OGG1 and breast carcinoma: That OGG1 levels can vary in vivo has recently been demonstrated by the identification of a common single nucleotide polymorphism (SNP rs2304277) at the 3′ end of the OGG1 gene that is associated with a lower expression of the enzyme and that has been linked to an increased ovarian cancer risk in breast cancer patients carrying mutations in BRCA1 (35).