Haptoglobin polymorphism and prostate cancer mortality

Prostate cancer is a common malignancy in men worldwide and it is known that oxidative stress is a risk factor for cancer development. A common functional haptoglobin (Hp) polymorphism, originating from a duplication of a gene segment spanning over two exons, results in three distinct phenotypes with different anti-oxidative capacities: Hp1-1, Hp1-2, and Hp2-2. The aim of the study was to investigate the relationship between this Hp polymorphism and prostate cancer mortality. The study was performed on 690 patients with histologically confirmed prostate cancer, recruited between January 2004 and January 2007. Hp genotypes were determined by a TaqMan fluorogenic 5'-exonuclease assay. Hp1-1 was present in 76 (11%), Hp1-2 in 314 (45.5%), and Hp2-2 in 300 (43.5%) patients. During a median follow-up of 149 months, 251 (35.3%) patients died. Hp genotypes were not significantly associated with higher overall mortality (HR 1.10; 95% CI 0.91-1.33; p = 0.34). This remained similar in a multivariate analysis including age at diagnosis, androgen deprivation therapy, and risk group based on PSA level, GS, and T stage (HR 1.11; 95% CI 0.91-1.34; p = 0.30). We conclude that the common Hp polymorphism does not seem to be associated with overall mortality in prostate cancer patients.