Caspase-8 （CASPS） plays a key role in apoptosis. We examined by genotyping whether the -652 six-nucleotide insertion-deletion （6N ins/del） polymorphism in the CASP8 promoter region was associated with prostate cancer risk in a hospital-based case-control study of 406 Chinese prostate cancer patients and 408 age-matched cancerfree controls. Additionally, 23 prostate cancer tissues were analyzed for CASP8 mRNA expression. We found a significantly decreased prostate cancer risk for the 6N ins/del genotype [adjusted odds ratio （OR）=0.68; 95% confidence interval （C/）=0.51-0.92] and del/del genotype （OR=0.34; 95% CI=0.19-0.63） compared with the ins/ins genotype. The 6N del allele was associated dose-dependently with decreased prostate cancer risk （Ptrend = 0.001）. RT-PCR showed that individuals with the 6N del allele had lower CASP8 mRNA levels than those with the ins/ ins genotype （P = 0.024）. These findings suggested that the CASPS-652 6N ins/del polymorphism may affect the susceptibility to prostate cancer and reduce prostate cancer risk among Chinese men.
