Medical Genetics Commons^™

Identification And Molecular Analysis Of Dna In Exosomes, Jena Tavormina

Dissertations and Theses (Open Access)

Exosomes are heterogeneous nanoparticles 50-150nm in diameter. Exosomes contain many functional cargo components, such as protein, DNA, and RNA. While protein and RNA exosome content has been extensively studied, very little work has been done to characterize exosomal DNA. Here, we demonstrate that exosomal DNA is heterogeneous and its packaging into exosomes is dependent on the cell of origin. Furthermore, through a rigorous assessment of various isolation methods, we identify Size Exclusion Chromatography (SEC) as the best method for the isolation of exosomal DNA for downstream applications. Additionally, we evaluate the methylation status of exosomal DNA and demonstrate that exosomal …

Microrna-374a, -4680, And -133b Suppress Cell Proliferation Through The Regulation Of Genes Associated With Human Cleft Palate In Cultured Human Palate Cells, Akiko Suzuki, Aimin Li, Mona Gajera, Nada Abdallah, Musi Zhang, Zhongming Zhao, Junichi Iwata

Faculty, Staff and Student Publications

BACKGROUND: Cleft palate (CP) is the second most common congenital birth defect; however, the relationship between CP-associated genes and epigenetic regulation remains largely unknown. In this study, we investigated the contribution of microRNAs (miRNAs) to cell proliferation and regulation of genes involved in CP development.

METHODS: In order to identify all genes for which mutations or association/linkage have been found in individuals with CP, we conducted a systematic literature search, followed by bioinformatics analyses for these genes. We validated the bioinformatics results experimentally by conducting cell proliferation assays and miRNA-gene regulatory analyses in cultured human palatal mesenchymal cells treated with …

Exploring The Potential Yield Of Prenatal Testing By Evaluating A Postnatal Population With Structural Abnormalities, Peyton Busby

Dissertations and Theses (Open Access)

After identification of one or more structural abnormalities in a fetus, pregnant women are offered a host of different testing options to identify a possible genetic cause for the structural abnormality(ies). When considering what type of test to undertake, there is limited information on the diagnostic yield of the varying testing options. Some women may miss an opportunity to gain the information they are seeking or make a less informed decision when they choose a testing option after identification of a structural abnormality due to this lack of information. This study aimed to identify the potential diagnostic yield of all …

The Impacts Of Insurance And Billing Considerations On The Practice And Attitudes Of Genetic Counselors, Emily Krosschell

Dissertations and Theses (Open Access)

Genesurance counseling has been identified as an integral part of many genetic counseling sessions, but little is known about the workflow impacts and genetic counselor perceptions of genesurance-related tasks. In this study, we aimed to characterize how insurance and billing considerations for genetic testing are being incorporated into genetic counselors’ practice; as well as describe current attitudes and challenges associated with their integration. An electronic survey was sent by email to members of the National Society of Genetic Counselors (NSGC). A total of 325 genetic counselors that provided direct patient care were included in data analysis. Results showed that the …

Melatonin Enhances Sorafenib-Induced Cytotoxicity In Flt3-Itd Acute Myeloid Leukemia Cells By Redox Modification, Tian Tian, Jiajun Li, Yizhuo Li, Yun-Xin Lu, Yan-Lai Tang, Hua Wang, Fufu Zheng, Dingbo Shi, Qian Long, Miao Chen, Guillermo Garcia-Manero, Yumin Hu, Lijun Qin, Wuguo Deng

Faculty, Staff and Student Publications

Acute myeloid leukemia (AML) with an internal tandem duplication in Fms-related tyrosine kinase 3 (FLT3-ITD) is identified as a subgroup with poor outcome and intrinsic resistance to chemotherapy and therefore urgent need for development of novel therapeutic strategies.

Methods: The antitumor effects of melatonin alone or combined with sorafenib were evaluated via flow cytometry and immunoblotting assays in FLT-ITD AML cells. Also, the ex vivo and in vivo models were used to test the synergistic effects of melatonin and sorafenib against leukemia with FLT3/ITD mutation.

Results: Our study shows for the first time that melatonin inhibits proliferation and induces apoptosis …

Knockdown Of Crispld2 In Zebrafish Identifies A Novel Network For Nonsyndromic Cleft Lip With Or Without Cleft Palate Candidate Genes, Brett T Chiquet, Qiuping Yuan, Eric C Swindell, Lorena Maili, Robert Plant, Jeffrey Dyke, Ryan Boyer, John F Teichgraeber, Matthew R Greives, John B Mulliken, Ariadne Letra, Susan H Blanton, Jacqueline T Hecht

Faculty, Staff and Student Publications

Orofacial development is a multifaceted process involving tightly regulated genetic signaling networks, that when perturbed, lead to orofacial abnormalities including cleft lip and/or cleft palate. We and others have shown an association between the cysteine-rich secretory protein LCCL domain containing 2 (CRISPLD2) gene and nonsyndromic cleft lip with or without cleft palate (NSCLP). Further, we demonstrated that knockdown of Crispld2 in zebrafish alters neural crest cell migration patterns resulting in abnormal jaw and palate development. In this study, we performed RNA profiling in zebrafish embryos and identified 249 differentially expressed genes following knockdown of Crispld2. In silico pathway analysis identified …

Outcomes Of Genetic Testing In A Genitourinary Genetics Clinic, Annelise Pace

Dissertations and Theses (Open Access)

Several known hereditary cancer syndromes confer an increased risk for genitourinary (GU)related malignancies. Various guidelines indicate when to refer patients to genetic counseling for GU-related hereditary cancer syndromes but there is limited research on the clinical picture of these patients, including their cancerous and non-cancerous features, the genetic testing strategy for this population, and the probability of having a positive germline mutation if testing is performed. The purpose of this study is to determine the most common indications for ordering genetic testing in a GU Genetics Clinic and evaluate whether there is a relationship between the indication for genetic testing …

Tumor Immunotherapy: Mechanisms Of Acquired Resistance And Characterization Of Immune Related To Xicities, Ashvin Jaiswal

Dissertations and Theses (Open Access)

Tumor immunotherapy has shown very promising clinical benefit across an array of cancers; however, two major challenges remain unresolved in the field. First, many patients do not respond to therapy at all or relapse after a period of remission. Second, there are often dose-limiting immune related adverse effects associated with immunomodulation.

In order to understand the mechanisms employed by tumors to evade immunotherapeutic responses, we established a murine model of melanoma designed to elucidate the molecular mechanisms underlying immunotherapy resistance. Through multiple in vivo passages, we selected a B16 melanoma tumor line that evolved complete resistance to combination blockade of …

Managing Variant Discrepancy In Hereditary Cancer: Clinical Practice, Barriers, And Desired Resources, Ellen Zirkelbach

Dissertations and Theses (Open Access)

Variants are changes in the DNA whose phenotypic effects may or may not be definitively understood. Because variant interpretation is a complex process, sources sometimes disagree on the classification of a variant, which is called a variant discrepancy. This study aimed to determine the practice of genetic counselors regarding variant discrepancies and to identify the barriers to counseling a variant discrepancy in hereditary cancer genetic testing. This investigation was unique because it was the first to address variant discrepancies from a clinical point of view. An electronic survey was sent to genetic counselors in the NSGC Cancer Special Interest Group. …

Genesurance Counseling: Patient Perspectives, Chelsea Wagner

Dissertations and Theses (Open Access)

Genetic counselors (GCs) have recently reported an increase in the discussion of insurance-related, or “genesurance,” topics during genetic counseling sessions. Despite increasing frequency, little knowledge exists about genesurance conversations and patient expectations. This study aimed to assess patient expectations of GCs in genesurance discussions and evaluate if health insurance literacy impacted these expectations. A 38-item survey, including a validated tool to assess health insurance literacy (HIL) was administered prior to patients receiving prenatal or cancer genetic counseling at three participating institutions. A total of 360 responses were analyzed. Key variables were compared using chi-square analysis and multivariable logistic regression was …

The Utilization Of Prenatal Microarray: A Survey Of Current Genetic Counseling Practices And Barriers, Leslie N. Durham, Leslie Durham

Dissertations and Theses (Open Access)

Chromosomal microarray (CMA) assesses chromosome copy number variants (CNVs) missed by standard karyotyping. The American College of Obstetricians and Gynecologists (ACOG) recommends CMA for all patients with fetuses with an ultrasound anomaly and suggests that it be made available to all women undergoing invasive testing. In order to assess prenatal genetic counselors’ (GCs) practices regarding the utilization of CMA we conducted a survey of their current practices, attitudes, and perceived barriers. Of the 192 respondents, 183 (95%) have incorporated CMA into clinical practice with the majority (64%) believing that the benefits of CMA outweigh the harms. However, only half (52%) …

Regulation Of Hnrnpa1 By Micrornas Controls The Mir-18a–K-Ras Axis In Chemotherapy-Resistant Ovarian Cancer, Cristian Rodriguez-Aguayo, Paloma Del C Monroig, Roxana S Redis, Emine Bayraktar, Maria I Almeida, Cristina Ivan, Enrique Fuentes-Mattei, Mohammed H Rashed, Arturo Chavez-Reyes, Bulent Ozpolat, Rahul Mitra, Anil K Sood, George A Calin, Gabriel Lopez-Berestein

Faculty, Staff and Student Publications

The regulation of microRNA (miRNA) biogenesis, function and degradation involves a range of mechanisms, including interactions with RNA-binding proteins. The potential contribution of regulatory miRNAs to the expression of these RNA interactor proteins that could control other miRNAs expression is still unclear. Here we demonstrate a regulatory circuit involving oncogenic and tumor-suppressor miRNAs and an RNA-binding protein in a chemotherapy-resistant ovarian cancer model. We identified and characterized miR-15a-5p and miR-25-3p as negative regulators of hnRNPA1 expression, which is required for the processing of miR-18a-3p, an inhibitor of the

Ethnic Identity And Teratogenic Risk Perceptions, Katie M. Chan

Dissertations and Theses (Open Access)

Elevated perceptions of teratogenic risk can cause anxiety and confusion among pregnant women. To assess whether ethnic identity and demographic factors can influence teratogenic risk perceptions, 194 pregnant women in Houston were surveyed using the Multigroup Ethnic Identity Measure (MEIM) and visual analog scales to quantify perceptions of teratogenic risk for common exposures during pregnancy. Overall, participants estimated an elevated baseline risk of 25% for birth defects among the general population. In addition, participants overestimated birth defect risks for specific exposures, such as alcohol and marijuana. Based on the MEIM scores, ethnic identity was not significantly associated with teratogenic risk …

No Difference In Health Related Quality Of Life Between Therapeutic Options For Type 1 Gaucher Disease, Victoria Wagner

Dissertations and Theses (Open Access)

Type 1 Gaucher disease (GD) is the most common lysosomal storage disorder. Previously, treatment for GD was limited to intravenous enzyme replacement therapy (ERT). ERT reduces symptoms and increases health­related quality of life (HRQoL) in people with this condition. In 2014, oral substrate reduction therapy (SRT) was approved for type 1 GD treatment. Although both therapies alleviate disease symptoms, effects of SRT on HRQoL and preferences for therapy are not well established. Electronic surveys were administered to adults with type 1 GD. HRQoL was scored with the Short Form­36 Version 2 ® Health Survey and descriptive statistics were used to …

Factors Influencing Uptake Of Risk-Reducing Salpingo-Oophorectomy By Brca1 And Brca2 Mutation Carriers, Victoria E. Breen

Dissertations and Theses (Open Access)

Germline mutations in the BRCA1 and BRCA2 genes are associated with significantly increased risks for ovarian cancer. The National Comprehensive Cancer Network (NCCN) currently recommends that female BRCA mutation carriers undergo risk-reducing salpingo-oophorectomy (RRSO) after age 35; however, not all women elect this option. The purpose of this study was to prospectively survey women with BRCA mutations currently undergoing ovarian cancer screening about their intention to have an RRSO and the various factors influencing their decision. Of the 26 women who completed our survey, 26 (100%, CI: 86.8-100) plan to undergo an RRSO in their lifetime. The average woman reported …

Cancer Incidence In First And Second Degree Relatives Of Brca1 And Brca2 Mutation Carriers, Haley Streff

Dissertations and Theses (Open Access)

Mutations in the BRCA1 or BRCA2 genes are associated with increased risks for breast, ovarian, and several other cancers. The purpose of this study was to evaluate the incidence of cancers in first and second degree relatives of BRCA mutation carriers compared to the general population. A total of 1086 pedigrees of BRCA mutation carriers were obtained from a prospectively maintained, internal review board approved study of persons referred for clinical genetic counseling at The University of Texas MD Anderson Cancer Center. We identified 9032 first and second degree relatives from 784 pedigrees which demonstrated a clear indication of parental …

Obstetrician And Gynecologist Utilization Of The Nipt Expanded Testing Option, Sarah Mayes Ba

Dissertations and Theses (Open Access)

Noninvasive prenatal testing (NIPT) enables the detection of common fetal aneuploidies such as trisomy 21, trisomy 18, trisomy 13, and sex chromosome abnormalities via analysis of cell-free fetal DNA circulating in maternal serum. Although the accuracy of NIPT for fetal aneuploidy is expected to be higher than that of currently available alternative maternal serum screening options, the implications of results are not straight forward. In October 2013, the option to screen for additional trisomies and select microdeletion syndromes, such as 22q11.2 deletion syndrome and 5 p- syndrome, became clinically available. Due to this rapidly evolving prenatal screening technology, clinicians must …

Genetics Of Obesity In Starr County, Texas Mexican Americans, Heather M. Highland

Dissertations and Theses (Open Access)

Currently, over two-thirds of Americans are classified as over-weight or obese. Obesity increases risk for many other diseases including type 2 diabetes, heart disease, stroke, and cancer, making obesity the largest public health problem in America and most other Westernized nations. Hispanics have a higher rate of both obesity and type 2 diabetes, making them a particularly interesting population in which to study obesity. For the last 33 years, the Starr County Health Studies has collected an array of phenotypes and biological samples from residents of Starr County, along Texas-Mexico border. This study includes 825 subjects who were not known …

Correlation Matrix Analysis Identifies Gene Signatures Of Immune Cell Subsets And Their Interactions In Follicular Lymphoma, Jason R. Westin

Dissertations and Theses (Open Access)

There are important but ill-defined interactions between benign immune cell subsets and neoplastic B cells within follicular lymphoma (FL). Using the novel technique of correlation matrix analysis (CMA) of publicly available FL whole-tumor gene expression profiling (GEP) data, we have identified signatures of immune cell subsets. Overall survival correlated most highly with a model using signatures of macrophages, T cells, and stroma, which was able to add significantly to existing clinical prognostic tools. From our own data of a cohort of 43 FL tumors sorted into B-cell and non-B cell (NB) fractions for GEP, CMA of the tumor infiltrating NB …

Dissecting The Roles Of Trim24 In Regulation Of Hepatic Lipid Metabolism And Inflammation, Lindsey C. Minter

Dissertations and Theses (Open Access)

DISSECTING THE ROLES OF TRIM24 IN REGULATION OF HEPATIC LIPID

METABOLISM AND INFLAMMATION

Lindsey Cauthen Minter, B.S., B.A.

Advisory Professor: Michelle C. Barton, Ph.D.

In this dissertation, I report the characterization of a new mouse model that recapitulates development of hepatocellular carcinoma (HCC) following spontaneous hepatic lipid accumulation, inflammation, and damage of liver tissue, due to complete loss of Trim24 expression. In human HCC and other cancers, TRIM24 expression is aberrantly high, while deletion of TRIM24 in the mouse has been shown to act as a liver specific tumor suppressor. The hypothesis tested here was that TRIM24, the E3 ubiquitin …

Modulated Functions Of The Fanconi Anemia Core Complex, Yaling Huang

Dissertations and Theses (Open Access)

Cells derived from Fanconi anemia (FA) patients are characterized by hypersensitivity to DNA interstrand crosslinks (ICLs), suggesting that FA genes play a role in ICL repair. Fanconi anemia core complex (including A, B, C, E, F, G, L, FAAP20, and FAAP100) activates the Fanconi pathway by providing the essential E3 ligase activity for FANCD2 mono-ubiquitination. Previous studies suggested the existence of three protein-protein interaction groups. However, the functions of most FA core complex protein are still limited to their presence in the complex. How the spatially-defined FANCD2 ubiquitination is accomplished by the core complex remains unknown.

To elucidate the roles …

Availability Of Dental Anomaly Phenotype In Individuals With Familial Adenomatous Polyposis, Andrea M. Lewis

Dissertations and Theses (Open Access)

Background: Mutations in the APC gene cause familial adenomatous polyposis (FAP), an autosomal dominant colorectal cancer predisposition associated with the development of hundreds to thousands of adenomatous colorectal polyps beginning in childhood or adolescence. Both malignant and non-malignant extracolonic manifestations are associated with APC gene mutations, including approximately 17% of individuals with various dental anomalies. The availability of dental anomaly information in the medical record remains to be evaluated.

Methods: Medical records were reviewed for documentation of dental anomalies. Dental questionnaires were mailed to 271 individuals with FAP at The University of Texas M. D. Anderson Cancer Center (UTMDACC) to …

Differential Regulation Of Iress In The Aurora A Mrna By Bfgf Through The Mtor Complex To Rc2 Modulates Aurora A Kinase Expression, Roy L. Voice Iii

Dissertations and Theses (Open Access)

Identifying the mechanisms that contribute to tumorigenesis is a major area of focus in our fight against cancer. Epithelial malignant tumors, such as breast, colon, ovarian and pancreatic cancers have been shown to overexpress proteins that control cell mitosis, growth, and proliferation. One of those proteins is the Aurora A kinase. Aurora A kinase is a member of a small family of kinases that contribute to mitotic events such as centrosome duplication, separation, and maturation. Aurora A overexpression leads to genomic instability, which can contribute to tumorigenesis, on the other hand, inhibiting Aurora A expression leads to apoptosis, making it …

Evaluation Of Current Clinical Criteria For Li-Fraumeni Syndrome In A Diverse Sample Of Tp53 Mutation Carriers, Emily A. Parham

Dissertations and Theses (Open Access)

Li-Fraumeni syndrome (LFS) is a hereditary cancer predisposition syndrome caused by heterozyogous germline mutations in the TP53 gene and characterized by an excess of early-onset cancers, high lifetime risk of cancer, and a wide range of tumor types. Recent studies suggesting a benefit in comprehensive screening protocols for both children and adults make the timely identification of individuals with LFS increasingly important.

A number of criteria have been proposed to identify patients with LFS. The National Comprehensive Cancer Network (NCCN) combines several in its Clinical Practice Guidelines for TP53 genetic testing. Prior studies have shown that the cumulative sensitivity of …

Cancers Associated With Brca1 And Brca2 Mutations Other Than Breast And Ovarian, Jacqueline Mersch

Dissertations and Theses (Open Access)

Mutations in BRCA1 and BRCA2 cause tumor development in Hereditary Breast and Ovarian Cancer syndrome (HBOC) through accumulation of unrepaired DNA damage. Extensive research of BRCA1 and BRCA2 mutations has led to well-defined breast and ovarian cancer risks in individuals with HBOC. Previous studies have reported additional cancers associated with BRCA mutations; however, the type of cancer, magnitude of risk, and differences between sexes remains to be clarified. Ultimately, a consensus of additional cancer risks can aid in better recommendations for genetic testing and more effective screening and prevention guidelines.

A retrospective chart review of MD Anderson Cancer Center patients …

Latinas And The Traditional Genetic Counseling Model: A Qualitative Study, Stephanie Thompson

Dissertations and Theses (Open Access)

The traditional genetic counseling model reflects an individualized counseling session that includes the presentation of information about genes, chromosomes, personalized risk assessment, and genetic testing and screening options. Counselors are challenged to balance providing educational information with discussion of implications of this information in an allotted amount of time. The aim of this study was to explore the perceptions of pregnant Latinas on the benefits and limitations of the traditional prenatal genetic counseling model and to determine the specific preferences for receiving prenatal genetic counseling. Data were collected through focus groups and one-on-one, semi-structured interviews of twenty-five Spanish speaking Latinas …

The Impact Of Family History On Medullary Thyroid Cancer In Men2a Patients, Nicole D. Mohrbacher

Dissertations and Theses (Open Access)

The American Thyroid Association recently classified all MEN2A-associated codons into increasing risk levels A-C and stated that some patients may delay prophylactic thyroidectomy if certain criteria are met. One criterion is a less aggressive family history of MTC but whether families with the same mutated codon have variable MTC aggressiveness is not well described. We developed several novel measures of MTC aggressiveness and compared families with the same mutated codon to determine if there is significant inter-familial variability. Pedigrees of families with MEN2A were reviewed for codon mutated and proportion of RET mutation carriers with MTC. Individuals with MTC were …

Mismatch Repair Deficient Tumors Lacking Known Sporadic Causes: Are They All Due To Lynch Syndrome?, Katherine M. Dempsey

Dissertations and Theses (Open Access)

BACKGROUND: Mismatch repair deficient (MMRD) colorectal (CRC) or endometrial (EC) cancers in the absence of MLH1 promoter hypermethylation and BRAF mutations are suggestive of Lynch syndrome (LS). Positive germline genetic test results confirm LS. It is unclear if individuals with MMRD tumors but no identified germline mutation or sporadic cause (MMRD+/germline-) have LS.

HYPOTHESIS: Since LS is hereditary, individuals with LS should have a stronger family history of LS-related cancers than individuals with sporadic tumors. We hypothesized that MMRD+/germline- CRC and/or EC patients would have less suggestive family histories than LS CRC and/or EC patients.

METHODS: 253 individuals with an …

Post-Transcriptional Regulation Of Mammalian Gene Expression In Non-Coding Region Of Target Rna, Jing Lin

Dissertations and Theses (Open Access)

Tumor Suppressor Candidate 2 (TUSC2) is a novel tumor suppressor gene located in the human chromosome 3p21.3 region. TUSC2 mRNA transcripts could be detected on Northern blots in both normal lung and some lung cancer cell lines, but no endogenous TUSC2 protein could be detected in a majority of lung cancer cell lines. Mechanisms regulating TUSC2 protein expression and its inactivation in primary lung cancer cells are largely unknown. We investigated the role of the 5’- and 3’-untranslated regions (UTRs) of the TUSC2 gene in the regulation of TUSC2 protein expression. We found that two small upstream open-reading frames (uORFs) …

Predictors Of Contralateral Breast Cancer In Brca Negative Women, Ann E. Simmons

Dissertations and Theses (Open Access)

Breast cancer is the most common cancer diagnosis and second leading cause of death in women. Risk factors associated with breast cancer include: increased age, alcohol consumption, cigarette smoking, white race, physical inactivity, benign breast conditions, reproductive and hormonal factors, dietary factors, and family history. Hereditary breast and ovarian cancer syndrome (HBOC) is caused by mutations in the BRCA1 and BRCA2 genes. Women carrying a mutation in these genes are at an increased risk to develop a second breast cancer. Contralateral breast cancer is the most common second primary cancer in patients treated for a first breast cancer. Other risk …