| 1. |
- Amini, Rose-Marie, et al.
(författare)
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A novel B-cell line (U-2932) established from a patient with a diffuse large B-cell lymphoma following Hodgkin lymphoma
- 2002
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Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 43:11, s. 2179-2189
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about mechanisms leading to secondary non-Hodgkin lymphomas (NHL) in patients treated for Hodgkin lymphoma (HL). Our aim was to characterise in detail a cell line derived from a diffuse large B-cell lymphoma (DLBCL) that had developed in a patient with relapsing HL. The cell line U-2932 was established from ascites in a patient suffering from DLBCL previously treated for HL with multiple chemotherapy regimens. Characterisation was based on morphology, immunophenotype, Epstein-Barr virus (EBV)-status, IgH gene rearrangement status, tumourigenicity, p53 sequencing, and immunohistochemical expression of p53, BCL-2 and BCL-6. The karyotype was investigated using G-banding, comparative genomic hybridisation (CGH) and spectral karyotype (SKY) analysis. This cell line shows typical morphological features of a DLBCL and grows as colonies in nude mice. It expresses a B-cell phenotype with a somatically hypermutated V(H)4-39 gene and is negative for EBV. The origin of U-2932 was confirmed by demonstrating an identical V(H)4 rearrangement in ascites from the patient. A point mutation of the tumour-suppressor gene p53 was detected in amino acid position 176 and immunohistochemical over-expression of the p53 protein was also demonstrated. U-2932 carries a complex karyotype including high-level amplifications of the chromosomal bands 18q21 and 3q27 and expresses aberrant BCL-2 and BCL-6 immunohistochemically. We were unable to investigate the clonal relationship between the original HL and U-2932. In conclusion, U-2932 is a unique B cell line established from a patient suffering from HL followed by NHL. Overexpression of BCL-2, BCL-6 and p53 may play a role in the tumourigenesis and drug resistance. This cell line may become a useful tool to better understand the mechanisms responsible for development of secondary NHL in patients treated for HL.
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| 2. |
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| 3. |
- Berglund, Mattias, et al.
(författare)
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Genomic imbalances during transformation from follicular lymphoma to diffuse large B-cell lymphoma
- 2007
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Ingår i: Modern Pathology. - : Elsevier BV. - 0893-3952 .- 1530-0285. ; 20:1, s. 63-75
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Tidskriftsartikel (refereegranskat)abstract
- Follicular lymphoma is commonly transformed to a more aggressive diffuse large B-cell lymphoma (DLBCL). In order to molecularely characterize this histiological and clinical transformation, comparative genomic hybridization was applied on 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 acquirement 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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| 4. |
- Berglund, Mattias, 1972-
(författare)
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Molecular Characterization of Diffuse Large B-cell Lymphoma and Aspects of Transformation
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lymphomas are a heterogeneous group of neoplasias originating from B- or T-lymphocytes. In this thesis, we determined the genetic and immunophenotypic characterization of DLBCL and their prognostic impact. Moreover, genomic alterations associated with the transformation to DLBCL from Hodgkin lymphoma (HL) and follicular lymphoma (FL) were elucidated. In order to outline the impact of cytogenetic as well as immunophenotypic prognostic markers in DLBCL, we firstly studied a series of 54 DLBCL tumors using comparative genomic hybridization (CGH) and we identified several frequently occurring chromosomal imbalances. Loss of 22q was more often found in the diagnostic tumors with a more advanced clinical stage, while gain of 18q21 was more commonly identified in relapses. Secondly, we correlated the expression patterns of CD10, bcl-6, IRF-4 and bcl-2 with clinical parameters in a series of 173 de novo DLBCL patients. Patients with a germinal center (GC) phenotype displayed a better survival than the non-GC group. Expression of bcl-6 and CD10 was correlated with a better survival while bcl-2 expression was associated with a poor prognosis.In approaching the HL transformation, two novel B-cell lines (U-2932 and U-2940), derived from patients with DLBCL following HL, were characterized. Interestingly, a translocation with materials from 2q and 7q as well as loss of material on 6q was found in both cell lines. For FL transformation, we assessed chromosomal alterations in a panel of 28 DLBCL patients with a previous history of FL. The DLBCL tumors displayed more chromosomal imbalances compared to FL tumors. Loss of 6q16-21 and gain of 7pter-q22 were more commonly found in the DLBCL counterparts, suggesting the chromosomal location of putative genes that may be involved in the transformation process.
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| 5. |
- Flordal Thelander, Emma, et al.
(författare)
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Detailed assessment of copy number alterations revealing homozygous deletions in 1p and 13q in mantle cell lymphoma
- 2007
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Ingår i: Leukemia Research. - : Elsevier BV. - 0145-2126 .- 1873-5835. ; 31:9, s. 1219-1230
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Tidskriftsartikel (refereegranskat)abstract
- Mantle cell lymphoma (MCL) is characterized by over-expression of cyclin Dl as a result of the characteristic t(11;14)(q13;q32). However, this translocation alone has proven not to be sufficient for lymphomagenesis, suggesting the involvement of additional alterations. We have characterized 35 cases of MCL by array comparative genomic hybridization with an average resolution of 0.97Mb distributed over the complete human genome. The most common alterations were losses in 1p13.2–p31.1, 6q16.2–q27, 8p21.3, 9p13.2–p24.3, 9q13–q31.3, 11q14.3–q23.3, 13q14.13–q21.31, 13q33.1–q34, and 22q11.23–q13.33 and gains involving 3q21.2–q29, 7p12.1–p22.3, 8q24.13–q24.23, and 18q21.33–q22.3. Four homozygous deletions were identified in totally three patients; two overlapping at 1p32.3, and two adjacent at 13q32.3. The homozygous deletions at 1p32.3 cover the CDKN2C locus (coding for p18), while the region at 13q32.3 does not encompass any known tumor suppressor genes. A gain in 3q was significantly associated with shorter survival (P=0.047).
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| 6. |
- Kharaziha, Pedram, et al.
(författare)
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Functional characterization of novel germline TP53 variants in Swedish families
- 2019
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Ingår i: Clinical Genetics. - : Wiley. - 0009-9163 .- 1399-0004. ; 96:3, s. 216-225
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic germline TP53 variants predispose to a wide range of early onset cancers, often recognized as the Li-Fraumeni syndrome (LFS). They are also identified in 1% of families with hereditary breast cancer (HrBC) that do not fulfill the criteria for LFS. In this study, we present a total of 24 different TP53 variants identified in 31 Swedish families with LFS or HrBC. Ten of these variants, nine exonic and one splice, have previously not been described as germline pathogenic variants. The nine exonic variants were functionally characterized and demonstrated partial transactivation activity compared to wild-type p53. Some show nuclear localization similar to wild-type p53 while others possess cytoplasmic or perinuclear localization. The four frameshift variants (W91Gfs*32, L111 Wfs*12, S227 Lfs*20 and S240Kfs*25) had negligible, while F134 L and T231del had low level of p53 activity. The L111 Wfs*12 and T231del variants are also deficient for induction of apoptosis. The missense variant R110C retain p53 effects and the nonsense E349* shows at least partial transcription factor activity but has reduced ability to trigger apoptosis. This is the first functional characterization of novel germline TP53 pathogenic or likely pathogenic variants in the Swedish cohort as an attempt to understand its association with LFS and HrBC, respectively.
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| 7. |
- Kwiecinska, Anna, et al.
(författare)
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Amplification of 2p as a Genomic Marker for Transformation in Lymphoma
- 2014
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264. ; 53:9, s. 750-768
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Tidskriftsartikel (refereegranskat)abstract
- To outline further genetic mechanisms of transformation from follicular lymphoma (FL) to diffuse large B-cell lymphoma (DLBCL), we have performed whole genome array-CGH in 81 tumors from 60 patients [29 de novo DLBCL (dnDLBCL), 31 transformed DLBCL (tDLBCL), and 21 antecedent FL]. In 15 patients, paired tumor samples (primary FL and a subsequent tDLBCL) were available, among which three possessed more than two subsequent tumors, allowing us to follow specific genetic alterations acquired before, during, and after the transformation. Gain of 2p15-16.1 encompassing, among others, the REL, BCL11A, USP34, COMMD1, and OTX1 genes was found to be more common in the tDLBCL compared with dnDLBCL (P < 0.001). Furthermore, a high-level amplification of 2p15-16.1 was also detected in the FL stage prior to transformation, indicating its importance during the transformation event. Quantitative real-time PCR showed a higher level of amplification of REL, USP34, and COMMD1 (all involved in the NF kappa B-pathway) compared with BCL11A, which indicates that the altered genes disrupting the NF kappa B pathway may be the driver genes of transformation rather than the previously suggested BCL11A. Moreover, a 17q21.33 amplification was exclusively found in tDLBCL, never in FL (P < 0.04) or dnDLBCL, indicating an upregulation of genes of importance during the later phase of transformation. Taken together, our study demonstrates potential genomic markers for disease progression to clinically more aggressive forms. We also confirm the importance of the TP53-, CDKN2A-, and NF kappa B-pathways for the transformation from FL to DLBCL.
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| 8. |
- Kwiecińska, Anna, et al.
(författare)
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Proteomic Profiling of Diffuse Large B-Cell Lymphomas
- 2018
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Ingår i: Pathobiology. - : S. Karger AG. - 1015-2008 .- 1423-0291. ; 85:4, s. 211-219
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to identify differences in proteome profiles of diffuse large B-cell lymphoma (DLBCL) of nongerminal center (non-GC) versus GC type in the search for new markers and drug targets. Methods: Six DLBCL, with 3 repeats for each, were used for the initial study by proteomics: 3 non-GC and 3 GC DLBCL cases. For immunohistochemistry, tissue microarrays were made from 31 DLBCL samples: 16 non-GC de novo lymphomas and 15 GC cases (11 transformed from follicular lymphomas and 4 de novo GC lymphomas). Proteome profiling was performed by two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry. Results: Ninety-one proteins were found differentially expressed in non-GC compared to GC type. The Cytoscape tool was used for systemic analysis of proteomics data, revealing 19 subnetworks representing functions affected in non-GC versus GC types of DLBCL. Conclusion: A validation study of 3 selected proteins (BiP/Grp78, Hsp90, and cyclin B2) showed the enhanced expression in non-GC DLBCL, supporting the proteomics data.
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| 9. |
- Lagercrantz, Svetlana
(författare)
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Genetic characterization of non-Hodgkin lymphomas using in situ hybridization
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fluorescence in situ hybridization (FISH) has been shown to be a valuable and important technique in cytogenetics, as a complement to traditional banding analysis. This thesis focus on the characterization of chromosomal rearrangements in two hematological neoplasias, myelodysplastic syndrome (MDS) and non-Hodgkin lymphoma (NHL) using FISH. The increased cytogenetic resolution obtained by FISH, made it possible to identify a true-whole arm translocation consisting of 17q and 18q, in a case of MDS. The derivative chromosome had a centromere with sequences from both chromosomes 17 and 18. Thus, a breakpoint on either of the p-arms could be excluded, and it could be concluded that the rearrangment resulted in monosomy of 17p and 18p without affecting expressed genes located in the centromeric region. Chromosome painting, FISH with chromosome specific libraries, on short term cultures of NHL showed that chromosomal rearrangements were often more complex than the banding analysis predicted. Painting analysis could contribute with new information, not only of translocations, but also of true deletions and amplification. This could significantly clarify the true karyotype of the malignant cell. A recurring rearrangement in NHL is additional material on the tip of the short arm of chromosome 1. Using chromosome specific libraries it was possible to show that, in three out of nine such cases, the extra chromosomal material originated from the long arm of chromosome 2, resulting in a der(1)t(1;2). The three cases were all follicular NHL, although none of them had the t(14;18) found in 85-90% of follicular lymphomas. In addition, one of the cases, had the der(1)t(1;2) as the only rearrangement in one of two malignant clones. All three cases had the der(1)t(1;2) in addition to two normal chromosome 2 homologs, leading to a duplication of 2q31-qter. These findings exemplifies that new cytogenetic subgroups can be identified when banding analysis is complemented with chromosome painting. Furthermore, we found a case of NHL with a der(22)t(2;22) as a sole aberration. This results in a cytogenetically identical duplication of 2q31-qter, as in the cases with der(1)t(1;2). These findings suggest that cancer relevant genes may be located at the distal 2q.LAZ3/BCL6 gene has been implicated in tumorigenesis of NHL. Therefore the expression pattern of the LAZ3/BCL6 gene was studied, using RNA in situ hybridization. It was shown that LAZ3/BCL6 is expressed in follicular center(FC) B-cells of both non-malignant reactive lymph nodes and FC-derived non-Hodgkin lymphomas. Furthermore, LAZ3/BCL6 is expressed in a number of different tissues such as skeletal muscle, spinal cord, trachea, and peripheral blood leukocytes. The data clearly show that the expression of the LAZ3/BCL6is not confined to the malignant cells, and thus its role in the malignant transformation must be reconsidered.
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| 10. |
- Li, Jingmei, et al.
(författare)
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Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort
- 2019
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 144:5, s. 1195-1204
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Tidskriftsartikel (refereegranskat)abstract
- Breast cancer patients with BRCA1/2-driven tumors may benefit from targeted therapy. It is not clear whether current BRCA screening guidelines are effective at identifying these patients. The purpose of our study was to evaluate the prevalence of inherited BRCA1/2 pathogenic variants in a large, clinically representative breast cancer cohort and to estimate the proportion of BRCA1/2 carriers not detected by selectively screening individuals with the highest probability of being carriers according to current clinical guidelines. The study included 5,122 unselected Swedish breast cancer patients diagnosed from 2001 to 2008. Target sequence enrichment (48.48 Fluidigm Access Arrays) and sequencing were performed (Illumina Hi-Seq 2,500 instrument, v4 chemistry). Differences in patient and tumor characteristics of BRCA1/2 carriers who were already identified as part of clinical BRCA1/2 testing routines and additional BRCA1/2 carriers found by sequencing the entire study population were compared using logistic regression models. Ninety-two of 5,099 patients with valid variant calls were identified as BRCA1/2 carriers by screening all study participants (1.8%). Only 416 study participants (8.2%) were screened as part of clinical practice, but this identified 35 out of 92 carriers (38.0%). Clinically identified carriers were younger, less likely postmenopausal and more likely to be associated with familiar ovarian cancer compared to the additional carriers identified by screening all patients. More BRCA2 (34/42, 81.0%) than BRCA1 carriers (23/50, 46%) were missed by clinical screening. In conclusion, BRCA1/2 mutation prevalence in unselected breast cancer patients was 1.8%. Six in ten BRCA carriers were not detected by selective clinical screening of individuals.
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