Abstract: Objective To determine the correlation of TMPRSS2-ERG(T-E) fusion gene to the survival rate in metastatic castration-resistant prostate cancer after docetaxel chemotherapy. Methods We included 20 patients with benign prostatic hyperplasia and 50 patients with prostate cancer(mCRPC) chemotherapy. The expression of T-E fusion gene in peripheral blood mononuclear cells was examined by quantitative real time polymerase chain reaction(qRT-PCR). Therapeutic responses of patients with different fusion gene expression were assessed by prostate specific antigen (PSA) response rate, PSA-progression free survival(PFS), radiological progression free survival(RX-PFS), and overall survival(OS). Results The T-E fusion gene was detected in 10 (20%) of 50 prostate cancer patients. The PSA response rate in the T-E positive group was lower than that in the negative group (32.52% vs 74.35%, P=0.040). Univariate survival analysis showed that PSA-PFS, RX-PFS, and OS were lower in T-E positive patients than in negative patients, and the difference was statistically significant (P<0.01). Multivariate Cox regression analysis showed that T-E positive was an independent risk factor for PSA-PFS, RX-PFS and OS (P=0.010, P=0.010, P=0.020). Conclusion This study demonstrates that T-E fusion gene expression is an independent risk factor for PSA-PFS, RX-PFS and OS in mCRPC patients treated with docetaxel.

Key words: TMPRSS2-ERG fusion gene, prostate cancer, chemotherapy, drug resistance