Positive SOX10 Expression in a Broad Range of Salivary Gland Tumors
Tony L Ng, Robert West, Shirley Kwok, Gerald Berry, Christina Kong. Stanford University, Stanford, CA
Background: SOX10 is a novel immunohistochemical marker that has shown diagnostic utility in melanocytic and nerve sheath tumors. However, the specificity in head and neck sites has not been fully explored. This is of particular importance due to the morphologic overlap between melanomas and other head and neck tumors such as salivary gland neoplasms. Previously, SOX10 expression has been reported in a small number of pleomorphic adenomas of the parotid gland. We wished to more fully explore SOX10 expression in the spectrum of salivary gland tumors.
Design: SOX10 immunohistochemistry was performed on tissue microarrays comprising 229 benign and malignant salivary gland neoplasms. Strong diffuse nuclear staining was scored as positive, while weak or subset staining in <50% of cells was scored as negative. Stains for p63 and smooth muscle heavy-chain myosin were also performed, and correlation with SOX10 staining was determined.
Results: Multiple salivary gland tumor types show a high proportion with strong SOX10 positivity: pleomorphic (38/48) and monomorphic adenomas (10/10), polymorphous low-grade adenocarcinoma (14/16), adenoid cystic carcinoma (81/84) and acinic cell carcinoma (22/23). While it has been previously shown that SOX10 highlights myoepithelial cells in various organ sites, staining was seen beyond the myoepithelial component of these tumors, including diffuse staining in luminal-type epithelial cells. Furthermore, SOX10 staining showed poor correlation with the expression of the myoepithelial markers p63 (r=0.074, p=0.26) and smooth muscle myosin (r=0.148, p=0.03). Virtually no staining was seen in certain tumor subtypes, including oncocytoma (0/12), mucoepidermoid carcinoma (1/24) and salivary duct carcinoma (0/3), suggesting a possible role for SOX10 as an aid in subclassification of salivary gland tumors.
Conclusions: SOX10 is expressed in a broad range of salivary gland tumors, limiting its utility in head and neck sites as a marker of melanocytic and nerve sheath differentiation. However, it may serve as a useful diagnostic tool to differentiate between common subtypes of salivary gland tumors.
Category: Head & Neck
Tuesday, March 5, 2013 9:30 AM
Poster Session III # 154, Tuesday Morning