Correlation between HER2/ neu overexpression/amplification and clinicopathologic parameters in advanced gastric cancer (AGC) patients (pts): A prospective study

• Published in: Journal of clinical oncology Vol. 24; no. 18_suppl; p. 4089
• Main Authors: Gravalos, C., Marquez, A., Colomer, R., Garcia-Carbonero, R., Sastre, J., Rivera, F., Saenz-Cusi, A., Velasco, A., Guzman, C., Jimeno, A.
• Format: Journal Article
• Language: English
• Published: 20-06-2006
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/jco.2006.24.18_suppl.4089

Abstract only 4089 Background: Trastuzumab is widely used in the treatment of HER2/neu overexpressing breast cancer pts and also exhibits activity in human gastric cancer cells that overexpress HER2/neu. We are conducting a phase II trial to assess the efficacy and tolerance of trastuzumab in combination with cisplatin as first line chemotherapy (CT) in HER2/neu positive AGC. Objectives: To determinate prospectively the frequency of HER2/neu expression and to evaluate the relationship with clinicopathologic characteristics in advanced gastric adenocarcinoma pts. Methods: Pts were screening for HER2/neu expression/amplification. Immunohistochemistry (IHQ) was performed using herceptest. A fluorescence in situ hybridization (FISH) assay was done when IHQ was = 2. HER2/neu expression was considered negative if IHQ = 0, 1 or IHQ = 2 and FISH negative; and positive if IHQ = 2 and FISH positive or IHQ = 3. Results: A hundred and twenty six pts were tested for HER2/neu status between 2/2004 and 12/2005. 96 (76%) males, median age 61 years (range 29–84). Histological characteristics: all were adenocarcinomas and 47% type intestinal, 33% diffuse, 20% unknown. Primary tumor localization was 101 (80%) gastric and 25 (20%) gastroesophageal junction (GEJ). 115 (91%) pts had metastases (47% liver; 45% lymph nodes; 27% peritoneum; 10% lung; 27% others) and 11 (9%) locoregional advanced disease. Prior therapies: 67 pts surgery, 18 adjuvant/neoadjuvant CT and 14 adjuvant irradiation. HER2/neu expression was negative in 109 (86.5%) cases. The positive cases were: type intestinal (15.5%); type diffuse (10%) (p = 0.54); 9% gastric localization and 29% GEJ tumors were HER2/neu positive too (p = 0.01). Conclusions: HER2/neu overexpression/amplification was found in 13.5% of AGC and is more common in gastroesophageal junction cancers. The study is ongoing. [Table: see text]