title: Immunohistochemical demonstration of the expression of CYP2E1 in human breast tumour and non-tumour tissues.
abstract: Environmental chemicals are one of the risk factors in breast cancer genesis. Cytochrome P450 2E1 (CYP2E1), a member of multigene superfamily of enzymes, plays a major role in the activation of some of these chemicals such as tobacco-derived N-nitrosamines. Using immunohistochemistry, the cellular distribution and the level of expression of CYP2E1 was assessed in breast tumour and surrounding tumour free (control) breast tissue in 25 pairs of samples obtained from females with infiltrating ductal carcinoma. Cells staining with the CYP2E1 antibody showed only cytoplasmic positivity with varying intensities in 100% (25/25) of tumours and 96% (24/25) of normal breast tissues. Cytoplasmic staining was present in invasive ductal carcinoma cells but not in tumour stroma. CYP2E1 was detected in normal epithelial, myoepithelial and to a lesser degree in some of the non-epithelial cells (e.g. endothelial cells). No positive staining was detected in other non-epithelial cells such as fibroblasts in normal breast tissues. When CYP2E1 staining was assessed semiquantitatively the mean staining score values of CYP2E1 was found to be significantly higher in tumours compared to that of normal breast tissues. These results show that CYP2E1 protein is expressed in both tumour and normal breast tissue with an increased expression in breast tumours.
authors.affiliation: Department of Pathology, Demetevler Oncology Hospital, Ankara, Turkey.
authors.forename: Nilgün
authors.initials: N
authors.lastname: Kapucuoglu
authors.forename: Tulay
authors.initials: T
authors.lastname: Coban
authors.forename: Hannu
authors.initials: H
authors.lastname: Raunio
authors.forename: Olavi
authors.initials: O
authors.lastname: Pelkonen
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Edwards
authors.forename: Alan R
authors.initials: AR
authors.lastname: Boobis
authors.forename: Mumtaz
authors.initials: M
authors.lastname: Iscan
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000378:metabolism*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism*; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008593:Menopause; D008875:Middle Aged; D011960:Receptors, Estrogen / Q000032:analysis
chemical_list: D011960:Receptors, Estrogen; D019392:Cytochrome P-450 CYP2E1