To investigate the factors regulating CYP2E1 gene expression, its protein levels were followed in breast cancer cells with different p53 and estrogen receptor status treated with either ethanol, which induces CYP2E1 enzymatic activity, or the topoisomerase II inhibitor etoposide, which induces DNA damage and activates p53 response. This evidence concerns the gene CYP2E1 and breast carcinoma.