As shown in Table 2, there were no differences in the frequencies of GSTM1 (null/present) and GSTT1 (null/present) variants between Han Chinese glioma patients and healthy controls: GSTM1 (43% vs. 48%; OR=1.07(0.93-1.21); P=0.31); GSTT1 (41.1% vs. 34.1%; OR=0.89(0.81-1.06); P=0.052). Here, GSTM1 is linked to central nervous system cancer.