PLAG1, SOX10, and Myb Expression in Benign and Malignant Salivary Gland Neoplasms

Abstract

BackgroundRecent findings in molecular pathology suggest that genetic translocation and/or overexpression of oncoproteins is important in salivary gland tumorigenesis and diagnosis. We investigated PLAG1, SOX10, and Myb protein expression in various salivary gland neoplasm tissues.MethodsA total of 113 cases of surgically resected salivary gland neoplasms at the National Cancer Center from January 2007 to March 2017 were identified. Immunohistochemical staining of PLAG1, SOX10, and Myb in tissue samples was performed using tissue microarrays.ResultsAmong the 113 cases, 82 (72.6%) were benign and 31 (27.4%) were malignant. PLAG1 showed nuclear staining and normal parotid gland was not stained. Among 48 cases of pleomorphic adenoma, 29 (60.4%) were positive for PLAG1. All other benign and malignant salivary gland neoplasms were PLAG1-negative. SOX10 showed nuclear staining. In normal salivary gland tissues SOX10 was expressed in cells of acinus and intercalated ducts. In benign tumors, SOX10 expression was observed in all pleomorphic adenoma (48/48), and basal cell adenoma (3/3), but not in other benign tumors. SOX10 positivity was observed in nine of 31 (29.0%) malignant tumors. Myb showed nuclear staining but was not detected in normal parotid glands. Four of 31 (12.9%) malignant tumors showed Myb positivity: three adenoid cystic carcinomas (AdCC) and one myoepithelial carcinoma with focal AdCC-like histology.ConclusionsPLAG1 expression is specific to pleomorphic adenoma. SOX10 expression is helpful to rule out excretory duct origin tumor, but its diagnostic value is relatively low. Myb is useful for diagnosing AdCC when histology is unclear in the surgical specimen.

Cytopathology and diagnostics of Warthin's tumour

“…Also, cytoplasm of oncocytoma neoplastic cells is more granular and denser in contrast to the finely foam characteristic cytoplasm of ACC . When cytologically differentiating ACC from other salivary gland neoplasms with oncocytic features SOX10 (SRY‐related HMG‐box 10) and DOG1 (discovered on gastrointestinal stromal tumour 1) are also useful in ruling out negative benign lesions such as WT and oncocytoma from SOX10 and DOG1 immunopositive ACC . However, some benign tumours as PA and basal cell adenoma are also SOX10 immunopositive.…”

“…However, some benign tumours as PA and basal cell adenoma are also SOX10 immunopositive. Moreover, negative results for SOX10 as well as DOG1 do not favour a benign diagnosis since subgroup of MEC and oncocytic carcinoma is often negative for both markers and DOG1 is negative in both oncocytoma and oncocytic carcinoma …”

Evaluation of NR4A3 immunohistochemistry (IHC) and fluorescence in situ hybridization and comparison with DOG1 IHC for FNA diagnosis of acinic cell carcinoma

“…In salivary gland cytology, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) are often used to aid diagnosis 3,5,6 . DOG1 and, to a lesser extent, SOX‐10 have been the primary markers of AcCC, although neither is entirely sensitive or specific 7‐14 . Also, AcCC is typically negative for p40 and p63 by IHC 12,14 .…”

SOX10 as an immunohistochemical marker in cancer diagnostics

“…Recently, a large group of patients with di erent salivary gland tumors was evaluated; the SOX10 expression depended on the histopathological type and presented as below: multiform adenoma -79%, monomorphic adenomas -100%, polymorphic adenocarcinoma of low malignancy -88%, adenoid cystic adenocarcinoma -96% and adenocarcinomas -96%. Moreover, there was no expression of the SOX10 protein in the other subtypes of salivary gland tumors; which means that the determination of the SOX10 protein expression may be a good marker supporting the di erential diagnosis of some tumors subtypes [40,41]. A few studies reported positive SOX10 expression in pheochromocytomas, PEComas and carcinoid carcinomas [42].…”