Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chimerism”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMed2005

[Construction and bio-activity of the chimeric protein of BMP2-EGFP].

OBJECTIVE: To construct the recombined retroviral expression vector of BMP2/pLEGFP and investigate the bio-activity of the expressed chimeric protein. METHODS: The recombinant vector constructed by gene recombinant technology was analyzed by restriction enzyme digestion and PCR. BMP2/pLEGFP was transfected into COS-7 cells with liposome transfection reagents for transient expression. The expression of chimeric protein BMP2/EGFP was identified by fluorescent microscope and Western blotting. The bio-activity was examined by the cellular activity and animal heterotopic osteogenesis experiment. RESULTS: The recombinant plasmid proved successful by restriction enzyme digestion and PCR. The expression of the chimeric protein was shown by fluorescent microscope and Western blotting. The chimeric protein had the double bio-activities of BMP2 and EGFP identified by the cellular activity and animal heterotopic osteogenesis tests. CONCLUSION: The recombinant vector of BMP2/pLEGFP is successfully constructed by the gene recombinant technology and its chimeric protein has double bioactivities of BMP2 and EGFP.

Animals↗
PubMed2003

[Expression, purification and serological reactivity of a chimeric antigen of GRA6 with P30 from Toxoplasma gondii].

Major surface protein (p30) and Dense Granule Antigen GRA6 of Toxoplasma gondii have good antigenicity, and could be used for detection of IgM against Toxoplasma gondii. GRA6 may complement P30 to reach more high sensitivity for detection of antibodies to Toxoplasma gondii, so, we try to express the chimeric protein of GRA6 and P30 by genetic engineering, identify its antignenicity and use for developing diagnosis reagent. Antigenic domains of p30 and GRA6 of Toxoplasma gondii were screened by analyzing their sequences using the software ANTHEWIN. Two DNA fragments encoding respectively antigenic domains of p30 and GRA6 were cloned, they were inserted into the same expression vector pET28a( + ) and expressed as a chimeric protein in Escherichia coli. BL21(DE3), the expressed chimeric protein of p30 with GRA6 in a form of inclusion body was about 25% of total proteins of E. coli. BL21(DE3). The inclusion body was washed once with 0.5% Triton X-100 and dissolved with 0.5% SKL, after renaturation by gradient dialysis, the recombinant protein was purified by DEAE-Sepharose FF cation column and then detected with 12% SDS-PAGE, it exists mainly in the eluted peak with 300 mmol/L NaCl and has high purity. By using enzyme-linked immunosorbent assay (ELISA), the recombinant protein was examined for reactivity with immunoglobulin M (IgM) antibodies in 6 sera from patients infected with Toxoplasma gondii ., it was reactive with all the 6 sera but not with sera from normal people, these results showed that the recombinant chimeric antigen has good antigenicity and specificity and could be used for detection of IgM against Toxoplasma gondii. The expressed chimeric protein could be used for epidemic investigation of Toxoplasma gondii, blood donor screening, especially for detection of pregnant women, and is of great significance in prevention of Toxoplasma gondii infection.

Animals↗
PubMed2006

[Construction and expression of human-mouse chimeric antibody against human CD40].

AIM: To construct and express a chimeric antibody against human CD40 molecule by genetic engineering antibody transformation. METHODS: Total RNA was extracted from the murine hybridoma cell 5C11 which secreted anti-CD40 monoclonal antibody (mAb). The genes encoding V(H) and V(L) of mAb 5C11 were amplified by RT-PCR. According to sequence analysis, the primer was designed to amplify signal peptide sequences relative to V(H) and V(L) genes. The V(H) and V(L) genes of mAb 5C11 and relative signal peptide sequences were spliced with C(H) and C(kappa) genes of human IgG1 to construct expression plasmid pIRES/h5C11 of human-mouse chimeric antibody gene and the plasmid was transfected into 293T cells under Lipofectamine mediation for transient expression. Expressed product was analyzed by flow cytometry. RESULTS: The result of NCBI gene data bank blast revealed that cloned gene sequence accorded with mice' V(H) and V(L) genes and feature of signal peptide sequence. The constructed plasmid pIRES/h5C11 was correct. The restriction endonuclease digestion analysis and PCR showed that the recombinant genes were subsequently cloned into vector pIRES. FACS analysis showed that human-mouse chimeric antibody against human CD40 maintained the binding activity and specificity to human CD40 molecule. CONCLUSION: The gene encoding variable region of human-mouse chimeric antibody against CD40 is cloned successfully and the human-mouse chimeric antibody against CD40 is expressed transiently in 293T cells.

Animals↗
PubMed2006

[Quantitative analysis of donor chimerism in adoptive immunotherapy following allogeneic hematopoietic stem cell transplantation].

OBJECTIVE: To investigate the value of sequential and quantitative analysis of donor chimerism (DC) to predict the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT), to determine the optimal time point of adoptive immunotherapy and to estimate the efficacy of adoptive immunotherapy. METHODS: Quantitative analysis of DC was performed with multiplex PCR amplification of short tandem repeats markers (STR-PCR) and capillary electrophoresis with fluorescence detection in 84 patients who received allo-HSCT. Sequential chimerism both prior to and following adoptive immunotherapy were evaluated in 16 patients. RESULTS: Increase of mixed chimerism and decrease of DC < 90% were found in 22 of the 84 patients. Six of the 22 patients who did not receive donor lymphocyte infusion (DLI) all died of relapse. Adoptive immunotherapy was used to treat the remaining 16 patients. Before the time of relapse or graft rejection, STR-PCR indicated decrease of DC in 12 of the 16 patients, with levels ranging from 24.8% - 86.2%. A response to immunotherapy was achieved in 11 of the 16 patients (68.8%). In these patients, the value of DC increased with conversion to a predominant donor profile (> or =90%). 6 of the 11 patients converted to stable full donor chimerism (FDC) and 5 of the 11 patients to transformed stable mixed chimerism (MC) shortly after immunotherapy. All these 11 patients who responded to immunotherapy developed graft versus host disease (GVHD). While in the patient without response, the level of DC decreased persistently or declined after a transient increase. Three patients without response received second DLI but still failed to response. CONCLUSION: The results demonstrate that sequential and quantitative monitoring of DC can identify the patients who have high risk of relapse or graft failure and can be used to guide adoptive immunotherapy at early stage to improve the response of immunotherapy in those patients who undergo cytogenetic or molecular relapse. Furthermore the serial and quantitative detection of DC has been shown to be a valuable tool to evaluate early the efficacy of treatment. As well, it can present a rational basis for treatment intensification in patients who did not respond to first-line adoptive immunotherapy treatment.

Adolescent↗
PubMed2006

[Immunotherapy with a chimeric AFP and HSP70 gene DNA vaccine targeting on a murine hepatocellular carcinoma].

OBJECTIVES: To investigate immune responses and the anti-tumor effect of a constructed Chimeric AFP-Mt.HSP70 DNA vaccine in mice. METHODS: Chimeric AFP-Mt.HSP70 was constructed by molecular clone techniques. Spleen cells derived from mice immunized twice were induced to secrete IFN gamma and were assayed using ELISA. The activity of the cytotoxic lymphocytes (CTL) derived from spleen cells was assayed using lactate dehydrogenase (LDH). 4 x 10(6) Hepa1-6 cells/200 microl were injected subcutaneously into the right axilla of each mouse bearing the tumor. The anti-tumor effect of the recombinant DNA vaccine was evaluated by measuring tumor sizes of the mice. RESULTS: AFP-specific CTL reaction was induced by our chimeric DNA vaccine and Mt.HSP70 enhanced this effect (P < 0.05). The CTL activity was about 32% at E/T=50:1. The IFN gamma secreted by spleen cells of mice immunized with chimeric plasmids was about 200 pg/ml. It was higher than those in the other groups; Tumor sizes of mice immunized with fused plasmids were smaller than those in the other groups. Survival times of mice immunized with the fused plasmids were prolonged. CONCLUSION: Chimeric DNA vaccine can induce AFP-specific CTL reaction and has an anti-tumor effect on transplanted tumors in our murine experiment.

Animals↗
PubMed1991

Preliminary studies for an immunotherapeutic approach to the treatment of human myeloma using chimeric anti-CD38 antibody.

Multiple myeloma is a disease in which conventional chemotherapy has only limited value, but which may be ideal for treatment with passive antibody against a suitable cell surface antigen on the neoplastic plasma cell. The CD38 antigen is known to be present on the majority of neoplastic plasma cells, and this was confirmed by detailed examination of bone marrow aspirates from three patients. Strong expression of CD38 was confined to cells which, by the criteria of light-scattering profiles and possession of cytoplasmic Ig, were plasma cells. The vast majority of neoplastic plasma cells appeared to be involved. Using a cell line as a model, it was found that the CD38 antigen acts as a target for a chimeric antibody prepared from the antibody OKT10. The chimeric antibody consists of the Fab portion of the mouse monoclonal antibody linked by a stable thioether bond to an Fc molecule derived from human IgG1, thereby forming mouse Fab-human Fc. In contrast to the parent antibody, the chimeric molecule mediates antibody-dependent cellular cytotoxicity (ADCC) very efficiently with human blood mononuclear effector cells, and is effective at low concentration. Also, even though the CD38 antigen is present on natural killer cells, there appears to be little deleterious action of the antibody on effector cell function. The antibody also failed to affect the growth of progenitor cells of the granulocyte/macrophage or erythroid lineages present in normal bone marrows, despite the suspicion that these cells express the antigen. Other advantages of the CD38 molecule are that it is not found in the serum of patients with myeloma, and it does not appear to modulate in vitro. Fourteen patients with florid myeloma and on various chemotherapeutic regimes had an undiminished capacity to mediate ADCC with the chimeric antibody, when compared with normal individuals. The maintenance of ADCC activity, coupled with the known suppression of the antibody response in these patients, augers well for treatment with chimeric antibody.

ADP-ribosyl Cyclase↗
PubMed1991

Impact of pretransplant conditioning and donor T cells on chimerism, graft-versus-host disease, graft-versus-leukemia reactivity, and tolerance after bone marrow transplantation.

Graft rejection, mixed chimerism, graft-versus-host disease (GVHD), leukemia relapse, and tolerance are interrelated manifestations of immunologic reactivity between donor and host cells that significantly affect survival after allogeneic bone marrow transplantation (BMT). In this report, a mouse model of BMT, in which the donor and host were compatible at the major histocompatibility complex (MHC), was used (1) to examine the interrelationship of pretransplant conditioning and T-cell content of donor BM with regard to lymphoid chimerism and GVHD and (2) to determine how these factors affected graft-versus-leukemia (GVL) reactivity and donor-host-tolerance. AKR (H-2k) host mice were administered optimal or suboptimal total body irradiation (TBI) as pretransplant conditioning followed by administration of BM cells from B10.BR (H-2k) donor mice with or without added spleen cells as a source of T lymphocytes. Transplanted mice were injected with a supralethal dose of AKR leukemia cells 20 and 45 days post-BMT to assess GVL reactivity in vivo. The pretransplant conditioning of the host and T-cell content of the donor marrow affected the extent of donor T-cell chimerism and the severity of GVH disease. GVL reactivity was dependent on transplantation of mature donor T cells and occurred only in complete chimeras. Transplantation of T-cell-deficient BM resulted in the persistence of host T cells, ie, incomplete donor T-cell chimerism, even when lethal TBI was used. Mixed chimerism was associated with a lack of GVL reactivity, despite the fact that similar numbers of donor T cells were present in the spleens of mixed and complete chimeras. In this model, moderate numbers of donor T cells facilitated complete donor T-cell engraftment, caused only mild GVHD, and provided a significant GVL effect without preventing the subsequent development of tolerance after conditioning with suboptimal TBI. In contrast, severe, often lethal, GVHD developed when the dose of TBI was increased, whereas tolerance and no GVH/GVL reactivity developed when the T-cell content of the marrow was decreased.

Animals↗
PubMed1990

Mapping the site of interaction between murine IgE and its high affinity receptor with chimeric Ig.

We have investigated the interaction of mouse (m) IgE with its Fc epsilon RI on rat basophilic leukemia cells using a set of chimeric Ig that were constructed by exchanging homologous H chain C domains between human (hu) IgG1 and mIgE. Binding affinities were examined with equilibrium and kinetic measurements, and we found that epsilon/C gamma 3 (mIgE with C epsilon 4 replaced by C gamma 3) was indistinguishable from mIgE. The huIgG1 and the other chimeric Ig, which did not contain both C epsilon 2 and C epsilon 3, did not bind detectably to rat basophilic leukemia cells (Ka less than 10(6) M-1). The ability of these chimeric Ig to stimulate a cellular response (degranulation) in the presence of multivalent Ag was also tested. The epsilon/C gamma 3 was indistinguishable from mIgE in eliciting a high level of degranulation, whereas the other chimeric Ig stimulated no response even when they were preaggregated to enhance their binding avidity. These results demonstrate that C epsilon 4 may be replaced by C gamma 3 without affecting the binding and cell activating properties of mIgE. The lack of binding by the other chimeric Ig indicates that both C epsilon 2 and C epsilon 3 are necessary for the binding interaction.

Animals↗
PubMed1990

[Construction, expression and characterization of a murine/human chimeric antibody with specificity for hepatitis B surface antigen].

A murine/human chimeric antibody with specificity for hepatitis B surface antigen has been produced by genetic engineering. The light and heavy chain variable region exons encoding the murine monoclonal antibody 2H1 were isolated and inserted into mammalian expression vectors containing the human kappa and gamma 1 constant region exons. The chimeric genes were transfected into murine SP2/0 hybridoma cells by electroporation, and transfectomas secreting chimeric antibody were isolated. Secretion levels ranged from 1-7pg/(cell.24hr). The chimeric antibody bound specifically to hepatitis B surface antigen and competed effectively with the parental murine monoclonal antibody for binding to these sites. Chimeric 2H1 is the first clinically relevant, genetically engineered anti-viral antibody and may represent an improved agent for the prevention of hepatitis B virus transmission.

Animals↗
PubMed1990

Cloning and expression of a chimeric antibody directed against the human transferrin receptor.

The cloning, construction and expression of chimeric Ig genes, encoding a mAb directed against the human transferrin receptor, is described. From a mouse hybridoma cell line, secreting an antitransferrin receptor antibody, mRNA was prepared and converted into cDNA using Ig-specific oligonucleotides. H and L chain encoding cDNA fragments were isolated and sequenced. Chimeric genes were constructed by linking the murine V region cDNA fragments to human C region exons. After sequential transfection of nonproducing mouse hybridoma cells with the expression vectors containing the chimeric H and L chain genes, antibody secreting transfectomas were obtained. ELISA and immunoblot analysis clearly demonstrate the secretion of human kappa- and gamma-1 chain. Flow microfluorimetry analysis of the chimeric antibody shows that the Ag-binding capacity has been retained. The chimeric antibody most likely will be less immunogenic then the original mouse antibody when used in human cancer therapy.

Amino Acid Sequence↗
PubMed1990

[Chimerism pattern following allogeneic bone marrow transplantation; a retrospective study of the connection with post-transplantation complications].

Allogeneic bone marrow transplantation is generally followed by disappearance of all host haematopoietic cells and replacement by donor cells, resulting in complete chimerism. In some cases, however, residual host cells can be detected after transplantation; this is called partial chimerism. We have analysed the chimerism pattern in 106 patients, by erythrocyte antigen typing, erythrocyte and leucocyte isoenzymes, immunoglobulin allotyping and karyotyping of bone marrow and blood. Recipients of a T cell-depleted marrow transplant exhibited partial chimerism significantly more often. In most cases this involved T lymphocytes, sometimes in combination with other cell populations. Persisting B lymphocytes of host origin were detected only in recipients of a T cell-depleted marrow graft. No relationship was found between chimerism pattern and GVHD, interstitial pneumonitis, relapse of the underlying disease or disease free survival.

Adult↗
PubMed1989

A chimeric mouse-human antibody that retains specificity for HIV gp120 and mediates the lysis of HIV-infected cells.

Murine mAb BAT123, which was made against the envelope glycoprotein gp120 of HTLV-IIIB strain of HIV type 1 (HIV-1), is capable of neutralizing HTLV-IIIB in vitro. It also inhibits the fusion between uninfected CD4+ cells and HIV-1-infected cells to form syncytia. As a step to explore the potential utility of the anti-HIV antibody in vivo, we have constructed a mouse-human chimeric antibody by rDNA techniques. The chimeric antibody, which bears the variable domains of mouse antibody BAT123 and constant domains Cr1 and C kappa of human Ig retains the Ag specificity of BAT123 as determined by its reactivity with HIV-1-infected H9 cells, gp120 in Western blot analysis, and the oligopeptide recognized by BAT123. The antiviral activities of the chimeric antibody in neutralizing HIV-1 infection as well as inhibiting the syncytia formation are also found identical to those of the parent murine antibody. Moreover, in the presence of human blood mononuclear cells, the chimeric antibody but not BAT123 (mouse IgG1) induces antibody-dependent cellular cytotoxicity. The findings point to the potential usefulness of the chimeric antibody in treating patients infected with HIV-1.

Amino Acid Sequence↗
PubMed1987

Development of a single probe for documentation of chimerism following bone marrow transplantation.

Although numerous genetic markers are available for studying chimerism after bone marrow transplantation (BMT), there remains a need for a practical and highly informative method that is applicable in the early posttransplantation period. Using DNA restriction-fragment-length polymorphisms (RFLPs), we have evaluated the feasibility of developing a single synthetic oligonucleotide probe to study post-BMT chimerism. We have thus tested three candidate probes, termed O-3315-32, O-3315-80, and O-AY-29, that are homologous to tandemly repetitive sequences. Our results demonstrated donor-specific and recipient-specific fragments in 11 of 11 HLA-matched sibling pairs tested using probes O-3315-32 and O-3315-80. When probe O-AY-29 was used, 14 of 17 sibling pairs showed both donor and recipient markers, one had only a recipient marker, and two were identical. We showed that each of the three synthetic probes was effective in documenting donor marrow engraftment, mixed hematopoietic chimerism, the patient's pre-BMT phenotype (by using cultured skin fibroblasts obtained after BMT), and the origin of the malignant hematopoietic cells (i.e., of donor or recipient origin) in patients who developed recurrent hematologic malignancy following BMT. Compared with the use of cloned genomic probes, there are several important advantages to the use of synthetic oligonucleotide probes in studying post-BMT chimerism. Synthetic probes have absolute hybridization specificity and can be designed to suit the purposes of an individual study, since they have adjustable specificity that can be altered by changes in the length of the probe and by changes in the hybridization temperature. A single synthetic probe analogous to several highly polymorphic loci can have a polymorphism information content sufficiently high so that all but a small percentage of BMT patients could be followed easily; for example, if a probe were complementary to three highly polymorphic unlinked loci, it would discriminate approximately 98% of sibling donor/recipient pairs. This would be accomplished using only one restriction-endonuclease digestion and only one gel electrophoresis. Since other genetic markers, e.g., red blood cell antigens, immunoglobulin allotypes, and chromosome analysis, are not uniformly informative and, in some cases, cannot be used in the early posttransplantation period, the use of synthetic oligonucleotide probes for analysis of DNA RFLP is emerging as the method of choice for studies of post-BMT chimerism. This method will allow for the development of new knowledge that has not been possible with previous methods.

Bone Marrow↗
PubMed1986

A genetically engineered murine/human chimeric antibody retains specificity for human tumor-associated antigen.

Chimeric immunoglobulin genes were constructed by fusing murine variable region exons to human constant region exons. The ultimate goal was to produce an antibody capable of escaping surveillance by the human immune system while retaining the tumor specificity of a murine monoclonal. The murine variable regions were isolated from the functionally expressed kappa and gamma 1 immunoglobulin genes of the murine hybridoma cell line B6.2, the secreted monoclonal antibody of which reacts with a surface antigen from human breast, lung, and colon carcinomas. The kappa and gamma 1 chain fusion genes were co-introduced into non-antibody producing murine myeloma cells by electroporation. Transfectants that produced murine/human chimeric antibody were obtained at high frequency as indicated by immunoblots probed with an antisera specific for human immunoglobulin. Enzyme-linked immunoabsorbent assay analysis demonstrated that this chimeric antibody was secreted from the myeloma cells and retained the ability to bind selectively to membrane prepared from human tumor cells. The chimeric immunoglobulin was also shown by indirect fluorescence microscopy to bind to intact human carcinoma cells with specificity expected of B6.2. The ability of chimeric antibody to recognize human tumor-associated antigen makes feasible a novel approach to cancer immunotherapy.

Animals↗
PubMed1988

Human lymphocyte and monocyte lysis of tumor cells mediated by a mouse/human IgG1 chimeric monoclonal antibody.

The mouse monoclonal antibody 17-1A (gamma 2a, kappa) recognizes a tumor-associated antigen expressed on human gastrointestinal malignancies and has been used in Phase I and II clinical trials. Chimeric genetic constructs have been produced using 17-1A variable region genes (VL and VH) and the constant region genes for human kappa light chains and gamma 1 heavy chains (C kappa and gamma 1). The chimeric gene constructs were transfected into mouse myeloma cells for antibody production. The secreted mouse/human chimeric antibody contains the antigen-binding domain of 17-1A and the human (gamma 1, kappa) constant regions. Native mouse 17-1A and the chimeric antibody (chIgG1) were analyzed for binding to two human colon cancer cell lines and for the mediation of cancer cell line antibody-dependent cellular cytotoxicity by normal human peripheral blood lymphocytes and monocytes in 4 h 51Cr-release assays. The 17-1A and chIgG1 gave similar results in these in vitro biologic assays. This study demonstrates the feasibility of using mouse/human chimeric antibodies in human therapeutic applications.

Animals↗
PubMed1987

Tumor-specific genetically engineered murine/human chimeric monoclonal antibody.

Murine variable and human constant region exons were fused to produce "chimeric" immunoglobulin gamma and kappa genes. These constructs were cotransfected into murine myeloma cells which then produced and secreted intact, functional antibody. Cells secreting the chimeric antibody were introduced into mice. The engineered immunoglobulin was subsequently harvested from ascites fluid and was purified by affinity chromatography. Its immunological properties were compared to those of the parental murine monoclonal (B6.2), which exhibits specificity for human breast, lung, and colon carcinoma cells. Competitive binding, immunofluorescent cell staining, and analysis of immunoprecipitated antigen gave similar results for the chimeric and murine B6.2. The biodistribution of chimeric and murine B6.2 after injection into mice bearing human tumors was found to be identical. These results suggest that murine/human chimeric antibodies may be viable clinical replacements for murine monoclonals with the potential for better immunological tolerance and pharmacological efficacy.

Animals↗
PubMed1987

Large numbers of primitive stem cells are active simultaneously in aggregated embryo chimeric mice.

The possibility has been repeatedly raised that erythropoiesis results from clonal succession--the differentiation of one or a very small number of the most primitive stem cells that are sequentially activated to proliferate forming clones of differentiated cells and then eventually decline, to be replaced by new stem cell clones. We studied this possibility in chimeric mice made by combining embryos from two different strains so that they would have two distinct stem cell populations, each of which produces a different hemoglobin type (d and s). These were compared with F1 hybrids in which every stem cell produces both types. We measured the percentage of type d in seven to ten serial samples of circulating reticulocytes taken at three- to seven-day intervals and found that the variability in percent of this hemoglobin was only slightly higher in the chimeric mice than in F1 controls; SD ranged from 2.7% to 5.5% in the chimeric mice and from 3.4% to 3.9% in the controls. Using the binomial formula, the numbers of new clones formed during the reticulocyte life span, approximately three days, ranged from 33 to 118 in the individual chimeric mice. However, these numbers are underestimates because estimated numbers of clones depend inversely on variabilities, and the calculations did not exclude the contribution of experimental error to the overall variability. Total percentages of type d hemoglobin were also measured in seven to nine successive serial samples at 60- to 136-day intervals. These gave mean values similar to measures of newly synthesized hemoglobin in the same mice, but SD were larger, ranging from 5.3% to 8.4%. This reflects experimental error, both because of excess day-to-day variability found in this type of measurement and because there could not be fewer primitive stem cells activated to form clones of erythrocytes during the 45-day erythrocyte life span than during the three-day life span of reticulocytes. Since most and maybe all of the variation between successive samples in the same chimeric mouse appear to result from experimental error, many or even all of the primitive stem cells may simultaneously contribute to erythropoiesis.

Animals↗
PubMed1995

Chimeric TLS/FUS-CHOP gene expression and the heterogeneity of its junction in human myxoid and round cell liposarcoma.

Myxoid liposarcomas have a unique and specific t(12;16)q13;p11) chromosomal translocation. The breakpoint has recently been identified and shown to involve the TLS/FUS gene on chromosome 16 and the CHOP gene on chromosome 12. This translocation causes fusion of these genes resulting in the expression of a novel chimeric TLS/FUS-CHOP message. Using the polymerase chain reaction with primer sets derived from sequences of TLS/FUS and CHOP cDNAs, we could amplify three types of the fusion transcripts from seven of seven samples of myxoid and round cell liposarcomas. In six of the seven positive samples, two kinds of chimeric messenger RNAs were found that have been reported previously. However, the last sample had a novel chimeric message that had an extra sequence of 33 bp derived from the TLS/FUS gene. Thus, it was shown that these fusion transcripts had a varying extent of the sequence of TLS/FUS gene incorporated at the site of the fusion. However, the TLS/FUS-CHOP fusion transcripts were not detected in two pleomorphic liposarcomas or in three myxoid variants of malignant fibrous histiocytomas. Our findings indicate that in liposarcomas TLS/FUS-CHOP fusion transcripts have variations at the junction of chimeric messages, which was the case for Ewing's sarcoma. Detection of the chimeric message by reverse transcription polymerase chain reaction was also suggested to be a useful approach for the diagnosis of myxoid and round cell liposarcomas that have (12;16) translocation, and for distinguishing them from pleomorphic liposarcoma and myxoid variant of malignant fibrous histiocytomas.

Adult↗