Citations

Abstract Background: Early adolescent weight may affect the risk of postmenopausal breast cancer, and this association may be modified by a family history of breast or ovarian cancer in a first-degree relative, and/or estrogen (ER) and progesterone (PR) receptor status of the disease. Methods: Relative weight at age 12 years (above, below, or average weight compared with peers) and family history were ascertained using a mailed questionnaire in 1986, in the Iowa Women's Health Study, a prospective cohort study of postmenopausal women. Incident breast cancer cases (including ER and PR status) were identified using the Iowa Surveillance, Epidemiology, and End Results Cancer Registry. Relative risks (RR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression, and were adjusted for breast cancer risk factors, including body mass index at age 18 years and body mass index at study baseline. Results: Through 2003, 2,503 cases of postmenopausal breast cancer were identified among 35,941 women in the analytic cohort. Compared with women with average weight at age 12 years, there was no association of below average weight with risk of breast cancer (RR, 1.02; 95% CI, 0.92-1.13), whereas women with above average weight had a lower risk (RR, 0.85; 95% CI, 0.74-0.98). There was no evidence of an interaction between weight at age 12 years and family history (P = 0.44). The inverse association of above average weight with risk of breast cancer was strongest for PR− tumors (RR, 0.62; 95% CI, 0.43-0.89), intermediate for ER+ (RR, 0.80; 95% CI, 0.67-0.96) and ER− (RR, 0.77; 95% CI, 0.50-1.19) tumors, and weakest for PR+ tumors (RR, 0.90; 95% CI, 0.74-1.09). These associations were not modified by a family history (all P > 0.18). In a joint ER/PR analyses, the strongest inverse association with above average weight at age 12 years was seen for ER+/PR− (RR, 0.49; 95% CI, 0.29-0.85). Conclusion: Above average weight at age 12 years was inversely associated with risk of postmenopausal breast cancer, and was not modified by a family history of the disease. The inverse association was strongest for ER+/PR− tumors. (Cancer Epidemiol Biomarkers Prev 2008;17(2):374–8)

ABSTRACT Alternative splicing generates functional diversity in higher organisms through alternative first and last exons, skipped and included exons, intron retentions and alternative donor, and acceptor sites. In large-scale microarray studies in humans and the mouse, emphasis so far has been placed on exon-skip events, leaving the prevalence and importance of other splice types largely unexplored. Using a new human splice variant database and a genome-wide microarray to probes thousands of splice events of each type, we measured differential expression of splice types across six pair of diverse cell lines and validated the database annotation process. Results suggest that splicing in humans is more complex than simple exon-skip events, which account for a minority of splicing differences. The relative frequency of differential expression of the splice types correlates with what is found by our annotation efforts. In conclusion, alternative splicing in human cells is considerably more complex than the canonical example of the exon skip. The complementary approaches of genome-wide annotation of alternative splicing in human and design of genome-wide splicing microarrays to measure differential splicing in biological samples provide a powerful high-throughput tool to study the role of alternative splicing in human biology.

Abstract Some autoimmune disorders are increasingly recognized as risk factors for non-Hodgkin lymphoma (NHL) overall, but large-scale systematic assessments of risk of NHL subtypes are lacking. We performed a pooled analysis of self-reported autoimmune conditions and risk of NHL and subtypes, including 29 423 participants in 12 case-control studies. We computed pooled odds ratios (OR) and 95% confidence intervals (CI) in a joint fixed-effects model. Sjögren syndrome was associated with a 6.5-fold increased risk of NHL, a 1000-fold increased risk of parotid gland marginal zone lymphoma (OR = 996; 95% CI, 216-4596), and with diffuse large B-cell and follicular lymphomas. Systemic lupus erythematosus was associated with a 2.7-fold increased risk of NHL and with diffuse large B-cell and marginal zone lymphomas. Hemolytic anemia was associated with diffuse large B-cell NHL. T-cell NHL risk was increased for patients with celiac disease and psoriasis. Results for rheumatoid arthritis were heterogeneous between studies. Inflammatory bowel disorders, type 1 diabetes, sarcoidosis, pernicious anemia, and multiple sclerosis were not associated with risk of NHL or subtypes. Thus, specific autoimmune disorders are associated with NHL risk beyond the development of rare NHL subtypes in affected organs. The pattern of associations with NHL subtypes may harbor clues to lymphomagenesis.

Eukaryotic initiation factor 2B (eIF2B)-related disorders are heritable white matter disorders with a variable clinical phenotype (including vanishing white matter disease and ovarioleukodystrophy) and an equally heterogeneous genotype. We report 9 novel mutations in the EIF2B genes in our subject population, increasing the number of known mutations to more than 120. Using homology modeling, we have analyzed the impact of novel mutations on the 5 subunits of the eIF2B protein. Although recurrent mutations have been found at CpG dinucleotides in the EIF2B genes, the high incidence of private or low frequency mutations increases the challenge of providing rapid genetic confirmation of this disorder, and limits the application of EIF2B screening in cases of undiagnosed leukodystrophy.

Background and Purpose— The extent of potential consent bias in observational studies elucidating genetic and environmental contributions to ischemic stroke is largely unknown. The purpose of this study was to assess differences in stroke cohort characteristics between those who provided informed consent and those whose enrollment was authorized by surrogate decision makers. Methods— The Ischemic Stroke Genetics Study (ISGS) is a prospective, 5-center, case-control study of first-ever ischemic stroke. Demographic, clinical, and stroke characteristics were compared between cases enrolled by self versus by surrogate. Data from one site that limits enrollment only to those able to self-consent were also analyzed to compare those who enrolled with those not able to consent. Results— Overall, 10% (54 of 517) were enrolled using surrogate authorization. Self-consented and surrogate-authorized cases did not differ significantly in age, sex, or conventional risk factors. Surrogate-authorized cases had significantly more severe stroke deficits, larger infarcts, and infarcts localizing to left supratentorial regions. Similarly, at the site restricting enrollment, stroke severity and characteristics differed between self-consented individuals and those otherwise eligible but unable to provide consent. Conclusions— Failure to permit surrogate authorization in genetic studies of ischemic stroke may skew enrollment toward less severe strokes caused by smaller infarcts. This potential consent bias may undermine the ability to identify genetic determinants of risk and severity and suggests that surrogate enrollment in these studies can be ethically justifiable.

AbstractIGFs are required for normal prenatal and postnatal growth. Although actions of IGFs can be modulated by a family of IGF-binding proteins (IGFBPs) in vitro, these studies have identified a complicated pattern of stimulatory and inhibitory IGFBP effects, so that understanding relevant aspects of IGFBP action in vivo has been limited. Here we have produced a null mutation of one specific IGFBP, IGFBP-4, which is coexpressed with IGF-II early in development. Surprisingly, mutation of IGFBP-4, believed from in vitro studies to be exclusively inhibitory, leads to a prenatal growth deficit that is apparent from the time that the IGF-II growth deficit first arises, which strongly suggests that IGFBP-4 is required for optimal IGF-II-promoted growth during fetal development. Mice encoding a mutant IGFBP-4 protease (pregnancy-associated plasma protein-A), which facilitates IGF-II release from an inactive IGF-II/IGFBP-4 complex in vitro, are even smaller than IGFBP-4 mutant mice. However, the more modest IGFBP-4 growth deficit is completely restored in double IGFBP-4/pregnancy-associated plasma protein-A-deficient mice. Taken together these results indicate not only that IGFBP-4 functions as a local reservoir to optimize IGF-II actions needed for normal embryogenesis, but also establish that IGFBP-4 proteolysis is required to activate most, if not all, IGF-II mediated growth-promoting activity.