Author
Leah M. Helvering
Bio: Leah M. Helvering is an academic researcher from Eli Lilly and Company. The author has contributed to research in topics: Mutation frequency & Retinoic acid receptor. The author has an hindex of 13, co-authored 18 publications receiving 6687 citations.
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TL;DR: A strong candidate for the 17q-linked BRCA1 gene, which influences susceptibility to breast and ovarian cancer, has been identified by positional cloning methods.
Abstract: A strong candidate for the 17q-linked BRCA1 gene, which influences susceptibility to breast and ovarian cancer, has been identified by positional cloning methods. Probable predisposing mutations have been detected in five of eight kindreds presumed to segregate BRCA1 susceptibility alleles. The mutations include an 11-base pair deletion, a 1-base pair insertion, a stop codon, a missense substitution, and an inferred regulatory mutation. The BRCA1 gene is expressed in numerous tissues, including breast and ovary, and encodes a predicted protein of 1863 amino acids. This protein contains a zinc finger domain in its amino-terminal region, but is otherwise unrelated to previously described proteins. Identification of BRCA1 should facilitate early diagnosis of breast and ovarian cancer susceptibility in some individuals as well as a better understanding of breast cancer biology.
6,118 citations
TL;DR: It is demonstrated that 7-oxygenated sterols function as high affinity ligands for both RORα and RORγ by directly binding to their ligand-binding domains, modulating coactivator binding, and suppressing the transcriptional activity of the receptors.
213 citations
TL;DR: Investigation of whether PTH regulates the expression and/or activity of Cbfa1 in osteoblastic cells and in a rat metatarsal organ culture assay suggests a requirement for CbFA1 in mediating the anabolic effects of PTH.
Abstract: The Cbfa1/Runx2 (referred to herein as Cbfa1) transcription factor has been shown to be essential for osteoblast differentiation and bone formation during embryogenesis. PTH given intermittently is a proven bone anabolic agent. Here, we investigated whether PTH regulates the expression and/or activity of Cbfa1 in osteoblastic cells and in a rat metatarsal organ culture assay. PTH was found to regulate Cbfa1 mRNA in the rat osteosarcoma cell line UMR106 in a concentration-dependent manner. The effect of PTH was mimicked by forskolin, an activator of adenylate cyclase leading to the protein kinase A pathway. PTH administered intermittently for 5 d in vivo was found to stimulate Cbfa1 protein in the rat proximal tibiae metaphysis. To demonstrate PTH regulation of Cbfa1 activity, a construct containing six tandem Cbfa1 binding elements fused to luciferase was shown to be rapidly stimulated in response to PTH. This stimulation preceded the effects on mRNA regulation and resulted from a protein kinase A-mediated increase in Cbfa1 activity. Finally, using a neonate rat metatarsal organ culture system, we demonstrated dose-dependent anabolic responsiveness to PTH and to Cbfa1 overexpression from an adenoviral construct. We further showed that Cbfa1 antisense oligonucleotides that blocked adenoviral Cbfa1-induced anabolic effects in this organ culture model also abolished the PTH-mediated anabolic increase. These findings suggest a requirement for Cbfa1 in mediating the anabolic effects of PTH. Thus, regulation of Cbfa1 expression or activity is an important mechanism by which PTH controls osteoblast function.
160 citations
TL;DR: The bone morphogenetic proteins 2 and 4 are known to be important in bone formation and are expressed in both the developing and adult mammalian bone and understanding the regulation of these genes in osteoblasts may yield methods by which to control expression to induce bone formation.
99 citations
TL;DR: The broad profiling of the gene and pathway changes that occur in vivo following treatment of intermittent versus continuous PTH is detailed for the first time and the in vivo regulation of BMP3 and multiple neuronal genes by PTH treatment is revealed.
Abstract: Teriparatide, human PTH (1-34), a new therapy for osteoporosis, elicits markedly different skeletal responses depending on the treatment regimen. In order to understand potential mechanisms for this dichotomy, the present investigation utilized microarrays to delineate the genes and pathways that are regulated by intermittent (subcutaneous injection of 80 μg/kg/day) and continuous (subcutaneous infusion of 40 μg/kg/day by osmotic mini pump) PTH (1–34) for 1 week in 6-month-old female rats. The effect of each PTH regimen was confirmed by histomorphometric analysis of the proximal tibial metaphysis, and mRNA from the distal femoral metaphysis was analyzed using an Affymetrix microarray. Both PTH paradigms co-regulated 22 genes including known bone formation genes (i.e., collagens, osteocalcin, decorin, and osteonectin) and also uniquely modulated additional genes. Intermittent PTH regulated 19 additional genes while continuous treatment regulated 173 additional genes. This investigation details for the first time the broad profiling of the gene and pathway changes that occur in vivo following treatment of intermittent versus continuous PTH (1–34). These results extend previous observations of gene expression changes and reveal the in vivo regulation of BMP3 and multiple neuronal genes by PTH treatment. © 2005 Wiley-Liss, Inc.
95 citations
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TL;DR: A new criterion for triggering the extension of word hits, combined with a new heuristic for generating gapped alignments, yields a gapped BLAST program that runs at approximately three times the speed of the original.
Abstract: The BLAST programs are widely used tools for searching protein and DNA databases for sequence similarities. For protein comparisons, a variety of definitional, algorithmic and statistical refinements described here permits the execution time of the BLAST programs to be decreased substantially while enhancing their sensitivity to weak similarities. A new criterion for triggering the extension of word hits, combined with a new heuristic for generating gapped alignments, yields a gapped BLAST program that runs at approximately three times the speed of the original. In addition, a method is introduced for automatically combining statistically significant alignments produced by BLAST into a position-specific score matrix, and searching the database using this matrix. The resulting Position-Specific Iterated BLAST (PSIBLAST) program runs at approximately the same speed per iteration as gapped BLAST, but in many cases is much more sensitive to weak but biologically relevant sequence similarities. PSI-BLAST is used to uncover several new and interesting members of the BRCT superfamily.
70,111 citations
University of Cambridge1, University of Toronto2, Yale University3, University of Iceland4, University of Melbourne5, Lund University6, National Institutes of Health7, Princess Anne Hospital8, The Chinese University of Hong Kong9, University of California, Irvine10, Pomeranian Medical University11, Helsinki University Central Hospital12, Institute of Cancer Research13, University of London14, St Mary's Hospital15
TL;DR: Risks in carriers were higher when based on index breast cancer cases diagnosed at <35 years of age and for variation in risk by mutation position for both genes, and some evidence for a reduction in risk in women from earlier birth cohorts is found.
Abstract: Germline mutations in BRCA1 and BRCA2 confer high risks of breast and ovarian cancer, but the average magnitude of these risks is uncertain and may depend on the context. Estimates based on multiple-case families may be enriched for mutations of higher risk and/or other familial risk factors, whereas risk estimates from studies based on cases unselected for family history have been imprecise. We pooled pedigree data from 22 studies involving 8,139 index case patients unselected for family history with female (86%) or male (2%) breast cancer or epithelial ovarian cancer (12%), 500 of whom had been found to carry a germline mutation in BRCA1 or BRCA2. Breast and ovarian cancer incidence rates for mutation carriers were estimated using a modified segregation analysis, based on the occurrence of these cancers in the relatives of mutation-carrying index case patients. The average cumulative risks in BRCA1-mutation carriers by age 70 years were 65% (95% confidence interval 44%-78%) for breast cancer and 39% (18%-54%) for ovarian cancer. The corresponding estimates for BRCA2 were 45% (31%-56%) and 11% (2.4%-19%). Relative risks of breast cancer declined significantly with age for BRCA1-mutation carriers (P trend.0012) but not for BRCA2-mutation carriers. Risks in carriers were higher when based on index breast cancer cases diagnosed at <35 years of age. We found some evidence for a reduction in risk in women from earlier birth cohorts and for variation in risk by mutation position for both genes. The pattern of cancer risks was similar to those found in multiple-case families, but their absolute magnitudes were lower, particularly for BRCA2. The variation in risk by age at diagnosis of index case is consistent with the effects of other genes modifying cancer risk in carriers.
3,384 citations
TL;DR: The lifetime risk of breast cancer appears similar to the risk in BRCA1 carriers, but there was some suggestion of a lower risk in bRCA2 carriers <50 years of age.
Abstract: The contribution of BRCA1 and BRCA2 to inherited breast cancer was assessed by linkage and mutation analysis in 237 families, each with at least four cases of breast cancer, collected by the Breast Cancer Linkage Consortium. Families were included without regard to the occurrence of ovarian or other cancers. Overall, disease was linked to BRCA1 in an estimated 52% of families, to BRCA2 in 32% of families, and to neither gene in 16% (95% confidence interval [CI] 6%-28%), suggesting other predisposition genes. The majority (81%) of the breast-ovarian cancer families were due to BRCA1, with most others (14%) due to BRCA2. Conversely, the majority of families with male and female breast cancer were due to BRCA2 (76%). The largest proportion (67%) of families due to other genes was found in families with four or five cases of female breast cancer only. These estimates were not substantially affected either by changing the assumed penetrance model for BRCA1 or by including or excluding BRCA1 mutation data. Among those families with disease due to BRCA1 that were tested by one of the standard screening methods, mutations were detected in the coding sequence or splice sites in an estimated 63% (95% CI 51%-77%). The estimated sensitivity was identical for direct sequencing and other techniques. The penetrance of BRCA2 was estimated by maximizing the LOD score in BRCA2-mutation families, over all possible penetrance functions. The estimated cumulative risk of breast cancer reached 28% (95% CI 9%-44%) by age 50 years and 84% (95% CI 43%-95%) by age 70 years. The corresponding ovarian cancer risks were 0.4% (95% CI 0%-1%) by age 50 years and 27% (95% CI 0%-47%) by age 70 years. The lifetime risk of breast cancer appears similar to the risk in BRCA1 carriers, but there was some suggestion of a lower risk in BRCA2 carriers <50 years of age.
2,892 citations
01 Jan 2012
TL;DR: The purpose of this document is to assist physicians, patients, health-care providers, and health-policy makers from Europe and worldwide in the decision-making process according to evidencebased data.
Abstract: EASL–EORTC Clinical Practice Guidelines (CPG) on the management of hepatocellular carcinoma (HCC) define the use of surveillance, diagnosis, and therapeutic strategies recommended for patients with this type of cancer. This is the first European joint effort by the European Association for the Study of the Liver (EASL) and the European Organization for Research and Treatment of Cancer (EORTC) to provide common guidelines for the management of hepatocellular carcinoma. These guidelines update the recommendations reported by the EASL panel of experts in HCC published in 2001 [1]. Several clinical and scientific advances have occurred during the past decade and, thus, a modern version of the document is urgently needed. The purpose of this document is to assist physicians, patients, health-care providers, and health-policy makers from Europe and worldwide in the decision-making process according to evidencebased data. Users of these guidelines should be aware that the recommendations are intended to guide clinical practice in circumstances where all possible resources and therapies are available. Thus, they should adapt the recommendations to their local regulations and/or team capacities, infrastructure, and cost– benefit strategies. Finally, this document sets out some recommendations that should be instrumental in advancing the research and knowledge of this disease and ultimately contribute to improve patient care. The EASL–EORTC CPG on the management of hepatocellular carcinoma provide recommendations based on the level of evidence and the strength of the data (the classification of evidence is adapted from National Cancer Institute [2]) (Table 1A) and the strength of recommendations following previously reported systems (GRADE systems) (Table 1B).
2,594 citations
American Cancer Society1, University of Washington2, University of Arkansas for Medical Sciences3, The Royal Marsden NHS Foundation Trust4, University of Washington Medical Center5, Memorial Sloan Kettering Cancer Center6, University of North Carolina at Chapel Hill7, University of Pennsylvania8, Northwestern University9, University of Toronto10, Sunnybrook Health Sciences Centre11, University of Southern California12
TL;DR: There are several risk subgroups for which the available data are insufficient to recommend for or against screening, including women with a personal history of breast cancer, carcinoma in situ, atypical hyperplasia, and extremely dense breasts on mammography.
Abstract: New evidence on breast Magnetic Resonance Imaging (MRI) screening has become available since the American Cancer Society (ACS) last issued guidelines for the early detection of breast cancer in 2003. A guideline panel has reviewed this evidence and developed new recommendations for women at different defined levels of risk. Screening MRI is recommended for women with an approximately 20-25% or greater lifetime risk of breast cancer, including women with a strong family history of breast or ovarian cancer and women who were treated for Hodgkin disease. There are several risk subgroups for which the available data are insufficient to recommend for or against screening, including women with a personal history of breast cancer, carcinoma in situ, atypical hyperplasia, and extremely dense breasts on mammography. Diagnostic uses of MRI were not considered to be within the scope of this review.
2,332 citations