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- Couch, Fergus J., et al.
(författare)
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AURKA F31I polymorphism and breast cancer risk in BRCA1 and BRCA2 mutation carriers: A consortium of investigators of modifiers of BRCA1/2 study
- 2007
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Ingår i: Cancer Epidemiology Biomarkers & Prevention. - 1538-7755. ; 16:7, s. 1416-1421
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Tidskriftsartikel (refereegranskat)abstract
- The AURKA oncogene is associated with abnormal chromosome segregation and aneuploidy and predisposition to cancer. Amplification of AURKA has been detected at higher frequency in tumors from BRCA1 and BRCA2 mutation carriers than in sporadic breast tumors, suggesting that overexpression of AURKA and inactivation of BRCA1 and BRCA2 cooperate during tumor development and progression. The F31I polymorphism in AURKA has been associated with breast cancer risk in the homozygous state in prior studies. We evaluated whether the AURKA F31I polymorphism modifies breast cancer risk in BRCA1 and BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2. Consortium of Investigators of Modifiers of BRCA1/2 was established to provide sufficient statistical power through increased numbers of mutation carriers to identify polymorphisms that act as modifiers of cancer risk and can refine breast cancer risk estimates in BRCA1 and BRCA2 mutation carriers. A total of 4,935 BRCA1 and 2,241 BRCA2 mutation carriers and 11 individuals carrying both BRCA1 and BRCA2 mutations was genotyped for F31I. Overall, homozygosity for the 311 allele was not significantly associated with breast cancer risk in BRCA1 and BRCA2 carriers combined [hazard ratio (HR), 0.91; 95% confidence interval (95% CI), 0.77-1.061. Similarly, no significant association was seen in BRCA1 (HR, 0.90; 95% Cl, 0.75-1.08) or BRCA2 carriers (HR, 0.93; 95% CI, 0.67-1.29) or when assessing the modifying effects of either bilateral prophylactic oophorectomy or menopausal status of BRCA1 and BRCA2 carriers. In summary, the F31I polymorphism in AURKA is not associated with a modified risk of breast cancer in BRCA1 and BRCA2 carriers.
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| 3. |
- Vall-llosera, Gemma, et al.
(författare)
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Photofragmentation of 2-deoxy-D-ribose molecules in the gas phase
- 2008
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Ingår i: ChemPhysChem. - : Wiley. - 1439-4235 .- 1439-7641. ; 9:7, s. 1020-1029
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Tidskriftsartikel (refereegranskat)abstract
- We have measured the synchrotron-induced photofragmentation of isolated 2-deoxy-D-ribose molecules (C5H10O4) at four photon energies, namely, 23.0, 15.7, 14.6, and 13.8 eV At all photon energies above the molecule's ionization threshold, we observe the formation of a large variety of molecular cation fragments, including CH3+, OH+, H3O+, C2H3+, C2H4+, CHxO+ (x=1,2,3), C2HxO+ (x=1-5), C3HxO+ (x=3-5), C2H4O2+, C3HxO2+ (x=1,2,4-6), C4H5O2+, C4HxO3+ (x=6,7), C5H7O3+, and C5H8O3+. The formation of these fragments shows a strong propensity of the DNA sugar to dissociate upon absorption of vacuum ultraviolet photons. The yields of particular fragments at various excitation photon energies in the range between 10 and 28 eV are also measured and their appearance thresholds determined. At all photon energies, the most intense relative yield is recorded for the m/q = 57 fragment (C3H5O+), whereas a general intensity decrease is observed for all other fragments- relative to the m/q=57 fragment-with decreasing excitation energy. Thus, bond cleavage depends on the photon energy deposited in the molecule. All fragments up to m/q=75 are observed at all photon energies above their respective threshold values. Most notably, several fragmentation products, for example, CH3+, H3O+, C2H4+, CH3O+, and C2H5O+, involve significant bond rearrangements and nuclear motion during the dissociation time. Multibond fragmentation of the sugar moiety in the sugar-phosphate backbone of DNA results in complex strand lesions and, most likely, in subsequent reactions of the neutral or charged fragments with the surrounding DNA molecules.
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| 4. |
- Vall-llosera, Gemma, et al.
(författare)
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VUV photoionisation of free azabenzenes : pyridine, pyrazine, pyrimidine, pyridazine and s-triazine
- 2008
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Ingår i: International Journal of Mass Spectrometry. - : Elsevier BV. - 1387-3806 .- 1873-2798. ; 275:1-3, s. 55-63
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Tidskriftsartikel (refereegranskat)abstract
- Photoionisation Mass spectrometry was used to obtain the fragmentation pathways of pyridine, pyridazine, pyrimidine, pyrazine and s-triazine molecules upon absorption of 23.0, 15.7 and 13.8eV synchrotron photons. The ionic fragments observed vary from molecule to molecule, however C2H2+, HCN+ and HCNH+ are common to all five molecules at the three photon energies. Furthermore, the presence of C2H2N2+,C3H3N+ and C4H4+ in the spectra of some of the molecules suggests dissociation pathways via loss of HCN moieties. The respective parent cations, m/q = 79, 80 and 81 have a greater yield at low photon energies when compared to the most intense fragment peak in each spectra. We recorded two of the fragment cation yields, as well as the parent photoion yield Curves of pyridine, pyridazine, and pyrimidine in the 8-30 eV range. The formation of abundant cation fragments show a strong propensity of the molecules for dissociation after the absorption of VUV photons higher than 14eV. The differences in relative fragment yields from molecule to molecule, and when changing the excitation energy, Suggest significant bond rearrangements and nuclear motion during the dissociation time. Thus, bond cleavage is dependent on the photon energy deposited in the molecule and on intramolecular reactivity. With the aid of photoion yield Curves and energy estimations we have assigned major peaks in the spectra and discussed their fragmentation pathways.
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