Browsing by Subject "Breast neoplasms"

Now showing 1 - 5 of 5

Open Access
The exon 13 duplication in the BRCA1 gene is a founder mutation present in geographicaly diverse populations
(Cell Press, 2000) Mazoyer, S.; Leary, J.; Kirk, J.; Fleischmann, E.; Wagner, T.; Claes, K.; Messiaen, L.; Foulkes, W.; Desrochers, M.; Simard, J.; Phelan, C. M.; Kwan, E.; Narod, S. A.; Vahteristo, P.; Nevanlinna, H.; Durando, X.; Bignon, Y. J.; Peyrat, J. P.; Bonnardel, C.; Sinilnikova, O. M.; Puget, N.; Lenoir, G. M.; Audoynaud, C.; Goldgar, D.; Maugard, C.; Caux, V.; Gad, S.; Stoppa-Lyonnet, D.; Noguès, C.; Lidereau, R.; Machavoine, C.; Bressac-De Paillerets, B.; Kuschel, B.; Betz, B.; Niederacher, D.; Beckmann, M. W.; Hamann, U.; Ponder, B. A. P.; Robinson, M.; Taylor G. R.; Bishop, T.; Catteau, A.; Solomon, E.; Cohen, B.; Steel, M.; Collins, N.; Stratton, M.; Van Der Looij, M.; Oláh, E.; Miller, N. J.; Barton, D. E.; Sverdlov, R. S.; Friedman, E.; Radice P.; Montagna, M.; Sensi, E.; Caligo, M.; Van Eijk, R.; Devilee, P.; Van Der Luijt, R.; Heimdal, K.; Møller, P.; Borg, Å.; Diez, O.; Cortes, J.; Domenech, M.; Baiget, M.; Osorio, A.; Benítez, J.; Maillet, P.; Sappino, A. P.; Özdag, H.; Özçelik, T.; Ozturk, M.; Rohlfs, E. M.; Boyd, J.; McDermott, D.; Offit, K.; Unger, M.; Nathanson, K.; Weber, B. L.; Sellers, T. A.; Hampton, E.; Couch, F. J.; Neuhausen, S.; Gayther, S. A.
Recently, a 6-kb duplication of exon 13, which creates a frameshift in the coding sequence of the BRCA1 gene, has been described in three unrelated U.S. families of European ancestry and in one Portuguese family. Here, our goal was to estimate the frequency and geographic diversity of carriers of this duplication. To do this, a collaborative screening study was set up that involved 39 institutions from 19 countries and included 3,580 unrelated individuals with a family history of the disease and 934 early-onset breast and/or ovarian cancer cases. A total of 11 additional families carrying this mutation were identified in Australia (1), Belgium (1), Canada (1), Great Britain (6), and the United States (2). Haplotyping showed that they are likely to derive from a common ancestor, possibly of northern British origin. Our results demonstrate that it is strongly advisable, for laboratories carrying out screening either in English-speaking countries or in countries with historical links with Britain, to include within their BRCA1 screening protocols the polymerase chain reaction-based assay described in this report.
Open Access
Gemcitabine integrated nano-prodrug carrier system
(American Chemical Society, 2017) Hamsici, S.; Ekiz, M. S.; Ciftci, G. C.; Tekinay, A. B.; Güler, Mustafa O.
Peptide nanomaterials have received a great deal of interest in drug-delivery applications due to their biodegradability, biocompatibility, suitability for large-scale synthesis, high drug-loading capacities, targeting ability, and ordered structural organization. The covalent conjugation of drugs to peptide backbones results in prolonged circulation time and improved stability of drugs. Therapeutic efficacy of gemcitabine, which is used for breast cancer treatment, is severely compromised due to its rapid plasma degradation. Its hydrophilic nature poses a challenge for both its efficient encapsulation into nanocarrier systems and its sustained release property. Here, we designed a new peptide prodrug molecule for the anticancer drug gemcitabine, which was covalently conjugated to the C-terminal of 9-fluorenylmethoxy carbonyl (Fmoc)-protected glycine. The prodrug was further integrated into peptide nanocarrier system through noncovalent interactions. A pair of oppositely charged amyloid-inspired peptides (Fmoc-AIPs) were exploited as components of the drug-carrier system and self-assembled into one-dimensional nanofibers at physiological conditions. The gemcitabine integrated nanoprodrug carrier system exhibited slow release and reduced the cellular viability of 4T1 breast cancer cell line in a time- and concentration-dependent manner.
Open Access
HER2 and proliferation of wound-induced breast carcinoma
(The Lancet Publishing, 2003-11-01) Tez, M.; Göçmen, E.; Özçelik, T.
Open Access
p53 mutation with frequent novel codons but not a mutator phenotype in BRCA1-and BRCA2-associated breast tumours
(Nature Publishing Group, 1998) Crook, T.; Brooks, L. A.; Crossland, S.; Osin, P.; Barker, K. T.; Waller, J.; Philp, E.; Smith, P. D.; Yulug, I.; Peto, J.; Parker, G.; Allday, M. J.; Crompton, M. R.; Gusterson, B. A.
The status of p53 was investigated in breast tumours arising in germ-line carriers of mutant alleles of BRCA1 and BRCA2 and in a control series of sporadic breast tumours. p53 expression was detected in 20/26 (77%) BRCA1-, 10/22 (45%) BRCA2-associated and 25/72 (35%) grade-matched sporadic tumours. Analysis of p53 sequence revealed that the gene was mutant in 33/50 (66%) BRCA-associated tumours, whereas 7/20 (35%) sporadic grade-matched tumours contained p53 mutation (P < 0.05). A number of the mutations detected in the BRCA-associated tumours have not been previously described in human cancer databases, whilst others occur extremely rarely. Analysis of additional genes, p16(INK4), Ki-ras and β-globin revealed absence or very low incidence of mutations, suggesting that the higher frequency of p53 mutation in the BRCA-associated tumours does not reflect a generalized increase in susceptibility to the acquisition of somatic mutation. Furthermore, absence of frameshift mutations in the polypurine tracts present in the coding sequence of the TGF β type II receptor (TGF β IIR) and Bax implies that loss of function of BRCA1 or BRCA2 does not confer a mutator phenotype such as that found in tumours with microsatellite instability (MSI). p21(Waf1) was expressed in BRCA-associated tumours regardless of p53 status and, furthermore, some tumours expressing wild-type p53 did not express detectable p21(Waf1). These data do not support, therefore, the simple model based on studies of BRCA-/- embryos, in which mutation of p53 in BRCA-associated tumours results in loss of p21(Waf1) expression and deregulated proliferation. Rather, they imply that proliferation of such tumours will be subject to multiple mechanisms of growth regulation.
Open Access
TP53 mutations in familial breast cancer: Functional aspects
(John Wiley & Sons, Inc., 2003) Gasco, M.; Yulug, I. G.; Crook, T.
Mutation in p53 (TP53) remains one of the most commonly described genetic events in human neoplasia. The occurrence of mutations is somewhat less common in sporadic breast carcinomas than in other cancers, with an overall frequency of about 20%. There is, however, evidence that p53 is mutated at a significantly higher frequency in breast carcinomas arising in carriers of germ-line BRCA1 and BRCA2 mutations. Some of the p53 mutants identified in BRCA1 and BRCA2 mutation carriers are either previously undescribed or infrequently reported in sporadic human cancers. Functional characterization of such mutants in various systems has revealed that they frequently possess properties not commonly associated with those occurring in sporadic cases: they retain apoptosis-inducing, transactivating, and growth-inhibitory activities similar to the wild-type protein, yet are compromised for transformation suppression and also possess an independent transforming phenotype. The occurrence of such mutants in familial breast cancer implies the operation of distinct selective pressures during tumorigenesis in BRCA-associated breast cancers.