Combined detection of Her2/neu gene amplification and protein overexpression in effusions from patients with breast and ovarian cancer

Purpose  

Her2/neu protein overexpression and gene amplification is found in 20–30% of breast cancer patients and correlates with poor clinical outcome. Patients who profit from anti-Her2/neu- therapy are routinely selected by examination of tumour specimens using immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH) separately. Many studies found a good correlation between both methods for score 1+ samples and for score 3+ samples, but not for score 2+ samples. In this study, we examined pleural and ascitic effusions with a combined approach using IHC and FISH on the same cells, under the following aspects: (1) frequency of Her2/neu protein expression and gene amplification in effusions; (2) correlation between score of protein expression and gene amplification; (3) impact of chromosome 17 polyploidy on Her2/neu protein expression.