FISH detection of TMPRSS2 and ERG gene status. A) No TMPRSS2-ERG fusion. B) Positive for the TMPRSS2-ERG fusion with translocation – arrows indicate the separate green 5' ERG signal. C) Positive for the TMPRSS2-ERG fusion with deletion – arrows indicate the combined blue/red TMPRSS2 and 3' ERG signal and the absence of the green 5' ERG signal. FISH signals in these pseudo-colored images are red (telomeric to TMPRSS2; RP11-35C4), green (5' ERG; RP11-95I21) and blue (3' ERG; RP11-476D17). Note that in non-rearranged chromosomes the proximity of the green and blue signals can result in an aqua-colored signal.