The Pathway Ontology (PW), is currently being developed at the Rat Genome Database. For more information about this vocabulary, please see Petri et al. The rat genome database pathway portal. Database (Oxford). 2011 Apr 8;2011:bar010. Print 2011 or contact us (http://rgd.mcw.edu/contact/index.shtml).
The aryl hydrocarbon receptor (AhR) is a transcription factor whose ligands include a variety of aromatic hydrocarbons and which regulates the expression of phase I and phase II drug- and xenobiotic-metabolizing enzymes. Phase I enzymes convert otherwise inactive hydrocarbons into active metabolites with potential carcinogenic effects, thus rendering AhR a player in tumor initiation.