Role of EGFR and HER-2/NEU Expression in Gall Bladder Carcinoma (GBC)

Background  Gall bladder carcinoma (GBC) is the most common malignancy of the biliary tract. Being known for its geographical and racial variations, and compared with the global statistics, its incidence is higher in the Indian subcontinent, mainly in the northern and eastern regions, accounting for 80 to 95% of cases. Aims and Objectives  This study was conducted to evaluate the clinic-pathological spectrum and expression of EGFR and HER-2/NEU in GBCs and to understand their relation to prognosis, paving the way for targeted therapies for better treatment outcomes and patient survival. Materials and Methods  This is a prospective study performed in a tertiary care hospital in 30 resected specimens of GBC cases recorded in our Department of Pathology from November 2017 to November 2019. Clinical history including the radiological reports and demographic parameters were included in the study pro forma. Immunohistochemical (IHC) staining for EGFR and HER-2/NEU was performed on all the selected cases. Clinicopathologic parameters like age, sex, histologic type, perineural, and lymphovascular invasion were compared and correlated with EGFR and HER-2/NEU status. Results  Expression of EGFR was found in 93.33% of cases, which showed a highly significant correlation with histological tumor type ( p = 0.000). HER-2/NEU expression was found in 56.66% of cases, which also showed a significant correlation with histological tumour type ( p = 0.021). We found most of the cases with strong EGFR immunoreactivity (3+) were poorly differentiated tumors and most of the cases showing weak immunoreactivity for EGFR (1+) were well-differentiated. Conversely, in case of HER-2/NEU immunoreactivity, strong staining (3+) was seen in well-differentiated tumors and weak staining (1+) in poorly differentiated tumors. A significant correlation was also found between EGFR and HER-2/NEU expression ( p = 0.000) and between cholelithiasis and EGFR expression ( p = 0 .033). Conclusion  EGFR is expressed in most cases of GBC. Its expression is more in poorly differentiated carcinomas as compared to the well-differentiated carcinomas, whereas HER-2/NEU expression is more in well-differentiated carcinomas. Therefore, they may serve as independent prognostic factors and also as targets for molecular therapy in GBCs.