Objective: The aim of our study is to find out the good responders for estramustine phosphate (EMP) therapy in patients with prostate cancer. We have focused on the metabolism of EMP and studied the association between a functional single-nucleotide polymorphism in the catechol-O-methyltransferase gene (Val158Met of COMT) and PSA-progression-free survival in Japanese patients with prostate cancer treated by EMP.
Methods: Seventy-two Japanese patients with previously untreated prostate cancer who were found to be eligible for low-dose EMP therapy were enrolled in the study. Genotyping of the Val158Met polymorphism of COMT was conducted by both the polymerase chain reaction-based restriction fragment length polymorphism method and TaqMan assay.
Results: Patients with the Val/Val genotype of COMT had a significantly higher PSA-progression-free rate as compared to those with the Val/Met or Met/Met genotype (p=0.027). The adjusted hazard ratio of biochemical PSA failure for the Val158Met genotype of COMT was 2.164 (95% CI, 1.111 to 5.525).
Conclusions: The Val158Met polymorphism of COMT is associated with the PSA-progression-free rate of EMP-treated patients in prostate cancer.