CYP1A1 and CYP3A4 are capable of metabolizing a variety of carcinogens, such as polycyclic aromatic hydrocarbons, heterocyclic amines, nitrosamines, azo-dyes, and alkylating agents [161,162], and by doing so may produce active derivatives that lead to the tumor initiation. This evidence concerns the gene CYP1A1 and neoplasm.