Genetic polymorphisms in the mEH gene in relation to tobacco smoking: role in lung cancer susceptibility and survival in north Indian patients with lung cancer undergoing platinum-based chemotherapy

Aim: Epoxide hydrolase is involved in oxidative defenses and is responsible for the activation of carcinogens. The relationship between EPHX1 polymorphisms (Tyr113His and His139Arg) and overall survival (OS) and lung cancer (LC) risk was investigated. Methods: The study comprised 550 cases and 550 controls. Genotyping and statistical analysis were applied. Results: The variant genotypes of EPHX1 polymorphisms exhibited no association with LC risk. The Tyr113His polymorphism exhibited twofold increased odds of lymph node invasion (p = 0.04). The Tyr/His genotype is a risk factor for smokers. Subjects carrying the combined genotype for His139Arg showed better median survival time (MST) and the heterozygous genotype revealed better MST in the case of small-cell lung cancer (SCLC; 11.30 vs 6.73 months; log-rank test: p = 0.02). The heterozygous genotype (His139Arg) had longer MST in patients receiving cisplatin/carboplatin and irinotecan (11.30 vs 7.23; log-rank test: p = 0.007) Conclusion: The Tyr113His polymorphism is associated with LC risk in smokers and is a potential prognostic factor for OS in patients with SCLC after irinotecan.

Evolutionarily conserved clusters of colon with lung cancer susceptibility loci, linked with most DUSP phosphatase genes, may help to dissect mechanisms of cancer susceptibility

We show evolutionarily conserved pairwise genetic linkage and clustering of majority of colon and lung cancer susceptibility QTLs in mice, rats and humans. The patterns of susceptibility or resistance to these two cancers in recombinant congenic mouse strains were concordant and the responsible susceptibility loci closely linked, in spite of completely different carcinogens and protocols used for induction of the two tumors. Most DUSP (Dual specificity phosphatase) genes are linked to these clusters. These data suggest that an important part of colon and lung cancer susceptibility is controlled by related and evolutionarily conserved processes.

Gene-gene Interaction of AhR with and within the Wnt Cascade Affects Susceptibility to Lung Cancer

Background Aberrant Wnt signalling, regulating cell development and stemness, influences the development of many cancer types. The Aryl hydrocarbon receptor (AhR) mediates tumorigenesis of environmental pollutants. Complex interaction patterns of genes assigned to AhR/Wnt-signalling were recently associated with lung cancer susceptibility. Aim To assess the association and predictive ability of AhR/Wnt-genes with lung cancer in cases and controls of European descent. Methods Odds ratios (OR) were estimated for genomic variants assigned to the Wnt agonist and the antagonistic genes DKK2, DKK3, DKK4, FRZB, SFRP4 and Axin2. Logistic regression models with variable selection were trained, validated and tested to predict lung cancer, at which other previously identified SNPs that have been robustly associated with lung cancer risk could also enter the model. Further, decision trees were created to investigate variant x variant interaction. All analyses were performed for overall lung cancer and for subgroups. Results No genome-wide significant association of AhR/Wnt-genes with overall lung cancer was observed, but within the subgroups of ever smokers (e.g. maker rs2722278 SFRP4; OR = 1.20; 95%-CI: 1.13–1.27; p = 5.6 10− 10) and never smokers (e.g. maker rs1133683 Axin2; OR = 1.27; 95%-CI: 1.19–1.35; p = 1.0 10− 12). Although predictability is poor, AhR/Wnt-variants are unexpectedly overrepresented in optimized prediction scores for overall lung cancer and for small cell lung cancer. Remarkably, the score for never-smokers contained solely two AhR/Wnt-variants. The optimal decision tree for never smokers consists of 7 AhR/Wnt-variants and only two lung cancer variants Conclusions The role of variants belonging to Wnt/AhR-pathways in lung cancer susceptibility may be underrated in main-effects association analysis. Complex interaction patterns in individuals of European descent have moderate predictive capacity for lung cancer or subgroups thereof, especially in never smokers.

Gene-gene Interaction of AhR With and Within the Wnt Cascade Affects Susceptibility to Lung Cancer

Introduction: Aberrant Wnt signalling, regulating cell development and stemness, is observed in many cancer entities. Aryl hydrocarbon receptor (AhR) mediates tumorigenesis of environmental pollutants. Complex interaction patterns of genes assigned to AhR/Wnt-signalling were recently associated to lung cancer susceptibility. Aim: To assess the association and predictive ability of AhR/Wnt-genes with lung cancer in cases and controls of European descent. Methods: Odds ratios (OR) were estimated for genomic variants assigned to the genes DKK2, DKK3, DKK4, FRZB, SFRP4 and Axin2 and other lung cancer-related genes. Logistic regression models with variable selection were trained, validated and tested to predict lung cancer. Further, decision trees were created to investigate variant x variant interaction. All analyses were performed for overall lung cancer and for subgroups. Results: No association with overall lung cancer was observed, but within the subgroups of ever smokers (e.g. maker rs2722278 SFRP4; OR=1.20; 95%-CI: 1.13-1.27; p=5.6 10-10) and never smokers. Although predictability is poor, AhR/Wnt-variants are unexpected overrepresented in optimized prediction scores for overall lung cancer and for small cell lung cancer. Remarkable, the score for never-smokers contained solely two AhR/Wnt-variants. The optimal decision tree for never smokers consists of 7 AhR/Wnt-variants and only two lung cancer variants, no assigned to any CHRN gene. Conclusions: The role of variants belonging to Wnt/AhR-pathways in lung cancer susceptibility may be underrated in main-effects association analysis. Complex interaction patterns in individuals of European descent have moderate predictive capacity for lung cancer or subgroups thereof, especially in never smokers.