ERG and prostate carcinoma: Given the status of TMRSS2-ERG as the most relevant genomic fusion event so far identified in prostate cancer, we tested the expression of PDE4D7 in 1106 patients with (Primary PCa, TMPRSS2-ERG positive; Figure 3) and without (Primary PCa, TMPRSS2-ERG negative; Figure 3) this gene fusion.