Surprisingly, the analysis of CYP1A, CYP2A, CYP2E1, CYP3A, and CYP4A protein levels in 25 non-neoplastic surgical tissue specimens of human esophageal mucosa did not reveal any significant associations with the patients’ medical history data and known esophageal cancer risk factors, such as tobacco smoke and GERD [24]. The gene discussed is CYP3A4; the disease is esophageal cancer.