But TCDD itself is carcinogenic, it induces a broad spectrum of biological responses, including induction of CYP1A1, disruption of normal hormone signaling pathways, reproductive and developmental defects, immunotoxicity, liver damage, wasting syndrome, and cancer [18], so non-toxic or low-toxic selective AhR modulators maybe served as possible agents for gastric cancer. The gene discussed is CYP1A1; the disease is gastric cancer.