[Frequent genetic deletion of detoxifying enzyme GSTM1 and GSTT1 genes in nasopharyngeal carcinoma patients in Guangxi Province, China].

OBJECTIVE: To study the genetic susceptibility to chemical carcinogens of nasopharyngeal carcinoma (NPC) patients in a high-risk area in Guangxi.
METHODS: PCR technique was used to examine the frequency of glutathione S-transferase M1 and T1 gene deletion in a matched case-control study of 91 patients with NPC and 135 control subjects.
RESULTS: The deletion frequency of control subjects was 47.4% (65/135) for GSTM1 and 40.7% (55/135) for GSTT1, whereas that of NPC patients was 61.5% (56/91) for GSTM1 and 59.3% (54/91) for GSTT1 with statistically significant difference between the patients and the controls (P < 0.05 and P < 0.01). Furthermore, the frequency of codeletion of both genes was also higher in NPC patients than the control with statistically significant difference (chi2 = 12.533, P = 0.002).
CONCLUSION: In high-risk area, nasopharyngeal carcinoma patients and local residents have high frequency of GSTM1 and/or GSTT1 gene deletion. It suggests that a genetic susceptibility to putative chemical carcinogens may be responsible for NPC clustering in the high-risk area studied.