ERG Tumor Type is Less Frequent in High Grade and High Stage Prostate Cancers of Chinese Men

Background: The incidence of prostatic adenocarcinoma has been rapidly increasing among Chinese men. This alarming trend prompted evaluations of early causal genomic alterations known to drive prostate tumorigenesis. Recurrent activation of the ETS-Related Gene (ERG) by genomic rearrangements is the most recognized early event in prostate cancer. Following the initial detection of ERG rearrangement at gene expression and genomic and levels, development of diagnostic quality antibodies against ERG oncoprotein have streamlined the rapid assessment of ERG frequencies world-wide. Unexpectedly, these studies revealed highest frequencies of ERG among Caucasian descents, lower frequencies among African Americans and even lower prevalence of ERG among Asian men. Objective: To asses in a prospective study ERG frequencies, clinico-pathological and prognostic associations of ERG among prostate cancer patients of the Dalian region of Northeast China, by an established immunohistochemical procedure that have been used in studies world-wide. Methods: Formalin fixed paraffin embedded specimens donated by patients (N=50) diagnosed with prostatic adenocarcinoma who underwent transurethral resection of the prostate (TURP) between 2007 and 2012 were evaluated for ERG by immunohistochemistry. Results: Of the 50 cases, 13/50 (26.0%) tumors were positive for ERG. In all cases, normal prostatic epithelial were ERG negative. ERG was more frequently detected in the lower Gleason score (≤7) and low T-stage. Consistent with reports from Asian countries the results of our study shows lower overall frequencies of ERG positive tumors when compared to reports from Western countries. Conclusion: The intriguing association of even lower ERG frequencies with high Gleason scores and higher T-stages provides impetus for current driver gene discoveries focused on the predominantly ERG negative prostate cancers of Asian men.