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| 2. |
- Henriksson, Roger, et al.
(författare)
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Brain Tumors - Prognostic and Predictive Markers
- 2009
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Ingår i: Histological and Serological Tumor Markers and Gene Expression and Their Clinical Usefulness in Cancers. - Hauppauge : Nova Science Publishers, Inc.. - 9781607413820 ; , s. 53-75
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Bokkapitel (refereegranskat)abstract
- This review summarizes the status of prognostic and predictive markers in brain tumors with a focus on the most frequent tumors, gliomas. Brain tumors are a heterogeneous group of different tumors with a huge variation in outcome. Although the most common tumor, high-grade malignant glioma, still has a dismal prognosis, the last years have seen a significant improvement in the management in this tumor as well as in most other brain tumors. Age, tumor grade and KPS are still the most reliable prognostic and predictive variables available for patients with brain tumors. Although chromosome 1p/19q co-deletion and methylation status of the promoter of the MGMT gene (encoding O6-methylguanine-DNA methyl transferase) have been identified as the most promising potential predictors of response to chemotherapy in malignant gliomas, there are as yet no reliable biomarkers for tumour grading or tumour monitoring in the clinical setting.
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| 3. |
- Mu, Xiangkui, et al.
(författare)
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Does electron and proton therapy reduce the risk of radiation induced cancer after spinal irradiation for childhood medulloblastoma? A comparative treatment planning study.
- 2005
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Ingår i: Acta oncologica (Stockholm, Sweden). - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 44:6, s. 554-62
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this treatment planning comparison study was to explore different spinal irradiation techniques with respect to the risk of late side-effects, particularly radiation-induced cancer. The radiotherapy techniques compared were conventional photon therapy, intensity modulated x-ray therapy (IMXT), conventional electron therapy, intensity/energy modulated electron therapy (IMET) and proton therapy (IMPT).CT images for radiotherapy use from five children, median age 8 and diagnosed with medulloblastoma, were selected for this study. Target volumes and organs at risk were defined in 3-D. Treatment plans using conventional photon therapy, IMXT, conventional electron therapy, IMET and IMPT were set up. The probability of normal tissue complication (NTCP) and the risk of cancer induction were calculated using models with parameters-sets taken from published data for the general population; dose data were taken from dose volume histograms (DVH).Similar dose distributions in the targets were achieved with all techniques but the absorbed doses in the organs-at-risk varied significantly between the different techniques. The NTCP models based on available data predicted very low probabilities for side-effects in all cases. However, the effective mean doses outside the target volumes, and thus the predicted risk of cancer induction, varied significantly between the techniques. The highest lifetime risk of secondary cancers was estimated for IMXT (30%). The lowest risk was found with IMPT (4%). The risks associated with conventional photon therapy, electron therapy and IMET were 20%, 21% and 15%, respectively.This model study shows that spinal irradiation of young children with photon and electron techniques results in a substantial risk of radiation-induced secondary cancers. Multiple beam IMXT seems to be associated with a particularly high risk of secondary cancer induction. To minimise this risk, IMPT should be the treatment of choice. If proton therapy is not available, advanced electron therapy may provide a better alternative.
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| 4. |
- Bjerkvig, Rolf, et al.
(författare)
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Cancer stem cells and angiogenesis
- 2009
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Ingår i: Seminars in Cancer Biology. - London : Academic Press. - 1044-579X .- 1096-3650. ; 19:5, s. 279-284
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Forskningsöversikt (refereegranskat)abstract
- Most cancers contain tumor cells that display stem cell-like characteristics. How and when such cells appear in tumors are not clear, but may involve both stochastic as well as hierarchical events Most. likely, tumor cells that display stem cell-like characteristics can undergo asymmetric cell division giving rise to tumor cells that trigger angiogenic programs. As normal stem cells the cancer stem-like cells seem to adapt to hypoxic environments and will use metabolic pathways that involve increased conversion of glucose to pyruvate and lactate, and a concomitant decrease in mitochondrial metabolism and mitochondrial mass. The molecular pathways responsible for inducing glycolysis are now being explored. These pathways seem to mediate multiple metabolic functions in cancer stem-like cells, leading to a highly migratory and angiogenesis-independent phenotype. Future challenges will be to identify and validate molecular targets involved in anaerobic metabolic pathways active in cancer stem-like cells and to determine how these pathways differ from regulatory pathways involved in normal stem cell function.
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| 5. |
- Glimelius, B., et al.
(författare)
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Number of patients potentially eligible for proton therapy
- 2005
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Ingår i: Acta Oncol. - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 44:8, s. 836-49
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Tidskriftsartikel (refereegranskat)abstract
- A group of Swedish radiation oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy in a facility where one of the principal aims is to facilitate randomized and other studies in which the advantage of protons can be shown and the magnitude of the differences compared with optimally administered conventional radiation treatment, also including intensity-modulated radiation therapy (IMRT) and brachytherapy, can be shown. The estimations have been based on current statistics of tumour incidence in Sweden, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours together with information on normal tissue complication rates. In Sweden, it is assessed that between 2200 and 2500 patients annually are eligible for proton beam therapy, and that for these patients the potential therapeutic benefit is so great as to justify the additional expense of proton therapy. This constitutes between 14-15% of all irradiated patients annually.
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| 6. |
- Hansson, Frida, et al.
(författare)
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Exit of pediatric pre-B acute lymphoblastic leukaemia cells from the bone marrow to the peripheral blood is not associated with cell maturation or alterations in gene expression
- 2008
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Ingår i: Molecular Cancer. - : Springer Science and Business Media LLC. - 1476-4598. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: Childhood pre-B acute lymphoblastic leukemia (ALL) is a bone marrow (BM) derived disease, which often disseminates out of the BM cavity, where malignant cells to a variable degree can be found circulating in the peripheral blood (PB). Normal pre-B cells are absolutely dependent on BM stroma for survival and differentiation. It is not known whether transformed pre-B ALL cells retain any of this dependence, which possibly could impact on drug sensitivity or MRD measurements. Results: Pre-B ALL cells, highly purified by a novel method using surface expression of CD19 and immunoglobulin light chains, from BM and PB show a very high degree of similarity in gene expression patterns, with differential expression of vascular endothelial growth factor (VEGF) as a notable exception. In addition, the cell sorting procedure revealed that in 2 out of five investigated patients, a significant fraction of the malignant cells had matured beyond the pre-B cell stage. Conclusion: The transition of ALL cells from the BM into the circulation does not demand, or result in, major changes of gene expression pattern. This might indicate an independence of BM stroma on the part of transformed pre-B cells, which contrasts with that of their normal counterparts. © 2008 Hansson et al, licensee BioMed Central Ltd.
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| 7. |
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| 8. |
- Isaksson, Mikael, et al.
(författare)
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Extentded Förster theory for determining intraprotein distances : 2. An accurate analysis of fluorescence depolarisation experiments
- 2007
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry. - 1463-9076 .- 1463-9084. ; 9:29, s. 3914-3922
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Tidskriftsartikel (refereegranskat)abstract
- The extended Förster theory (EFT) is for the first time applied to the quantitative determination of the intramolecular distances in proteins. It is shown how the EFT (J. Chem. Phys., 1996, 105, 10896) can be adapted to the analyses of fluorescence depolarisation experiments based on the time-correlated single photon counting technique (TCSPC). The protein system studied was the latent form of plasminogen activator inhibitor type I (PAI-1), which was mutated and labelled by the thiol reactive BODIPY® derivative {N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl iodoacetamide}. The energy migration occurs within pairs of photophysically identical donor groups that undergo reorientational motions on the timescales of energy migration and fluorescence relaxation. Unlike all models currently used for analysing fluorescence TCSPC data, the EFT explicitly accounts for the time-dependent reorientations that influence the rate of electronic energy transfer/migration in a complex manner. The complexity is related to the “κ2 problem”, which has been discussed for years. The EFT brings the analyses of DDEM data to the same level of molecular description as in ESR and NMR spectroscopy, i.e. it yields microscopic information about the reorientation correlation times, the order parameters, as well as inter-chromophoric distances.
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| 9. |
- Isaksson, Mikael, 1974-
(författare)
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On the quantitative analysis of electronic energy transfer/migration in proteins studied by fluorescence spectroscopy
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Two recently developed theories of electronic energy transfer/migration were for the first time applied to real protein systems for extracting molecular distances. The partial donor-donor energy migration (PDDEM) is an extension to the previously developed donor-donor energy migration (DDEM, F Bergström et al PNAS 96, 1999, 12477) which allows using chemically identical but photophysically different fluorophores in energy migration experiments. A method based on fluorescence quenching was investigated and applied to create an asymmetric energy migration between fluorophores which were covalently and specifically attached to plasminogen activator inhibitor type 2 (PAI-2). It was also shown experimentally that distance information can be obtained if the fluorescence relaxation for photophysically identical donors, exhibits multi-exponential relaxation. An extended Förster theory (EFT) that was previously derived (L. B.-Å. Johansson et al J. Chem. Phys., 1996, 105) ha been developed for analysis of donor-acceptor energy transfer systems as well as DDEM systems. Recently the EFT was also applied to determine intra molecular distances in the protein plasminogen activator inhibitor type 1 (PAI-1) which was labelled with a sulfhydryl specific derivative of BODIPY. The EFT explicitly accounts for the time-dependent reorientations which in a complex manner influence the rate of electronic energy transfer/migration. This difficulty is related to the “k2-problem”, which has been solved. It is also shown experimentally that the time-correlated single-photon counting (TCSPC) data is sensitive to the mutual configuration between the interacting fluorophores. To increase the accuracy in the extracted parameters it is furthermore suggested to collect the fluorescence data under various physico-chemical conditions. It was also shown that the Förster theory is only valid in the initial part of the fluorescence decay.
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| 10. |
- Isaksson, Mikael, et al.
(författare)
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On the quantitative molecular analysis of electronic energy transfer within donor–acceptor pairs
- 2007
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 9, s. 1941-51
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Tidskriftsartikel (refereegranskat)abstract
- An extended Förster theory (EFT) on electronic energy transfer is presented for the quantitative analysis of time-resolved fluorescence lifetime and depolarisation experiments. The EFT, which was derived from the stochastic Liouville equation, yields microscopic information concerning the reorientation correlation times, the order parameters, as well as inter chromophoric distances. Weakly interacting donor and acceptor groups, which reorient and interact in a pair wise fashion, are considered, under isotropic and anisotropic conditions. For the analysis of experiments it is shown that not only do we need to consider the orientational distributions of the transition dipoles, but the internal reorienting molecular dynamics within the pair which is of even greater importance. The latter determines the shape as well as the rate of the observed donor fluorescence and depolarisation decays, which are most often not mono-exponential functions. It is shown that the commonly used Förster theory is a special case of the EFT. Strategies are presented for applying the EFT, which makes use of Brownian dynamics simulation.
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