Potential for molecular targeted therapy of HER-2/neu for invasive bladder cancer: examination of gene amplification by fluorescence in situ hybridization.

Analysis of HER-2/neu gene amplification by fluorescence in situ hybridization was performed in 40 patients with invasive bladder cancer in order to evaluate the potential for molecular targeted therapy of HER-2 as a tailor-made treatment for patients with invasive bladder cancer. This study included 40 patients seen at the Aichi Medical University Hospital from January 2001 to December 2004 and were pathologically diagnosed with invasive transitional cell carcinoma of the bladder (pT2-pT4). The PathVysion kit was used to evaluate the status of HER-2/neu gene amplification, and a signal ratio > or =2.0 was considered positive for HER-2/neu gene amplification. In primary foci 5 patients (12.5%) were positive for HER-2/neu gene amplification. According to the classification of grade and stage, no statistically significant difference was observed. Lymph node metastasis was found in 10 patients, and 3 patients (30%) were positive for HER-2/neu gene amplification. In the patients with HER-2/neu gene-amplified metastatic lymph nodes, primary foci were also positive for gene amplification, showing a statistically significant difference. This study indicates that 12.5% of patients with invasive bladder cancer may benefit from molecular targeted therapy of HER-2, and that molecular targeted therapy can be expected to be effective even for patients with lymph node metastases as long as their primary foci are positive for HER-2/neu gene amplification.