Involvement of cytochrome P450 genes (CYPs) in breast cancer (BCa) may differ between populations, withexpression patterns affected by tumorigenesis. This may have an important role in the metabolism of anticancerdrugs and in the progression of cancer. The aim of this study was to determine the mRNA expression patternsof four cytochrome P450 genes (CYP2W1, 3A5, 4F11 and 8A1) in Mexican women with breast cancer. RealtimePCR analyses were conducted on 32 sets of human breast tumors and adjacent non-tumor tissues, as wellas 20 normal breast tissues. Expression levels were tested for association with clinical and pathological data ofpatients. We found higher gene expression of CYP2W1, CYP3A5, CYP4F11 in BCa than in adjacent tissues andonly low in normal mammary glands in our Mexican population while CYP8A1 was only expressed in BCa andadjacent tissues. We found that Ki67 protein expression was associated with clinicopathological features as wellas with CYP2W1, CYP4F11 and CYP8A1 but not with CYP3A5. The results indicated that breast cancer tissuesmay be better able to metabolize carcinogens and other xenobiotics to active species than normal or adjacentnon-tumor tissues.
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