Comparison of Five Antibodies as Markers in the Diagnosis of Melanoma in Cytologic Preparations

Abstract

We determined the sensitivity and specificity of 3 novel antibodies (microphthalmia transcription factor [Mitf], Melan-A, and tyrosinase) as markers for melanoma in cytologic preparations and compared the results with those of commonly used markers (S-100 protein [S-100] and HMB-45). We stained 72 cell blocks from 40 patients with melanoma and 32 with nonmelanocytic malignant neoplasms with antibodies against S-100, HMB-45, Mitf, Melan-A, and tyrosinase. Histologic correlation was available in more than 95% of cases. Nuclear stainingfor Mitf and cytoplasmic stainingfor S-100, HMB-45, Melan-A, and tyrosinase in more than 10% of tumor cells was considered positive. All 3 novel markers demonstrated sensitivity superior to S-100 and HMB-45. HMB-45, Melan-A, and Mitf demonstrated specificities of 97%. S-100 protein and tyrosinase were less specific. Sensitivity and specificity for the combination Mitf+/Melan-A+ were 95% and 100%, respectively, whereas they were 80% and 100%, respectively, for S-100+/HMB-45+. Mitf Melan-A, and tyrosinase are sensitive markersfor epithelioid melanoma. Mitf and Melan-A seem more specific than S-100 and tyrosinase. An antibody panel consisting of Mitf and Melan-A is superior to a panel of S-100 and HMB-45 in the diagnosis of melanoma in cytologic specimens.

Primary malignant melanoma of the female urethra: a rare case of cytological observation

“…However, although HMB-45 is quite specific for melanocytic neoplasms, it is less sensitive than S-100 protein for diagnosing melanoma [14]. In the present case, strong immunoreactivity against HMB-45 was conclusively positive in the melanoma cells, whereas the positive reaction to S-100 protein was weak.…”

“…The most frequently used melanocytic markers are S-100 protein and HMB-45. Monoclonal antibodies against S-100 protein react with more than 90% of melanomas [14].…”

The epigenetic reprogramming of poorly aggressive melanoma cells by a metastatic microenvironment

“…For example, melanoma antigen (family A,8 and family D,2), preferred expression in melanoma, tyrosinase-related protein 1, and Melan-A were all down-regulated in MUM-2B (and C918) aggressive melanoma cells, but not in MUM-2C or OCM-1A poorly aggressive cells -until they were exposed to the MUM-2B preconditioned matrix microenvironment. The expression of melanoma associated antigen genes has been linked to a favorable disease outcome in advanced stage melanoma [32], and several of these antigens are used as important markers in the diagnosis of melanoma [33,34]. Collectively, these data suggest that melanoma cells appear to dedifferentiate as they acquire an aggressive phenotype, which might make them more difficult to identify using routine histopathological markers for diagnosis.…”

Malignant Melanoma in Genito-Urinary Tract

“…Cytological features of a melanoma resemble those of the other poorly differentiated neoplasms like carcinomas, lymphomas, and sarcomas. 30 For diagnostic purposes immunocytochemical staining is used. In clinical practice, mostly S100 protein, and HMB 45 antibodies, and recently found MART 1 melanocyte antigens have been used.…”

“…In clinical practice, mostly S100 protein, and HMB 45 antibodies, and recently found MART 1 melanocyte antigens have been used. 30,31 S100 protein is a calcium binding protein which had been isolated from brain tissue, and it is 90% sensitive for melanoma. However its sensitivity might drop to 70 % with respect to its discriminative potential between malignant melanomas, and spindle cell lesions with similar cytomorphologic features.…”