Our haplotype analyses showed that G355C4326G−1293 was the most common haplotype found in both the patient and control groups (Table 4), and also confirmed that both mutation alleles, CYP1B1*2 355T and CYP2E1*5 -1293C, are high risk genetic factors for developing laryngeal cancer, while the mutation allele CYP1B1*3 4326G is a protective genetic factor. This evidence concerns the gene CYP2E1 and laryngeal carcinoma.