At the Gesellschaft für Schwerionenforschung in Darmstadt a therapy unit for heavy ion cancer treatment has been established in collaboration with the Deutsches Krebsforschungszentrum Heidelberg, the Radiologische Universitätsklinik Heidelberg and the Forschungszentrum Rossendorf. For quality assurance the dual-head positron camera BASTEI (Beta Activity meaSurements at the Therapy with Energetic Ions) has been integrated into this facility. It measures ß+-activity distributions generated via nuclear fragmentation reactions within the target volume. BASTEI has about 4 million coincidence channels. The emission data are acquired in a 3D regime and stored in a list mode data format. Typically counting statstics is two to three orders of magnitude lower than those of typical PET-scans in nuclear medicine. Two iterative 3D reconstruction algorithms based on ISRA (Image Space Reconstruction Algorithm) and MLEM (Maximum Likelihood Expectation Maximization), respectively, have been adapted to this imaging geometry. The major advantage of the developed approaches are run-time Monte-Carlo simulations which are used to calculate the transition matrix. The influences of detector sensitivity variations, randoms, activity from outside of the field of view and attenuation are corrected for the individual coincidence channels. Performance studies show, that the implementation based on MLEM is the algorithm of merit. Since 1997 it has been applied sucessfully to patient data. The localization of distal and lateral gradients of the ß+-activity distribution is guaranteed in the longitudinal sections. Out of the longitudinal sections the lateral gradients of the ß+-activity distribution should be interpreted using a priori knowledge.

Radiofrequency ablation (RFA) is a clinic tool for the treatment of various target tissues. However, one of the major limitations with RFA is the ‘small’ size of target tissues that can be effectively ablated. By small it is meant the size of the target tissue is less than 3 cm in diameter of the tissue otherwise ‘large’ size of tissue in this thesis. A typical problem with RFA for large target tissue is the incompleteness of tumour ablation, which is an important reason for tumour recurring. It is widely agreed that two reasons are responsible for the tumour recurring: (1) the tissue charring and (2) the ‘heat-sink’ effect of large blood vessels (i.e. ≥3 mm in diameter). This thesis study was motivated to more quantitatively understand tissue charring during the RFA procedure and to develop solutions to increase the size of target tissues to be ablated. The thesis study mainly performed three tasks: (1) evaluation of the existing devices and protocols to give a clear understanding of the state of arts of RFA devices in clinic, (2) development of an accurate mathematical model for the RFA procedure to enable a more quantitative understanding of the small target tissue size problem, and (3) development of a new protocol based on the existing device to increase the size of target tissues to be ablated based on the knowledge acquired from (1) and (2). In (1), a design theory called axiomatic design theory (ADT) was applied in order to make the evaluation more objective. In (2), a two-compartment finite element model was developed and verified with in vitro experiments, where liver tissue was taken and a custom-made RFA system was employed; after that, three most commonly used internally cooled RFA systems (constant, pulsed, and temperature-controlled) were employed to demonstrate the maximum size of tumour that can be ablated. In (3) a novel feedback temperature-controlled RFA protocol was proposed to overcome the small target tissue size problem, which includes (a) the judicious selection of control areas and target control temperatures and (b) the use of the tissue temperature instead of electrode tip temperature as a feedback for control. The conclusions that can be drawn from this thesis are given as follows: (1) the decoupled design in the current RFA systems can be a critical reason for the incomplete target tissue necrosis (TTN), (2) using both the constant RFA and pulsed RFA, the largest TTN can be achieved at the maximum voltage applied (MVA) without the roll-off occurrence. Furthermore, the largest TTN sizes for both constant RFA and pulsed RFA are all less than 3 cm in diameter, (3) for target tissues of different sizes, the MVA without the roll-off occurrence is different and it decreases with increase of the target tissue size, (4) the largest TTN achieved by using temperature-controlled RFA under the current commercial protocol is still smaller 3 cm in diameter, and (5) the TTN with and over 3 cm in diameter can be obtained by using temperature-controlled RFA under a new protocol developed in this thesis study, in which the temperature of target tissue around the middle part of electrode is controlled at 90 ℃ for a standard ablation time (i.e. 720 s). There are a couple of contributions with this thesis. First, the underlying reason of the incomplete TTN of the current commercially available RFA systems was found, which is their inadequate design (i.e. decoupled design). This will help to give a guideline in RFA device design or improvement in the future. Second, the thesis has mathematically proved the empirical conclusion in clinic that the limit size of target tissue using the current RFA systems is 3 cm in diameter. This has advanced our understanding of the limit of the RFA technology in general. Third, the novel protocol proposed by the thesis is promising to increase the size of TTN with RFA technology by about 30%. The new protocol also reveals a very complex thermal control problem in the context of human tissues, and solving this problem effectively gives implication to similar problems in other thermal-based tumour ablation processes.

A recent clinical trial for locally advanced breast cancer patients treated with epirubicin and docetaxel prior to surgery reported significant dose-dependent reductions in tumour RNA integrity values which correlated with pathological complete response. The purpose of the present study was to assess whether similar chemotherapy-dependent alterations in RNA integrity could occur in vitro and to assess its relationship, if any, to apoptosis. Treatment of wildtype A2780 ovarian carcinoma cells with taxanes resulted in dose- and time-dependent RNA degradation, identified as several unique bands on electropherograms having mobilities lower than the 28S and 18S rRNAs. We refer to this chemotherapy-dependent generation of aberrant RNA bands on electropherograms as “RNA disruption”. RNA disruption was found to be temporally associated with the induction of apoptosis, as determined by the appearance of a sub G1 peak of DNA content, positive annexin-V staining, and both PARP-1 and caspase-3 cleavage. Treatment of cells with a caspase-3 inhibitor resulted in a significant reduction in rRNA disruption, suggesting the involvement of caspase-3 or related caspases in RNA disruption. In contrast, docetaxel-dependent rRNA disruption was absent when docetaxel was administered to docetaxel-resistant A2780DXL cells, indicating that changes in RNA integrity may possibly differentiate between responsive and non-responsive tumours in cancer patients.

The type II tumour suppressor ING3 has been shown to modulate transcription, cell cycle control, and apoptosis. To investigate the putative role of ING3 in melanoma development, we examined the expression of ING3 in 58 dysplastic nevi, 114 primary melanomas, and 50 metastatic melanomas with tissue microarray and immunohistochemistry. Overall ING3 was reduced in metastatic melanomas compared with dyslastic nevi and primary melanomas. Reduced nuclear ING3 staining also correlated with melanoma progression, increased cytoplasmic ING3 level, tumour location at sun-exposed sites, and a poorer disease-specific 5-year survival of patients with primary melanoma. Multivariate analysis revealed that nuclear ING3 staining can independently predict patient outcome in primary melanomas. In melanoma cells, ING3 expression was rapidly induced by UV irradiation. Using stable clones of melanoma cells overexpressing ING3, we showed that ING3 significantly promoted UV-induced apoptosis. Unlike its homologues ING1b and ING2, ING3-enhanced apoptosis upon UV irradiation was independent of functional p53. Furthermore, ING3 did not affect the expression of mitochondrial proteins but increased the cleavage of Bid and caspases. Moreover, ING3 upregulated Fas expression and ING3-mediated apoptosis was blocked by inhibiting caspase-8 or Fas activation. Knockdown of ING3 expression decreased UV-induced apoptosis remarkably, suggesting that ING3 plays a crucial role in cellular response to UV radiation. To explore how ING3 is deregulated in advanced melanomas, we examined ING3 expression in metastatic melanoma cells and found that ING3 was downregulated due to a rapid protein turnover in these cells. Further studies demonstrated that ING3 undergoes degradation via the ubiquitin-proteasome pathway. We also demonstrate that ING3 interacts with the SCF (Skp1/Cul1/Roc1/Skp2) E3 ligase complex. Knockdown of Cul1 or Skp2 significantly stabilized ING3 in melanoma cells. In addition, lysine residue 96 is essential for ING3 ubiquitination as its mutation to arginine completely abrogated ING3 turnover and enhanced ING3-stimulatd apoptosis upon UV irradiation. Taken together, ING3 is deregulated in melanomas as a result of both nucleus-to-cytoplasm shift and rapid degradation. The level of ING3 in the nucleus may be an important marker for human melanoma progression and prognosis. Restoration of ING3 expression significantly sensitizes melanoma cells to UV radiation through the activation of Fas/caspase-8 pathway.

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate the expression of mRNA targets, and are aberrantly expressed in several cancers, including breast cancer. Using a transgenic mouse model of mammary tumorigenesis (MTB-IGFIR), a miRNA array was previously performed in our lab to study the expression level of various miRNAs in mammary tumours compared to wild-type mammary tissue. Next, the expression of a number of the differentially expressed miRNAs was confirmed and manipulated in a tumour cell line (RM11A) generated from a MTB-IGFIR mammary tumour. Synthetic miRNA precursors and inhibitors were then used to overexpress and knockdown, respectively, the levels of five miRNAs: miR-31, miR-183, miR-200c, miR-210, and miR-378. Upon optimization of miRNA overexpression and downregulation in RM11A cells, this study tested the effects of these miRNAs on cellular growth, survival, or invasiveness in vitro. Compared to negative controls, overexpression of all five miRNAs was associated with a significant decrease in cellular invasion, while only the overexpression of miR-31 had a significant effect on proliferation. No significant effects were found on cell survival. Our results implicate these five miRNAs in different aspects of mammary tumorigenesis, as well as having a tissue specific role in RM11A cells.

This work explored features of canine mast cell tumours (MCT) to improve prognosis and to discover potential therapeutic targets. Subcutaneous MCT - a subset of these tumours arising in the subcutis - are usually grouped with cutaneous MCT, but there is evidence that they may be clinically different. The first objective was to develop a grading scheme for subcutaneous MCT. Over 300 canine subcutaneous MCT were evaluated retrospectively and parameters were correlated with clinical outcomes, making this the largest retrospective survival study of these tumours to date. The results of the study showed that the majority of subcutaneous MCT had excellent outcomes and key prognostic markers were identified (mitotic index, surgical margins and degree of infiltration). A subset of the subcutaneous MCT from the retrospective study was further evaluated to assess the cellular localization of KIT - a receptor tyrosine kinase (RTK) which is dysregulated and constitutively activated in some cutaneous MCT - as well as Ki67, a proliferation marker. In addition, evaluation of mutations of c-KIT, the gene for KIT, was determined for each MCT. Cytoplasmic KIT localization and high Ki67 values were predictive of decreased survival time and time to local reoccurrence, but no c-KIT mutations were detected. The majority of canine MCT do not appear to depend solely upon KIT for tumour progression and few other RTK targets have been studied in canine MCT. Based on evidence that vascular endothelial growth factor receptors (VEGFR) and platelet-derived growth factor receptors (PDGFR) - may play a role in the progression of canine MCT; the expression and distribution of these RTK were evaluated. The results showed that canine MCT have unique expression profiles and activity of KIT, VEGFR2 and PDGFR. Two novel mast cell tumour cell lines were generated and used to assess signalling of KIT and VEGFR2 in vitro. Stimulatory and inhibitory responses were assessed and found to be different in both cell lines. Both had autophosphorylated VEGFR2 and an autocrine VEGF/VEGFR2 signalling pathway existed for both cell lines. These findings are unique and the first that identify autocrine VEGF signalling as a possible survival mechanism for canine MCT. / Pet Trust Foundation, Ontario Veterinary College

While researchers have explored many important aspects of living with childhood cancer, including the multitude of strains on family members and their reactions, very little is known about the experiences of children with brain tumours and their parents. Grounded theory methods were utilized to explore the unique and shared elements of the experiences of childhood brain tumours, from the perspectives of these children and their parents. Woven throughout their stories were expressions of grief and uncertainty related to the tumour and its effects on their lives. Children and parents tried to maintain a positive outlook and a sense of normalcy, in order to cope and to adapt to the struggles and the changes in their lives. A substantive theory of Balancing Grief and Survival was developed, offering a lens through which to view the children’s and parents’ complex experiences, struggles and coping strategies as integrated, dynamic processes.

FES protein-tyrosine kinase (PTK) activation downstream of the KIT receptor in mast cells (MC) promotes cell polarization and migration towards the KIT ligand Stem cell factor (SCF). A variety of tumours secrete SCF to promote MC recruitment and release of mediators that enhance tumour vascularization and growth. This study investigates whether FES promotes MC migration via regulation of microtubules (MTs), and if FES is required for MC recruitment to the tumour microenvironment. MT binding assays showed that FES has at least two MT binding sites, which likely contribute to the partial co-localization of FES with MTs in polarized bone marrow-derived mast cells (BMMCs). Live cell imaging revealed a significant defect in chemotaxis of FES-deficient BMMCs towards SCF embedded within an agarose drop, which correlated with less MT organization compared to control cells. To extend these results to a tumour model, mouse mammary carcinoma AC2M2 cells were engrafted under the skin and into the mammary fat pads of immune compromised control (nu/nu) or FES-deficient (nu/nu:fes-/-) mice. A drastic reduction in tumour-associated MCs was observed in FES-deficient mice compared to control in both mammary and skin tissue sections. This correlated with a trend towards reduced tumour volumes in FES-deficient mice. These results implicate FES signaling downstream of KIT, in promoting MT reorganization during cell polarization and for chemotaxis of MCs towards tumour-derived SCF. Thus, FES is a potential therapeutic target to limit recruitment of stromal mast cells or macrophages to solid tumours that enhance tumour progression. / Thesis (Master, Biochemistry) -- Queen's University, 2011-09-14 11:49:32.871

No description available.

This qualitative multi case research asks how the needs of caregivers of primary malignant brain tumour (PMBT) patients are met through structured neuro-oncology programs in Canadian centres. Utilizing telephone interviews with eleven social workers and one psychologist the study analyses their perspectives on the scope and nature of services to brain tumour patients and their caregivers. PMBT is a rare and palliative disease often with neurocognitive and neurobehavioral effects posing special challenges for caregivers. Health care system reliance on family caregivers has resulted in significant implications for their emotional and physical risk. Findings show exclusive patient focused health care in ambulatory programs with fragmented care resulting in marginalization and invisibility of caregivers. This approach is inconsistent with current literature promoting collaborative family centered care, recommended for continuity of care throughout the illness trajectory. Recommendations focus on systemic caregiver service improvements.