FIGURE 4

The immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) results in two representative cases. Two representative cases are shown for the IHC staining and PathVysion FISH assay orange signals are for HER-2/neu gene, and the green signals are for chromosome 17 centromere). A, one case that had monosomy 17 (chromosome 17 copy number, 1.11 signals per cell) and HER-2/neu gene amplification by PathVysion criterion (HER-2/neu gene to chromosome 17 ratio, 2.98), but no HER-2/neu protein overexpression ACIS IHC score, 1.8). It had no HER-2/neu gene amplification by the alternative FISH criterion (HER-2/neugene copy number, 3.26 signals per cell). B, one case had high polysomy 17 (chromosome 17 copy number, 7.02 signals per cell), HER-2/neu gene amplification by PathVysion criterion (HER-2/neu gene to chromosome 17 ratio, 2.40), and HER-2/neu protein overexpression (ACIS score, 3.0). It also had concurrent HER-2/neu gene amplification by the alternative FISH criterion (HER-2/neu gene copy number, 16.87 signals per cell). Because of the three-dimensional nature of the cells, not all signals are present in the plane of this particular figure.