To identify risk variants for lung cancer, we conducted a multistage genome-wide association study. In the discovery phase, we analyzed 315,450 tagging SNPs in 1,154 current and former (ever) smoking cases of European ancestry and 1,137 frequency-matched, ever-smoking controls from Houston, Texas. For replication, we evaluated the ten SNPs most significantly associated with lung cancer in an additional 711 cases and 632 controls from Texas and 2,013 cases and 3,062 controls from the UK. Two SNPs, rs1051730 and rs8034191, mapping to a region of strong linkage disequilibrium within 15q25.1 containing PSMA4 and the nicotinic acetylcholine receptor subunit genes CHRNA3 and CHRNA5, were significantly associated with risk in both replication sets. Combined analysis yielded odds ratios of 1.32 (P < 1 × 10 −17 ) for both SNPs. Haplotype analysis was consistent with there being a single risk variant in this region. We conclude that variation in a region of 15q25.1 containing nicotinic acetylcholine receptors genes contributes to lung cancer risk.Lung cancer is frequently cited as a malignancy attributable solely to environmental exposures -primarily cigarette smoke. However, evidence that genetic factors influence lung cancer © 2008 Nature Publishing Group Correspondence should be addressed to C.I.A. (E-mail: camos@mdanderson.org). 6 These authors contributed equally to this work. AUTHOR CONTRIBUTIONS Texas: C.I.A. and M.R.S. conceived of this study. M.R.S. established the Texas lung cancer study. C.I.A. supervised and performed the analyses. G.M. provided oversight in manuscript development and in the conduct of genetic studies. I.P.G., Q.D., Q.Z., W.V.C. and X.G. performed statistical analyses. S.S. developed and implemented statistical procedures for joint analysis. X.W. and J. Direct evidence for a genetic predisposition to lung cancer is provided by the increased risk associated with constitutional TP53 (tumor protein p53) 4 and RB1 (retinoblastoma) 5,6 gene mutations, rare mendelian cancer syndromes such as Bloom's 7 and Werner's syndromes 8 , and strongly familial lung cancer 9 . The genetic basis of inherited susceptibility to lung cancer outside the context of these disorders is at present undefined, but a model in which high-risk alleles account for all of the excess familial risk seems unlikely. Alternatively, part of the inherited genetic risk may be caused by low-penetrance alleles. This hypothesis implies that testing for allelic association should be a powerful strategy for identifying alleles that predispose to lung cancer.We conducted a genome-wide association study (GWAS) of histologically confirmed nonsmall cell lung cancer (NSCLC) to identify common low-penetrance alleles influencing lung cancer risk. To minimize confounding effects from cigarette smoking and increase the power to detect genetic effects, we frequency matched controls to cases according to smoking behavior. We also matched controls to cases by age (within 5 year categories) and sex, and we further matched former smokers by year...
The major function of vascular smooth muscle cells (SMCs) is contraction to regulate blood pressure and flow. SMC contractile force requires cyclic interactions between SMC alpha-actin (encoded by ACTA2) and the beta-myosin heavy chain (encoded by MYH11). Here we show that missense mutations in ACTA2 are responsible for 14% of inherited ascending thoracic aortic aneurysms and dissections (TAAD). Structural analyses and immunofluorescence of actin filaments in SMCs derived from individuals heterozygous for ACTA2 mutations illustrate that these mutations interfere with actin filament assembly and are predicted to decrease SMC contraction. Aortic tissues from affected individuals showed aortic medial degeneration, focal areas of medial SMC hyperplasia and disarray, and stenotic arteries in the vasa vasorum due to medial SMC proliferation. These data, along with the previously reported MYH11 mutations causing familial TAAD, indicate the importance of SMC contraction in maintaining the structural integrity of the ascending aorta.
The vascular smooth muscle cell (SMC)-specific isoform of alpha-actin (ACTA2) is a major component of the contractile apparatus in SMCs located throughout the arterial system. Heterozygous ACTA2 mutations cause familial thoracic aortic aneurysms and dissections (TAAD), but only half of mutation carriers have aortic disease. Linkage analysis and association studies of individuals in 20 families with ACTA2 mutations indicate that mutation carriers can have a diversity of vascular diseases, including premature onset of coronary artery disease (CAD) and premature ischemic strokes (including Moyamoya disease [MMD]), as well as previously defined TAAD. Sequencing of DNA from patients with nonfamilial TAAD and from premature-onset CAD patients independently identified ACTA2 mutations in these patients and premature onset strokes in family members with ACTA2 mutations. Vascular pathology and analysis of explanted SMCs and myofibroblasts from patients harboring ACTA2 suggested that increased proliferation of SMCs contributed to occlusive diseases. These results indicate that heterozygous ACTA2 mutations predispose patients to a variety of diffuse and diverse vascular diseases, including TAAD, premature CAD, ischemic strokes, and MMD. These data demonstrate that diffuse vascular diseases resulting from either occluded or enlarged arteries can be caused by mutations in a single gene and have direct implications for clinical management and research on familial vascular diseases.
Amplification and overexpression of the HER-2 oncogene in breast cancer is felt to be stable over the course of disease and concordant between primary tumor and metastases. Therefore, patients with HER-2-negative primary tumors rarely will receive anti-Her-2 antibody (trastuzumab, Herceptin) therapy. A very sensitive blood test was used to capture circulating tumor cells (CTCs) and evaluate their HER-2 gene status by fluorescence in situ hybridization. The HER-2 status of the primary tumor and corresponding CTCs in 31 patients showed 97% agreement, with no false positives. In 10 patients with HER-2-positive tumors, the HER-2͞chromosome enumerator probe 17 ratio in each tumor was about twice that of the corresponding CTCs (mean 6.64 ؎ 2.72 vs. 2.8 ؎ 0.6). Hence, the ratio of the CTCs is a reliable surrogate marker for the expected high ratio in the primary tumor. Her-2 protein expression of 10 CTCs was sufficient to make a definitive diagnosis of the HER-2 gene status of the whole population of CTCs in 19 patients with recurrent breast cancer. Nine of 24 breast cancer patients whose primary tumor was HER-2-negative each acquired HER-2 gene amplification in their CTCs during cancer progression, i.e., 37.5% (95% confidence interval of 18.8 -59.4%). Four of the 9 patients were treated with Herceptin-containing therapy. One had a complete response and 2 had a partial response.
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