Our findings suggested that CYP1A1 or GSTM1 variants may significantly modify the associations between level of serum trace metals (Cu, Zn, Se or Cr) and NSCLC, indicating the intriguing pathogenesis of lung cancer.
This meta-analysis demonstrated that the MspI and Ile-Val polymorphism of CYP1A1 is a risk factor associated with increased lung cancer susceptibility, but these associations vary in different ethnic populations.
Therefore, we conducted this study to determine whether CYP1A1/GSTM1 polymorphisms can affect the relationship between TP53 mutation and CDKN2A hypermethylation in lung cancer.
While exploring non-linear interactions through CART analysis, smokers carrying the combination of EPHX1 113TC (Tyr/His), SULT1A1 213GG (Arg/Arg) or AA (His/His) and GSTM1 null genotypes showed the highest risk for lung cancer (OR = 3.73;95%CI = 1.33-10.55,p = 0.006), whereas combined effect of CYP1A1*2A 6235CC or TC, SULT1A1 213GG (Arg/Arg) and betel quid chewing showed maximum risk in non-smokers (OR = 2.93;95%CI = 1.15-7.51,p = 0.01).
This meta-analysis suggests that the MspI and exon 7 polymorphisms of CYP1A1 correlate with increased lung cancer susceptibility and there is an interaction between two genotypes of CYP1A1 polymorphism and smoking, but these associations vary in different ethnic populations, histological types of lung cancer and gender of case and control population.
1.The CYP1A1T6235C polymorphism (rs4646903) gene polymorphism has been linked to the development of coronary heart disease and cigarette smoking-related lung cancer.
Two CYP1A1 polymorphisms, m1 (T6235C transition) and m2 (A4889G transition), are associated with greater enzymatic activity and have been described as genetic susceptibility factors for lung cancer.
The polymorphism of CYP1A1*2A or CYP1A1*2B, and the linkage of CYP1A1*2A, CYP1A1*2B, GSTM1 and GSTT1 polymorphisms have been established as susceptible genes or gene-gene interactions of tobacco-related lung cancer.
CYP1A1 haplotypes (in allele order CYP1A1*4, CYP1A1*2C, CYP1A1*2A) CGC and CGT were associated with an increased risk of lung cancer, whereas AAT was associated with decreased lung cancer risk in this population.
The most significant risk for LC (OR = 3.2; 95% CI: 0.7-3.8) was found in the association of the homozygous variant of CYP1A1 gene at A2455G base change at Exon 7 (Val/Val) genotype.
Several polymorphisms within the CYP1A1 locus have been identified and have been shown to be associated with lung cancer risk, particularly in Asian populations.
Moreover, the association between CYP1A1rs2606345 genotype and lung cancer was significantly modified by intensity of cigarette smoking, suggesting an underlying dose-response mechanism.
Our data thus provides evidence of CYP1A1 expression in freshly isolated blood lymphocytes and differences in reactivity in individuals with variant genotypes of CYP1A1, suggesting that blood lymphocyte CYP1A1 expression profile could help in identifying individuals at risk to environment induced lung cancer.
The polymorphic frequency of 10 genetic susceptibility genes and their association with lung cancer were examined in a northern Thai population: CYP1A1 (MspI), CYP1A1 (Ile462Val), CYP2E1 (PstI), CYP2E1 (DraI), GSTM1, GSTT1, MPO (AciI), OGG1 (Ser326Cys), TP53 (Arg72Pro), and MMP1(AluI).
Therefore, in 46 published studies in Chinese populations, we found evidence of an association between the CYP1A1 variant and GSTM1 null genotypes and increased risk of lung cancer.
DNA was obtained from blood samples and we studied by PCR-RFLP the distribution of CYP1A1 *2B (n=248) and *4 (n=222) polymorphisms in healthy controls and 222 lung cancer patients from a Mexican population.
Theses results suggest that the CYP1A1Ile462Val polymorphism is associated with a reduced risk of lung adenocarcinoma in never-smoking Korean women, whereas specific combinations of variant genotypes for metabolic enzymes increase lung cancer risk considerably.
The lung cancer risk was increased several two-to fourfold in the patients carrying the genotype combinations of CYP1A1*2A and GSTM1 suggesting the role of gene-gene interaction in lung cancer.