Correlation of polymorphism of the coding region of glutathione S- transferase M1 to susceptibility of nasopharyngeal carcinoma in South China population.

BACKGROUND AND OBJECTIVE: Glutathione S-transferase M1 (GSTM1) deficiency may increase the risk of nasopharyngeal carcinoma (NPC). This study was to evaluate the correlation of the single nucleotide polymorphism (SNP) in the coding region of GSTM1 gene to NPC susceptibility in southern China population. METHODS: In total 239 NPC patients and 286 age-matched healthy controls were entered into the study. Among them, 225 out of 239 NPC patients and 273 out of 286 controls were used for statistical analysis. SNP screening of all exons, relevant intron-exon boundaries, and the promoter region of GSTM1, in total 4739bp, was performed by PCR direct sequencing. The loci T1270533G and C1256088C were selected for the case-control study using the tetra-Primer ARMS-PCR, as well as the sequencing method. RESULTS: In total 29 SNPs of GSTM1 were identified by sequencing. Missense mutation occurred in the polymorphic loci of T1270533G and C1256088C. However, no evident relationships between the variants of T1270533G and clinical phenotypes of NPC were observed in the NPC group and healthy control group (OR = 0.170, 95%CI = 0.95-0.306 for homozygote TT). The deletion frequency of C1256088C was 45% (45/100) for NPC patients and 42% (42/100) for controls. CONCLUSIONS: The polymorphism of T1270533G does not affect the detoxification function of GSTM1. The T1270533G locus has no apparent association with genetic susceptibility to NPC in the southern China population. The loss rate of C1256088C is high in this study.

[Association of the T1270533G polymorphism in GSTM1 gene coding region with susceptibility to nasopharyngeal carcinoma in a Chinese population].

OBJECTIVE: To explore the association of T1270533G polymorphism in the glutathione S-transferase M1 (GSTM1) gene with the susceptibility to nasopharyngeal carcinoma (NPC) and clinical phenotype of NPC in Chinese population. METHDOS: The genomic DNAs were obtained from 27 Chinese subjects, and the single nucleotide polymorphism (SNP) in all the exons and relevant intron-exon boundaries of GSTM1 were determined by PCR and direct sequencing. A case-control study was performed to analyze the SNP site T1270533G (the rare allele frequency is 22.2% in Chinese population) in the coding region by means of tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) and sequencing. RESULT: Sequence analysis identified 29 SNPs in GSTM1 gene, among which 13 SNPs presented high linkage disequilibrium with each other. No obvious relations were found between the variation in the coding region T1270533G and the clinical phenotype of NPC (RR=0.170, 95% CI =0.95-0.306 for TT homozygotes). CONCLUSION: The missense mutation in the coding region T1270533G of GSTM1 gene that causes an amino acid change does not affect the detoxification function of GSTM1, and the T1270533G polymorphism does not have apparent relations to NPC susceptibility in Chinese subjects in Guangdong Province.