[514] Rabbit Polyclonal Anti-SOX10 Is a Reliable IHC Marker for Melanoma and Its Mimics

George G Yang, Ashot Minasyan, Jeff Gordon, Mike Lacey, Kurt Lundquist. Cell Marque Incorporation, Rocklin, CA

Background: SOX10 is a transcription factor that participates in melanocytic and Schwann cell differentiation. It has been reported that SOX10 antibody is a sensitive marker for melanomas. However, thus far the primary antibody against SOX10 protein in the research and publications has been antiserum from goat, which hinders the antibody's acceptance, particularly in laboratories for clinical diagnosis. Here we report the assessment of SOX10 expression of melanomas, carcinomas, mesenchymal neoplasms, nerve tumors, and mesotheliomas using rabbit polyclonal anti-SOX10 antibody.
Design: In this study, we evaluated this rabbit polyclonal anti-SOX10 for benign tissue cross-reactivity, neoplastic expression, sensitivity and specificity on whole tissue sections and tissue microarray by routine immunohistochemistry.
Results: The results are summarized in the table 1.

Table 1
NeoplasmPositive cases/Total casesSensitivity (%)
Melanoma, conventional37/3995%
Melanoma, desmoplastic11/11100%
Melanoma, spindle cell (metastasis to lymph node3/3100%
Malignant peripheral nerve sheath tumor3/475%
Granular cell tumor5/5100%
Mesenchymal tumors0/160%

Thirty seven of 39 conventional melanoma cases showed strong and diffuse nuclear staining with this antibody. All eleven desmoplastic melanoma cases and three spindle cell melanomas in lymph nodes were all positive for anti-SOX10. Most of malignant peripheral nerve sheath tumors (3/4) were strongly reactive for the antibody. All schwannoma, neurofibroma, and granular cell tumor were stained with the anti-SOX10. None of the 153 cases of carcinomas were positive, in which there were 47 breast ductal carcinomas and 43 colorectal carcinomas. No other carcinomas of GI, respiratory, genitourinary tract primaries were found positive for anti-SOX10. However, 7 cases of colorectal carcinoma showed weak cytoplasmic staining. All lymphomas, mesenchymal tumors, and mesotheliomas were negative. In normal benign tissue, the antibody stained benign melanocytes, nerve sheath cells, and myoepithelial cells in sweat gland, mammary duct and salivary gland. Prostate basal cells are not stained.
Conclusions: Rabbit polyclonal anti-SOX10 antibody is a reliable, ready-to-use, sensitive, and specific IHC biomarker for melanoma, especially desmoplastic and spindle cell melanoma, whether it be, in situ, invasive or metastatic. We have found it also useful in differentiating spindle cell neoplasms/peripheral nerve sheath tumor from other mesenchymal neoplasm and carcinoma.
Category: Dermatopathology

Tuesday, March 5, 2013 9:30 AM

Poster Session III # 47, Tuesday Morning


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