Relationship between deletion of GSTM1, GSTT1 genes and susceptibility to lung cancer

  Objective   To study the relationship between the deletion of glutathione S transferase M1(GSTM1), glutathione S transferase T1(GSTT1)and susceptibility to lung cancer and its mechanism.

  Methods   Using the method of PCR to detect the genotypes of GSTM1 and GSTT1 in 77 lung cancer patients and 107 healthy people.Using SDS-PAGE and Western-blot to detect the expression of P16 protein in normal lung tissue.

  Results   There were 58.4% (45/77)patients with GSTM1 null genotype in all cases and 42.1% (45/107)persons with GSTM1 null genotype in the healthy people, and there was significant difference between the two groups(χ²=4.811, P=0.028), and its OR was 1.938(95% CI=1.095~3.581);There were 57.1% (44/77)patients with GSTT1 null genotype in all cases and 50.5% (54/107)persons with GSTT1 null genotype in the healthy people, and there wasn't significant difference between the two groups(χ²=0.802, P= 0.371);There were 26 cases with GSTM1 null/GSTT1 null genotype in patients which was significantly higher than those in the healthy people, and its OR was 2.451(95% CI=1.067~5.633).There was significant difference on the levels of P16 protein between individuals with GSTM1 null genotype and those with GSTM1 non-null genotype as well as the group of GSTM1/GSTT1 combined null genotype and those of GSTM1/GSTT1 combined positive(P < 0.05).

  Conclusion   GSTM1 null genotype and GSTM1/GSTT1 combined null genotype laid in much more lung cancer patients than healthy people, and it could highly increase the risk of lung cancer occurrence.The deletion of GSTM1 gene and GSTM1/GSTT1 combined null genotype were related to the low expression of P16 protein.