CYP1B1 and laryngeal carcinoma: Analyses for the joint effect of the three SNPs plus smoking/drinking on the risk for laryngeal cancer revealed that smokers with two of the aforementioned high risk alleles (mutation allele CYP1B1*2 355T and wild type allele CYP1B1*3 4326C) were at a significantly increased risk for developing laryngeal cancer (Table 5).