Publications by authors named "Ulf Thunberg"

42 Publications

Epidermal Keratinocyte Depletion during Five Weeks of Radiotherapy is Associated with DNA Double-Strand Break Foci, Cell Growth Arrest and Apoptosis: Evidence of Increasing Radioresponsiveness and Lack of Repopulation; the Number of Melanocytes Remains Unchanged.

Radiat Res 2020 05 20;193(5):481-496. Epub 2020 Mar 20.

Department of Oncology.

During fractionated radiotherapy, epithelial cell populations are thought to decrease initially, followed by accelerated repopulation to compensate cell loss. However, previous findings in skin with daily 1.1 Gy dose fractions indicate continued and increasing cell depletion. Here we investigated epidermal keratinocyte response with daily 2 Gy fractions as well as accelerated and hypofractionation. Epidermal interfollicular melanocytes were also assessed. Skin-punch biopsies were collected from breast cancer patients before, during and after mastectomy radiotherapy to the thoracic wall with daily 2 Gy fractions for 5 weeks. In addition, 2.4 Gy radiotherapy four times per week and 4 Gy fractions twice per week for 5 weeks, and two times 2 Gy daily for 2.5 weeks, were used. Basal keratinocyte density of the interfollicular epidermis was determined and immunostainings of keratinocytes for DNA double-strand break (DSB) foci, growth arrest, apoptosis and mitosis were quantified. In addition, interfollicular melanocytes were counted. Initially minimal keratinocyte loss was observed followed by pronounced depletion during the second half of treatment and full recovery at 2 weeks post treatment. DSB foci per cell peaked towards the end of treatment. p21-stained cell counts increased during radiotherapy, especially the second half. Apoptotic frequency was low throughout radiotherapy but increased at treatment end. Mitotic cell count was significantly suppressed throughout radiotherapy and did not recover during weekend treatment gaps, but increased more than threefold compared to unexposed skin 2 weeks post-radiotherapy. The number of melanocytes remained constant over the study period. Germinal keratinocyte loss rate increased gradually during daily 2 Gy fractions for 5 weeks, and similarly for hypofractionation. DSB foci number after 2 Gy irradiation revealed an initial radioresistance followed by increasing radiosensitivity. Growth arrest mediated by p21 strongly suggests that cells within or recruited into the cell cycle during treatment are at high risk of loss and do not contribute significantly to repopulation. It is possible that quiescent (G) cells at treatment completion accounted for the accelerated post-treatment repopulation. Recent knowledge of epidermal tissue regeneration and cell cycle progression during genotoxic and mitogen stress allows for a credible explanation of the current finding. Melanocytes were radioresistant regarding cell depletion.
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http://dx.doi.org/10.1667/RR15417.1DOI Listing
May 2020

Metastatic colorectal carcinomas with high SATB2 expression are associated with better prognosis and response to chemotherapy: a population-based Scandinavian study.

Acta Oncol 2020 Mar 26;59(3):284-290. Epub 2019 Nov 26.

Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.

Survival and response to therapy in patients with metastatic colorectal cancer (mCRC) are very heterogeneous. There is an unmet need for better markers of prognosis and treatment benefit for mCRC patients. The homeobox 2 gene has a highly specific expression in colorectal tissue and is associated with better prognosis in non-metastatic CRC. A population-based cohort of 798 mCRC patients was analysed. From primary tumour material, protein expression was assessed by immunohistochemistry. and mutation status was also determined. Associations with clinicopathological data, overall and progression-free survival and response to first-line chemotherapy were analysed. Tumour tissue and clinical data were available from 467 patients. SATB2 was strongly expressed in 58% of cases, significantly more in left-sided, low-grade and wild-type tumours. Patients with high SATB2 tumours had longer overall survival compared with low SATB2 tumours (median 13 vs 8 months respectively,  < .001). Chemotherapy was given to 282 patients (63%). Patients with high SATB2 tumours had longer OS (median 22 vs 15 months respectively,  = .001) and more often responded to chemotherapy than those with low SATB2 (objective response 43% vs 29%,  = .02; clinical response 83% vs 67%,  = .004). Progression-free survival on first-line irinotecan chemotherapy was longer in high SATB2 cases (median 8 vs 4 months respectively,  = .019). Patients with both low SATB2 expression and mutated ( = 69) had particularly poor survival compared to the rest (median 8 and 12 months respectively,  = .001). In multivariable analysis, the SATB2 findings were independent of known clinicopathological prognostic markers, including mutation status. Patients with mCRC expressing high level of SATB2 have better prognosis and response to chemotherapy than those with low SATB2 expression. Patients with both low SATB2 expression and mutated had particularly poor prognosis and could thus benefit from more aggressive therapies.
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http://dx.doi.org/10.1080/0284186X.2019.1691258DOI Listing
March 2020

High BRAF Mutation Frequency and Marked Survival Differences in Subgroups According to KRAS/BRAF Mutation Status and Tumor Tissue Availability in a Prospective Population-Based Metastatic Colorectal Cancer Cohort.

PLoS One 2015 29;10(6):e0131046. Epub 2015 Jun 29.

Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.

RAS and BRAF mutations impact treatment and prognosis of metastatic colorectal cancer patients (mCRC), but the knowledge is based on trial patients usually not representative for the general cancer population. Patient characteristics, treatment and efficacy according to KRAS, BRAF and MSI status were analyzed in a prospectively collected unselected population-based cohort of 798 non-resectable mCRC patients. The cohort contained many patients with poor performance status (39% PS 2-4) and elderly (37% age>75), groups usually not included in clinical trials. Patients without available tissue micro array (TMA) (42%) had worse prognostic factors and inferior survival (all patients; 7m vs 11m, chemotherapy-treated;12m vs 17m). The 92 patients (21%) with BRAF mutation had a poor prognosis regardless of microsatellite instability, but receipt of 1-2nd chemotherapy was similar to wildtype BRAF patients. Median survival in this cohort varied from 1 month in BRAF mutated patients not given chemotherapy to 26 months in wildtype KRAS/BRAF patients <75 years in good PS. TMA availability, BRAF mutation and KRAS mutation were all independent prognostic factors for survival. The observed 21% BRAF mutation incidence is higher than the previously and repeatedly reported incidence of 5-12% in mCRC. Screening for BRAF mutations before selection of treatment is relevant for many patients, especially outside clinical trials. A BRAF mutation only partly explained the very poor prognosis of many mCRC patients. Survival in unselected metastatic colorectal cancer patients is extremely variable and subgroups have an extremely short survival compared to trial patients. Patients without available TMA had worse prognostic factors and shorter survival, which questions the total generalizability of present TMA studies and implies that we lack information on the biologically worst mCRC cases. Lack of available tissue is an important underexposed issue which introduces sample bias, and this should be recognized more clearly when conclusions are made from translational mCRC studies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0131046PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4484806PMC
April 2016

The MDM2 polymorphism SNP309 is associated with clinical characteristics and outcome in diffuse large B-cell lymphoma.

Eur J Haematol 2014 Dec 21;93(6):500-8. Epub 2014 Jun 21.

Department of Radiology, Oncology and Radiation Sciences, Section of Oncology, Uppsala University, Uppsala, Sweden.

Introduction: The murine double minute 2 (MDM2) gene encodes a regulatory protein of the p53 pathway. A single nucleotide polymorphism (T to G change) at position 309 (SNP309) in the promotor region of MDM2 affects the transcription activity of MDM2 and has been found to be a negative prognostic marker in several cancers.

Patients And Methods: In this study, the MDM2 SNP309 polymorphism was analysed in 201 patients with diffuse large B-cell lymphoma and analysed in relation to clinical characteristics and prognosis.

Results: Patients homozygous for SNP309T had a significantly longer overall survival, lymphoma-specific survival and disease-free survival (P = 0.002; 0.004 and 0.006 respectively) compared to patients carrying a G allele. The longer overall survival was seen in the subgroup of patients not treated with Rituximab, however, not for Rituximab-treated patients (P = 0.01 and 0.2 respectively). The group homozygous for the T allele also had lower age at diagnosis, a tendency towards lower aaIPI and a significantly lower proportion of patients with p53 aberrations compared to the group including at least one G allele. However, the survival differences persisted even after removal of cases with known p53 aberrations from the analysis.

Conclusion: Polymorphism in MDM2 SNP309 could be correlated to some clinical characteristics and for patients not treated with immunotherapy, a G allele was correlated to poor survival, whereas no survival differences were found for patients treated with Rituximab. Herewith, we provide additional information about Diffuse large B-cell Lymphoma (DLBCL) biology and highlight the importance of evaluation of molecular markers in relation to treatment.
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http://dx.doi.org/10.1111/ejh.12388DOI Listing
December 2014

Low expression of microRNA-129-5p predicts poor clinical outcome in diffuse large B cell lymphoma (DLBCL).

Int J Hematol 2013 Apr 5;97(4):465-71. Epub 2013 Mar 5.

Department of Radiology, Oncology, and Radiation Sciences, Uppsala University, Uppsala, Sweden.

Diffuse large B cell lymphoma (DLBCL) is a heterogeneous group of B cell lymphomas. MicroRNA expression provides a new and interesting tool for understanding the biology and clinical course of DLBCL. The present study presents microRNA-129-5p expression data from DLBCL patients treated with CHOP or R-CHOP. Patients with low microRNA-129-5p expression had a median survival of 23 months and a significantly shorter overall survival (P = 0.0042) compared to patients with high microRNA-129-5p expression, who had a median survival of 58 months. We also found that patients treated with R-CHOP only and displaying low microRNA-129-5p expression had a significantly shorter overall survival compared to patients with high microRNA-129-5p expression; all such patients were still alive at the time of last follow-up (P = 0.043). No significant difference was found among microRNA-129-5p expression in tumor tissue, the tissue surrounding the tumor, and normal controls. To our knowledge, this is the first report to show that the expression of microRNA-129-5p can affect the clinical outcome of DLBCL patients and that microRNA-129-5p may be involved in the biology of DLBCL development, although larger studies are necessary to confirm this. Further investigations may also help to elucidate the biological role of microRNA-129-5p in DLBCL.
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http://dx.doi.org/10.1007/s12185-013-1303-2DOI Listing
April 2013

High expression of microRNA-200c predicts poor clinical outcome in diffuse large B-cell lymphoma.

Oncol Rep 2013 Feb 10;29(2):720-4. Epub 2012 Dec 10.

Department of Radiology, Oncology and Radiation Sciences, Uppsala University, Uppsala, Sweden.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of B-cell lymphomas. A new and important tool for understanding the biology and clinical course of DLBCL is microRNA expression. This study presents microRNA-200c expression data from 61 DLBCL patients treated with CHOP or R-CHOP. Patients with high microRNA-200c expression had a median survival of 20.3 months and a significantly shorter overall survival (P=0.019) compared to patients with low microRNA-200c expression, who had a median survival of 35.8 months. We also found that patients treated with R-CHOP only and displaying high microRNA-200c expression had a significantly shorter overall survival compared to patients with low microRNA-200c expression, where all patients were still alive at the time of the last follow-up (P=0.0036). Lastly, we found that patients with high microRNA-200c expression had a significantly shorter time from initial diagnosis to the first relapse compared to patients with low microRNA-200c expression (P=0.0001). To our knowledge, this is the first study showing that the expression of microRNA-200c affects the clinical outcome of DLBCL patients, and that microRNA-200c is involved in the biology of DLBCL development, although larger studies are necessary to confirm this. Further investigations may also help to elucidate the biological role of microRNA-200c in DLBCL.
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http://dx.doi.org/10.3892/or.2012.2173DOI Listing
February 2013

The combined effects of single-nucleotide polymorphisms, tobacco products, and ethanol on normal resting blood mononuclear cells.

Nicotine Tob Res 2013 May 4;15(5):890-5. Epub 2012 Oct 4.

Department of Radiology, Oncology and Radiation Sciences, Section of Oncology, University Hospital , Uppsala, Sweden.

Introduction: Tobacco and ethanol consumption are crucial factors in the development of various diseases including cancer. In this investigation, we evaluated the combined effects of a number of single nucleotide polymorphisms (SNPs), with ethanol and tobacco products on healthy individuals.

Methods: Pure nicotine, cigarette smoke extract, and Swedish snuff (snus) extract were used. The effects were examined by means of in vitro cell cycle progression and cell death of peripheral blood mononuclear cells (PBMCs) obtained from healthy donors.

Results: After 3 days, in vitro, resting PBMCs entered the S and G2 stage in the presence of 100 µM nicotine. The PBMCs only proceeded to S stage, in the presence of 0.2% ethanol. The nicotine- and ethanol-induced normal cell cycle progression correlated to a number of SNPs in the IL12RB2, Rad 52, XRCC2, P53, CCND3, and ABCA1 genes. Certain SNPs in Caspases 8, IL12RB2, Rad 52, MMP2, and MDM2 genes appeared to significantly influence the effects of EtOH-, snus-, and snus + EtOH-induced cell death. Importantly, the highest degree of cell death was observed in the presence of smoke + EtOH. The amount of cell death under this treatment condition also correlated to specific SNPs, located in the MDM2, ABCA1, or GASC1 genes.

Conclusions: Cigarette smoke in combination with ethanol strongly induced massive cell death. Long-term exposure to smoke and ethanol could provoke chronic inflammation, and this could be the initiation of disease including the development of cancer at various sites.
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http://dx.doi.org/10.1093/ntr/nts207DOI Listing
May 2013

miR-34a expression, cell cycle arrest and cell death of malignant mesothelioma cells upon treatment with radiation, docetaxel or combination treatment.

Oncology 2011 10;81(5-6):330-5. Epub 2012 Jan 10.

Department of Oncology, Rudbeck Laboratory, Uppsala University Hospital, Uppsala, Sweden.

Objective: Malignant mesothelioma (MM) is a highly aggressive tumour related to asbestos exposure. Histopathologically, the tumour is classified as epithelial, sarcomatoid or biphasic. To date, MM is still an incurable disease.

Methods: To evaluate treatment strategies on MM cells, the effects of radiotherapy, docetaxel or a combination of both on MM cells derived from the sarcomatoid type ZL34 and the epithelial type M28K were investigated. The TP53 gene, micro-RNA expression, cell cycle distribution and cell death were assessed as indicators of treatment effects.

Results: Despite the normal TP53 gene sequences in these cell lines, radiation-induced miR-34a expression was detected only in the M28K cells. Increasing G0/G1 cell numbers were detected in irradiated M28K and ZL34 cells. There was more radiation-induced cell death in M28K compared to ZL34 cells. The highest degree of cell cycle arrest at G2 and cell death in both cell types was obtained in the presence of docetaxel. The combination of docetaxel and radiation did not show any additive effects on miR-34a expression, cell cycle arrest or cell death in either the M28K or ZL34 cells.

Conclusion: Microtubule formation and other related functions by docetaxel might be the most suitable treatment modulation in both sarcomatoid and epithelial types of MM.
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http://dx.doi.org/10.1159/000334237DOI Listing
June 2012

Mast cell infiltration is a favourable prognostic factor in diffuse large B-cell lymphoma.

Br J Haematol 2007 Jul;138(1):68-71

Department of Oncology, Radiology and Clincial Immunology, Uppsala University, Uppsala, Sweden.

Previous studies indicate that the inflammatory response in diffuse large B-cell lymphomas (DLBCL) is important for the clinical outcome. Mast cells are key regulators in this response; we investigated whether the number of tryptase-positive mast cells is correlated with clinical outcome. Patients with many mast cells had a significantly better event-free survival (EFS) compared to those with few mast cells (P < 0.03 in both germinal centre (GC) and non-GC DLBCL. This supports the idea that the infiltration of mast cells is a reflection of the host inflammatory response and is related to a favourable outcome.
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http://dx.doi.org/10.1111/j.1365-2141.2007.06612.xDOI Listing
July 2007

Telomere length and correlation with histopathogenesis in B-cell leukemias/lymphomas.

Eur J Haematol 2007 Apr 5;78(4):283-9. Epub 2007 Feb 5.

Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden.

Telomere length was recently reported to correlate with cellular origin of B-cell malignancies in relation to the germinal center (GC). In this report, we measured telomere length by quantitative-PCR in 223 B-cell lymphomas/leukemias and correlated results with immunoglobulin (Ig) mutation status and immunostainings for GC/non-GC subtypes of diffuse large B-cell lymphoma (DLBCL). Shortest telomeres were found in Ig-unmutated chronic lymphocytic leukemia (CLL) [median telomere to single copy gene value (T/S) 0.33], differing significantly to Ig-mutated CLL (0.63). Contrary to this, mantle cell lymphomas (MCLs) exhibited similar telomere lengths regardless of Ig mutation status (0.47). Telomere length differed significantly between GC-like (0.73) and non-GC-like DLBCLs (0.43), and follicular lymphomas (FLs) had shorter telomeres (0.53) than GC-DLBCL. Hairy cell leukemias, which display Ig gene intraclonal heterogeneity, had longer telomeres (0.62) than FLs and non-GC-DLBCL, but shorter than GC-DLBCL. We conclude that although DLBCL and CLL subsets can be clearly distinguished, telomere length reflects many parameters and may not simply correlate with GC-related origin.
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http://dx.doi.org/10.1111/j.1600-0609.2007.00817.xDOI Listing
April 2007

Genomic imbalances during transformation from follicular lymphoma to diffuse large B-cell lymphoma.

Mod Pathol 2007 Jan 29;20(1):63-75. Epub 2006 Sep 29.

Department of Molecular Medicine and Surgery, Karolinska University Hospital - Solna, Stockholm, Sweden.

Follicular lymphoma is commonly transformed to a more aggressive diffuse large B-cell lymphoma (DLBCL). In order to provide molecular characterization of this histological and clinical transformation, comparative genomic hybridization was applied to 23 follicular lymphoma and 35 transformed DLBCL tumors from a total of 30 patients. The results were also compared with our published findings in de novo DLBCL. Copy number changes were detected in 70% of follicular lymphoma and in 97% of transformed DLBCL. In follicular lymphoma, the most common alterations were +18q21 (33%), +Xq25-26 (28%), +1q31-32 (23%), and -17p (23%), whereas transformed DLBCL most frequently exhibited +Xq25-26 (36%), +12q15 (29%), +7pter-q22 (25%), +8q21 (21%), and -6q16-21(25%). Transformed DLBCL showed significantly more alterations as compared to follicular lymphoma (P=0.0001), and the alterations -6q16-21 and +7pter-q22 were only found in transformed DLBCL but not in follicular lymphoma (P=0.02). Alterations involving +13q22 were significantly less frequent, whereas -4q13-21 was more common in transformed as compared to de novo DLBCL (P=0.01 and P=0.02, respectively). Clinical progression from follicular lymphoma to transformed DLBCL is on the genetic level associated with acquisition of increasing number of genomic copy number changes, with non-random involvement of specific target regions. The findings support diverse genetic background between transformed and de novo DLBCL.
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http://dx.doi.org/10.1038/modpathol.3800708DOI Listing
January 2007

Strikingly homologous immunoglobulin gene rearrangements and poor outcome in VH3-21-using chronic lymphocytic leukemia patients independent of geographic origin and mutational status.

Blood 2006 Apr 29;107(7):2889-94. Epub 2005 Nov 29.

Department of Genetic and Pathology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala, Sweden.

We recently reported that Swedish VH3-21-using chronic lymphocytic leukemia (CLL) patients showed restricted immunoglobulin gene features and poor prognosis despite VH mutation status. To investigate this further, we analyzed the VH and VL gene rearrangements in 90 VH3-21+ patients from Sweden, Germany, Italy, United States, Finland, and Australia and correlated these data with survival and other prognostic markers. Sixty-three percent exhibited mutated VH genes and 37% unmutated VH genes. Fifty (56%) patients displayed a short and homologous heavy-chain CDR3, many of these with the amino acid motif DANGMDV. Also, a highly biased Vlambda2-14 use was evident in 72% of patients with a restricted light-chain CDR3, QVWDS(S/G)SDHPWV. Combined restricted heavy- and light-chain CDR3s were found in patients from all included countries. Although VH3-21+ CLLs have a remarkably predominant lambda expression, analyses of kappa deleting element indicated a conserved light-chain rearrangement order. The overall survival was poor in the VH3-21+ cohort (median survival, 88 months), with no significant difference in relation to mutation status or CDR3 homology. High ZAP-70 and CD38 expression was found in both mutated and unmutated VH3-21+ cases as well as a slight increase of 11q-aberrations. In summary, highly restricted B-cell receptors and worse outcome characterize VH3-21+ CLLs independent of geographic origin and mutation status.
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http://dx.doi.org/10.1182/blood-2005-06-2227DOI Listing
April 2006

Mitogen induced activation, proliferation and surface antigen expression patterns in unmutated and hypermutated chronic lymphocytic leukemia cells.

Eur J Haematol 2005 Jul;75(1):34-40

Department of Clinical Chemistry, University of Tampere Medical School and Laboratory Center of Tampere University Hospital, Tampere, Finland.

Objectives: To determine whether the immunoglobulin V(H) gene mutational status has an effect on the activation, proliferation and surface antigen expression of chronic lymphocytic leukemia (CLL) cells when stimulated in vitro.

Methods: The proliferation and activation responses of CLL cells were studied in 22-immunoglobulin gene V(H) unmutated (UM-CLL) and 12 hypermutated (M-CLL) CLL cases in 4-day cultures. As the mitogen responses have been previously shown to be diverse in CLL, a case-specific strategy based on optimized mitogen combinations (OMCs) of interleukin-2 (IL-2), 12-O-tetradecanoylphorbol 13-acetate (TPA), Staphylococcus aureus Cowan 1 (SAC), and human recombinant tumor necrosis factor alpha (TNF) was applied in cell stimulation. The expression of 23 surface membrane antigens (CD5, CD11c, CD19, CD20, CD21, CD22, CD23, CD25, CD27, CD38, CD40, CD45, CD45RA, CD45RO, CD79b, CD80, CD95, CD124, CD126, CD130, FMC7, IgD, and IgM) was studied by flow cytometry at days 0 and 4.

Results: The proliferation and activation responses were similar in UM-CLL and M-CLL when OMCs contained IL-2, TPA or TNF. SAC induced faster proliferation in UM-CLL than in M-CLL. OMC stimulation induced preferential down-regulation of growth- promoting cell surface receptors CD5, CD21, and CD124 and preferential up-regulation of growth-inhibiting antigen CD80 in M-CLL.

Conclusions: Difference in immunophenotypic evolution of UM-CLL and M-CLL can be demonstrated if appropriate matrix signals are provided. The pathways for CD5, CD21, CD124 (IL4R), and CD80 (B7-1) regulation should be further explored in relation with somatic hypermutation and outcome of CLL.
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http://dx.doi.org/10.1111/j.1600-0609.2005.00443.xDOI Listing
July 2005

Evaluation of immunophenotype in diffuse large B-cell lymphoma and its impact on prognosis.

Mod Pathol 2005 Aug;18(8):1113-20

Department of Oncology, Radiology, and Clinical Immunology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden.

Diffuse large B-cell lymphoma (DLBCL) has been shown to be comprised of at least two prognostic entities, depending on its resemblance to normal germinal center or activated B cells, using global gene expression profiling. Also, the expression patterns of bcl-6, CD10 and IRF-4 (also known as MUM1) have been suggested as alternative means of identifying the germinal- and nongerminal center (activated B-cell like) groups. In the present study, we evaluated by immunohistochemistry the expression patterns of CD10, bcl-6, IRF-4 and bcl-2 in a large material of 161 DLBCL patients. Using two different approaches, patients with germinal center phenotype displayed a significantly better survival than the nongerminal center group. Positive staining for bcl-6 or CD10 predicted for superior survival, while expression of IRF-4 alone showed no association with prognosis. Furthermore, expression of bcl-2 was associated with worse event-free survival and overall survival. In a multivariate analysis, a high international prognostic index score (3-5), non-GC phenotype and bcl-2 were independent adverse prognostic factors. Here we confirm the prognostic importance of determining the germinal- or nongerminal center phenotype in patients with DLBCL.
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http://dx.doi.org/10.1038/modpathol.3800396DOI Listing
August 2005

Patients with chronic lymphocytic leukemia with mutated VH genes presenting with Binet stage B or C form a subgroup with a poor outcome.

Haematologica 2005 Apr;90(4):465-9

Dept. of Genetics and Pathology, Uppsala University, Uppsala, Sweden.

Background And Objectives: The immunoglobulin VH gene mutation status is a strong prognostic indicator in B-cell chronic lymphocytic leukemia (CLL), since unmutated VH genes are correlated with short survival. However, the traditional cut-off level dividing mutated and unmutated cases, i.e. more or less than 2% mutations, has been questioned and other cut-offs have been suggested. We investigated whether an alternative cut-off should be applied and the relation of mutational status to another prognostic marker, Binet staging.

Design And Methods: VH gene mutation status was assessed in 332 CLL cases by polymerase chain reaction amplification and nucleotide sequencing and was further correlated with overall survival using different VH mutation cut-offs (1-7%) and Binet stage.

Results: After testing different mutation borders, the 2% cut-off remained the best discriminative level for determining prognosis. Interestingly, prognostic stratification was improved by combining the information on VH gene mutation status with that of Binet stage: unmutated cases (all stages, n=151, mutated cases with stage A (n=77), and mutated cases with stage B or C (n=37) had a median survival of 82, 179 and 74 months, respectively.

Interpretation And Conclusions: CLL cases displaying mutated VH genes with Binet stage B or C had a survival similar to that of unmutated cases and significantly shorter than that of mutated stage A CLL. Our result reveals clinical heterogeneity within the VH mutated CLL group by inclusion of Binet stage data, a finding which is of importance when considering surrogate marker(s) for VH mutation status.
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April 2005

Distinctive gene expression pattern in VH3-21 utilizing B-cell chronic lymphocytic leukemia.

Blood 2005 Jul 7;106(2):681-9. Epub 2005 Apr 7.

Unit of Environmental Medicine, Center for Nutrition and Toxicology, Department of Biosciences at Novum, Karolinska Institutet, SE-14157 Huddinge, Sweden.

The usage of the immunoglobulin (Ig) V(H)3-21 gene is associated with poor prognosis in B-cell chronic lymphocytic leukemia (B-CLL) despite V(H) gene mutation status. Many V(H)3-21+ patients also display restricted heavy- and light-chain Ig gene rearrangements, implying a role of antigen selection in disease development. To explore the specific phenotypic/genotypic features among V(H)3-21+ B-CLLs, we compared gene expression patterns in 15 V(H)3-21+ and 24 non-V(H)3-21 patients (11 with unmutated and 13 with mutated V(H) genes) using Affymetrix microarray analysis (approximately 12,500 genes). A distinct expression profile was identified for V(H)3-21+ patients in contrast to the Ig-unmutated and -mutated groups. By applying different algorithms, the data enabled an efficient class discrimination of the V(H)3-21+ subset based on 27 or 57 genes. A set of genes was sorted out which, using different analytical methods, consistently gave a distinction between V(H)3-21+ and non-V(H)3-21 samples. Several of these genes are involved in regulation of DNA replication/cell-cycle control, transcription and protein kinase activity, which may render the V(H)3-21+ cells with a higher proliferative drive. However, no clear evidence of increased B-cell receptor signaling was found in the V(H)3-21+ group. Altogether, our identification of a specific V(H)3-21 profile may provide insights into the pathogenesis of the V(H)3-21+ subgroup.
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http://dx.doi.org/10.1182/blood-2004-10-4073DOI Listing
July 2005

Telomere length as a prognostic parameter in chronic lymphocytic leukemia with special reference to VH gene mutation status.

Blood 2005 Jun 3;105(12):4807-12. Epub 2005 Mar 3.

Department of Medical Biosciences, Pathology, Umeå University, SE-90187 Umeå, Sweden.

B-cell chronic lymphocytic leukemia (CLL) consists of 2 prognostic entities where cases with mutated immunoglobulin V(H) genes have better outcome than unmutated cases. V(H)-mutated CLLs display longer telomeres compared with unmutated cases and telomere length has been indicated to predict outcome, although the prognostic value of telomere length has not been fully established in CLL. We analyzed telomere length, V(H) gene mutation status, and clinical parameters in a large series of CLL. Telomere length was assessed by quantitative polymerase chain reaction (PCR), giving a very good correlation to telomere length estimated by Southern blotting (P < .001). The prognostic information given by mutation status (n = 282) and telomere length (n = 246) was significant (P < .001, respectively). Telomere length was a prognostic factor for stage A (P = .021) and stage B/C (P = .018) patients, whereas mutation status predicted outcome only in stage A patients (P < .001). Furthermore, mutated CLLs were subdivided by telomere length into 2 groups with different prognoses (P = .003), a subdivision not seen for unmutated cases (P = .232). Interestingly, the V(H)-mutated group with short telomeres had an overall survival close to that of the unmutated cases. Thus, by combining V(H) mutation status and telomere length, an improved subclassification of CLL was achieved identifying previously unrecognized patient groups with different outcomes.
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http://dx.doi.org/10.1182/blood-2004-11-4394DOI Listing
June 2005

Similar humoral immunity parameters in chronic lymphocytic leukemia patients independent of VH gene mutation status.

Leuk Lymphoma 2004 Dec;45(12):2451-4

Department of Internal Medicine, Tampere University Hospital, Finland.

Chronic lymphocytic leukemia (CLL) is a clonal B-cell disorder, which has recently been divided into 2 subtypes based on the somatic hypermutation status of the immunoglobulin heavy chain (IgVH) genes. In patients with unmutated tumor cells the survival time is approximately half of that in mutated cases, but the reason for this difference is poorly understood. Since infections are the major cause of mortality in CLL, we investigated the effect of the mutation status on host immunity and proneness to infections in patients with CLL. As expected, the disease progression seemed to be faster and the disease more advanced (Binet B and C) among unmutated patients than in the mutated ones. Surprisingly, no differences in humoral immunity [immunoglobulin G (IgG), IgM, IgA, IgG subclasses, anti-ABO blood group antibodies and mannan-binding lectin (MBL)] or immune responses (Haemophilus influenzae serotype b conjugate vaccination) were detected between these 2 patient groups. Furthermore, UM-patients were not more prone to infections compared to M-patients, and therapy had no impact on the incidence and pattern of infections in either of the patient groups. The current findings within this patient cohort reveal that the worse outcome in the unmutated subgroup is not caused by more severe defects in immunity and increased susceptibility to infections when compared with the hypermutated group. It is thus conceivable that active immunization procedures such as vaccination can successfully be applied on patients with unmutated IgVH gene and advanced disease stage.
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http://dx.doi.org/10.1080/10428190400007763DOI Listing
December 2004

Heterogeneous somatic hypermutation status confounds the cell of origin in hairy cell leukemia.

Leuk Res 2005 Feb;29(2):153-8

Department of Genetics and Pathology, Rudbeck Laboratary, Uppsala University, SE-751 85 Uppsala, Sweden.

Hairy cell leukemia (HCL) is thought to arise from a post-germinal center (GC) B-cell, however the exact normal counterpart remains unclear. We performed VH gene analysis of 32 HCL cases, revealing somatically mutated VH genes (<98% homology) in 27 cases and unmutated VH genes in five cases, four of which displayed germline VH genes. Intraclonal heterogeneity was evident in the majority of eight mutated HCLs investigated, although at a lower level compared to GC-derived lymphomas. A novel finding of preferential VH3-30 gene usage was detected (19% of HCLs). Our data confounds the postulated post-GC origin in HCL considering (1) the finding of unmutated HCLs, generally correlating with a pre-GC origin, and (2) the presence of intraclonal variation in mutated HCLs. The latter suggests that the transformed B-cell was frozen when it still had an active mutation process, implying a closer relation to the GC than previously assumed. Furthermore, restricted VH3-30 usage indicates that antigen selection could be a promoting factor in HCL development.
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http://dx.doi.org/10.1016/j.leukres.2004.05.016DOI Listing
February 2005

VH gene mutation status and cellular drug resistance in chronic lymphocytic leukaemia.

Eur J Haematol 2004 Dec;73(6):407-11

Department of Internal Medicine, Uppsala University, Uppsala, Sweden.

Objective: B-cell chronic lymphocytic leukaemia (B-CLL) can be divided into two clinical entities based on the immunoglobulin variable heavy chain (VH) gene mutation status, as cases with unmutated VH genes display a more aggressive disease with shorter survival time than mutated cases. The aim of this study was to investigate whether differences in cellular drug resistance could give an explanation for these divergent clinical courses.

Methods: The VH gene mutation status was analysed in patients with previously untreated B-CLL using VH gene family-specific PCR amplification and nucleotide sequencing. In vitro sensitivity to cytarabine, fludarabine, cladribine, doxorubicin, idarubicin, vincristine, cyclophosphamide, melphalan and prednisolone was assessed using the non-clonogenic in vitro assay, fluorometric microculture cytotoxicity assay.

Results: The VH genes and in vitro drug resistance were successfully analysed in 46 cases, revealing that 25 (54%) cases showed unmutated and 21 (46%) cases mutated VH genes. Interestingly, the unmutated group generally tended to be more chemosensitive than the mutated group with significant differences for cytarabine and prednisolone (P < or = 0.01).

Conclusion: The propensity of inferior drug response in mutated B-CLL may reflect a more differentiated disease than in unmutated B-CLL. We conclude that the difference in prognosis between B-CLL cases with unmutated and mutated VH genes could not be explained by difference in cellular drug resistance.
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http://dx.doi.org/10.1111/j.1600-0609.2004.00334.xDOI Listing
December 2004

Different gene expression in immunoglobulin-mutated and immunoglobulin-unmutated forms of chronic lymphocytic leukemia.

Cancer Genet Cytogenet 2004 Aug;153(1):69-72

Department of Pathology and Medical Genetics, Haartman Institute, University of Helsinki, and Helsinki University Central Hospital Laboratory Diagnostics, Haartmaninkatu 3, FIN-00014 Helsinki, Finland.

The mutation status of the immunoglobulin heavy chain variable regions (IgVH) has been found to be a good prognostic indicator for B-cell chronic lymphocytic leukemia (CLL) because unmutated VH genes are associated with rapid disease progression and shorter survival time. To study the differences in gene expression between the Ig-unmutated and Ig-mutated CLL subtypes, we performed gene expression profiling on 31 CLL cases and investigated the VH gene mutation status by sequencing. The array data showed that the greatest variances between the unmutated (20 cases) and the mutated (11 cases) group were in expressions of ZAP70, RAF1, PAX5, TCF1, CD44, SF1, S100A12, NUP214, DAF, GLVR1, MKK6, AF4, CX3CR1, NAFTC1, and HEX. ZAP70 was significantly more expressed in the Ig-unmutated CLL group, whereas the expression of all the other genes was higher in the Ig-mutated cases. These results corroborate a recent finding, according to which the expression of ZAP70 can predict the VH mutation status and suggest that RAF1, PAX5, and other differentially expressed genes may offer good markers for differentiating unmutated cases from mutated cases and thus serve as prognostic markers.
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http://dx.doi.org/10.1016/j.cancergencyto.2003.12.016DOI Listing
August 2004

Subsets with restricted immunoglobulin gene rearrangement features indicate a role for antigen selection in the development of chronic lymphocytic leukemia.

Blood 2004 Nov 24;104(9):2879-85. Epub 2004 Jun 24.

Dept of Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden.

We recently identified a chronic lymphocytic leukemia (CLL) subgroup using the immunoglobulin variable heavy-chain (V(H)) gene V(H)3-21 with almost identical heavy-chain complementarity determining region 3s (HCDR3s) and preferential variable light-chain (V(L)) gene usage, suggesting recognition of a common antigen epitope in this subset. To further explore the B-cell receptors (BCRs) in CLL, we characterized 407 V(H) rearrangements amplified from 346 CLLs regarding V(H), diversity (D), and joining (J(H)) gene usage and performed multiple alignment of the HCDR3 sequences. These analyses revealed 3 small subsets (2 V(H)1-69 groups, 7 cases; and 1 V(H)1-2 group, 5 cases) with highly restricted HCDR3 features including identical V(H)/D/J(H) usage, HCDR3 lengths, and shared N-sequences, in addition to the V(H)3-21 group (22 cases). Furthermore, another 3 groups (9 V(H)1-3(+) cases, 3 V(H)1-18(+) cases, and 5 V(H)4-39(+) cases) had essentially identical V(H)/D/J(H) use and similar HCDR3 lengths but less conserved N-regions. Analysis in all 6 of these subgroups showed restriction in V(L) gene use, whereas no association between V(H) and V(L) usage was found in cases without HCDR3 similarities. Altogether, structurally similar HCDR3s associated with preferential V(L) gene usage implies selection of BCRs, especially in subsets showing high HCDR3 similarities, thus pointing to restricted antigen recognition sites and possibly involvement of specific antigens in CLL development.
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http://dx.doi.org/10.1182/blood-2004-01-0132DOI Listing
November 2004