IMMUNOHISTOCHEMICAL LOCALIZATION OF CYTOCHROME-P450 2E1 IN HUMAN PULMONARY-CARCINOMA AND NORMAL BRONCHIAL TISSUE

Cytochrome P450 2E1 (CYP2E1) is a major xenobiotic-metabolizing enzyme but data concerning its extrahepatic expression are few. CYP2E1 can m etabolically activate many procarcinogens and therefore its presence i n the lung might play a role in bioactivation of procarcinogens, so we studied the expression and localization of CYP2E1 in primary pulmonar y carcinomas and surrounding normal bronchial tissue from 28 patients. Seromucous glands showed expression of CYP2E1 in 19 and bronchial epi thelium in 18 of the 28 samples of normal bronchial tissue. Thirteen o f the corresponding cases of primary pulmonary carcinoma showed staini ng for CYP2E1. In 11 of these 13 cases, CYP2E1 was also present in nor mal bronchial tissue. There was no statistically significant differenc e in the expression of CYP2E1 between adenocarcinomas and squamous cel l carcinomas. No association was observed between the expression of CY P2E1 in tumour tissue and normal bronchial tissue. However, there was a significant correlation between the expression of CYP2E1 in seromuco us glands and bronchial epithelium (r=0.61, P<0.01) of normal tissue. We conclude that CYP2E1 can be present in both normal and neoplastic b ronchial tissue.