Detection of the TMPRSS2-ETS fusion gene in prostate carcinomas: retrospective analysis of 55 formalin-fixed and paraffin-embedded samples with clinical data

The recent identification of fusion genes involving ETS family members in human prostate adenocarcinoma has confirmed the hypothesis that recurrent specific aberrations such as fusion genes may be as frequent in epithelial tumors as they are in leukemias and sarcomas. However, reciprocal translocations with fusion genes are often not detectable in carcinomas by conventional karyotyping because of additional complex chromosomal abnormalities. We retrospectively analyzed a large series of formalin-fixed, paraffin-embedded samples including 55 prostate carcinomas and 11 benign prostate tumors. We identified the fusion gene TMPRSS2-ERG by reverse-transcriptase polymerase chain reaction (RT-PCR) in 40/55 carcinomas (72%). Our study demonstrates that the detection of ETS fusion gene by RT-PCR is feasible on formalin-fixed and paraffin-embedded samples. No significant association between the presence of the fusion gene and any clinical feature, such as preoperative serum prostate-specific antigen (PSA) level (PSA>20 or PSA< or =20), pTNM stage including capsule invasion, seminal vesicle invasion, and lymph nodes metastases, or recurrence was observed in our series.