Medicine and Health Sciences Commons^™

Genetic Counselors' Approaches To Direct-To-Consumer Genetic Testing For Hereditary Breast Cancer, Sarah Burke

Dissertations & Theses (Open Access)

Given the increasing availability of health-related direct-to-consumer genetic testing (DTC-GT) and third-party interpretation (TPI) services, it is likely that genetic counselors (GCs) will continue to encounter consumers that require follow-up counseling for their results. The National Comprehensive Cancer Network recommends clinical-grade genetic testing to confirm commercial results; however, the type of testing that GCs select remains uncharacterized. Therefore, we aimed to describe the specific recommendations that cancer GCs make for confirmatory genetic testing in probands who have already obtained DTC-GT results or TPI data that reported a BRCA1/2 pathogenic variant. We recruited 80 GCs specializing in hereditary cancer and administered …

Identification And Molecular Analysis Of Dna In Exosomes, Jena Tavormina

Dissertations & 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 …

Modeling Proton Relative Biological Effectiveness Using Monte Carlo Simulations Of Microdosimetry, Mark A. Newpower

Dissertations & Theses (Open Access)

Proton therapy is a radiotherapy modality that can offer a better physical dose distribution when compared to photon radiotherapy by taking advantage of the Bragg peak, a narrow region of rapid energy loss. Proton therapy is also known to offer an enhanced relative biological effectiveness (RBE) compared to photons. In the current clinical standard, RBE is fixed at 1.1 at all points along the proton beam, meaning protons are assumed to require 10% less dose than photons to achieve target coverage and organ at risk (OAR) sparing. However, there is mounting clinical evidence, and a significant number of in vitro …

Oxidative Phosphorylation: A Critical Feature And Novel Therapeutic Target In Melanoma Brain Metastases, Grant Fischer

Dissertations & Theses (Open Access)

We recently showed via RNA-sequencing (RNA-seq) analysis of clinical samples that melanoma brain metastases (MBMs) have higher expression of oxidative phosphorylation (OXPHOS) genes (including PPARGC1A or PGC1α) than patient-matched extracranial metastases (ECMs). Thus, the central hypothesis of this dissertation is that OXPHOS plays a critical role in the pathogenesis of MBMs.

RNA-seq analysis identified increased expression of OXPHOS genes in intracranial (ICr) vs. subcutaneous (SQ) xenografts of 4 different human melanoma cell lines. Increased OXPHOS in the ICr xenografts was confirmed by direct metabolite analysis and [U-¹³C]-glucose tracing analysis. Together, these studies indicate that the brain TME …

Evaluating The Therapeutic Efficacy Of Grb2 Inhibition In Ovarian Malignancies, Olivia Lara

Dissertations & Theses (Open Access)

Purpose: Adaptor proteins such as growth factor receptor-bound protein-2 (Grb2) play important roles in cancer cell signaling. In the present study, we examined the biological effects of liposomal antisense oligodeoxynucleotide that blocks Grb2 expression (L-Grb2) in ovarian cancer models.

Experimental Design: Murine orthotopic models of ovarian cancer (OVCAR5 and SKOV3ip1) were used to study the biological effects of L-Grb2 on tumor growth. In vitro experiments (cell viability assay, Western blot analysis, siRNA transfection, and reverse phase protein array) were carried out to elucidate the mechanism and potential predictors of tumor response to L-Grb2.

Results: Treatment with L-Grb2 decreased tumor growth …

Tracking Treatment Response And Resistance To Parp Inhibition (Talazoparib) In Hereditary Pancreatic Cancer., Jennifer Goldstein

Dissertations & Theses (Open Access)

polyADP ribose polymerase (PARP) inhibitors are a class of drugs that block the PARP enzymes, involved in the repair of singe-stranded DNA breaks through the base excision repair pathway. PARP inhibition leads to replication-associated double stranded DNA breaks, which are repaired by homologous recombination (HR). In tumors with HR defects (i.e. BRCA mutants), there is a shift to error-prone DNA repair and subsequent genomic instability and cell death.

In 2014, Olaparib became the first FDA-approved PARP inhibitor for the treatment of BRCA-mutant ovarian cancer. In the phase III POLO (Pancreas cancer OLaparib Ongoing) trial presented at the American Society …

Genetic Evolution And Prognostic Determinants Of Pancreatic Cancer On Longitudinal Liquid Biopsies, Vincent Bernard

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) has one of the lowest 5-year survival rates amongst solid tumors. As early detection of PDAC is unusual and typically incidental, most patients present with locally advanced and metastatic disease where effective therapeutic strategies remain a significant unmet need. Specifically, surrogate biomarkers for tumor monitoring of PDAC may lead to improved elucidation of clinical actionability and prognostic potential. On the other hand, tumor tissue is rarely sampled in patients presenting with de novo or recurrent metastatic PDAC, apart from a fine needle aspiration or a core needle biopsy performed for diagnosis. This precludes the opportunity for …

Omics Approaches To Uncover Germline And Somatic Variation Underlying Inherited Sarcomagenesis, Justin Wong

Dissertations & Theses (Open Access)

Sarcomas are rare mesenchymal tumors, making up 15% of all childhood and 1% of all adult tumors. They account for a disproportionate share of mortality in young adults, and if left untreated, are highly likely to metastasize. However, sarcoma etiology is poorly understood, and having numerous histological subtypes has complicated elucidation. To better understand factors underlying sarcomagenesis, we leveraged two rare inherited cancer predisposition syndromes, Li-Fraumeni Syndrome (LFS), and LFS-like (LFSL), both with a high incidence of sarcomas. LFS is caused by mutations in the tumor suppressor gene TP53 (p53), but has variable and incomplete penetrance, suggesting additional acquired …

Development And Commissioning Of An Independent Peer Review System For A Small Animal Irradiator, Mary Peters

Dissertations & Theses (Open Access)

Dosimetry for small animal irradiators lacks the standardization of clinical radiotherapy practice, yet plays a central translational role in human trial design. The purpose of this work was to improve the dosimetric accuracy and consistency of animal studies by developing an independent peer review system to verify dose delivery from animal irradiators. This study focused on the development of a mouse phantom and characterization of the thermoluminescent dosimetry system for a commonly used small animal irradiator.

First, a mouse model and irradiation stand were designed with the purpose of being used in a mailable audit. Two mouse phantoms were machined …

Design, Fabrication, And Validation Of 3d Printed, Patient-Specific Compensators For Postmastectomy Radiation Therapy, Daniel Craft

Dissertations & Theses (Open Access)

The purpose of this study was to use 3D printed, patient-specific tissue compensators to overcome the 3D planning limitations for postmastectomy radiation therapy (PMRT). Tissue compensators can be used to reduce dose heterogeneity, hot and cold spots at field junctions, and treatment complexity, but are currently seldom used due to the difficulty in designing, fabricating, and validating them.

To produce compensators using 3D printing technology, suitable materials had to be found and characterized. Several materials were found to be promising, but previously unreported material uncertainties were also discovered that must be carefully controlled for in 3D printing studies. A new …

Equipment To Address Infrastructure And Human Resource Challenges For Radiotherapy In Low-Resource Settings, Rachel Mccarroll

Dissertations & Theses (Open Access)

Millions of people in low- and middle- income countries (LMICs) are without access to radiation therapy and as rate of population growth in these regions increase and lifestyle factors which are indicative of cancer increase; the cancer burden will only rise. There are a multitude of reasons for lack of access but two themes among them are the lack of access to affordable and reliable teletherapy units and insufficient properly trained staff to deliver high quality care. The purpose of this work was to investigate to two proposed efforts to improve access to radiotherapy in low-resource areas; an upright radiotherapy …

Development Of 3d-Printed Patient Specific Bolus For Clinical Use In Total Scalp Irradiation, Garrett Baltz

Dissertations & Theses (Open Access)

Total scalp irradiation (TSI) is a specialized radiation therapy technique that aims to deliver a uniform dose to the entire scalp. Original electron-based TSI techniques had limited homogeneity due to hot and cold spots created at field junctions due to the multiple matched fields that were required to treat the entire scalp. The transition to photon volumetric-modulated arc therapy based TSI techniques has improved homogeneity, to the point where non-conformal bolus is now a limiting factor. Bolus is required to build-up full dose to the scalp surface in total scalp irradiation. Creating bolus that is conformal to the scalp is …

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

Dissertations & 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 …

Patient Attitudes Toward Genetic Testing For Inherited Predispositions To Hematologic Malignancies, Taylor Beecroft

Dissertations & Theses (Open Access)

Although inherited predispositions to hematologic malignancies have previously been considered extremely rare, approximately 12 causative genes have been implicated in the last decade. Since individuals diagnosed with leukemia have not historically been considered for evaluation of inherited predispositions, genetic testing is underperformed in this population. This study used focus group discussions to explore the attitudes, motivations, and barriers to genetic testing for 23 patients with leukemia. Participants generally exhibited a positive regard for the utility of genetic testing, and were primarily motivated by concern for their family and a sense of altruism toward all leukemia patients. While drawbacks and barriers …

Evaluating The Therapeutic Efficacy Of Restoring Wild-Type P53 Activity In P53-Mutant Tumors, Connie A. Larsson

Dissertations & Theses (Open Access)

The p53 transcription factor is the most frequently altered in human cancers usually via missense mutations that undermine its transcriptional activity. Clinically, TP53 mutations have been shown to be remarkably predictive of refractoriness to treatment, resulting in poor outcome. Consequently, the development of p53 pathway activating agents is rapidly evolving and gaining more attention in cancer therapeutics research, with several small molecule compounds currently in preclinical and clinical trials. However, it remains largely unknown what types or proportions of p53-mutant tumors will respond to p53 restoration-based therapies.

Using a mouse model of Li Fraumeni syndrome, we genetically restored wild-type …

Impact Of Kras/Nras Mutational Heterogeneity On Clinical Outcomes In Colorectal Cancer, Jonathan M. Loree

Dissertations & Theses (Open Access)

Introduction: Mutations in KRAS/NRAS (RAS) predict a lack of benefit from anti-EGFR agents in metastatic colorectal cancer (mCRC). As next generation sequencing (NGS) has advanced, we are discovering atypical and low allele frequency mutations. We aimed to evaluate how NGS can optimally define RAS mutant CRC and the role of relative mutant allele frequency (rMAF) as a biomarker.

Methods: Using institutional and public cohorts of mCRC patients with NGS results, we described the prevalence and clinical impact of atypical (not in current guidelines) and low rMAF RAS mutations (RAS MAF by the MAF of the mutated gene with …

Dynamic Assessment Of Nk Cell Interactions With Pediatric Tumor Cells To Predict Response To Immunotherapy, Arianexys Aquino Lopez

Dissertations & Theses (Open Access)

Due to Natural Killer (NK) cells’ capacity to target tumor cells without prior sensitization, adoptive NK cell therapy represents a promising immunotherapy approach for pediatric cancer patients. Our laboratory has developed an NK cell expansion protocol that generates large quantities of NK cells for therapeutic infusion. Given that NK cells are heterogeneous, with variable receptor expression and potential to target tumor cells, the purpose of my study was to determine whether subpopulations of NK cells with enhanced anti-tumor potential could be identified for increased potency of the NK cell infusion product. In addition, we previously showed that our expanded NK …

Memory Potential, Molecular Characterization, And Translational Applications Of The Novel Theo/Tceo T Cell Phenotype, Todd Bartkowiak, Todd Bartkowiak

Dissertations & Theses (Open Access)

T cells comprise a substantial arm of the immune system and are exquisitely adapted to combat pathogens and tumors. The inflammatory environment largely dictates the nature of T cell response. A hallmark of T cell-mediated immunity is formation of immunological memory; the ability to respond more potently to re-encounter with pathogens. The immune system is also capable of recognizing tumors as foreign, much like viral or bacterial pathogens. Tumors have evolved, though, to generate an immunosuppressive environment to avoid destruction. The field of immunotherapy seeks to overcome immune suppression, in part by targeting T cell co-receptors on the cell surface …

Membrane Bound Il21 Promotes Natural Killer Cell Expansion Through Mir 124-3p Mediated Regulation, Anitha Somanchi

Dissertations & Theses (Open Access)

Natural Killer (NK) cells are cells of the innate immune system that act as first line of defense against viral infections and participate in tumor immune surveillance. NK cells do not cause graft versus host disease (GvHD), or require prior antigen exposure to exert anti-tumor activity, hence are an attractive choice for immunotherapy applications. Owing to small numbers of NK cells in peripheral blood (1-32%, with a 6% median), ex vivo expansion of NK cells is critical for NK cell adoptive immunotherapy, various expansion platforms have been explored over the decades. We developed a robust platform for ex vivo expansion …

Improvements In Four-Dimensional And Dual Energy Computed Tomography, Rachael M. Martin

Dissertations & Theses (Open Access)

Dual energy and 4D computed tomography (CT) seek to address some of the limitations in traditional CT imaging. Dual energy CT, among other purposes, allows for the quantification and improved visualization of contrast materials, and 4D CT is often used in radiation therapy applications as it allows for the visualization and quantification of object motion. While much research has been done with these technologies, areas remain for potential improvement, both in preclinical and clinical settings, which will be explored in this dissertation. Preclinical dual energy cone-beam CT (CBCT) can benefit from wider separation between the peak energy of the two …

Improving Nk Cell Therapy For Osteosarcoma, Jennifer Foltz

Dissertations & Theses (Open Access)

Osteosarcoma (OS) is the most common primary bone tumor. Despite new treatment options, 5-year survival for metastatic OS has remained at only 30% for the last 30 years. Adoptive transfer of Natural Killer (NK) cells holds promise for a new, non-toxic therapy for OS. NK cells are part of the innate immune system and readily kill metastatic and chemotherapy-resistant OS in vitro and in murine models. However, there is little data regarding their efficacy in animal models with an intact immune system. In addition, the OS tumor microenvironment is highly suppressive, producing TGFβ which impedes NK cell killing of solid …

Hsp27 And Chemotherapy-Induced Autophagy As Biomarkers In Osteosarcoma, John Andrew Livingston

Dissertations & Theses (Open Access)

Survival for patients with osteosarcoma has not improved for > 30 years. Despite aggressive multi-agent chemotherapy combined with surgical resection, a significant fraction of patients with localized disease relapse after optimal treatment. We evaluated the occurrence of cytoplasmic LC3B (light chain 3B)-positive puncta (a marker of autophagy) and presence of HSP27 (heat shock protein 27) in cancer cells within pre-treatment biopsy, post-treatment surgical resection, and metastatic osteosarcoma specimens by immunohistochemistry in 260 patients. LCB3+ puncta expression was seen in 34% of pre-treatment. 50% of resection, and 67% of metastasis samples. Sixty-six percent of all specimens were scored positive for HSP27 (85% …

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

Dissertations & 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. …

Cyclin B1 Mediates The Effect Of Uchl1 In Promoting Cell Cycle Progression In Uterine Papillary Serous Carcinoma, Suet Ying Kwan

Dissertations & Theses (Open Access)

Uterine papillary serous carcinoma (UPSC) is an aggressive form of endometrial cancer with poor survival rates and a high risk of recurrence. The rarity of UPSC poses challenges to the discovery of novel targeted therapies. Therefore, the purpose of this dissertation was to identify novel therapeutic targets that could aid in the management of UPSC. To do so, we began with the relatively large cohort of UPSC cases in the TCGA data set, which was used to identify differentially expressed genes between UPSC and low-grade endometrioid endometrial carcinoma (EEC) and normal tissue.

We identified Ubiquitin Carboxyl-Terminal Hydrolase L1 (UCHL1 …

Parp Inhibitor Upregulates Pd-L1 Expression And Enhances Cancer-Associated Immunosuppression, Shiping Jiao

Dissertations & Theses (Open Access)

With recent approvals for therapeutic antibodies that block CTLA4, PD-1 and PD-L1, immune checkpoints have emerged as new targets in cancer therapy. In addition, there is accumulating evidence highlighting the role of cancer-associated immunity in patient response to cytotoxic anticancer agents. Inhibitors of poly (ADP-ribose) polymerase (PARP) have shown substantial cytotoxic effects against tumors with defects in DNA damage responses. However, whether a crosstalk between PARP inhibition and immune checkpoints exists remains unclear. Here, it has been shown that PARP inhibitors (PARPis) upregulate PD-L1 expression in multiple cancer cell lines, human xenograft tumors, and syngeneic mouse tumors. Mechanistically, PARPi inactivates …

Her4 Promotes A Stem-Like Phenotype In Osteosarcoma, Rocio K. Rivera-Valentin

Dissertations & Theses (Open Access)

Metastatic disease to the lungs is the primary cause of death for patients with pediatric osteosarcoma (OS). OS has a high degree of heterogeneity and genomic instability, making understanding the pathogenesis and drivers of metastasis of this disease challenging. In an effort to explain tumoral heterogeneity, the tumor initiating cell model (TIC) states that tumors are composed of cells that form the majority of the tumor and are terminally differentiated. This model however, attributes tumorigenesis, metastasis and chemoresistance to a distinct cell population with a stem-like phenotype that can be identified using selective markers. OS appears to follow this model …

Repetitive, Pre-Anesthetic Fasting And Malnutrition In A Pediatric Oncology Population Undergoing Radiation Therapy, Laura P. Santibáñez

Dissertations & Theses (Open Access)

Background: Pediatric oncology patients often experience nutritional status changes, particularly malnutrition, which may adversely affect their outcomes. Although the consequences of malnutrition are elucidated, its causes remain unclear. A possible cause of malnutrition in pediatric oncology patients is repetitive, pre-anesthetic fasting prior to non-invasive procedures and treatments, such as anesthesia-assisted radiation therapy (AART). This exploratory study investigated the association between repetitive, pre-anesthetic fasting and non-fasting days and malnutrition in pediatric oncology patients receiving AART.

Procedure: A retrospective cohort of 138 pediatric oncology patients (£ 10 years of age) who received any type of radiation therapy (RT) with or without anesthesia …

A Phase I Dose-Escalation Study Of The Braf Inhibitor Vemurafenib In Combination With The Mtor Inhibitor Everolimus In Subjects With Advanced Cancer, Javier Munoz

Dissertations & Theses (Open Access)

Vemurafenib has been approved in the United States for the treatment of relapsed or refractory BRAF mutation positive malignant melanoma and is being investigated in various other malignancies. The RAS/RAF/MEK/ERK (MAPK) pathway is critical to cell proliferation in many human cancers. The mTOR inhibitors are well known to exert profound anticancer effects across malignancies through inhibition of the PTEN/PI3K/AKT/mTOR (mTOR) pathway. We hypothesize that the toxicity profile of the combination of vemurafenib and everolimus will be well tolerated. The primary objective is to find the maximum tolerated dose (MTD) and the toxicity of the combination of vemurafenib and everolimus following …

Development Of Rational Combination Therapy With Parp Inhibitors And Kinase Inhibitors In Tnbc, Wen-Hsuan Yu

Dissertations & Theses (Open Access)

Poly (ADP-ribose) polymerase inhibitors (PARPi) emerge as potential targeting drugs for BRCA-deficient cancers including triple negative breast cancer (TNBC). However, it has been reported that a subgroup of patients even with BRCA mutation fails to respond to PARPi in multiple clinical trials. In this study, we identified c-Met, a tyrosine kinase, phosphorylates PARP1 at Y907 and that the phosphorylation increases PARP1 activity, thereby rendering cancer cells resistant to PARPi. The combination of c-Met inhibitors (METi) and PARPi has a synergistic effect for c-Met overexpressed TNBC in vitro and in vivo. In addition to c-Met, through functional analysis, we found …

Potentially Inappropriate Medication Use In Older Patient With Breast And Colorectal Cancer, Meghan S. Karuturi

Dissertations & Theses (Open Access)

Our objective was to determine predictors of potentially inappropriate medication (PIM) use and its impact on outcomes (including ER visits, hospitalization, all cause death, and composite of three) in breast and colorectal cancer patients receiving chemotherapy. We used data from the SEER database linked to Medicare claims. Our cohort included patients ≥ 66 years diagnosed with of Stage II/III breast or colorectal cancer between 7/1/2007-12/31/2009. Baseline PIM was defined using the Drugs to Avoid in the Elderly list (DAE) or Beers criteria. Univariate and multivariable logistic regression were used to determine the associations of baseline PIMs with different covariates. Event-free …