Correlation of ErbB2 gene status, mRNA and protein expression in a panel of >100 human tumor xenografts of different origin.

INTRODUCTION: The receptor tyrosine kinase ErbB2 is an important prognostic marker and therapeutic target in breast cancer. The aim of this study was to investigate the correlation between ErbB2 gene amplification, mRNA and protein expression in a panel of >100 patient-derived nude mouse tumor xenografts of different histological origin. MATERIALS AND METHODS: Data were obtained using fluorescence in situ hybridization, GenChip expression analysis, immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). Tumors included the following types: urinary bladder, breast, colon, stomach, kidney, liver, lung, melanoma, ovary, pancreas, prostate, uterus/cervix uteri and others. RESULTS: All tumors with high-level ErbB2 gene amplification expressed ErbB2 mRNA at a level >10-fold above average and protein at a level >20-fold above average (ELISA). Correlation was found between ErbB2 mRNA and protein expression. CONCLUSION: Based on expression data, cervical, gastric and adenocarcinomas of the lung emerged as new potential indications for ErbB2-directed cancer therapies.