Neoplasms Commons^™

Evaluating The Nccn Clinical Criteria For Hereditary Breast And Ovarian Cancer Syndrome Genetic Testing, Caiqian Wu

Dissertations and Theses (Open Access)

Hereditary Breast and Ovarian Cancer (HBOC) syndrome predisposes females with a BRCA1 or BRCA2 mutation to an up to 85% lifetime risk for breast cancer and an up to 40% lifetime risk for ovarian cancer. It is crucial for individuals with HBOC to be identified to allow for proper screening, management, and identification of at-risk family members in order to reduce mortality. The National Comprehensive Cancer Network (NCCN) has established clinical guidelines for when to recommend BRCA1/2 testing. A retrospective chart review of 1123 M.D. Anderson Cancer Center breast cancer patients was performed in order to evaluate the positive predictive …

Gene Set Analysis Of Post-Lactational Mammary Gland Involution Gene Signatures In Inflammatory And Triple Negative Breast Cancer, Arvind Bambhroliya

Dissertations and Theses (Open Access)

With each cycle of pregnancy and lactation, the mammary gland undergoes dramatic changes. Clarkson et al. (2004) and Stein et al. (2004) conducted a detailed analysis of these changes in the mouse mammary gland. Their results showed that tissue remodeling during post-lactational involution period mimics wound healing and tumorigenesis like pathological conditions. This indicates that post-lactational involution may create the microenvironment that initiates the development of precancerous mammary cells and promotes the progression of precancerous cells into cancer cells. Moreover, epidemiological studies have found that triple-negative (TN) breast cancer (BC) is associated with lower frequency and duration of breastfeeding compared …

Role Of The Ang-Tie2 Pathway In The Invasive Recurrence Of Gbm Following Anti-Vegf Therapy, Nahir Cortes Santiago

Dissertations and Theses (Open Access)

Strong pre-clinical and clinical data supporting the effectiveness of bevacizumab, a humanized monoclonal anti-VEGF antibody, for the treatment of gliomas led to its accelerated approval for the treatment of patients with recurrent glioma. However, despite strong anti-tumor effects, upon treatment with bevacizumab, patients will invariably recur with a tumor characterized by enhanced invasiveness and resistance to therapy. This study aims to elucidate the mechanisms leading to this enhanced malignancy with the hope of uncovering new potential therapeutic targets for combined treatment. Using tissue sections from U87-derived glioma bearing mice treated with or without aflibercept (another anti-VEGF antibody) we have gathered …

Role Of Macrophages In Adaptive Resistance To Anti-Vegf Therapy, Heather Dalton

Dissertations and Theses (Open Access)

Background: The clinical implementation of therapies targeting the VEGF pathway in cancer has been limited by acquired resistance; yet, the mechanisms by which this occurs is unclear. We investigated the role of macrophages in the development of acquired resistance to anti-VEGF antibody (AVA) therapy.

Materials and Methods: We first established a murine ovarian cancer model of resistance to anti-VEGF therapy. Using this model we investigated changes in macrophage infiltration during AVA sensitive and resistant phases. We also investigated the in vivo effects of macrophage depletion at the emergence of anti-VEGF resistance and in upfront combination with AVA therapy. In vitro …

Notch Signaling Inhibited By Ikaros1 In Human T-Cell Acute Lymphoblastic Leukemia, Camille W. Graham

Dissertations and Theses (Open Access)

The highly conserved Notch signaling pathway regulates cell growth, differentiation, survival and apoptosis. In hematopoiesis, Notch signaling drives commitment to the T-cell fate and promotes differentiation, T-cell receptor signaling and immune function. In T-cells, Notch signaling is oncogenic when constitutively active, promoting proliferation and survival while inhibiting differentiation. The majority of patients with T-cell acute lymphoblastic leukemia (TALL) have activating Notch mutations. Similarly, Notch activation is present in more than 75% of murine T-ALL models. In murine T-ALL, loss of Ikaros, a zinc finger transcriptional regulator, leads to disrupted differentiation and also cooperates with activated Notch signaling to promote T-ALL. …

Targeting The Redox System To Overcome Mechanisms Of Drug Resistance In Chronic Lymphocytic Leukemia, Marcia A. Ogasawara

Dissertations and Theses (Open Access)

Chronic Lymphocytic Leukemia (CLL) is the most common form of leukemia diagnosed in Western countries and is characterized by clonal expansion of B cells. The clinical course of CLL is diverse and nearly 50% of patients present with chromosomal abnormalities. Deletion of the short arm on chromosome 17 (del17p) occurs in 5-7% of cases and presents with the shortest median survival time and often respond poorly to therapy. The tumor suppressor gene, TP53 is located on this region and it is well established that the p53 protein regulates multiple functions including: mitochondria biogenesis, response to DNA damage and redox balance. …

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 …

Mechanisms Underlying The Heterogeneous Sensitivities Of Cancer Cells To Proteasome Inhibitors, Matthew C. White

Dissertations and Theses (Open Access)

The mechanisms underlying cellular response to proteasome inhibitors have not been clearly elucidated in solid tumor models. Evidence suggests that the ability of a cell to manage the amount of proteotoxic stress following proteasome inhibition dictates survival. In this study using the FDA-approved proteasome inhibitor bortezomib (Velcade®) in solid tumor cells, we demonstrated that perhaps the most critical response to proteasome inhibition is repression of global protein synthesis by phosphorylation of the eukaryotic initiation factor 2-α subunit (eIF2α). In a panel of 10 distinct human pancreatic cancer cells, we showed marked heterogeneity in the ability of cancer cells to induce …

Characterization Of Differentiation And Prognostic Biomarkers On Cd8+ Tumor-Infiltrating Lymphocytes In Metastatic Melanoma, Richard C. Wu

Dissertations and Theses (Open Access)

CD8⁺ cytotoxic T lymphocytes (CTL) frequently infiltrate tumors, yet most melanoma patients fail to undergo tumor regression. We studied the differentiation of the CD8⁺ tumor-infiltrating lymphocytes (TIL) from 44 metastatic melanoma patients using known T-cell differentiation markers. We also compared CD8⁺ TIL against the T cells from matched melanoma patients’ peripheral blood. We discovered a novel subset of CD8⁺ TIL co-expressing early-differentiation markers, CD27, CD28, and a late/senescent CTL differentiation marker, CD57. This CD8⁺CD57⁺ TIL expressed a cytolytic enzyme, granzyme B (GB), yet did not express another cytolytic pore-forming molecule, perforin (Perf). In …

The Histone Deacetylase Inhibitor, Ms-275, Sensitizes Metastatic Osteosarcoma To Fasl-Induced Cell Death: A Role For C-Flip, Krithi R. Bindal

Dissertations and Theses (Open Access)

The purpose of this study was to determine the effects of the histone deacetylase inhibitor, MS-275, on the Fas signaling pathway and susceptibility of osteosarcoma (OS) to Fas ligand (FasL)-induced cell death. OS metastasizes almost exclusively to the lungs. We have shown that Fas expression in OS cells is inversely correlated with their metastatic potential. Fas⁺ cells are rapidly eliminated when they enter the lungs via interaction with FasL, which is constitutively expressed in the lungs. Fas^- OS cells escape this FasL-induced apoptosis and survive in the lung microenvironment. Moreover, upregulation of Fas in established OS lung metastases …

Taz As A Regulator Of Mesenchymal Transformation And Clinical Aggressiveness In Gliomas, Katrina Salazar

Dissertations and Theses (Open Access)

Glioblastoma multiforme (GBM) is an aggressive, high grade brain tumor. Microarray studies have shown a subset of GBMs with a mesenchymal gene signature. This subset is associated with poor clinical outcome and resistance to treatment. To establish the molecular drivers of this mesenchymal transition, we correlated transcription factor expression to the mesenchymal signature and identified transcriptional co-activator with PDZ-binding motif (TAZ) to be highly associated with the mesenchymal shift. High TAZ expression correlated with worse clinical outcome and higher grade. These data led to the hypothesis that TAZ is critical to the mesenchymal transition and aggressive clinical behavior seen in …

Bim Mediates Imatinib-Induced Apoptosis Of Gastrointestinal Stromal Tumors: Translational Implications, David Reynoso

Dissertations and Theses (Open Access)

Gastrointestinal stromal tumors (GISTs) are oncogene-addicted cancers driven by activating mutations in the genes encoding receptor tyrosine kinases KIT and PDGFR-α. Imatinib mesylate, a specific inhibitor of KIT and PDGFR-α signaling, delays progression of GIST, but is incapable of achieving cure. Thus, most patients who initially respond to imatinib therapy eventually experience tumor progression, and have limited therapeutic options thereafter. To address imatinib-resistance and tumor progression, these studies sought to understand the molecular mechanisms that regulate apoptosis in GIST, and evaluate combination therapies that kill GISTs cells via complementary, but independent, mechanisms. BIM (Bcl-2 interacting mediator …

Chemosensitization Of Hepatocellular Carcinoma To Gemcitabine By Non-Invasive Radiofrequency Field-Induced Hyperthermia, Mustafa Raoof

Dissertations and Theses (Open Access)

Gemcitabine is a potent nucleoside analogue against solid tumors however drug resistance rapidly emerges. Removal of gemcitabine incorporated in the DNA by repair mechanisms could potentially contribute to resistance in chemo-refractory solid tumors. In this study, we evaluated homologous recombination repair of gemcitabine-stalled replication forks as a potential mechanism contributing to resistance. We also studied the effect of hyperthermia on homologous recombination pathway to explain the previously reported synergy between gemcitabine and hyperthermia. We found that hyperthermia degrades and inhibits localization of Mre11 to gemcitabine-stalled replication forks. Furthermore, gemcitabine-treated cells that were also treated with hyperthermia demonstrate a prolonged passage …

The Role Of Cell Sterilization In Population Based Studies Of Radiogenic Second Cancers Following Radiation Therapy, Annelise Giebeler

Dissertations and Theses (Open Access)

Advances in radiotherapy have generated increased interest in comparative studies of treatment techniques and their effectiveness. In this respect, pediatric patients are of specific interest because of their sensitivity to radiation induced second cancers. However, due to the rarity of childhood cancers and the long latency of second cancers, large sample sizes are unavailable for the epidemiological study of contemporary radiotherapy treatments. Additionally, when specific treatments are considered, such as proton therapy, sample sizes are further reduced due to the rareness of such treatments. We propose a method to improve statistical power in micro clinical trials. Specifically, we use a …

The Mechanism Of Tumorigenesis In The Immortalized Human Pancreatic Cell Lines: Cell Culture Models Of Human Pancreatic Cancer, Zhe Chang

Dissertations and Theses (Open Access)

The mechanism of tumorigenesis in the immortalized human pancreatic cell lines: cell culture models of human pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal cancer in the world. The most common genetic lesions identified in PDAC include activation of K-ras (90%) and Her2 (70%), loss of p16 (95%) and p14 (40%), inactivation p53 (50-75%) and Smad4 (55%). However, the role of these signature gene alterations in PDAC is still not well understood, especially, how these genetic lesions individually or in combination contribute mechanistically to human pancreatic oncogenesis is still elusive. Moreover, a cell culture transformation model with sequential …

Atm Signaling To Tsc2: Mechanisms And Implications For Cancer Therapy, Angela Alexander

Dissertations and Theses (Open Access)

Ataxia telangiectasia mutated (ATM) is a critical component of the cellular response to DNA damage, where it acts as a damage sensor, and signals to a large network of proteins which execute the important tasks involved in responding to the damage, namely inducing cell cycle checkpoints, inducing DNA repair, modulating transcriptional responses, and regulating cell death pathways if the damage cannot be repaired faithfully. We have now discovered that an additional novel component of this ATM-dependent damage response involves induction of autophagy in response to oxidative stress. In contrast to DNA damage-induced ATM activation however, oxidative stress induced ATM, occurs …

The Effects Of Curcumin On Body Composition Of Patients With Advanced Pancreatic Cancer, Henrique A. Parsons Md

Dissertations and Theses (Open Access)

Cachexia is very common among patients with advanced pancreatic cancer and is a marker of poor prognosis. Weight loss in cachexia is due to both adipose and muscle compartments, and sarcopenia (severe muscle depletion) is associated with worse outcomes. Curcumin has shown a myriad of biological effects, including anti-cancer and anti-inflammatory. The ability of curcumin to attenuate cachexia and muscle loss has been tested in animal models, with conflicting results so far. The hypothesis of this study was that patients with advanced pancreatic cancer treated with curcumin for two months have less fat and muscle loss as compared to matched …

Improving Quantitative Treatment Response Monitoring With Deformable Image Registration, Blake A. Cannon

Dissertations and Theses (Open Access)

Quantitative imaging with 18F-FDG PET/CT has the potential to provide an in vivo assessment of response to radiotherapy (RT). However, comparing tissue tracer uptake in longitudinal studies is often confounded by variations in patient setup and potential treatment induced gross anatomic changes. These variations make true response monitoring for the same anatomic volume a challenge, not only for tumors, but also for normal organs-at-risk (OAR). The central hypothesis of this study is that more accurate image registration will lead to improved quantitation of tissue response to RT with 18F-FDG PET/CT. Employing an in-house developed “demons” based deformable image registration algorithm, …

Modeling Sporadic Tumor Formation Driven By Telomere Dysfunction In The Gastrointestinal Tract, Suzanne S. Chan

Dissertations and Theses (Open Access)

Colorectal cancer is a complex disease that is thought to arise when cells accumulate mutations that allow for uncontrolled growth. There are several recognized mechanisms for generating such mutations in sporadic colon cancer; one of which is chromosomal instability (CIN). One hypothesized driver of CIN in cancer is the improper repair of dysfunctional telomeres. Telomeres comprise the linear ends of chromosomes and play a dual role in cancer. Its length is maintained by the ribonucleoprotein, telomerase, which is not a normally expressed in somatic cells and as cells divide, telomeres continuously shorten. Critically shortened telomeres are considered dysfunctional as they …