Objectives/hypothesis: Glutathione S-transferase P1-1 (GSTP1-1) is an important enzyme because it plays a major role in many detoxification reactions, including tobacco-related metabolic products. GSTP1-1 is the most abundant of all glutathione S-transferase (GST) enzymes in normal human head and neck epithelium, whereas it is overexpressed in head and neck malignancies. At least three different GSTP1 genotypes exist, AA, AB, and BB, which have been correlated with reduced enzyme activity. Many authors have studied the GSTP1 genotypes in relation to the risk for human head and neck squamous cell carcinoma (HNSCC). A correlation between GSTP1-1 genotype and GSTP1-1 plasma levels has not been made before. We investigated the correlation between GSTP1 genotype and GSTP1-1 plasma levels.
Study design: To evaluate the possible association between the genetic polymorphisms in GSTP1 and the phenotypic expression (GSTP1-1 plasma levels) in patients with HNSCC.
Methods: GSTP1 genotype and GSTP1-1 plasma level were established in 87 patients with HNSCC and 51 patients with benign head and neck lesions who served as control subjects.
Results: For all GSTP1 genotypes (AA, AB, and BB) in patients with HNSCC, the mean plasma GSTP1-1 values were significantly higher compared with the control subjects. There was no significant difference in the plasma GSTP1-1 levels between the different genotypes in patients with HNSCC.
Conclusion: There is no association between GSTP1 genotype and GSTP1-1 plasma levels in patients with head and neck cancer.