Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The multidrug-resistance gene, MDR1 is expressed in many normal tissues, but little is known about its expression in normal hematopoietic cells. Using the monoclonal antibody C219 and flow cytometric analysis, P-glycoprotein (P-gp) was found to be expressed in all peripheral blood (PB) subpopulations (CD4, CD8, CD14, CD19, CD56) except granulocytes. To specifically determine MDR1 gene expression, these PB subpopulations were isolated by fluorescence-activated cell sorting (FACS) and analyzed for MDR1 mRNA by polymerase chain reaction (PCR). All subsets were positive by PCR, but only minimal MDR1 mRNA was detected in monocytes and granulocytes. Significant efflux of Rhodamine-123 (Rh-123), a measure of P-gp function, was detected in CD4+, CD8+, CD14+, CD19+, and CD56+ cells but not in granulocytes. Next, PCR-analysis was performed on FACS-sorted bone marrow (BM) cells to assess MDR1 expression in different maturational stages. Precursors (CD34+), early and late myeloid cells (CD33+/CD34+, CD33+/CD34-) as well as lymphocytes of the B-cell lineage (CD19+/CD10+, CD19+/CD10-) expressed the MDR1 gene. BM monocytic cells (CD33++/CD34-) were negative, and a very weak signal was detected in erythroid cells (glycophorin A+). Significant Rh-123 efflux was found in CD34+, CD10+, CD33+, and CD33++ BM cells, but not in glycophorin A+ cells. We conclude that PB and BM lymphocytes, PB monocytes, BM progenitors, and immature myeloid cells, but not late BM monocytes, erythroid cells, and PB granulocytes, express MDR1 mRNA and a functional P-gp. These results have to be taken into account when MDR1 expression is determined in tumor samples containing normal blood cells.
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PMID:Subpopulations of normal peripheral blood and bone marrow cells express a functional multidrug resistant phenotype. 850 83

Human CD34+ hematopoietic stem cells were purified using a new technology in which monoclonal antibodies are covalently immobilized on polystyrene surfaces. The CD34+ cell isolation scheme involved three sequential processes: (1) purification of bone marrow mononuclear cells; (2) enrichment of CD34+ cells using covalently immobilized soybean agglutinin; and (3) positive selection of CD34+ cells using polystyrene surfaces coated with the anti-CD34 monoclonal antibody ICH3. CD34+ cells purified by this process have both low-to-medium forward light scatter and low 90 degrees light-scatter properties. Moreover, the purified CD34+ cells are greater than 85% viable, express appropriate characteristic surface antigens, and are 10-50-fold enriched in short- and long-term hematopoietic activity. CD34+ cells collected in this manner from bone marrow samples contaminated with radiolabeled breast carcinoma, neuroblastoma, acute myelogenous leukemia, or small cell lung carcinoma cells were 99.9% depleted of the tumor cells. The CD34+ cell selection devices are sterile and are easily scaled-up to process clinical scale bone marrow samples.
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PMID:Rapid isolation of human CD34 hematopoietic stem cells--purging of human tumor cells. 137 43

To help understanding host-tumor relationships in acute myelogenous leukemia (AML) and better define indications for interleukin 2 (IL-2) therapy in this disease, we studied the relationship between the susceptibility of leukemic cells of 44 AML patients to lysis by autologous (26 cases) and/or allogeneic (41 cases) lymphokine-activated killer (LAK) cells and characteristics of the leukemia. Lymphocytes were activated in the presence of 1000 u/ml recombinant IL-2 for 5 days. Lysis of AML cells was studied by 51Cr release. Average lysis of AML cells by autologous LAK cells was 9 +/- 13% and by allogeneic LAK cells 10 +/- 9% with a significant correlation between lyses by both effectors (p = 0.01). Autologous (p = 0.005) and allogeneic (p = 0.004) lyses were higher in patients with initial infection. Allogeneic lysis was correlated with initial WBC count (p = 0.009), serum lactic-dehydrogenase level (p = 0.05), and expression of CD13 (p = 0.01). Autologous lysis was inversely correlated with expression of CD34 (p = 0.003). Expression of adhesion molecules CD54 (ICAM-1) and CD58 (LFA-3) by the leukemic cells did not correlate with their lysis by LAK cells. Susceptibility of leukemic cells to lysis by LAK cells did not correlate with prognosis of the leukemia.
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PMID:Susceptibility of acute myelogenous leukemia blasts to lysis by lymphokine-activated killer (LAK) cells and its clinical relevance. 137 19

Identification of a glycoprotein expressed on 1.2% of normal bone marrow cells, including progenitors of all hematolymphopoietic lineages and pluripotent stem cells, has allowed the production of several monoclonal antibodies directed against the same structure and included in the new differentiation cluster CD34. Availability of these antibodies coupled with techniques of positive selection of normal progenitors has opened an interesting and new alternative for purging bone marrow. Two of these techniques (avidin-biotin immunoadsorption on column and paramagnetic microspheres) have found clinical application and recently data on the first series of patients transplanted with CD34+ cells enriched marrows have been published. In the area of peripheral blood stem cells transplantation, detection by flow cytometry of CD34+ cells in the peripheral blood should replace the poorly standardized CFU-GM assay, allowing the best timing of apheretic procedures and the easy quantification of stem cells number in a harvest. Combination of negative (tumor cell killing) and positive (hemopoietic stem cell purification) selection might result in a significant improvement of the purging procedure and in a larger application of autologous hematopoietic stem cell transplantation for hematological and non-hematological malignancies.
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PMID:[CD34+ cells in the autotransplant of bone marrow and peripheral blood]. 138 Jan 74

Moloney Murine Leukemia Virus (MoMuLV) causes T cell neoplasms in rodents but is not known to be a pathogen in primates. The core protein and enzyme genes of the MoMuLV genome together with an amphotropic envelope gene are utilized to engineer the cell lines that generate retroviral vectors for use in current human gene therapy applications. We developed a producer clone that generates a very high concentration of retroviral vector particles to optimize conditions for gene insertion into pluripotent hematopoietic stem cells. This producer cell line also generates a much lower concentration of replication-competent virus that arose through recombination. Stem cells from rhesus monkeys were purified by immunoselection with an anti-CD34 antibody, incubated in vitro for 80-86 h in the presence of retroviral vector particles with accompanying replication-competent virus and used to reconstitute recipients whose bone marrow had been ablated by total body irradiation. The retroviral vector genome was detected in circulating cells of five of eight transplant recipients of CD34+ cells and in the circulating cells of two recipients of infected, unfractionated bone marrow mononuclear cells. Three recipients of CD34+ cells had a productive infection with replication-competent virus. Six or seven mo after transplantation, each of these animals developed a rapidly progressive T cell neoplasm involving the thymus, lymph nodes, liver, spleen, and bone marrow. Lymphoma cells contained 10-50 copies of the replication-competent virus, but lacked the retroviral vector genome. We conclude that replication-competent viruses arising from producer cells making retroviral vectors can be pathogenic in primates, which underscores the importance of carefully screening retroviral producer clones used in human trials to exclude contamination with replication-competent virus.
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PMID:Helper virus induced T cell lymphoma in nonhuman primates after retroviral mediated gene transfer. 138 75

The adenoid variant of squamous cell carcinoma has been well-documented in several anatomic sites, including the skin. This tumor is characterized by acantholytic arrays of neoplastic keratinocytes that form pseudoglandular profiles. Although it is typically confused with adenocarcinomas, adenoid squamous cell carcinoma also may be mistaken for malignant vascular proliferations. This report concerns six acantholytic cutaneous squamous cell carcinomas that closely simulated angiosarcomas on conventional histologic examination. They arose in sun-exposed skin areas in middle-aged or elderly patients (mean age, 60 years), five of whom were men. In contrast to the typical clinical appearance of angiosarcoma, pseudovascular adenoid squamous cell carcinoma presented itself as a discrete cutaneous ulcer or crusted tanpink nodule. Microscopically, this lesion was characterized by interanastomosing cordlike arrays of polygonal or flattened tumor cells, with internal pseudolumina that contained detached tumor cells. A connection between the dermal neoplasm and the epidermis was apparent in three cases, but it was focal. Erythrocytes were seen in pseudovascular spaces in five tumors. Immunohistochemically, all examples of pseudovascular adenoid squamous carcinoma were reactive with antibodies to cytokeratin and epithelial membrane antigen (EMA). In addition, three expressed vimentin, two exhibited blood group antigen-positivity, and two bound Ulex europaeus I agglutinin. None of them was immunoreactive for Factor VIII-related antigen, and two of three studied for CD34-reactivity were likewise negative. A control group of six cutaneous angiosarcomas was uniformly nonreactive for cytokeratin and EMA, but they showed positivity for vimentin, Ulex binding, and CD34 positivity in all instances. Pseudovascular adenoid squamous cell carcinoma may be distinguished effectively from angiosarcoma of the skin by attention to its clinical features and by appropriate immunohistochemical studies. These two tumors differ in biologic behavior; three patients with pseudovascular adenoid squamous cell carcinoma died of their tumors, whereas all angiosarcomas in this series proved fatal.
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PMID:Pseudovascular adenoid squamous cell carcinoma of the skin. A neoplasm that may be mistaken for angiosarcoma. 159 22

Immunologic strategies for removal of malignant cells from autologous marrow grafts by "negative selection" (i.e., "purging") requiring multiple specific monoclonal antibodies for each tumor type. "Positive selection" of marrow stem cells for grafting is a possible alternative strategy, using a monoclonal antibody which selectively recognizes lymphohematopoietic stem cells. The human hematopoietic progenitor cell antigen, CD34, is an integral cell membrane glycoprotein of approximately 115 kD, which has been molecularly cloned and sequenced. Although its function has not been determined, the glycoprotein has been characterized biochemically, including preliminary epitope mapping. Collective results from several laboratories indicate that CD34 monoclonal antibodies (My10, BI-3C5, 12.8, etc.) have the appropriate specificity to warrant testing their utility in positive selection for autologous bone marrow transplantation. First, precursors for all human hematopoietic lineages assayed (including most CFU-GM, BFU-E, CFU-MEG, CFU-EO, CFU-MIX or CFU-GEMM, pre-CFU, CFUBLAST, and terminal transferase+ B [and probably T] lymphoid precursors) are CD34+. Second, only 1.5% (mean) of low density human marrow mononuclear cells express CD34; mature human blood and marrow cells are CD34-. Endothelial cells are the only fixed tissue cells which express CD34. Third, the expression of CD34 in malignancies appears to parallel normal cellular expression: of hematopoietic malignancies, some acute leukemias and chronic myelogenous leukemia blasts are CD34+, but chronic lymphois leukemias, lymphomas, myelomas and non-hematopoietic malignancies are uniformly CD34-. Fourth, it appears feasible to isolate CD34+ cells from clinical marrow harvest samples in large scale, using either columns or immunomagnetic microspheres. Fifth, recent studies in very small numbers of non-human primates and human patients suggest that isolated CD34+ cells include the true hematopoietic stem cell, since transplantation of CD34+ cells, into myeloblated recipients results in at least short-term hematopoietic engraftment. It is anticipated that transplantation of CD34+ marrow cells may have broad applicability in clinical bone marrow transplantation.
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PMID:Positive stem cell selection--basic science. 168 54

It has been reported that the human haemopoietic progenitor cell antigen CD34 is also expressed by vascular structures. To investigate its precise vascular localization, we have studied the cellular and subcellular distribution of CD34 in normal tissues and pathologic tissues with neovascularization. In normal resting tissues, anti-CD34 antibodies, ICH3 and QBEND-10 predominantly stain the luminal endothelial membrane, whereas the abluminal membrane is negative or weakly positive. In contrast, a striking staining of endothelial abluminal microprocesses (EAM) was found in the tumor stroma. These structures, measuring up to 20 microns in length, could be observed in thick vibratome sections both at the tips of vascular sprouts and, also frequently, on fully formed microvessels. The number of vascular sprouts and EAM varied widely between different tumors. CD34-stained EAM were sparsely present in fetal tissue of 10 weeks gestation, but they could not be demonstrated in granulation tissue of wound healing. By immunoelectron microscopy, the EAM were continuous with the cytoplasm of endothelial cells showing an immature phenotype as seen in regeneration. In cultured human umbilical vein endothelium, CD34 was preferentially found on a small subset of cells with the morphologic appearance of migrating cells. These findings suggest that CD34 is an endothelial marker for EAM present during angiogenesis.
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PMID:Leukocyte antigen CD34 is expressed by a subset of cultured endothelial cells and on endothelial abluminal microprocesses in the tumor stroma. 169 54

The CD34 antigen is expressed by 1% to 4% of human and baboon marrow cells, including virtually all hematopoietic progenitors detectable by in vitro assays. Previous work from our laboratory has shown that CD34+ marrow cells can engraft lethally irradiated baboons. Because the CD34 antigen has not been detected on most solid tumors, positive selection of CD34+ cells may be used to provide marrow cells capable of engraftment, but depleted of tumor cells. In seven patients with stage IV breast cancer and two patients with stage IV neuroblastoma, 2.5 to 17.5 x 10(9) marrow cells were separated by immunoadsorption with the anti-CD34 antibody 12-8 and 50 to 260 x 10(6) positively selected cells were recovered that were 64 +/- 16% (range 35% to 92%) CD34+. The patients received 1.0 to 5.2 x 10(6) CD34-enriched cells/kg after marrow ablative therapy. Six patients engrafted, achieving granulocyte counts of greater than 500/mm3 at 34 +/- 10 (range 21 to 47) days and platelets counts of greater than 20,000/mm3 at 46 +/- 14 (range 28 to 66) days posttransplant. Five of these patients showed durable engraftment until the time of death 82 to 386 days posttransplant. One patient failed to sustain engraftment associated with metastatic marrow disease. Three patients died at days 14, 14, and 17 posttransplant, two of whom had evidence of early engraftment. These studies suggest that CD34+ marrow cells are capable of reconstituting hematopoiesis in humans.
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PMID:Engraftment after infusion of CD34+ marrow cells in patients with breast cancer or neuroblastoma. 170 96

The human hematopoietic progenitor cell antigen CD34 is synthesized and expressed by early normal hematopoietic progenitor cells and by many acute leukemias. Anti-CD34 antibodies also have been reported to stain blood vessels in tissue sections, and, more recently, CD34 mRNA has been detected in vascular endothelial cells. Therefore, the authors studied the diagnostic utility of immunohistochemical CD34 antigen detection in tumors of endothelial cell derivation and compared the results with stains for von Willebrand (vW) factor. A wide variety of epithelial and mesenchymal neoplasms also were examined to assess the specificity of CD34 for vascular neoplasia. Seven cases of angiosarcoma (seven of seven), five cases of Kaposi's sarcoma (five of five), and eight cases of epithelioid hemangioendothelioma (eight of eight) were moderately to strongly positive for CD34. This reactivity was equally intense in frozen sections, alcohol-fixed tissue, and formalin-fixed specimens. In many cases, the malignant endothelial cells stained more strongly than adjacent benign endothelium. Moreover, in most cases CD34 positivity was quantitatively and qualitatively stronger than staining for vW factor. Two cases of hemangiopericytoma (two of two) were CD34 positive but stained less intensely than the angiosarcomas, Kaposi's sarcomas, or hemangioendotheliomas. Five of six cases of hemangioma also stained positively for CD34; the nonreactive tumor in this group was the only one among 28 vascular neoplasms studied that was not reactive for CD34. In comparison, 9 of the 28 vascular tumors did not stain for vW factor. Three hundred fifty-seven tumors of nonvascular derivation also were examined for CD34 antigen expression. Focal light staining was seen in one pulmonary squamous cell carcinoma; moderate to intense staining was observed in half of the epithelioid sarcomas studied (8 of 16) and in a minority of leiomyosarcomas (3 of 22). These findings indicate that CD34 is a sensitive and relatively specific marker for neoplasms of vascular origin.
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PMID:The human hematopoietic progenitor cell antigen (CD34) in vascular neoplasia. 171 41


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