Expression of HER2 in adenoid cystic carcinoma and mucoepidermoid carcinoma of salivary glands as a prognostic marker

Objectives: To determine the expression of HER2 in adenoid cystic and mucoepidermoid carcinoma of salivary glands, if can be used as a prognostic marker as well as for therapeutic approach. Methodology: Forty cases of mucoepidermiod carcinoma (n=20) and adenoid cystic carcinoma (n=20) were taken from various hospitals of Lahore. Relevant clinical data was recorded and blocks were examined for histological diagnosis. HER2 immunopositivity was assessed by immunohistochemistry. Tumors with (+2) to (+3) score were considered as positive for overexpression. Results: Mean age was 32.35 +/- 13.674 and 41.50 +/- 12.224 while male to female ratio was 1.5:1 and 1:1.5 in mucoepidermoid carcinoma and adenoid cystic, respectively. Parotid gland was the common site in mucoepidermoid carcinoma, while minor salivary glands was the most affected site in adenoid cystic carcinoma. Both carcinomas were found on the right side mostly. In mucoepidermoid carcinoma, 40% were grade III and 35% and 25% were grade I and III, respectively. Out of 20 cases, 80% were grade I while 5% and 15% were grade II and grade III correspondingly in adenoid cystic carcinoma. Lymph node involvement was seen 45% of mucoepidermoid carcinoma while it was not present in adenoid cystic carcinoma. HER 2 immunopositivity was seen as brownish membranous staining in 85% among 100 cases of both mucoepidermoid carcinoma adenoid cystic carcinoma. Statistically, significant association was found between HER2 expression and tumor grade. Conclusion: Positive expression of HER2 in both mucoepidermoid and adnoidcyctic carcinoma shows the development and progression of carcinoma. It could be used as a prognostic marker and also for potential therapeutic approach.