Kanayama K, et al. - This study was carried out to evaluate the association between HER2 gene amplification and tumor progression in early gastric cancer. For this investigation, the HER2 status was assessed in 149 lesions from 141 consecutive subjects with early gastric cancer who had endoscopic resection by immunohistochemistry and dual color in situ hybridization. They found HER2 gene amplification in noninvasive carcinoma. A significant association was noted between HER2 status and T factor. Findings revealed that HER2 gene amplification occurred during the early stages of gastric cancer and exhibited heterogeneity in several cases. In early gastric cancer, HER2 gene amplification might be involved in tumor progression.