Immunohistochemical evaluation of human epidermal growth factor receptor 2 expression in salivary gland malignancies
K. Barath Raj, Lloyd A. I. Joseph, B. Premalatha, K. Ramadoss, V. Veeravarmal, S. AmuthanAbstract
Background:
Salivary gland carcinomas (SGCs) are rare neoplasms characterized by marked histological heterogeneity and a lack of uniform treatment strategies. Human epidermal growth factor receptor 2 (HER2) has emerged as a potential biomarker and therapeutic target in various epithelial malignancies. However, its expression profile in SGCs remains underexplored. This study aimed to evaluate the immunohistochemical expression of HER2 in malignant SGCs and to compare it with normal salivary gland tissues, with the intent of assessing its therapeutic relevance across different histological subtypes.
Materials and Methods:
Formalin-fixed, paraffin-embedded specimens of malignant SGCs (
Results:
HER2 expression was absent (score 0) in all normal salivary gland samples. Among the malignant tumours, 15% (3/20) showed weak membranous immunoreactivity (score 1+), while none demonstrated moderate or strong positivity (2+ or 3+). HER2 expression was observed in 40% of adenoid cystic carcinoma (ACC) cases and 20% of polymorphous adenocarcinoma (PAC) cases. No expression was observed in mucoepidermoid carcinoma, acinic cell carcinoma, or carcinoma ex pleomorphic adenoma. Statistical comparison revealed no significant difference in HER2 expression among subtypes (
Conclusions:
The study indicates weak HER2 expression in a subset of malignant salivary gland tumours, specifically in ACC and PACs, with complete absence in normal tissues. These findings suggest limited but potentially meaningful scope for HER2-targeted therapies in select histological subtypes.