Clinical significance of ERG rearrangement subtype and its association with increased p53 expression in Japanese and German prostate cancer.

This study investigated differences in prevalence of the androgen-regulated transmembrane protease serine 2 (TMPRSS2) and ETS transcription factor family member, v-ets erythroblastosis virus E26 oncogene homolog (ERG) fusion gene (TMPRSS2-ERG fusions) in clinically localized prostate cancer Japanese and German patients. A total of 105 specimens, including 69 Japanese and 36 German patients, were collected. The status of TMPRSS2-ERG fusion was determined by fluorescence in situ hybridization, and correlations of the TMPRSS2-ERG fusion with clinicopathological characteristics and immunohistochemistry were studied. Gene fusions were identified in 20% (14/69) of Japanese and 53% (19/36) of German patients (P < 0.001). The difference in the type of gene fusion between the two ethnic groups was statistically significant (P=0.024). Overexpression of ERG protein was significantly associated with gene fusion. Biochemical recurrence was significantly higher in patients with ERG overexpression than in those without, and not related to TMPRSS2-ERG fusion status. Interestingly, two types of gene fusions (deletion and increase of copy number) were significantly associated with increased p53 expression (P = 0.005). Association of specific gene fusions harboring higher genomic alterations with p53 expression levels suggests that p53 mutation might drive more aggressive rearrangements of TMPRSS2-ERG fusion in prostate cancer.