[536] SOX10 Expression in Malignant Melanoma, Carcinomas, and Normal Tissues

Amr Rashed, Raul Gonzalez, Diane Lawson, Jason Wang, Cynthia Cohen. Emory University Hospital, Atlanta, GA

Background: SOX10 (Sry-related HMg-Box gene 10) is a nuclear transcription factor that plays an important role in melanocytic cell differentiation. It has been shown to be a sensitive marker of melanoma including spindle and desmoplastic subtypes. We assessed its expression in melanomas, carcinomas and benign tissues.
Design: In order to assess sensitivity and specificity, we studied melanomas, carcinomas, benign nevi, and normal tissues in tissue microarrays with routine immunohistochemistry for SOX10.
Results: All melanomas were strongly and diffusely nuclear SOX10-positive.They included 2 spindle cell, 1 desmoplastic and 2 in situ melanomas.

Type of tissue	Number of Cases	Sox10 Positive number/Percent
Primary melanoma	82	82(100%)
Metastatic melanoma	14	14(100%)
Ovarian cancer	24	0(0%)
Breast cancer	26	2(8%)
Endometrial cancer	23	0(0%)
Lung cancer	26	0(0%)
Colon cancer	25	0(0%)

Normal tissues	Number of Cases	Sox10 Positive number/Percent
Benign nevi	4	4(100%)
Ovary	2	0(0%)
Breast	8	8(100%)
Endometrium	4	0(0%)
Lung	5	0(0%)
Large bowel	5	0(0%)

Two of 26 (8%) breast carcinoma and all 4 benign nevi were SOX10 positive. The sensitivity and negative predictive value for SOX10 in the diagnosis of melanoma is 1.0 ; the specificity and positive predictive value is 0.98.
Conclusions: SOX10 is a sensitive, specific marker for melanoma. As benign nevi also express SOX10, it cannot be used as a differentiation marker between benign and malignant pigmented skin lesions. Only a small number of breast carcinoma (<10%) express SOX10; no carcinoma of ovary, endometrium, lung or colon expressed SOX10.
Category: Dermatopathology

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 75, Monday Morning