TUMOR-SPECIFIC EXPRESSION OF CYTOCHROME-P450 CYP1B1

Cytochrome P450 CYP1B1 is a recently cloned dioxin-inducible form of t he cytochrome P450 family of xenobiotic metabolizing enzymes. An antib ody raised against a peptide specific for CYP1B1 was found to recogniz e CYP1B1 expressed in human lymphoblastoid cells but not to recognize other forms of cytochrome P450, particularly CYP1A1 and CYP1A2. Using this antibody, the cellular distribution and localization of CYP1B1 we re investigated by immunohistochemistry in a range of malignant tumors and corresponding normal tissues, CYP1B1 was found to be expressed at a high frequency in a wide range of human cancers of different histog enetic types, including cancers of the breast, colon, Lung, esophagus, skin, lymph node, brain, and testis, There was no detectable immunost aining for CYP1B1 in normal tissues. These results provide the basis f or the development of novel methods of cancer diagnosis based on the i dentification of CYP1B1 in tumor cells and the development of anticanc er drugs that are selectively activated in tumors by CYP1B1.