Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The promyelocytic leukemia (PML) gene encodes a putative tumor suppressor gene involved in the control of apoptosis, which is fused to the retinoic acid receptor alpha (RARalpha) gene in the vast majority of acute promyelocytic leukemia (APL) patients as a consequence of chromosomal translocations. The PMLRARalpha oncoprotein is thought to antagonize the function of PML through its ability to heterodimerize with and delocalize PML from the nuclear body. In APL, this may be facilitated by the reduction to heterozygosity of the normal PML allele. To determine whether PML acts as a tumor suppressor in vivo and what the consequences of deregulated programmed cell death in leukemia and epithelial cancer pathogenesis are, we crossed PML(-/-) mice with human cathepsin G (hCG)-PMLRARalpha or mammary tumor virus (MMTV)/neu transgenic mice (TM), models of leukemia and breast cancer, respectively. The progressive reduction of the dose of PML resulted in a dramatic increase in the incidence of leukemia, and in an acceleration of leukemia onset in PMLRARalpha TM. By contrast, PML inactivation did not affect neu-induced tumorigenesis. In hemopoietic cells from PMLRARalpha TM, PML inactivation resulted in impaired response to differentiating agents such as RA and vitamin D3 as well as in a marked survival advantage upon proapoptotic stimuli. These results demonstrate that: (a) PML acts in vivo as a tumor suppressor by rendering the cells resistant to proapoptotic and differentiating stimuli; (b) PML haploinsufficiency and the functional impairment of PML by PMLRARalpha are critical events in APL pathogenesis; and (c) aberrant control of programmed cell death plays a differential role in solid tumor and leukemia pathogenesis.
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PMID:Role of promyelocytic leukemia (PML) protein in tumor suppression. 1118 7

HER2 (neu, erbB-2), a receptor related to the human epidermal growth factor receptor, has now become more important as a predictive marker of treatment response. While the value and direction of the treatment/HER2 interaction may vary, depending on the agents, dose, or schedule of drug administration, there is little disagreement that HER2 testing is an important part of breast cancer evaluation. In 1998, trastuzumab (Herceptin) was approved for the treatment of HER2-positive metastatic breast cancer patients by the Food and Drug Administration of the USA. Patients with abnormal HER2 in their breast cancer cells (generally 2 or 3+ with the HercepTest, overexpression by other immunohistochemical assays or amplification by fluorescence in situ hybridization [FISH] assay) have demonstrated the greatest response to trastuzumab treatment. It is unclear which test (method, reagent, cut-off points, etc.) is best to use to evaluate HER2 for this purpose because parallel testing of the same cancers from patients who received trastuzumab has only recently been initiated and the data are limited. It is widely believed that breast cancers without HER2 alterations will not be responsive to trastuzumab, although a clinical trial to test this specific hypothesis has not been initiated. There are also concerns that clonal heterogeneity for HER2 within a tumor, or between primary and metastatic cancer foci, may affect treatment response; yet we do not currently evaluate these parameters. Consensus regarding the best methods, reagents, or cut-off points to define HER2 status for determining trastuzumab responsivity has not yet been reached. HER2 testing for other prognostic or predictive purposes, e.g. to determine whether patients are likely to respond to other agents, such as dose-intensive doxorubicin, may be less. Data from the Cancer and Leukemia Group B trial 8541 (companion 8869) suggest that, with proper controls in high-volume laboratories, many of the available methods produce comparable results.
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PMID:HER2--a discussion of testing approaches in the USA. 1152 14

This article focuses on the recent dramatic advances in the applications of monoclonal antibody therapy to hematopoietic and neoplastic disease. The increase in the understanding of the role of growth factors and their receptors in the pathogenesis of malignancy and other undesirable hematological events taken in conjunction with the ability to produce humanized chimeric monoclonal antibodies to these targets is providing a new perspective for the treatment of leukemia, lymphoma and breast cancer, autoimmune disease and for prevention of ischemic complications. Dr. Waldmann describes approaches targeting the Her2/neu and the II-2/IL-15 receptor systems. The Her2/neu receptor is overexpressed in select breast, ovarian, gastric and pancreatic neoplasms. The use of trastuzumab (Herceptin) in the treatment of patients with breast cancer whose tumors overexpress this receptor are reviewed. The IL-2 receptor (Tac) is expressed on select malignant cells (adult T cell leukemia, hairy cell leukemia) and activated T cells involved in autoimmune disease and organ rejection. Humanized anti-Tac alone (daclizumab, Zenapax) or armed with toxins or radionuclides have been used successfully in the treatment of leukemia. Dr. Levy updates the experience with rituximab targeting CD20 on B cell lymphomas and reviews the antibodies to CD3, CD22, CD33, CD52, HLA-DR beta chain and HLA-D currently in or proposed for clinical trials, including radiolabelled antibodies. In the last section, Dr. Coller reviews the therapeutic results achieved with abciximab (ReoPro), an antagonist of platelet receptor GPIIbIIIa for the prevention of restenosis in percutaneous coronary interventions and the treatment of unstable angina. The mechanism of action, pharmacology and safety and efficacy of abciximab are reviewed.
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PMID:Emerging Therapies: Spectrum of Applications of Monoclonal Antibody Therapy. 1170 53

Clinically effective cancer immunotherapy has been sought for more than 100 years and has been recently applied most successfully in strategies that passively deliver immune effectors such as monoclonal antibodies (anti-CD20 for lymphoma and anti-HER2/neu for breast cancer), donor lymphocyte infusions in chronic myelongenous leukemia and non-myeloablative allogeneic peripheral blood progenitor transplants for renal cell carcinoma. There is mounting enthusiasm for strategies employing active stimulation of antitumour immune responses. These include vaccines based on tumour antigen proteins and peptides, autologous, allogeneic or gene-modified tumour cells, dendritic cells and antigen-encoding viral vector constructs. Indeed, randomised Phase III clinical trials of autologous tumour cell vaccines for colorectal cancer demonstrated an improvement in disease free survival and a trend toward improved overall survival [1]. Despite these preliminary successes, it is clear that the many strategies under development cannot all be evaluated for survival benefit in large clinical trials that require many years, patients and resources to complete. This highlights the need to develop intermediate markers to help prioritise which agents to test in prospective randomised Phase III trials.
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PMID:Surrogate markers of response to cancer immunotherapy. 1172 26

It has long been a matter of debate whether tumors are spontaneously immunogenic in patients. With the availability of sensitive methods, naturally occurring T cells directed against tumor-associated antigens (TAAs) can be frequently detected in cancer patients. In this review, we summarize the current data on T cell responses to TAAs in various malignancies, including melanoma, colorectal cancer, leukemia, and breast cancer. T cell responses against various antigens, including melanoma differentiation antigens, carcinoembryonic antigen, epithelial cell adhesion molecule, her-2/neu, Wilms' tumor protein, proteinase 3, NY-ESO-1, and surviving, have been reported in a substantial number of patients. In contrast, other TAAs, including most antigens of the MAGE family, do not usually elicit spontaneous T cell responses. A distinction between direct ex vivo T cell responses and in vitro-generated T cell responses is provided because in vitro stimulation results in quantitative and functional changes of T cell responses. The possible role of TAA-specific T cells in immunosurveillance and tumor escape and the implications for immunological treatment strategies are discussed. Naturally occurring T cells against TAAs are a common phenomenon in tumor patients. Understanding the mechanisms and behavior of natural TAA-specific T cells could provide crucial information for rational development of more efficient T cell-directed immunotherapy.
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PMID:Natural T cell immunity against cancer. 1455 98

The fusion of a murine B cell and a myeloma cell generates a hybridoma that produces monoclonal antibody (mAb). These murine mAb induce the HAMA (human anti-mouse antibodies) response. Murine mAb have been modified by genetic engineering, producing molecules with a higher proportion of human protein. At present, chimeric, humanized and fully human mAb are available. mAb block interactions between target molecules and their ligands or trigger the lyses of mAb-coated tumor cells. Numerous mAb have been developed using the recombinant DNA technology and several are available in the market. Trastuzumab, against HER2/neu, is useful in breast cancer; rituximab, against CD20 in B lymphocytes is useful in lymphoma; alemtuzumah, against CD52 is used in lymphoma and leukemia; daclizumab and basiliximab block the IL-2 receptor interaction and reduce acute rejection in kidney transplantation; abciximab, an antagonist of GPIIb/IIIa platelet receptor, is used in patients undergoing acute coronary syndromes. In autoimmunity diseases, blocking tumor necrosis factor by infliximab and adalimumab has demonstrated excellent results. Thus, infliximab is useful in the treatment of rheumatoid arthritis (RA), Crohn's disease and ulcerative colitis while adalimumab is the first fully human mAb available for RA. Infliximab and adalimumab reduce signs and symptoms in RA and they also interfere with progression of joint damage. Finally, the direct benefits of antagonist treatment can occur at the expense of a major adverse effect in some other biological function.
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PMID:[New immunological weapons for medicine in the 21st Century: biological therapy based on the use of the latest generation monoclonal antibodies]. 1502 9

mAbs capable of disabling heterodimeric kinase complexes of the epidermal growth factor receptor (EGFR) and human EGFR type 2/neu have therapeutic relevance to various human cancers. In this study, we demonstrate that in addition to the dimer, EGFR and human EGFR type 2 can associate as homo- and heterotetramers. EGF-induced phosphorylation of the tetramers was significantly lower than that of the dimers, indicating that the tetrameric receptor complexes have impaired signaling activity. Targeting v-erb-b2 erythroblastic leukemia viral oncogene homolog (erbB) receptors with mAbs promoted erbB tetrameric assembly, suggesting that a component of the antitumor activity may be mediated by the ability of Abs to shift the equilibrium from active dimeric to impaired tetrameric receptor complex states. This study suggests a novel therapeutic approach to disable signaling of erbB and potentially other receptors in tumors by biologic agents capable of inducing receptor tetramerization.
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PMID:Targeted antireceptor therapy with monoclonal antibodies leads to the formation of inactivated tetrameric forms of ErbB receptors. 1720 65

Given the important prognostic and predictive utility of v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ErbB2) [human epidermal growth factor receptor-2 (HER2/neu)] in breast cancer, it is recommended that ErbB2 testing be performed on all invasive breast cancers at the time of diagnosis. A consensus, however, has not yet been reached as to the optimal method of evaluating ErbB2 status. Immunohistochemistry to detect protein overexpression and fluorescence in situ hybridization (FISH) to detect ErbB2 gene amplification are the most frequently used methods. As no one detection method fulfills all necessary requirements of reliability, reproducibility, and ease of use, we developed a novel approach in the form of a simple assay we refer to as protein and gene double staining (PGDS) which simultaneously evaluates protein overexpression and gene amplification by combining immunohistochemistry with chromogenic in situ hybridization (CISH). A total of 134 invasive breast carcinomas, including 81 cases with a full-face section and 53 cases included in a tissue microarray (TMA), were assessed by PGDS, and the results were correlated with ErbB2 gene amplification status as determined by FISH. ErbB2 gene copy number determined by CISH analysis in the PGDS assay showed excellent concordance with that of FISH (correlation coefficient 0.82; P<0.001 with full-face section cases, and 0.98; P<0.001 with cases in a TMA). The overall concordance rate for gene amplification status between PGDS and FISH was 90.12% in cases with a full-face section and 92.45% with TMA cases. Perfect correlation was seen between the PGDS assay and FISH in cases that were considered either nonamplified or highly amplified by the dual assay. Of the 17 cases that showed low amplification by PGDS, 5 were classified as nonamplified by FISH. Correction for chromosome 17 copy number in the FISH assessment contributed to the discordance between CISH and FISH results. This newly developed PGDS method represents a novel approach to ErbB2 status determination that combines the assessment of both protein overexpression and gene amplification in one simple assay. It is likely that this assay will aid in immunohistochemical calibration and will also increase the sensitivity and specificity of ErbB2 testing.
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PMID:PGDS, a novel technique combining chromogenic in situ hybridization and immunohistochemistry for the assessment of ErbB2 (HER2/neu) status in breast cancer. 1772 Dec 78

Forkhead box protein P3 (FOXP3) contributes to a unique transcriptional signature and serves as a functional marker of CD4(+)CD25(+) natural regulatory T cells. Dysfunction of FOXP3 in human is associated with fatal autoimmune disease known as immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) or X-linked autoimmunity-allergic disregulation syndrome (XLAAD). FOXP3 also can act as a breast tumor suppressor of the v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (neuro/glioblastoma derived oncogene homolog (avian)) (Her2/neu) gene. While the suppressive functions of FOXP3 in maintaining the immune balance between tolerance and autoimmunity are obvious, the underlying molecular mechanism remains almost entirely undefined. Recent studies indicate that FOXP3 may form a dynamic superamolecular complex with a variety of molecular partners including transcription factors and enzymatic proteins to regulate transcription. How the FOXP3 ensemble changes in response to T-cell receptor signals and/or proinflammatory signal remains unclear although work from this laboratory has revealed its complexity. Structural information on FOXP3 complex may offer novel functional insights, as well as facilitate the development of rational means to modulate regulatory T-cell function in various human diseases.
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PMID:FOXP3 and its partners: structural and biochemical insights into the regulation of FOXP3 activity. 1862 75

Overexpression and activation of the steroid receptor coactivator amplified in breast cancer 1 (AIB1)/steroid receptor coactivator-3 (SRC-3) have been shown to have a critical role in oncogenesis and are required for both steroid and growth factor signaling in epithelial tumors. Here, we report a new mechanism for activation of SRC coactivators. We demonstrate regulated tyrosine phosphorylation of AIB1/SRC-3 at a C-terminal tyrosine residue (Y1357) that is phosphorylated after insulin-like growth factor 1, epidermal growth factor, or estrogen treatment of breast cancer cells. Phosphorylated Y1357 is increased in HER2/neu (v-erb-b2 erythroblastic leukemia viral oncogene homolog 2) mammary tumor epithelia and is required to modulate AIB1/SRC-3 coactivation of estrogen receptor alpha (ERalpha), progesterone receptor B, NF-kappaB, and AP-1-dependent promoters. c-Abl (v-Abl Abelson murine leukemia viral oncogene homolog 1) tyrosine kinase directly phosphorylates AIB1/SRC-3 at Y1357 and modulates the association of AIB1 with c-Abl, ERalpha, the transcriptional cofactor p300, and the methyltransferase coactivator-associated arginine methyltransferase 1, CARM1. AIB1/SRC-3-dependent transcription and phenotypic changes, such as cell growth and focus formation, can be reversed by an Abl kinase inhibitor, imatinib. Thus, the phosphorylation state of Y1357 can function as a molecular on/off switch and facilitates the cross talk between hormone, growth factor, and intracellular kinase signaling pathways in cancer.
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PMID:Tyrosine phosphorylation of the nuclear receptor coactivator AIB1/SRC-3 is enhanced by Abl kinase and is required for its activity in cancer cells. 1876 37


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