ABSTRACT
Objective: To investigate whether the real-time polymerase chain reaction (R-PCR) assay with SYBR green I and melting curve analysis could be used for glutathione S-transferase M1 gene (GSTM1) polymorphism detection in Thai nasopharyngeal carcinoma (NPC) patients by comparing the results of this assay with the conventional PCR (C-PCR) assay. Methods: DNA samples from peripheral blood leukocytes of 60 Thai NPC patients were investigated in this study. GSTM1 polymorphism [GSTM1 normal genotype (GSTM1+) and GSTM1 null genotype (GSTM1-)] were examined by using the R-PCR assay with SYBR green I and melting curve analysis and the C-PCR assay. Results: The results of GSTM1 polymorphism detection by the R-PCR assay were in concordance with the C-PCR assay (k = 1.0). Twenty-six individuals with GSTM1+ in the R-PCR assay showed 2 peaks of melting point at 82.5oC and 87.5oC that correlated with the appearance of 2 DNA bands of GSTM1 [215 base pair (bp)] and b-globin (268 bp) in the C-PCR assay, respectively. In addition, thirty-four individuals with GSTM1- in the R-PCR assay showed only 1 peak of melting point at 87.5oC that correlated with the appearance of 1 DNA band of b-globin (268 bp) in the C-PCR assay. Moreover, we found that the R-PCR assay was a faster and safer method for detection of GSTM1 polymorphism than the C-PCR assay. Conclusion: The present study suggests that the R-PCR assay with SYBR Green I and melting curve analysis may be a useful screening tool for more convenient, rapid, reliable, and safer detection of GSTM1 polymorphism in Thai NPC as compared to the C-PCR assay.