Genetic deletions of glutathione-S-transferase as a risk factor in squamous cell carcinoma of the larynx: A preliminary report

Purpose: To test whether genetic deletions of glutathione-S-transferase (GST) are associated with squamous cell carcinoma (SCC) of the larynx. GST are a group of detoxifying enzymes that may help reduce the risk of developing cancer in response to environmental carcinogens. Polycyclic aromatic hydrocarbons, found in high concentration in cigarette smoke, are known carcinogens especially for SCC of the larynx. Individuals with absolute or relative deficiency of the GST enzyme system may therefore be at a higher risk of developing laryngeal carcinoma. Materials and Methods: Genotyping for GST-MI and GST-TI was performed using polymerase chain reaction (PCR) assay on fresh frozen tissue specimens of 20 patients with SCC of the larynx and on 20 control subjects with a similar smoking history. Because this assay results in the absence of a PCR product in individuals expressing the GST-M1/ GST-T1 null genotype, oligonucleotide primers that amplify a portion of the albumin gene were included in a multiplex PCR as a positive control for DNA quality and PCR conditions. The chi-square test was used for statistical analysis. Results: GST-M1 gene was deleted in 80% of patients with laryngeal SCC and in 50% of control subjects (P < .05). No statistically significant difference was observed in the incidence of GST-TI gene deletion in patients with SCC of the larynx and control subjects. Conclusion: GST-MI gene deletion was significantly associated with SCC of the larynx and may produce a risk for this particular disease.