Despite the advancement in the treatment from genotoxic drugs to more targeted therapies, multiple myeloma (MM) remains incurable. MM is known for its complex genetic heterogeneity as different genetic lesion accrue over the course of the disease. The current work focuses on the functional analysis of genetic lesions found at the time of diagnosis and relapse and their potential role regarding therapy response and refractory disease. Genetic lesions involving tumor suppressor gene TP53, are found at diagnosis and tend to accrue during disease progression. Different types of mono- and biallelic TP53 alterations were emulated in the AMO1 cell line model, were functionally characterized and tested for their potential role in therapy response. Both types of single hit TP53 alteration (deletion 17p and TP53 point mutations) were found to have similar adverse effects on the functionality of the p53 system and response to genotoxic drugs which were completely abolished in the case of double hit TP53 alterations (no p53 expression, or mutant overexpression in wild type TP53 deletion background). Whereas, sensitivity to proteasome inhibitors remained unaltered. Using the clonal competition assay (CCA), single TP53 hit clones were found to have a fitness advantage over wildtype cells. Proliferative cell fitness was further enhanced in double hit TP53 clones, as they dominated wildtype and single hit TP53 clones in the CCA. Presence of external selection pressure in the form of low dose melphalan expedited the intrinsic fitness advantage. Alterations found in CUL4B, a component of CRL4-CRBN protein complex, a target of immunomodulatory drugs (IMiDs), were also functionally analyzed in the current study. Hotspot mutations and mutations found in IMiDs refractory patients were modelized in L363 cells and their role in IMiDs sensitivity was studied. CUL4B mutations were found not to be involved in providing lenalidomide resistance to the cell, whereas knocking CUL4B out was observed to provide negative fitness to the cells in CCA. In the presence of external selection pressure, these clones showed fitness, which was lost in the case of lenalidomide withdrawal. This shows that some alterations may play a role in refractory patients only in the presence of therapy, and as soon as therapy is discontinued, these altered clones may disappear such as clones with alterations in CUL4B. On the other hand, some alterations provide drug-independent intrinsic positive fitness, however, be further enhanced by drug exposure, such as seen in case of TP53 altered clones. Therefore, close monitoring and functional analysis of evolving clones is desired during disease progression, as it can be helpful in therapeutic guidance to achieve a better outcome for patients. / Das Multiple Myelom (MM) ist im Normalfall eine unheilbare Erkrankung, trotz etlicher Fortschritte hinsichtlich der Behandlung, angefangen von genotoxischen Medikamenten bis hin zu zielgerichteten Therapien. Eine komplexe genetische Heterogenität, bei der sich Läsionen im Verlauf der Krankheit ansammeln, ist typisch für das MM. Diese Arbeit beschäftigt sich mit der funktionellen Analyse von genetischen Läsionen zum Erstdiagnose-Zeitpunkt bzw. Rezidiv und ihrer potenziellen Bedeutung bezüglich des Ansprechens auf die Therapie und einer refraktären Verlaufsform. Genetische Veränderungen des Tumorsuppressorgens TP53 sind mitunter schon bei der Erst-Diagnose nachweisbar und nehmen im Krankheitsverlauf weiter zu. Deshalb wurden verschiedene mono- und biallelische TP53 Mutationen in AMO1 Zelllinien-Modellen nachgebildet, funktionell charakterisiert und auf ihre potenzielle Rolle im Therapie-Ansprechen getestet. Dabei wurden für beide Formen von single hit TP53 Alterationen (17p Deletionen und TP53 Punktmutationen) ähnlich nachteilige Effekte auf die Funktionalität des p53 Systems und das Ansprechen auf genotoxische Medikation gefunden. Im Falle von double hit TP53 Alterationen (keinerlei p53 Expression oder aber hohe Spiegel von mutiertem p53 bei TP53 wildtype deletierem Hintergrund) wurden diese Effekte noch weiter verstärkt. Die Sensitivität gegenüber Proteasom-Inhibitoren blieb indessen unbeeinträchtigt. Mithilfe des Clonal Competition Assays (CCA), wurde festgestellt, dass single hit TP53 Klone gegenüber wildtypischen Zellen einen Fitnessvorteil haben. In double hit TP53 Klonen war die proliferative Zell-Fitness zu dem gesteigert, sodass diese über wildtypische und single hit TP53 Klone im CCA dominierten. Die Anwesenheit eines externen Selektionsdrucks in Form von Niedrigdosis-Melphalan verstärkte zusätzlich den intrinsischen Fitnessvorteil. Aberrationen in CUL4B, einer Untereinheit des CRL4-CRBN Protein Komplexes, dem Angriffspunkt der Immunmodulatoren (IMiDs), wurden in dieser Studie ebenfalls funktionell analysiert. Hotspot Mutationen und solche Mutationen, die gehäuft in IMiD refraktären Patienten auftreten, wurden in L363 Zellen modelliert und hinsichtlich ihres Einflusses auf die IMiD Sensitivität untersucht. CUL4B Mutationen waren nicht in Lenalidomid-Resistenz involviert, ein Knockout von CUL4B äußerte sich aber in einer negativen Allgemeinzustand der Zellen im CCA. In Anwesenheit eines externen Selektionsdrucks, zeigten diese Klone einen Fitnessvorteil, der wieder verloren ging, wenn kein Lenalidomid mehr zugegeben wurde. Dies zeigt, dass manche Alterationen nur dann eine Rolle in refraktären Patienten zu spielen scheinen, wenn diese therapiert werden. Sobald die Therapie eingestellt oder unterbrochen wird, könnten solche Klone verschwinden wie z.B. CUL4B-Alterationen. Auf der anderen Seite bedingen manche Veränderungen wiederum einen Medikamenten-unabhängigen, intrinsisch Fitnessvorteil, der jedoch durch Medikamenten-Exposition noch zusätzlich verstärkt werden kann, wie beispielweise bei TP53 mutierten Klonen. Daher ist eine engmaschige Überwachung während der Krankheits-Progression sowie eine funktionelle Analyse der sich entwickelnden Klone wünschenswert. Dies könnte für die therapeutische Beratung hilfreich sein um somit ein besseres Behandlungsergebnis für die Patienten zu erzielen.

Cheng Suk Hang. / "February 2005." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 142-160) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Ng Heung-ling, Margaret. / "April 2003." / Thesis (M.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 216-237). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

published_or_final_version / abstract / Medicine / Doctoral / Doctor of Philosophy

No description available.

MMed (Haematology), Faculty of Health Sciences, University of the Witwatersrand / Multiple Myeloma (MM) is a malignancy of plasma cells. The incidence worldwide has been reported to be 3-4/100 000 of the population. The exact aetiology is not known, but several factors have been implicated in the aetio-pathogenesis of the disease. Chromosomal abnormalities are well documented in MM. Their detection is important, as some of the cytogenetic abnormalities such as the 13q deletion are associated with a poor prognosis. Knowledge of the prognostic factors guides the clinician with respect to the appropriate management of the patient. Prior to the use of fluorescence in situ hybridisation (FISH) as a technique for detecting cytogenetic abnormalities in MM, progress was slow in this field because of the difficulty of obtaining analysable metaphases in view of the low proliferative activity of plasma cells. FISH has significantly improved the detection rate over conventional cytogenetics. Objective: The present study set out to determine the proportion of patients with MM who have a detectable chromosome 13q deletion using conventional cytogenetic and FISH analysis. The FISH technique was specifically studied to see if the detection rate of the 13q deletion is improved compared to conventional cytogenetics. Furthermore, the cytogenetic abnormalities detected were correlated with the course of the disease, as well as other parameters of prognostic significance. vi Methods: Bone marrow aspiration specimens were obtained from thirty (30) patients with MM. Both newly and previously diagnosed patients were included. The sample size was however reduced to twenty (20) because of the need to optimise the technique and improve signal detection. Conventional cytogenetic and FISH analysis was performed using the LSI D13S319 DNA probe as the test probe, and the centromeric alpha 11 and 18 as control probes. The analysis was carried out by two observers. Results: In the current study, the detection of chromosomal aberrations was much better with FISH analysis compared to conventional cytogenetics i.e. 25% versus 5%. Of all the patients with chromosomal aberrations, 25% (5/20) had the specific deletion 13q14 (D13S319). Most of our patients (70%) presented with stage III disease. 60% of those were positive for deletion 13q14 (D13S319), i.e 3/5 patients had stage III disease. However, there was no correlation between disease stage and chromosome status, as the majority of the patients presented with advanced stage disease, irrespective of their chromosomal status. Other factors of prognostic significance such as the haemoglobin level, beta-2 microglobulin and creatinine levels were not found to correlate with the presence of the chromosomal aberration but with disease stage. Furthermore, median survival did not correlate with the presence of the chromosomal abnormality. Conclusion: FISH analysis improves the detection rate of chromosomal abnormalities in MM compared to conventional cytogenetics. The prevalence of 13q14 deletion in our patient population is lower than that reported in the

Bortezomib-based induction therapies have shown to increase complete response rates and are used as an upfront therapy for newly diagnosed multiple myeloma patients. The standard treatment uses twice a week bortezomib at 1.3 mg/m^2 with dexamethasone PO on the day of and day after bortezomib, however, peripheral neuropathy is often a dose-limiting factor. For elderly patients with multiple co-morbidities and polypharmacy, we propose an alternate schedule of once a week bortezomib IV at 1.6 mg/m^2 with dexamethasone PO on the day of and day after bortezomib. In this phase II, open-labeled, multi-site study, we hypothesize that patients receiving weekly bortezomib will have comparable efficacy as the standard twice a week schedule with increased convenience and lower toxicity profile, especially related to peripheral neuropathy. METHODS: 50 patients with newly diagnosed symptomatic multiple myeloma who were ineligible for transplant or postponed transplant were enrolled from 12 Veterans Affairs hospitals. One cycle consisted of once a week 1.6 mg/m2 bortezomib IV (days 1, 8, 15, 22) plus dexamethasone PO on the day of and after bortezomib (days 1, 2, 8, 9, 15, 16, 22, 23) for 4 weeks, with the 5th week off of treatment. Responding patients could receive up to 6 cycles. RESULTS: The median age of patients was 71 ± 1.46 years (range: 50-89) with β-2 microglobulin of 5.80 ± 0.46 mg/L and c-reactive protein of 10.61 ± 5.54 mg/L. Patients also had multiple co-morbidities including cardiovascular disease (76%) renal insufficiency (54%) and pulmonary problems (36%) and were receiving a median of 13 concurrent medications at baseline. Of the fifty patients, 43 patients were evaluable for response. Seven patients received <1 cycle or died before response could be evaluated. An objective response rate of 79% was observed in 43 evaluable patients with 14% achieving nCR/CR, and at least VGPR in 44% of patients. The median progression-free survival was 9.6 months and overall survival was 46.5 months. The most common toxicity of all grades was thrombocytopenia (42%), lymphopenia (46%), asthenia (48%), and constipation (38%). Peripheral neuropathy occurred in 24% with grade 3 neuropathy occurring only in 6% of patients. In conclusion, a weekly bortezomib plus dexamethasone regimen is efficacious and safe, with lower neurotoxicity in elderly patients with newly diagnosed multiple myeloma complicated by extensive co-morbidities and polypharmacy.

Multiple myeloma is a plasma cell cancer that affects the bones, immune system, and kidneys. In this thesis, we focus on the impact on the bone, specifically routine bone remodeling. The bone remodeling process is governed by chemical signaling between several cell populations. In multiple myeloma patients, this process is out of balance. Bone destruction outpaces bone replacement, leaving patients with bone lesions. We describe the cell-signaling network that regulates bone remodeling and explain how it is impacted by multiple myeloma. We then present a series of mathematical models describing the bone remodeling process. We lay a thorough mathematical foundation, starting with the derivation of Savageau's power law approximations. Next, we introduce a novel one-dimensional moving-boundary partial differential equation model of this biological system. Our model improves upon models from the literature by including new cell populations, specifically osteoclast precursors, stromal cells, and tumor cells. We also discuss the model's computational results and their significance. We then discuss image processing techniques that can be used on bone marrow biopsies to gather data on the growth of a multiple myeloma tumor. By analyzing these medical images, we can extract tumor cell counts. In particular, we give the results of such an analysis for one patient using color unmixing. Image processing techniques, such as the ones presented here, could be used for validation of the models we present. The long-term goal of this project is the creation of a diagnostic tool that will aid oncologists in selecting the best treatment plan for their patients with multiple myeloma.

Thalidomid ist eine in der Therapie des fortgeschrittenen refraktären oder rezidivierten multiplen Myeloms (MM) wirksame Substanz, obwohl dosislimitierende Toxizitäten (DLT) ihren Einsatz beschränken können. In der vorliegenden Phase-I-Studie mit 28 Patienten mit rezidiviertem oder refraktärem MM nach konventioneller Chemotherapie oder Hochdosis (HD)-Chemotherapie mit Stammzelltransplantation (SCT) konnte gezeigt werden, dass eine Kombination von niedrig dosiertem Thalidomid mit Bendamustin und Prednisolon (BPT) die Wirksamkeit beibehält oder erhöht und gleichzeitig keine DLT auftritt. Die BPT-Therapie umfasste eine Dosis von Bendamustin (60mg/m2) Tag 1, 8 und 15 und Prednisolon (100mg) Tag 1, 8, 15 und 22, und eine eskalierende tägliche Dosis Thalidomid (50, 100, 200mg). Die Behandlungszyklen wurden alle 28 Tage bis zum Auftreten des maximalen Ansprechens, DLT oder Fortschreiten der Erkrankung wiederholt. 24 Patienten sprachen nach mindestens zwei Zyklen auf die Therapie an (vier komplette, sechs sehr gute partielle und 14 partielle Remissionen). Das mediane progressionsfreie Überleben und Gesamtüberleben für alle Patienten betrug 11 und 19 Monate. Nur leichte oder mittelschwere nicht-hämatologische Nebenwirkungen wurden beobachtet und kein Patient entwickelte dosislimitierende Hämatotoxizitäten. Die BPT-Therapie weist bei Patienten mit rezidiviertem oder refraktärem MM eine gute Verträglichkeit mit einem Ansprechen von über 80% auf. Die maximal tolerierte Dosis von Thalidomid wurde in dieser Studie nicht erreicht.

Background: MY7 clinical trial compared dexamethasone plus melphalan (MD) vs. prednisone plus melphalan (MP) in multiple myeloma treatment and found no statistically significant difference in overall survival (OS) between the two groups. But, patients reacted to treatment differently. We aimed to identify patients who might have benefited from dexamethasone, and characterize them by their baseline demographic and clinical factors. Methods: First, the prognostic model for OS was developed on the MP arm. The estimated coefficients and baseline hazard were applied to the MD arm to derive martingale residuals (MR). Classification and regression tree analysis was done to identify independent predictive factors for OS and MR was used as response variable. All covariates in categorical shape were used as independent variables to develop the predictive model in MD arm. MP arm was divided accordingly. Subgroups with negative mean MR (survived > expected) were candidates for positive responders while those with positive mean MR (survived < expected) were candidates of negative responders. Mean MR in each subgroup and p values from comparison of OS (log rank test stratified by subgroups) were used to combine the appropriate subgroups as the positive responders or negative responders. Results: A total of 97 patients (42%) in MD arm were identified as positive responders and their OS (median of 44.5 months) was significantly longer than that (median of 33 months) in the corresponding subgroups in MP arm (HR = 0.56, 95% CI 0.4-0.8; p = 0.0014). All positive responders had three common baseline characteristics: aged ≤75 years, calcium concentration ≤2.6 mmol/L and Durie-Salmon stages 2 or 3. Among patients with ECOG performance status<2 those with either HGB≥100 mg/dl or HGB<100 mg/dl and WBC≥4,000 and <4 lytic bone lesions were categorized as positive responders. Also, among the patients with ECOG performance status≥2, males with >3 lytic bone lesions were positive responders. Negative responders (HR = 1.56, 95% confidence interval 1.1 – 2.2; p = 0.006) included patients aged >75 or aged ≤75 with calcium concentration >2.6 mmol/L or aged ≤75 with calcium concentration ≤2.6 mmol/L but had Durie-Salmon stage 1. Conclusions: Evaluation of the hypotheses validity warrants further studies. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2008-07-21 13:46:53.748