Genetic polymorphisms of <i>CYP1A1</i>, <i>CYP2E1</i>, <i>GSTM1</i>, and <i>GSTT1</i> associated with head and neck cancer

GSTM1 null alone or associated with CYP1A1 increased the risk of head and neck cancer; the CYP2E1PstI mutated allele increased the risk for only oral cancer.