Genetic polymorphism in ornithine decarboxylase and risk of breast cancer.

Ornithine decarboxylase (ODC), the first enzyme in the biosynthesis of polyamines, has increased activity in breast cancer tissue compared with benign and normal tissues. The ODC gene contains a single nucleotide polymorphism in which a guanine is substituted for an adenine. This study investigated whether the ODC +316 G > A polymorphism (rs2302615) was associated with the risk of developing breast cancer. A case-control study involving 121 controls, without breast cancer, 46 patients with breast cancer but without a family history, and 130 breast cancer cases with a family history of breast cancer was conducted. A nested PCR-restriction fragment length polymorphism procedure and the TaqMan 5' nuclease assay was used to genotype individuals. Risk was significantly lower for heterozygote (GA genotype) individuals [odds ratio (OR) = 0.39, 95% confidence interval (CI) 0.17-0.86, P = 0.018], or individuals with at least one A allele (OR = 0.44, 95% CI 0.21-0.92, P = 0.027), without family history. This protective effect of having at least one copy of the variant A allele was not as strong, however, in those with a family history of the disease. In sporadic breast cancer, the presence of at least one A allele is protective against the disease. The influence of this polymorphism may be less important in individuals with an inherited breast cancer predisposition.