While some studies have suggested that the presence of TMPRSS2:ERG fusions is associated with more aggressive disease or higher Gleason tumor grade, other investigators did not reach the same conclusion (12, 14, 17, 20, 23, 42) . We also did not find such an association in a small series of samples. However, all of these results are defective due to small sample size. The technology described here should make possible a larger scale investigation to find whether there is a correlation between the aggressiveness of the disease and the presence of specific fusion genes.