Expression of Her2-Neu in Primary Gastric and Gastroesophageal Adenocarcinoma: An Experience from a Tertiary Center in South India

Roopa Rachel Paulose Gastric cancer is one of the most commonly occurring cancers worldwide, often presenting at an advanced stage. Combining targeted therapy with chemotherapeutic agents can enhance and extend the survival of these patients. This 4-year retrospective study aims to assess the prognostic role of Her2-Neu expression in gastric and gastroesophageal (GE) cancer. Clinicopathological features, histological type (Lauren classification) of adenocarcinoma, and Her2 immunohistochemical expression were correlated with disease-free and overall survival in 114 patients. A Her2 score of 0 and 1+ indicated negativity, while 3+ marked positivity. For cases with a 2+ score, fluorescent in situ hybridization (FISH) was conducted for definitive categorization. Statistical analysis employed IBM SPSS version 20.0 software. Among 114 patients, 13 displayed strong Her2-Neu immunopositivity (3 + ), 9 scored 2 + , and 92 were negative (0 [89] and 1+ [3]). FISH classified 4 and 5 cases as positive and negative, respectively. Most (64.7%) Her2-Neu-positive tumors occurred in the proximal stomach/GE junction (GEJ) and exhibited intestinal morphology (94.1%) with moderate differentiation ( p -value < 0.05). Notably, 76.5% of Her2-Neu-positive patients exhibited advanced-stage disease with nodal/distant metastasis. The average disease-free survival was 15.4 months (standard error: 3.55) for positive Her2-Neu expression and 22.07 months (standard error: 1.364) for negative expression. The mean overall survival was 21.14 months (standard error: 3.702) for positive expression and 23.91 months (standard error: 1.474) for negative expression. Her2-Neu expression in gastric/GEJ adenocarcinomas correlates with reduced survival. Evaluating Her2-Neu in proximal gastric/GEJ cancers displaying low-grade intestinal morphology serves as both a predictive and prognostic indicator.