Catechol-O-Methyltransferase (COMT) gene polymorphism and breast cancer risk in young women

Oestrogen exposure has long been considered to be a main risk factor of bre ast cancer. More recently, interest has also focused on the possible carcin ogenic influence from oestrogen metabolites, such as catechol oestrogens. O -methylation, catalysed by Catechol-O-Methyltransferase (COMT), is one path way by which the potentially carcinogenic catechol oestrogens can be inacti vated. The gene coding for COMT protein contains a single-nucleotide polymo rphism (SNP), resulting in an amino acid shift Val --> Met, which has been shown to determine high- and low-activity configuration of the enzyme. We h ypothesized that the low-activity allele, COMTMet, may be implicated in ear ly onset breast cancer. In the present case-control study, including 126 yo ung breast cancer patients (less than or equal to 36 years) and 117 healthy female blood donors, we analysed the association between COMTMet genotype and risk of breast cancer. No significant difference in the frequency of lo w-/high-activity alleles was found between cases and controls, indicating t hat the polymorphism, as a single factor, may not contribute to breast carc inogenesis in young women. (C) 2001 Cancer Research Campaign.