| 1. |
- Akhoondi, Shahab, et al.
(författare)
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FBXW7/hCDC4 is a general tumor suppressor in human cancer
- 2007
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Ingår i: Cancer Research. - 0008-5472 .- 1538-7445. ; 67:19, s. 9006-9012
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Tidskriftsartikel (refereegranskat)abstract
- The ubiquitin-proteasome system is a major regulatory pathway of protein degradation and plays an important role in cellular division. Fbxw7 (or hCdc4), a member of the F-box family of proteins, which are substrate recognition components of the multisubunit ubiquitin ligase SCF (Skpl-Cdc53/ Cullin-F-box-protein), has been shown to mediate the ubiquitin-dependent proteolysis of several oncoproteins including cyclin El, c-Myc, c-Jun, and Notch. The oncogenic potential of Fbxw7 substrates, frequent allelic loss in human cancers, and demonstration that mutation of FBXW7 cooperates with p53 in mouse tumorigenesis have suggested that Fbxw7 could function as a tumor suppressor in human cancer. Here, we carry out an extensive genetic screen of primary tumors to evaluate the role of FBXW7 as a tumor suppressor in human tumorigenesis. Our results indicate that FBXW7 is inactivated by mutation in diverse human cancer types with an overall mutation frequency of ∼ 6%. The highest mutation frequencies were found in tumors of the bile duct (cholangio-carcinomas, 35%), blood (T-cell acute lymphocytic leukemia, 31%), endometrium (9%), colon (9%), and stomach (6%). Approximately 43% of all mutations occur at two mutational "hotspots," which alter Arg residues (Arg465 and Arg479) that are critical for substrate recognition. Furthermore, we show that Fbxw7Arg465 hotspot mutant can abrogate wild-type Fbxw7 function through a dominant negative mechanism. Our study is the first comprehensive screen of FBXW7 mutations in various human malignancies and shows that FBXW7 is a general tumor suppressor in human cancer.
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| 2. |
- Kotsopoulos, Joanne, et al.
(författare)
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Infertility, treatment of infertility, and the risk of breast cancer among women with BRCA1 and BRCA2 mutations : a case-control study
- 2008
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 1573-7225 .- 0957-5243. ; 19:10, s. 9-1111
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Women with a breast cancer susceptibility gene 1 (BRCA1) or breast cancer susceptibility gene 2 (BRCA2) mutation are at increased risk for developing breast and ovarian cancer. Various reproductive and hormonal factors have been shown to modify the risk of breast cancer. These studies suggest that estrogen exposure and deprivation are important in the etiology of hereditary cancer. Many patients are interested in the possibility of an adverse effect of fertility treatment on breast cancer risk. It is important to evaluate whether or not infertility per se or exposure to fertility medications increase the risk of breast cancer in genetically predisposed women.METHODS: We conducted a matched case-control study of 1,380 pairs of women with a BRCA1 or BRCA2 mutation to determine if a history of infertility, the use of fertility medications, or undergoing in vitro fertilization (IVF) were associated with and increased the risk of breast cancer.RESULTS: Sixteen percent of the study subjects reported having experienced a fertility problem and 4% had used a fertility medication. Women who had used a fertility medication were not at significantly increased risk of breast cancer (odds ratio [OR] = 1.21; 95% confidence interval [CI] = 0.81-1.82) compared to non-users. Furthermore, there was no risk associated with a history of use of a fertility medication when the subjects were stratified by parity: (OR = 1.29; 95% CI = 0.83-2.01 for nulliparous women and OR = 0.81; 95% CI = 0.30-2.22 for parous women).CONCLUSIONS: The results of this study suggest that the use of fertility medications does not adversely affect the risk of breast cancer among BRCA mutation carriers. Given the small sizes of the exposed subgroups, these findings should be interpreted with caution and confirmatory studies are required.
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| 3. |
- Qiu, Minghui, et al.
(författare)
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Observation of Feshbach Resonances in the F + H2 → HF + H Reaction
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 311:5766, s. 1440-1443
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Tidskriftsartikel (refereegranskat)abstract
- Reaction resonances, or transiently stabilized transition-state structures, have proven highly challenging to capture experimentally. Here, we used the highly sensitive H atom Rydberg tagging time-of-flight method to conduct a crossed molecular beam scattering study of the F + H2 → HF + H reaction with full quantum-state resolution. Pronounced forward-scattered HF products in the v′ = 2 vibrational state were clearly observed at a collision energy of 0.52 kcal/mol; this was attributed to both the ground and the first excited Feshbach resonances trapped in the peculiar HF(v′ = 3)-H′ vibrationally adiabatic potential, with substantial enhancement by constructive interference between the two resonances.
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