Figure 4
p63-expressing prostate tumors do not rearrange the ERG gene locus or express ERG protein. ERG break-apart FISH assay in a usual-type carcinoma occurring concurrently with a p63-expressing tumor demonstrates rearrangement involving TMPRSS2 locus (green probe), which is spatially separated from the red and orange probes (centromeric and telomeric relative to the ERG gene, respectively) ( × 630 magnification). In contrast, the p63-expressing tumor from the same patient is negative for any rearrangement at this locus. Notably, neither tumor expresses ERG protein, despite positivity in endothelial cell nuclei that provide an internal positive control (arrowheads). Lack of ERG staining in the TMPRSS2-rearranged usual-type acinar carcinoma could be consistent with a rearrangement involving another ETS-family gene ( × 400 magnification).
