TMPRSS2: ERG gene fusion associated with lethal prostate cancer in a watchful waiting cohort

The identification of the TMPRSS2:ERG fusion in prostate cancer suggests that distinct molecular subtypes may de. ne risk for disease progression. In surgical series, TMPRSS2:ERG fusion was identified in 50% of the tumors. Here, we report on a population-based cohort of men with localized prostate cancers followed by expectant (watchful waiting) therapy with 15% (17/111) TMPRSS2:ERG fusion. We identified a statistically significant association between TMPRSS2:ERG fusion and prostate cancer specific death (cumulative incidence ratio = 2.7, P < 0.01, 95% confidence interval = 1.3-5.8). Quantitative reverse-transcription-polymerase chain reaction demonstrated high estrogen-regulated gene (ERG) expression to be associated with TMPRSS2: ERG fusion (P < 0.005). These data suggest that TMPRSS2:ERG fusion prostate cancers may have a more aggressive phenotype, possibly mediated through increased ERG expression.