Thesis (Ph. D.)--University of Virginia, 2008. / Includes bibliographical references. Also available online through Digital Dissertations.

Many breast cancer diagnoses and second cancers are associated with BRCA gene mutations. Early detection of cancer is necessary to improve health outcomes, particularly with second cancers. Little is known about the influence of risk factors on time to diagnosis of second primary cancers after diagnosis with BRCA-related breast cancer. The purpose of this cohort study was to examine the risk of diagnosis of second primary cancers among women diagnosed with breast cancer after adjusting for BRCA status, age, and ethnicity. The study was guided by the empirical evidence supporting the mechanism of action in the mutation of BRCA leading to the development of cancer. Composite endpoint was used to define second primary cancer occurrences, and Kaplan-Meier survival curves were used to compare the median time-to-event among comparison groups and BRCA gene mutation status. Cox proportional hazards was used to examine the relationships between age at diagnosis, ethnicity, BRCA gene mutation status, and diagnosis of a second primary cancer. The overall median time to event for diagnosis of second primary cancers was 14 years. The hazard ratios for BRCA2 = 1.47, 95% CI [1.03 - 2.11], White = 1.511, 95% CI [1.18 - 1.94], and American Indian/Hawaiian = 1.424, 95% CI [1.12 -1.81] showing positive significant associations between BRCA2 mutation status and risk of diagnosis of second primary colorectal, endometrial, cervical, kidney, thyroid, and bladder cancers. Data on risk factors for development of second cancers would allow for identification of appropriate and timely screening procedures, determining the best course of action for prevention and treatment, and improving quality of life among breast cancer survivors.

Background. Both basal-like subtype and BRCA1-related breast cancers tend to have a poor overall prognosis and lack of effective treatments. Given that the lung cancer drug gefitinib and the leukemia drug dasatinib inhibit proteins also belonging to the molecular signature of this subtype, we and others hypothesized that they might be useful therapies for those two breast cancer subgroups. / Methods. Eight breast cancer cell lines were characterized by immunohistochemistry and western blotting and were treated with both drugs. Response was measured by using the sulphorhodamine B (SRB) assay. / Results. Two out of six basal-like cell lines were sensitive to gefitinib and five of six to dasatinib. BRCA1-related breast cancers were also responsive to dasatinib (three out of four). Moreover, EGFR and caveolin-1 act as markers for dasatinib sensitivity, but do not appear to be the primary targets of this drug. The presence of SRC but not ABL is necessary to achieve a response to dasatinib. / Conclusion. Dasatinib is more effective in the treatment of basal-like breast cancers than gefitinib and acts by inhibiting SRC and other molecules that are yet to be determined.

Dissertation (Ph.D.)--University of South Florida, 2008. / Title from PDF of title page. Document formatted into pages; contains 111 pages. Includes vita. Includes bibliographical references.

Thesis (Ph.D. in Experimental Pathology, Program in Cancer Biology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 144-158). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T23:12:48Z No. of bitstreams: 1 AnaRafaelaDeSouzaTimoteo_TESE.pdf: 3659954 bytes, checksum: d2c8b061166b6be5547b4452cf6fed7b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-20T21:54:51Z (GMT) No. of bitstreams: 1 AnaRafaelaDeSouzaTimoteo_TESE.pdf: 3659954 bytes, checksum: d2c8b061166b6be5547b4452cf6fed7b (MD5) / Made available in DSpace on 2017-04-20T21:54:51Z (GMT). No. of bitstreams: 1 AnaRafaelaDeSouzaTimoteo_TESE.pdf: 3659954 bytes, checksum: d2c8b061166b6be5547b4452cf6fed7b (MD5) Previous issue date: 2016-12-12 / A S?ndrome de c?ncer de mama e ov?rio heredit?rio corresponde a 10-15% de todos os casos diagnosticados de c?ncer de mama no mundo. A maioria das muta??es germinativas s?o identificadas nos genes BRCA1 e BRCA2, contudo, a aplica??o de pain?is multig?nicos tem aumentado o n?mero de variantes patog?nicas detectadas em outros genes supressores de tumor. De acordo com a vers?o atual do protocolo americano NCCN (National Comprehensive Cancer Network), as muta??es em BRCA1 e BRCA2, TP53 e PTEN conferem alto risco de desenvolver c?ncer de mama, e muta??es em CDH1, CHEK2, PALB2, ATM e BRIP podem aumentar em 20% o risco para o desenvolvimento desta doen?a. Neste estudo foram analisados 157 indiv?duos com hist?rico pessoal e/ou familiar de c?ncer de mama. O DNA gen?mico foi isolado a partir de sangue perif?rico por meio de extra??o ? base de solu??o salina e as amostras foram analisadas usando o sequenciamento de nova gera??o (NGS). Foram identificadas 15 variantes patog?nicas e 4 VUS (Variants of Uncertain Significance) em 27 indiv?duos (27/157; 17%), dos quais tr?s s?o assintom?ticos. Foram identificadas sete novas variantes em 4 genes: BRCA1_c.3409A>G; BRCA2_g.26826_30318del, BRCA2_c.5800C>T; BRCA2_c.5228G>A; BRCA2_c.5305delG; ATM_c.634delT e ATR_c.3043C>T. Sessenta e oito por cento (13/19; 68%) de variantes foi detectada nos genes BRCA1 e BRCA2, enquanto 32% (6/19) foram identificados nos genes de risco moderado ATM (2/19); ATR (1/19); CDH1 (1/19); MLH1 (1/19) e MSH6 (1/19). Os indiv?duos foram separados em dois grupos para a an?lise comparativa: portadores de muta??o nos genes de alto risco e nos genes de risco moderado. Entre os tr?s indiv?duos assintom?ticos, duas variantes est?o presentes nos genes de risco moderado ATM e MLH1. Entre os indiv?duos com c?ncer de mama, dezoito pacientes (18/24; 75%) apresentaram muta??es em genes de alto risco, enquanto seis (6/24; 25%) s?o portadores de muta??es em genes de risco moderado. Ambos os grupos apresentaram alta incid?ncia de c?ncer de mama precocemente (83% dos indiv?duos). O grupo de portadores de muta??o nos genes de alto risco apresentaram maior ocorr?ncia de tumores de alto grau (83% vs 67%, P = 0,0090). No grupo de indiv?duos com muta??es em genes de risco moderado, os tumores apresentaram um fen?tipo mais agressivo com c?ncer bilateral (33% versus 11%, P = 0,0002), ocorr?ncia de met?stases (33% vs 5,6%, P <0,0001) e ?bito (33% vs 5,6%, P <0,0001). Ao todo, 1/3 de variantes foram identificadas em genes de risco moderado em pacientes com c?ncer mais agressivo. Estes resultados refor?am a import?ncia da aplica??o de an?lise multig?nica em indiv?duos em situa??o de risco para c?ncer de mama, especialmente em uma popula??o heterog?nea como brasileira. / Hereditary breast and ovarian cancer (HBOC) corresponds to 10-15% of all diagnosed cases of breast cancer in the world. The majority germline mutations are identified in BRCA1 and BRCA2 genes, however the application of multigene panels has increased the number of pathogenic variations detected in DNA repair genes. According to the current version of NCCN (National Comprehensive Cancer Network) Guideline, mutations in BRCA1, BRCA2, TP53 and PTEN confers high risk to develop breast cancer, and mutations in CDH1, CHEK2, PALB2, ATM and BRIP can increases over than 20% this risk. We analyzed 157 individuals with personal and/or familial breast cancer history. Genomic DNA was isolated from peripheral blood through saline-based extraction and samples were analyzed using next-generation sequencing (NGS). We identified 15 pathogenic variants and 4 VUS (Variants of Uncertain Significance) in 27 individuals (27/157; 17%), in which three are asymptomatic. Seven novel variants in 4 genes were identified: BRCA1_c.3409A>G; BRCA2_g.26826_30318del, BRCA2_c.5800C>T; BRCA2_c.5228G>A; BRCA2_c.5305delG; ATM_c.634delT and ATR_c.3043C>T. Sixty-eight percent (13/19; 68%) of variants was detected in BRCA1 and BRCA2 genes, while 32% (6/19) were identified in moderate risk genes ATM (2/19); ATR (1/19); CDH1 (1/19); MLH1 (1/19) and MSH6 (1/19). The individuals were separated in two groups for comparative analysis: high-risk genes and moderate risk genes. Among three asymptomatic individuals, two present variants in moderate risk genes ATM and MLH1. Among breast cancer individuals, eighteen patients (18/24; 75%) presented mutations in high-risk genes, while six (6/24; 25%) harbored mutations in moderate risk genes. Both groups had a high incidence of early-onset breast cancer, 83%. The group of individuals harboring variants in high-risk genes presented a greater occurrence of high-grade tumors (83% vs. 67%, P= 0.0090). In the group of individuals harboring mutation in moderate risk genes, tumors presented a more aggressive phenotype with bilateral cancer (33% vs. 11%, P= 0.0002), occurrence of metastasis (33% vs. 5.6%, P<0.0001) and incidence of deaths (33% vs. 5.6%, P<0.0001). Altogether, 1/3 of variants were identified in moderate risk genes in patients presenting a more aggressive phenotype. These results reinforce the importance of applying multigene analysis in individuals at-risk for breast cancer, especially in a heterogeneous population as Brazilian.

BACKGROUND: The inactivation of the tumor suppressor gene BRCA1 is a predisposing factor for a breast/ovarian cancer development. Formation of cancer-specific alternative splicing variants with aberrant biological properties can represent additional mechanism decreasing the overall BRCA1 activity in DNA double strand break (DDSB) repair. In this study, we analyzed BRCA1 alternative splicing variants BRCA114-15 and 17-19 ascertained previously during the screening of high-risk breast cancer individuals. METHODS: We established a stable MCF-7 cell line-based model system for an in vitro analysis of BRCA1 variants. Using this system, we analyzed the impact of BRCA114-15 and 17-19 variants on DNA repair kinetics using comet assay and confocal immunomicroscopy. The capacity of DNA repair was assessed directly by an in vitro NHEJ assay and indirectly by a mitomycin C sensitivity test. The proliferation activities were determined by a clonogenic assay and growth curves. RESULTS: Overexpression of BRCA114-15 and 17-19 increases the endogenous level of DNA damage, slows down the DDSB repair, and decelerates the initial phase of radiation-induced foci formation and prolongs their persistence. Moreover, BRCA114-15 and 17-19 differentially influence the activity of HR and NHEJ and sensitivity of MCF-7 cells to ionizing...

Summary: Background: An increased risk for development of hereditary breast cancer is associated with germline mutations in BRCA1/2 and the influence of NBN mutations is also supposed. The aim of this study is to specify the frequency of recurrent mutations in BRCA1/2 in unselected breast cancer patients and the frequency of most common pathogenic mutations in NBN in Czech republic, to assess current criteria for genetic testing and to consider the addition of NBN to the tested genes. Methods: Screening for recurrent mutations 5382insC and 300T>G in BRCA1 was performed by RFLP, screening for mutations in exon 11 of BRCA1 was performed by PTT, screening for mutations in a selected region of exon 11 of BRCA2 by DHPLC, and screening for mutations in exon 6 of NBN by HRMA. All the mutations were confirmed by direct sequencing. Results: In 679 unselected breast cancer patients 7 carriers of 5382insC, 3 of 300T>G, and 4 of other mutations in BRCA1 were identified. 2 locally prevalent mutations were found in BRCA2. In 730 controls only one 5382insC BRCA1 mutation was identified. Out of 5 NBN mutations found in 600 high-risk patients two were 657del5 and one R215W. A total of 8 NBN mutation carriers were identified among 703 breast cancer patients, 2 of them 657del5 carriers and three R215W carriers. In 915...

BACKGROUND: The inactivation of the tumor suppressor gene BRCA1 is a predisposing factor for a breast/ovarian cancer development. Formation of cancer-specific alternative splicing variants with aberrant biological properties can represent additional mechanism decreasing the overall BRCA1 activity in DNA double strand break (DDSB) repair. In this study, we analyzed BRCA1 alternative splicing variants BRCA114-15 and 17-19 ascertained previously during the screening of high-risk breast cancer individuals. METHODS: We established a stable MCF-7 cell line-based model system for an in vitro analysis of BRCA1 variants. Using this system, we analyzed the impact of BRCA114-15 and 17-19 variants on DNA repair kinetics using comet assay and confocal immunomicroscopy. The capacity of DNA repair was assessed directly by an in vitro NHEJ assay and indirectly by a mitomycin C sensitivity test. The proliferation activities were determined by a clonogenic assay and growth curves. RESULTS: Overexpression of BRCA114-15 and 17-19 increases the endogenous level of DNA damage, slows down the DDSB repair, and decelerates the initial phase of radiation-induced foci formation and prolongs their persistence. Moreover, BRCA114-15 and 17-19 differentially influence the activity of HR and NHEJ and sensitivity of MCF-7 cells to ionizing...

Summary: Background: An increased risk for development of hereditary breast cancer is associated with germline mutations in BRCA1/2 and the influence of NBN mutations is also supposed. The aim of this study is to specify the frequency of recurrent mutations in BRCA1/2 in unselected breast cancer patients and the frequency of most common pathogenic mutations in NBN in Czech republic, to assess current criteria for genetic testing and to consider the addition of NBN to the tested genes. Methods: Screening for recurrent mutations 5382insC and 300T>G in BRCA1 was performed by RFLP, screening for mutations in exon 11 of BRCA1 was performed by PTT, screening for mutations in a selected region of exon 11 of BRCA2 by DHPLC, and screening for mutations in exon 6 of NBN by HRMA. All the mutations were confirmed by direct sequencing. Results: In 679 unselected breast cancer patients 7 carriers of 5382insC, 3 of 300T>G, and 4 of other mutations in BRCA1 were identified. 2 locally prevalent mutations were found in BRCA2. In 730 controls only one 5382insC BRCA1 mutation was identified. Out of 5 NBN mutations found in 600 high-risk patients two were 657del5 and one R215W. A total of 8 NBN mutation carriers were identified among 703 breast cancer patients, 2 of them 657del5 carriers and three R215W carriers. In 915...