ERBB2 and invasive ductal breast carcinoma: The aim of this study was to resolve the HER2 gene and chromosome 17 status in cases of invasive ductal carcinoma, where gene copy number and chromosome status were equivocal and/or discordant (based on previously performed IHC and FISH analysis), by using a clinical array CGH assay for copy number evaluation of multiple loci along chromosome 17.