CYP3A4 and esophageal cancer: A study of esophageal microsomal samples from patients in the United States and Henan Province (China), a high-risk area for esophageal cancer, demonstrated that CYP3A4 and CYP2E1 are involved in the activation of tobacco carcinogens N’-nitrosonornicotine and N-nitrosodimethylamine, respectively, in the human esophagus [66].