RELATIONSHIP BETWEEN ENDOSCOPIC PROPERTIES, HISTOPATHOLOGY AND HER2 OVEREXPRESSION IN GASTRIC ADENOCARCINOMA

Objective: HER2 may have a prognostic value in gastric cancer and test for HER2 overexpression help to select the patients for the targeted therapy with trastuzumab. Our aim was to study endoscopic properties, histopathology of gastric adenocarcinoma and their relationship with HER2 overexpression. Materials and Methods: Between 3/2010 and 05/2011, 64 patients with gastric cancer were tested for HER2 status by immunohistochemical staining of formalin-fixed paraffin-embedded endoscopic biopsy samples. Design: Cross-sectional study. Results: According to Borrmann, polypoid, fungating, ulcerated, and infiltrative type cancer. According to Lauren’s classification, 42.2% were intestinal, 57.8% were diffuse. According to WHO, 43.8% were tubular adenocarcinoma, 7.8% were mucinous adenocarcinoma, 17.2% were signet-ring cell carcinoma, and 31.3% were undifferentiated carcinoma. 29.7% were well-differentiated tumors, 18.8% were moderately-differentiated tumors, and 51.6% were poorly-differentiated tumors. HER2 overexpression was present in 23.5% of gastric carcinomas. 40% cardia tumors and 22% non-cardia tumors were HER2 positive. HER2 overexpressions were different between polypoid, fungating, ulcerated, and infiltrative types with rate of 30.8%, 37%, 6.3% and 0%, respectively (p = 0.04). HER2 overexpression of intestinal type tumors was higher than diffuse type tumors (37% vs 13.5%, p=0.04). HER2 overexpression in tubular adenocarcinoma, mucinous adenocarcinoma, signet-ring cell carcinoma, and undifferentiated carcinoma was 35.7%, 9.1%, 20% and 15%, respectively. 36.8% of well-differentiated tumors, 33.3% moderately-differentiated tumors, and 12.1% of poorly-differentiated tumors overexpress HER2. Conclusions: HER2 overexpression was found in 23.5% of gastric carcinomas and was associated to endoscopic properties, histopathologic type of tumors. Keywords: HER2, gastric cancer.