Some authors have suggested a concordance of HER-2 and TOPOIIα gene amplification in breast cancer,3 while others have demonstrated that TOPOIIα amplification, identified by fluorescence in situ hybridization (FISH), may occur with or without HER-2 duplication and is often associated with TOPOIIα expression evaluated by immunohistochemistry.1 This evidence concerns the gene ERBB2 and breast cancer.