To test the hypothesis whether higher CYP2E1 cellular levels in stage I breast tumors compared to stages II, III, and IV were a result of differential transcriptional regulation of its gene expression and potential involvement of p53 [46] in this process, we followed the CYP2E1 protein levels in five different breast cancer cells with different migratory potential and p53 status, namely MCF7 [20], T47D [20], MDA-MB-231 [21], MDA-MB-468 and MDA-MB-157 [20] exposed to either ethanol (MCF7, MDA-MB-231and MDA-MB-468) or etoposide (etop) (MCF7, MDA-MB-231, T47D and MDA-MB-157) treatment. This evidence concerns the gene CYP2E1 and breast neoplasm.