The Aryl hydrocarbon receptor (AhR), which binds to polycyclic aromatic hydrocarbons (PAHs), and halogenated aromatic hydrocarbons (HAHs) can activate the expression of CYP1A1, CYP1A2, and CYP1B1; consequently, these enzymes have the capacity to activate procarcinogens resulting in lung cancer [52]. The gene discussed is AHR; the disease is lung carcinoma.