Zhao YN et al. – Significantly deceased expression of estradiol–metabolizing enzymes might result in the excess exposure of intratumoural E2, which could be one of the important risk factors for breast cancer. Significantly elevated COMT expression suggested that COMT could play a key role in breast tumor formation.Methods
- The mRNA expression levels of cytochrome P450 (CYP) 1A1, 1B1 and 3A4 and catechol–O–methyltransferase (COMT) were examined in the breast tumor tissues, matched adjacent non–tumor tissues and the tissues with benign breast disease (BBD) by fluorescent quantitative real–time PCR.
- Compared to BBD tissue, the mRNA expression of CYP1A1, CYP1B1 and CYP3A4 significantly reduced by 81.8%, 77.5%, and 85.6%, respectively, in the breast tumor tissue and by 27.2%, 38.8%, and 51.3%, respectively, in the adjacent non–tumor tissue in average (p<0.0001).
- COMT mRNA was 6.9 and 6.4 fold higher in the breast tumor and match non–tumor tissue (p<0.0001) than in the BBD, respectively.
- The level of COMT detected in pre–menopausal group and lymph nodal stage N1–N2 group was lower than that in post–menopausal group (p=0.0292) and N0 group (p=0.0389), respectively.