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)

Chronic myeloid leukemia is still the most characteristic entity of the chronic myeloproliferative diseases. The tumor promoter role of able-dependent tyrosine kinase activation, which is enhanced by bcr/abl rearrangement (due the classical translocation of Philadelphia chromosomal abnormality) has been quite well clarified. The better understanding of the role of altered cell signalling pathways in the pathogenesis of chronic myeloid leukaemia opened new areas for extensive and fruitful pharmacological research. The first, non-myelosuppressive agent, which was able to reduce the number of Philadelphia positive clonal cells was the interferon group, which drug could substantially prolong the chronic phase and mortality of chronic myeloid leukaemia. Imatinib mesylate, a tyrosine-kinase inhibitor seems to be able to produce clinical and major cytogenetic response in more than 80% of patients. Imatinib is also a powerful agent in the accelerated or blastic phased of chronic myeloid leukaemia. With the advent of these new drugs the therapeutic algorithm of chronic myeloid leukaemia and allogenous bone marrow transplantation seems to be reconsidered, too.
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PMID:[Chronic myeloid leukemia]. 1577 11

The diagnostic and treatment options for patients with GIST have evolved rapidly with the discovery of uncontrolled KIT tyrosine kinase and Gleevec that selectively inhibits Kit. Gleevec has already revolutionized the treatment of patients with metastatic disease and is also currently being tested as an adjuvant therapy after the resection of primary GIST. But the majority of responses are limited to partial responses and secondary resistances are emerging. These observations suggest that initial surgical resection remains a vital component of the treatment for patients with primary resectable cKIT+ GISTs and raises the question of secondary surgery after Gleevec. The objective of secondary surgery is to obtain a complete remission when the response to Gleevec is maximum. Surgery should be discussed between 6 and 12 months treatment when no additional improvement is observed on 2 consecutive CT scan. Three subgroups may benefit from secondary surgery: primary unresectable tumors amenable to surgery with Gleevec even in case of complete response, huge necrotic masses before expected complication, local re-progressions. Gleevec should also be discussed when a functionnal benefit can be expected by a tumor size decrease. Surgery is being evaluated in the other responding patients. The majority of responses being limited to partial responses, best indications of surgery are when complete resection may be expected (< 10%).
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PMID:[Surgical management of GIST in the era of Gleevec]. 1578 16

Imatinib mesylate is a novel anti-tumor agent useful in the clinical management of chronic myelogenous leukemia and gastrointestinal stromal tumors with minimal toxicity relative to other forms of cancer therapy. Its clinical activity and minimal toxicity are related to specific inhibition of cellular targets including BCR-ABL, platelet-derived growth factor receptor and c-kit kinases, resulting in the collapse of downstream signaling cascades important for transformation. In some patients, unexpected toxicities arise that are not associated with inhibition of any known cellular imatinib target. In this report, we investigated the effects of imatinib on squamous carcinoma cell signaling. Imatinib induced expression of COX-2 in a dose-dependent manner with concomitant accumulation of prostaglandin E2. COX-2 induction by imatinib was initiated through epidermal growth factor (EGF) receptor kinase activation and downstream signaling through mitogenic-activated protein kinase. COX-2 induction by imatinib was blocked by MEK1 or EGF receptor inhibition. Imatinib did not activate stressor cytokine-signaling pathways (p38 kinase, nuclear factor-kB nuclear translocation) or affect COX-1 expression. Imatinib failed to activate EGF receptor signals in other tumor types, suggesting that COX-2 induction in imatinib-treated cells is mediated through release of autocrine factors expressed or activated in squamous tumors. COX-2 induction by imatinib in squamous tumors derived from the head and neck region is unique with respect to other target-specific agents and may represent one of the unintended toxic effects of imatinib described in some patients.
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PMID:Cyclooxygenase-2 induction and prostaglandin E2 accumulation in squamous cell carcinoma as a consequence of epidermal growth factor receptor activation by imatinib mesylate. 1584 61

Gastrointestinal stromal tumor (GIST), a form of soft-tissue sarcoma, is the most common noncarcinomatous tumor of the gastrointestinal tract. Despite its high incidence of recurrence, the malignant potential of GIST has been under-recognized. Advances in diagnostic technology since 2000 have led to increased diagnoses of GIST, suggesting that GIST is more common than previously suspected. Historically, the only treatment for GIST was surgical resection, but recent advances in the understanding of the pathogenesis of the disease have led to the development of a new treatment. A key factor in the growth and survival of cancerous GIST cells is the uncontrolled activation of a signaling enzyme known as KIT, a receptor tyrosine kinase, which becomes locked in an activated state. The abnormal signaling from the overactive KIT enzyme causes GIST cells to survive and proliferate uncontrollably. Imatinib mesylate is an oral drug designed to inhibit the kinase enzyme activity of KIT. Imatinib has been proven in several clinical trials to be effective against GIST and is currently the firstline medical therapy for malignant metastatic or recurrent GIST. Imatinib is administered as an outpatient oral drug and warrants nursing management with particular attention to potential side effects, significant drug interactions, monitoring, and patient education. This article--based on published trials and clinical experience--summarizes the nursing implications, clinical efficacy, and safety of imatinib as an effective and rationally targeted treatment for GIST.
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PMID:Nursing implications of imatinib as molecularly targeted therapy for gastrointestinal stromal tumors. 1585 60

Prostate cancer cells metastasize to the bone where their interaction with osteoclasts and osteoblasts can lead to alterations in the structure of the bone. We determined whether the systemic administration of the bisphosphonate, zoledronate, could prevent bone lysis and halt the proliferation of human prostate cancer cells injected into the tibia of nude mice. Zoledronate did not affect the in vitro proliferation of human prostate cancer PC-3MM2 cells. The in vivo administration of zoledronate produced significant bone preservation but did not inhibit the progressive growth of PC-3MM2 cells. The systemic administration of STI571 (imatinib mesylate, Gleevec), an inhibitor of phosphorylation of the platelet-derived growth factor receptor, in combination with paclitaxel, produced apoptosis of tumor cells and bone- and tumor-associated endothelial cells. The systemic administration of zoledronate with STI571 and paclitaxel produced a significant preservation of bone structure, a decrease in tumor incidence and weight, and a decrease in incidence of lymph node metastasis. This therapeutic activity was correlated with inhibition of osteoclast function, inhibition of tumor cell proliferation, and induction of apoptosis in tumor-associated endothelial cells and tumor cells. Cancer is a heterogeneous disease that requires multimodality therapy. The present data recommend the combination of a bisphosphonate agent with protein tyrosine kinase inhibitor and an anticycling drug for the treatment of prostate cancer bone metastasis.
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PMID:Modulation of bone microenvironment with zoledronate enhances the therapeutic effects of STI571 and paclitaxel against experimental bone metastasis of human prostate cancer. 1586 66

The authors report a unique case of an intra-abdominal, epithelioid mesenchymal tumor that had an activating mutation of PDGFRA and a strong PDGFRA immunoreactivity but lacked both c-kit mutation and c-kit protein (CD117) expression. IHC study showed that the tumor cells were diffusely and strongly positive for PDGFRA, vimentin, CD34, and Bcl-2 but completely negative for CD117 as well as for muscle, epithelial, endothelial, endocrine, mesothelial, neural, and melanocytic cell markers. Molecular study revealed a mutation at the juxtamembrane domain of exon 12 in PDGFRA gene with GTC to GAC transition at codon 561 (V561D), as shown in the previous mutational studies on gastrointestinal stromal tumor (GIST). This case likely represents an example of GIST with PDGFRA activating mutation and PDGFRA immunoreactivity without CD117 positivity, which has not been documented in the literature. STI 571 (imatinib mesylate [Gleevec]) might be an effective therapy in this case, since Gleevec targets both PDGFRA and c-kit oncoproteins.
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PMID:Epithelioid gastrointestinal stromal tumor with PDGFRA activating mutation and immunoreactivity. 1589 28

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm arising in the stomach. These tumors were previously classified as smooth muscle tumors, but in recent years it has become clear that they are clinically, pathologically, and molecularly distinct from other tumors and are much more common than previously appreciated. Historically, patients with primary localized or advanced GIST have been managed surgically, as there was no proven role of other treatment modalities such as radiation or chemotherapy. However, the field of GIST was revolutionized with the 1998 discovery that the vast majority of these tumors have oncogenic gain-of-function mutations of the KIT receptor tyrosine kinase. Follow-up studies have confirmed that KIT is both a useful diagnostic marker and an excellent therapeutic target. Imatinib, an inhibitor of KIT kinase activity, is now the standard front-line therapy for patients with advanced GIST. In this review, we discuss pathological and molecular features of gastric GISTs and review the historic and current roles of surgery in the treatment of patients with primary or metastatic GIST. The importance of a multi-disciplinary approach using both surgery and imatinib therapy is emphasized.
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PMID:Gastric GI stromal tumors (GISTs): the role of surgery in the era of targeted therapy. 1589 40

The therapy of choice of resectable GIST is complete surgical removal of the tumor. Lymphadenectomy is not necessary. Following R0 resection of the primary tumor long term follow up of the patients is essential. In case of high risk primary (large tumor, high proliferation rate) patients are encouraged to participate in clinical trials administering imatinib mesylate as adjuvant therapy. Patients with non-resectable, residual, locally recurrent or metastatic GIST should be treated with 400 mg/day imatinib mesylate (Glivec). In case of primary imatinib resistance patients are advised to participate in clinical trials of new tyrosine kinase inhibitors. In secondary imatinib resistance the daily dose of the drug should be increased up to 800 mg. If further progression occurs one of the new tyrosine kinase inhibitors can be tested in clinical trials. If an originally non-resectable GIST can be rendered resectable with "neoadjuvant" imatinib therapy, removal of the tumor should be considered. If resection is not possible imatinib treatment should be continued until progression or toxicity. Efficacy of imatinib therapy can be monitored by CT, MR or PET scans. Treatment of patients with GIST is multidisciplinary, needing strong cooperation among surgical- and medical oncologists, pathologists and imaging specialists. The complex therapy of GIST patients is ideally performed at specialized oncological centers.
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PMID:[Current aspects of treatment in gastrointestinal stromal tumors (GIST)]. 1592 8

The successful period of targeted molecular therapy of malignancies started with the beneficial clinical application of trastuzumab and imatinib. Imatinib is a targeted molecule capable to inhibit tyrosine kinase active in the production of abl-bcr protein responsible for the translocation of 9 and 22 chromosome in chronic myeloid leukemia. Simultaneously the drug may be active against C-kit PDGFRalpha and beta, COL 1a1 and FIPI-LI gene mutations as well. Consequently, imatinib exerts a therapeutic effect upon chronic myeloid leukemia, gastrointestinal stroma tumor, dermatofibrosarcoma protuberans and hypereosinophilic syndroma. Besides, several studies are ongoing in other solid tumours characterized by those mutations, which might be blocked through imatinib treatment. Studies are in progress determining the place of imatinib in the "complex therapy". Resistance developed against the drug may be overcome by new molecules, such as SU 11248 or everolimus. It can be stated that imatinib--a drug which is applied orally and has a highly tolerable toxicity profile--signifies a new perspective for a successful targeted molecular therapy.
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PMID:[Clinical studies with imatinib in 2004]. 1592 9

In the past 10 years, progress made in cancer biology, genetics, and biotechnology has led to a major transition in cancer drug design and development. There has been a change from an emphasis on non-specific, cytotoxic agents to specific, molecular-based therapeutics. Mechanism-based therapy is designed to act on cellular and molecular targets that are causally involved in the formation, growth, and progression of human cancers. These agents, which may have greater selectivity for cancer versus normal cells, and which may produce better anti-tumor efficacy and lower host toxicity, can be small molecules, natural or engineered peptides, proteins, antibodies, or synthetic nucleic acids (e.g. antisense oligonucleotides, ribozymes, and siRNAs). Novel targets are identified and validated by state-of-the-art approaches, including high-throughput screening, combinatorial chemistry, and gene expression arrays, which increase the speed and efficiency of drug discovery and development. Examples of oncogene-based, molecular therapeutics that show promising clinical activity include trastuzumab (Herceptin), imatinib (Gleevec), and gefitinib (Iressa). However, the full potential of oncogenes as novel targets for cancer therapy has not been realized and many challenges remain, from the validation of novel targets, to the design of specific agents, to the evaluation of these agents in both preclinical and clinical settings. In maximizing the benefits of molecular therapeutics in monotherapy or combination therapy of cancer, it is necessary to have an understanding of the underlying molecular abnormalities and mechanisms involved. This is the first part of a four-part review in which we discuss progress made in the last decade as it relates to the discovery of novel oncogenes and signal transduction pathways, in the context of their potential as targets for cancer therapy. This part delineates the latest discoveries about the potential use of growth factors and protein tyrosine kinases as targets for therapy. Later parts focus on intermediate signaling pathways, transcription factors, and proteins involved in cell cycle, DNA damage, and apoptotic pathways.
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PMID:Oncogenes as novel targets for cancer therapy (part I): growth factors and protein tyrosine kinases. 1595 71


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