Relation between single nucleotide polymorphism in estrogen-metabolizing genes COMT, CYP17 and breast cancer risk among Chinese women / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To test the hypothesis whether polymorphism in estrogen-metabolizing genes, COMT and CYP17, impacts on the risk of breast cancer among Chinese women.</p><p><b>METHODS</b>COMT (Val158Met) and CYP17 (T1931C) polymorphisms were detected by PCR-based restriction fragment length polymorphism analysis in 250 breast cancer patients and 250 frequency-matched normal controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression.</p><p><b>RESULTS</b>COMT Met/Met genotype was found in 10.4% of breast cancer patients, which was significantly higher (P = 0.03) than that in controls (5.2%). Women with Met/Met genotype showed 2-fold increased risk for breast cancer (adjusted OR 2.1, 95% CI 1.1 - 4.5) compared with those with Val/Val or Val/Met genotypes. Stratified analysis showed that the elevated risk of breast cancer, associating with the COMT Met/Met genotype, was evident only among premenopausal women (adjusted OR 4.1, 95% CI 1.2 - 17.3) but not among postmenopausal women (adjusted OR 1.3, 95% CI 0.5 - 3.5). There was no significant difference in the distribution of CYP17 genotypes between breast cancer patients and the control subjects (P = 0.83).</p><p><b>CONCLUSION</b>The allele encoding for low activity COMT, but not CYP17, may be a genetic risk factor for breast cancer among Chinese women.</p>

Poly(AT) polymorphism in DNA repair gene XPC and lung cancer risk / 中华肿瘤杂志

<p><b>OBJECTIVE</b>It has been shown that suboptimal DNA repair capacity is associated with cancer risk and that a poly(AT) polymorphism in XPC gene (XPC PAT) may influence DNA capacity. This study was designed to assess the relationship between XPC PAT polymorphism and susceptibility to lung cancer in the Chinese population.</p><p><b>METHODS</b>XPC genotypes were determined by PCR methods in 509 healthy controls and 597 patients with lung cancer. The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariate logistic regression model.</p><p><b>RESULTS</b>Genotype frequencies of XPC PAT among controls were 37.9% (PAT-/-), 49.7% (PAT+/-) and 12.4% (PAT+/+), respectively. They were not significantly different from those among lung cancer patients (42.1%, 46.7% and 11.2%, respectively; P = 0.37). Individuals carrying XPC PAT+/+ genotype were not at increased risk for lung cancer as compared with those with PAT+/- or PAT-/- genotype (adjusted OR, 0.8; 95% CI, 0.55 approximately 1.16). No interaction between XPC genotype and smoking was observed.</p><p><b>CONCLUSION</b>Our findings indicate that the XPC PAT polymorphism may not be associated with risk of lung cancer in the Chinese population.</p>

Association of genetic polymorphisms in the DNA repair gene XPD with risk of lung and esophageal cancer in a Chinese population in Beijing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>XPD polymorphisms at Asp312Asn and Lys751Gln sites have been shown to modulate DNA repair capacity. The authors therefore assessed the relationship between these XPD polymorphisms and susceptibility to lung and esophageal cancer in a Chinese population via a hospital-based, case-control study.</p><p><b>METHODS</b>Genotypes were determined by PCR-restriction fragment length polymorphism approaches in 383 healthy controls, 351 patients with lung cancer, and 325 patients with esophageal squamous cell carcinoma (SCC). The adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using multivariate logistic regression.</p><p><b>RESULTS</b>Individuals carrying at least one 312Asn variant allele (Asp/Asn and Asn/Asn genotypes) were at an increased risk for lung SCC as compared with those with the Asp/Asp genotype (OR 1.80; 95% CI: 1.10-2.93; adjusted for age, sex and smoking), but this increased risk was not observed among patients with adenocarcinoma of the lung (adjusted OR: 1.07; 95% CI: 0.55-2.08). Furthermore, stratified analysis indicated a multiplicative interaction between tobacco smoking and the variant XPD 312Asn and 751Gln alleles on risk of lung SCC. The ORs of lung SCC for the variant XPD 312Asn and 751Gln alleles with smoking>or=29 pack/year were 12.44 (95% CI: 4.97-31.17) and 10.74 (95% CI: 4.51-25.57), respectively. No significant association between the Asp312Asn or Lys751Gln polymorphism and the risk of esophageal cancer was found.</p><p><b>CONCLUSION</b>The above findings indicate that the Asp312Asn and Lys751Gln polymorphisms in the XPD locus are associated with the risk of lung SCC but not lung adenocarcinoma or esophageal SCC in this Chinese population.</p>