Fig. 4

Representative images of ERG immunostainings. a Negative ERG immunostaining from a homogeneous ERG negative prostate cancer. The blue arrow indicates positive ERG immunostaining in endothelial cells as a positive control, b positive ERG immunostaining from a homogeneous ERG positive prostate cancer, c positive ERG immunostaining (red circle) and negative ERG immunostaining (green circle) from an intrafocal heterogeneous prostate cancer; the blue arrow indicates positive ERG immunostaining in endothelial cells as a positive control, d false heterogeneity, positive cancer (left), false negative cancer (right), the blue arrow indicates endothelial cells also lacking ERG immunostaining (d)