As the upper aero digestive tract is exposed to numerous potential carcinogens such as phenolic xenobiotics, polycyclic aromatic hydrocarbons and heterocyclic aromatic amines contained in cigarette smoking, environmental pollutants and some food, this result manifests that the mutation within SULT1A1 causes the low SULT1A1 activity and is associated with high susceptibility to cancers related with environment. Here, SULT1A1 is linked to cancer.