Journal of the National Cancer Institute
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J. Natl. Cancer Inst. · Feb 2009
T670X KIT mutations in gastrointestinal stromal tumors: making sense of missense.
Chronic myeloid leukemia, gastrointestinal stromal tumors (GISTs), and idiopathic hypereosinophilic syndrome are associated with pathological deregulation of the tyrosine kinases BCR-ABL, KIT, and PDGFRA, respectively. Patients who become resistant to imatinib treatment often develop secondary mutations, the most common of which results in a substitution of isoleucine for threonine at the same location in the ATP-binding domain in all three kinases (in KIT this occurs at amino acid 670). We sought to determine why Thr is always replaced by Ile. ⋯ This combination of in vitro and molecular modeling analyses shows why, among all possible amino acid substitutions at position 670 of KIT, only Ile is naturally selected as a resistance mutant in imatinib-treated GIST patients.
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J. Natl. Cancer Inst. · Feb 2009
Estimated risk of radiation-induced breast cancer from mammographic screening for young BRCA mutation carriers.
BRCA mutation carriers are recommended to start mammographic screening for breast cancer as early as age 25-30 years. We used an excess relative risk model (based on a pooled analysis of three cohorts with 7600 subjects who received radiation exposure) to estimate the lifetime risk of radiation-induced breast cancer from five annual mammographic screenings in young (<40 years) BRCA mutation carriers. We then estimated the reduction in breast cancer mortality required to outweigh the radiation risk. ⋯ If we assume that the mortality reduction from mammography is 15%-25% or less for young women, these results suggest that there would be no net benefit from annual mammographic screening of BRCA mutation carriers at age 25-29 years; the net benefit would be zero or small at age 30-34 years, but there should be some net benefit at age 35 or older. These results depend on a number of assumptions due to the absence of empiric data. The impact of varying these assumptions was therefore examined.
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J. Natl. Cancer Inst. · Jan 2009
Meta AnalysisMeta-analysis of risk reduction estimates associated with risk-reducing salpingo-oophorectomy in BRCA1 or BRCA2 mutation carriers.
Risk-reducing salpingo-oophorectomy (RRSO) is widely used by carriers of BRCA1 or BRCA2 (BRCA1/2) mutations to reduce their risks of breast and ovarian cancer. To guide women and their clinicians in optimizing cancer prevention strategies, we summarized the magnitude of the risk reductions in women with BRCA1/2 mutations who have undergone RRSO compared with those who have not. ⋯ The summary estimates presented here indicate that RRSO is strongly associated with reductions in the risk of breast, ovarian, and fallopian tube cancers and should provide guidance to women in planning cancer risk reduction strategies.