteins (analysis)
• Predictive Value of Tests
• Retrospective Studies
• S100 Proteins (analysis)
• Sensitivity and Specificity
• Skin Neoplasms (pathology)
• Transcription Factors (analysis)