ERG rearrangement and protein expression in the progression to castration-resistant prostate cancer.

BACKGROUND: Approximately half of the prostate carcinomas are characterized by a chromosomal rearrangement fusing the androgen-regulated gene TMPRSS2 to the oncogenic ETS transcription factor ERG. Aim of this study was to comprehensively analyze the role and impact of the ERG rearrangement and protein expression on the progression to castration-resistant (CR) disease. METHODS: We used a tissue microarray (TMA) constructed from 114 hormone naive (HN) and 117 CR PCs. We analyzed the ERG rearrangement status by fluorescence in situ hybridization and the expression profiles of ERG, androgen receptor (AR) and the proliferation marker Ki67 by immunohistochemistry. RESULTS: Nearly half of the PC tissue specimens (HN: 38%, CR: 46%) harbored a TMPRSS2-ERG gene fusion. HN PCs with positive translocation status showed increased tumor cell proliferation (P<0.05). As expected, TMPRSS2-ERG gene fusion was strongly associated with increased ERG protein expression in HN and CR PCs (both P<0.0001). Remarkably, the study revealed a subgroup (26%) of CR PCs with ERG rearrangement but without any detectable ERG protein expression. This subgroup showed significantly lower levels of AR protein expression and androgen-regulated serum PSA (both P<0.05). CONCLUSIONS: In this study, we identified a subgroup of ERG-rearranged CR PCs without detectable ERG protein expression. Our results suggest that this subgroup could represent CR PCs with a dispensed AR pathway. These tumors might represent a thus far unrecognized subset of patients with AR-independent CR PC who may not benefit from conventional therapy directed against the AR pathway.

Spontaneous hepatic rupture in amyloidosis - report of a case.

In systemic amyloidosis spontaneous rupture of the liver is a rare complication. Here we report on a patient with unrecognized systemic amyloidosis who presented to an outside hospital with unspecific abdominal pain. Under the signs of a hemorrhagic shock, distended abdomen and intraabdominal bleeding a laparotomy was performed. Due to uncontrollable hemorrhage of the ruptured right liver lobe a packing was performed. After being transferred to the reporting institution a CT scan was performed showing a grade IV laceration of the right liver. Therefore a transarterial embolization of the right hepatic artery was carried out. The following day an infection of the abdominal cavity and the abdominal wall with gas-producing bacteria was noticed and a relaparotomy, necrectomy and repacking due to diffuse bleeding were performed. The situation deteriorated and at the second relaparotomy the following day an almost completely necrotic liver was found. The patient deceased the following day. Life-threatening spontaneous liver rupture due to systemic amyloidosis might only successfully be cured by high urgency liver transplantation as presented in the literature. However, in two published cases interventional therapy by embolization of bleeding vessels has saved patients' life.

ERG protein expression and genomic rearrangement status in primary and metastatic prostate cancer--a comparative study of two monoclonal antibodies.

BACKGROUND: Overexpression of the ERG protein is highly prevalent in prostate cancer (PCa) and commonly results from gene fusions involving the ERG gene. Recently, N-terminal epitope-targeted mouse and a C-terminal epitope-targeted rabbit monoclonal anti-ERG antibody (ERG-MAbs) have been introduced for the detection of the ERG protein. Independent studies reported that immunohistochemistry (IHC) with both ERG-MAbs highly correlates with the underlying ERG gene rearrangement status. However, comparative studies of both antibodies are lacking. Here, we are among the first to compare the mouse ERG-MAb with the rabbit ERG-MAb for their concordance on the same PCa cohort. Furthermore, we assessed whether the ERG protein expression is conserved in lymph node and distant PCa metastases. METHODS: We evaluated tissue microarrays of 278 specimens containing 265 localized PCa, 29 lymph node, 30 distant metastases and 13 normal prostatic tissues. We correlated ERG protein expression with ERG rearrangement status using an ERG break-apart fluorescence in-situ hybridization assay and IHC of both ERG-MAbs. RESULTS: ERG expression and ERG rearrangement status were highly concordant regardless of whether the mouse or rabbit ERG-MAb was used (97.8% versus 98.6%, respectively). Of interest, both ERG antibodies reliably detected the ERG expression in lymph node and distant PCa metastases, of which a subset underwent decalcification. Lymphocytes only revealed immunoreactivity using the rabbit ERG-MAb. If ERG protein expression was present in localized PCa, we observed the same pattern in the corresponding lymph node metastases. CONCLUSIONS: By demonstrating a broad applicability of IHC to study ERG protein expression using either antibody, this study adds an important step toward a facilitated routine clinical application. Further, we demonstrate that the clonal nature of the ERG rearrangement is not restricted to the genomic level, but proceeds in the proteome. Together, our results simplify future efforts to further eliucidate the biological role of ERG in PCa.

[Frequent gene fusion in prostate cancer: clinical applications in diagnosis, prognosis and therapy]. / Eine häufige Genfusion im Prostatakarzinom: Klinische Anwendungsmöglichkeiten für Diagnostik, Prognose und Therapie.

The discovery of TMPRSS2-ETS gene fusions in prostate cancer dramatically changed our view of solid tumors. Unveiling the molecular principles of the fusion illustrates the potential for clinical applications with regard to prognosis, diagnosis and therapy. In this review, we summarize the current knowledge about TMPRSS2-ETS gene fusions and delineate how genetic analysis of fusion positive prostate cancer cases can be used as a prognostic marker in clinical routine. The characteristic morphological features of the gene fusion and its detection in prostate biopsies and in urine make it a promising target to identify aggressive tumors. By increasing our knowledge about fusion positive prostate cancer, we will improve the possibility to offer target specific and individualized therapeutic approaches.