Haptoglobin polymorphism is not associated with prostate cancer in blacks

Background: Prostate cancer (Pca) disease burden is highest among male blacks. Oxidative stress due to hemoglobin-related oxygen reactive species is a risk factor for cancer development. The polymorphic haptoglobin (Hp) protein inhibits hemoglobin-related oxidative stress. The antioxidant capacity of Hp is genetically determined. We studied the effect of Hp polymorphism on susceptibility to Pca.

Subjects and methods: In a case-control study, 201 participants (60 hospital-based controls, 62 benign prostate hypertrophy (BPH) and 79 prostate cancer (Pca) patients were studied. Serum prostate specific antigen (PSA) was measured using an immunoradiometric assay and Hp phenotype was determined using starch gel electrophoresis. Haptoglobin phenotype distribution was compared between groups according to disease state.

Results: Serum PSA concentrations were markedly elevated in BPH and Pca patients compared to control subjects. Overall, Hp 1-1 was present in 50 individuals (25%), Hp 2-1 in 91 persons (46%) and 46 subjects (23%) had Hp 2-2. Thirteen individuals (6%) were anhaptoglobinaemic. The Hp1 allele frequency was not significantly different according to clinical history; 0.472 (95% CI 0.343-0.601), 0.567 (95% CI 0.395-0.619) and 0.507 (95% CI 0.441-0.693) for control group, BPH and Pca patients, respectively.

Conclusion: Our results suggest that Hp polymorphism is neither associated with risk of developing Pca nor outcome of the disease.