Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009402 (colorectal cancer)
 53,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The epidermal growth factor receptor (EGFR) is widely expressed in advanced colorectal cancers (CRCs), and higher levels of EGFR are inversely related to survival in these patients. Two general strategies have been used to block EGFR signaling: preventing ligand binding with anti-EGFR monoclonal antibodies (eg, cetuximab and ABX-EGF) and inhibiting its intrinsic tyrosine kinase with small molecules (eg, gefitinib [Iressa] and erlotinib [OSI-774,Tarceva]). Phase II trials of cetuximab suggest that it might be an effective treatment option alone or in combination with standard therapies as first- or second-line therapy. Phase I studies evaluating other EGFR inhibitors in patients with CRC have been reported. The inclusion of anti-EGFR therapies into standard treatment is the subject of current clinical trials.
Clin Colorectal Cancer 2003 Feb
PMID:Epidermal growth factor receptor as a therapeutic target in colorectal cancer. 1262 Jan 47

Inhibitors of epidermal growth factor receptor tyrosine kinase (EGFR-TK) activity have shown promise as novel anticancer agents in a variety of common solid tumors. In preclinical studies and phase I trials, tumor responses to EGFR-TK inhibitors (EGFR-TKIs), such as gefitinib (Iressa, AstraZeneca Pharmaceuticals LP, Wilmington, DE) and erlotinib (Tarceva, OSI Pharmaceuticals, Melville, NY, and Genentech, Inc., South San Francisco, CA) were observed in heavily pretreated patients with advanced non-small cell lung cancer (NSCLC), head and neck cancer, breast cancer, colorectal cancer, and other solid tumors. Subsequent phase II studies resulted in tumor responses, disease stabilization, symptom improvement, and improved quality of life in patients with advanced NSCLC who had received prior platinum-based chemotherapy or platinum and docetaxel chemotherapies. Side effects related to treatment with EGFR-TKIs were generally mild, reversible, and noncumulative. Severity and frequency of drug-related adverse events were related directly to dose. The potential role of EGFR-TKIs in treating other solid tumors currently is being studied. Furthermore, research is being conducted to explore the potential use of EGFR-TKIs in novel combinations with chemotherapy, radiation therapy, endocrine therapy, and other molecular targeted therapies.
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PMID:Epidermal growth factor receptor tyrosine kinase inhibitors: evolving role in the treatment of solid tumors. 1510 18

Angiogenesis is a strongly regulated process, which is dependent upon a complex interplay between inhibitory and stimulatory angiogenic factors. It is essential for tumor growth and metastasis: increased angiogenesis is correlated with poor prognosis in cancer patients. Many novel compounds that potently inhibit formation of neoplastic blood vessels have been recently developed. Major categories of angiogenesis antagonists include protease inhibitors, direct inhibitors of endothelial cell proliferation and migration, angiogenic growth factor suppressors, inhibitors of endothelial-specific integrin/survival signalling, copper chelators, and inhibitors with other specific mechanisms. There is increasing interest in developing angio-suppressive agents for colorectal cancer treatment. Some 20 direct and indirect antiangiogenesis drugs are currently being evaluated in clinical trials in colorectal cancer (CRC). Promising results have been reported. These include an increase in overall survival and reduction in the risk of death (Bevacizumab), reversal of cellular resistance (Cetuximab) and activity as second-line therapy in patients who have exhausted other available treatment options (Cetuximab, ABX-EGF, PTK-787, Gefitinib, Erlotinib). This review will outline the mechanisms of action of the principal antiangiogenic drugs, summarize the available data on the use of these new drugs in colorectal cancer, discuss their impact in clinical practice and offer a glimpse into how antiangiogenetic therapy will be integrated into the future care of patients with gastrointestinal cancers.
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PMID:Colorectal cancer and antiangiogenic therapy: what can be expected in clinical practice? 1589 May 25

Receptor and non-receptor tyrosine kinases (TKs) have emerged as clinically useful drug target molecules for treating gastrointestinal cancer. Imatinib mesilate (STI-571, Gleevec(TM)), an inhibitior of bcr-abl TK, which was primarily designed to treat chronic myeloid leukemia is also an inhibitor of c-kit receptor TK, and is currently the drug of choice for the therapy of metastatic gastrointestinal stromal tumors (GISTs), which frequently express constitutively activated forms of the c-kit-receptor. The epidermal growth factor receptor (EGFR), which is involved in cell proliferation, metastasis and angiogenesis, is another important target. The two main classes of EGFR inhibitors are the TK inhibitors and monoclonal antibodies. Gefitinib (ZD1839, Iressa(TM)) has been on trial for esophageal and colorectal cancer (CRC) and erlotinib (OSI-774, Tarceva(TM)) on trial for esophageal, colorectal, hepatocellular, and biliary carcinoma. In addition, erlotinib has been evaluated in a Phase III study for the treatment of pancreatic cancer. Cetuximab (IMC-C225, Erbitux(TM)), a monoclonal EGFR antibody, has been FDA approved for the therapy of irinotecan resistant colorectal cancer and has been tested for pancreatic cancer. Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) are critical regulators of tumor angiogenesis. Bevacizumab (Avastin(TM)), a monoclonal antibody against VEGF, was efficient in two randomized clinical trials investigating the treatment of metastatic colorectal cancer. It is also currently investigated for the therapy of pancreatic cancer in combination with gemcitabine. Other promising new drugs currently under preclinical and clinical evaluation, are VEGFR2 inhibitor PTK787/ZK 222584, thalidomide, farnesyl transferase inhibitor R115777 (tipifarnib, Zarnestra(TM)), matrix metalloproteinase inhibitors, proteasome inhibitor bortezomib (Velcade(TM)), mammalian target of rapamycin (mTOR) inhibitors, cyclooxygenase-2 (COX-2) inhibitors, platelet derived growth factor receptor (PDGF-R) inhibitors, protein kinase C (PKC) inhibitors, mitogen-activated protein kinase kinase (MEK) 1/2 inhibitors, Rous sarcoma virus transforming oncogene (SRC) kinase inhibitors, histondeacetylase (HDAC) inhibitors, small hypoxia-inducible factor (HIF) inhibitors, aurora kinase inhibitors, hedgehog inhibitors, and TGF-beta signalling inhibitors.
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PMID:Molecularly targeted therapy for gastrointestinal cancer. 1589 18

Bevacizumab (Avastin) has unprecedented survival benefit in patients with metastatic colorectal cancer. Trials are already in progress to investigate the potential of bevacizumab in indications including metastatic renal cell cancer (RCC), non-small cell lung cancer (NSCLC), pancreatic cancer, breast and ovarian cancer. Bevacizumab offers the potential to increase survival without substantially altering the toxicity profile in these tumor types. Bevacizumab has shown activity in patients with refractory metastatic RCC, where progression-free survival (PFS) was significantly longer in patients treated with bevacizumab (10 mg/kg every 2 weeks) than those treated with placebo (hazard ratio=2.55, p<0.001). In addition, combining bevacizumab with erlotinib (Tarceva) has shown a median time to progression of more than 11 months. In NSCLC, a phase II trial revealed that adding bevacizumab to chemotherapy increased therapeutic benefit compared with chemotherapy alone. Adverse events were mild and easily managed, but six patients receiving bevacizumab developed severe hemoptysis. Entry criteria for NSCLC trials have been adjusted to exclude patients with squamous cell histology to try to avoid this issue. Adding bevacizumab (10 mg/kg) to the current standard of care, gemcitabine, in stage IV pancreatic cancer has also shown promising efficacy. Partial responses were seen in 19% of patients, with a further 48% having stable disease. Several ongoing clinical trials are also studying bevacizumab with various chemotherapy and radiotherapy regimens. Bevacizumab combined with carboplatin (Paraplatin)/paclitaxel (Taxol) was further examined in a phase III randomized trial that accrued 878 patients with advanced non-squamous cell NSCLC. Patients given chemotherapy (paclitaxel and carboplatin) plus bevacizumab had a higher response rate, longer PFS and an increase in survival compared with patients on chemotherapy alone. Both regimens were generally well tolerated. Bevacizumab has also shown activity in patients with metastatic breast cancer. In 715 patients, a significant, 2-fold increase in response rate was observed in patients receiving bevacizumab plus paclitaxel compared with paclitaxel alone. Median PFS was also significantly increased (p<0.001). Bevacizumab has the potential to provide significant efficacy benefits for patients with metastatic RCC, NSCLC, pancreatic cancer, and other tumor types when used first line in combination with standard therapy.
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PMID:Investigating the potential of bevacizumab in other indications: metastatic renal cell, non-small cell lung, pancreatic and breast cancer. 1630 35

Several monoclonal antibodies directed against EGFR are currently in clinical evaluation and include notably the agent cetuximab (C225). Tyrosine kinase inhibitors have chemical structures close to that of ATP and are thus ATP competitors on the tyrosine kinase site (ATP pocket) which is located in the intracellular domain of EGFR (gefitinib and erlotinib, respectively Tarceva and Iressa being the most advanced in clinical development). Well-conducted experimental studies open the way to new clinical applications with the most rewarding currently being the association between cetuximab and irinotecan. The two approaches of EGFR targeting have the same target and similar intracellular molecular impacts but they may differ under several aspects. For instance for the mechanism of action where, for monoclonal antibodies, there is a potential complement of cytotoxic activity brought by the ADCC phenomenon (antibody-directed cell cytotoxicity). One of the main current questions about the clinical use of anti-EGFR drugs is to dispose of faithful predictors for identifying tumors sensitive to this targeted treatment. The agents targeting VEGF are conceptually the same to those applied to EGFR. A major therapeutic advance brought by antiangiogenic drugs in colorectal cancer is attributable to bevacizumab. Bevacizumab is a monoclonal antibody impacting VEGF itself. A controlled clinical trial recently conducted on more than 800 advanced colorectal cancer patients concluded to a significant improvement in both response rate and global survival. This trial was comparing the combination 5FU-leucovorin-bevacizumab to 5FU-leucovorin and the advantage was in favor of the triple combination.
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PMID:[Pharmacological skills for targeting EGFR and VEGF]. 1638 65

Erlotinib (Tarceva, OSI-774), a potent epidermal growth factor receptor tyrosine kinase inhibitor (EGFR), was evaluated in a phase II study to assess its activity in patients with metastatic colorectal cancer. In all, 38 patients with metastatic colorectal cancer were treated with erlotinib at a continuous daily oral dose of 150 mg. Radiological evaluation was carried out every 8 weeks and tumour biopsies were performed before treatment and on day 8. Of 31 evaluable patients, 19 (61%) had progressive disease and 12 (39%) had stable disease (s.d.). The median time to progression for those patients having s.d. was 123 days (range 108-329 days). The most common adverse events were rash in 34 patients and diarrhoea in 23 patients. Correlative studies were conducted to investigate the effect of erlotinib on downstream signalling. Tumour tissue correlations were based on usable tissue from eight match paired tumour samples pre- and on therapy, and showed a statistically significant decrease in the median intensity of both pEGFR (P=0.008) and phospho-extracellular signal-regulated kinase (ERK) (P=0.008) a week after commencement of treatment. No other statistically significant change in tumour markers was observed. Erlotinib was well tolerated with the most common toxicities being rash and diarrhoea. More than one-third of evaluable patients had s.d. for a minimum of 8 weeks. Correlative studies showed a reduction in phosphorylated EGFR and ERK in tumour tissue post-treatment.
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PMID:Phase II study of erlotinib (OSI-774) in patients with metastatic colorectal cancer. 1657 47

AREG (Amphiregulin), BTC (beta-cellulin), EGF, EPGN (Epigen), EREG (Epiregulin), HBEGF, NRG1, NRG2, NRG3, NRG4 and TGFA (TGFalpha) constitute EGF family ligands for ERBB family receptors. Cetuximab (Erbitux), Pertuzumab (Omnitarg) and Trastuzumab (Herceptin) are anti-cancer drugs targeted to EGF family ligands, while Gefitinib (Iressa), Erlotinib (Tarceva) and Lapatinib (GW572016) are anti-cancer drugs targeted to ERBB family receptors. AREG and TGFA are biomarkers for Gefitinib non-responders. The TCF/LEF binding sites within the promoter region of human EGF family members were searched for by using bioinformatics and human intelligence (Humint). Because three TCF/LEF-binding sites were identified within the 5'-promoter region of human AREG gene, comparative genomics analyses on AREG orthologs were further performed. The EPGN-EREG-AREG-BTC cluster at human chromosome 4q13.3 was linked to the PPBP-CXCL segmental duplicons. AREG was the paralog of HBEGF at human chromosome 5q31.2. Chimpanzee AREG gene, consisting of six exons, was located within NW_105918.1 genome sequence. Chimpanzee AREG was a type I transmembrane protein showing 98.0% and 71.4% total amino-acid identity with human AREG and mouse Areg, respectively. Three TCF/LEF-binding sites within human AREG promoter were conserved in chimpanzee AREG promoter, but not in rodent Areg promoters. Primate AREG promoters were significantly divergent from rodent Areg promoters. AREG mRNA was expressed in a variety of human tumors, such as colorectal cancer, liver cancer, gastric cancer, breast cancer, prostate cancer, esophageal cancer and myeloma. Because human AREG was characterized as potent target gene of WNT/beta-catenin signaling pathway, WNT signaling activation could lead to Gefitinib resistance through AREG upregulation. AREG is a target of systems medicine in the field of oncology.
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PMID:Canonical WNT signaling pathway and human AREG. 1668 31

Anti-EGFR (epidermal growth factor receptor) therapies, including tyrosine kinase inhibitors (TKIs) and monoclonal antibodies, demonstrate activity in a variety of tumor types. While both inhibit the EGFR pathway, they act via different mechanisms. Monoclonal antibodies bind to the extracellular domain of EGFR, preventing ligand binding and interrupting the signaling cascade. Tyrosine kinase inhibitors bind to the intracellular domain of EGFR and inhibit the downstream effects of EGFR ligand binding. Both categories of agents have been evaluated in a variety of clinical settings and tumor types, including colorectal cancer, non-small-cell lung cancer (NSCLC), and squamous cell carcinoma of the head and neck (SCCHN). Phase II/III trials in patients with previously treated or untreated metastatic colorectal cancer, including those with documented refractory disease, demonstrate activity of the monoclonal antibody cetuximab (Erbitux) as a single agent or in combination with both irinotecan (Camptosar)- and oxaliplatin (Eloxatin)-based chemotherapy. Activity of cetuximab added to chemotherapy in patients who previously progressed on the same regimen suggests an ability to overcome chemotherapy resistance in some patients. In NSCLC, phase II trials of the TKI gefitinib (Iressa) plus combination chemotherapy showed impressive activity with considerable toxicity. Large, randomized, phase II trials (IDEAL 1 and 2) reported modest activity of gefitinib in NSCLC; however, phase III trials (INTACT 1 and 2)failed to demonstrate a benefit to adding gefitinib to chemotherapy. A similar trend was noted in trials of erlotinib (Tarceva) (TALENT and TRIBUTE). Phase II/III trials have shown promising activity of cetuximab in SCCHN, generating significantly improved survival in combination with radiotherapy over radiotherapy alone in locally advanced disease and significantly improved response rates in combination with chemotherapy over chemotherapy alone in recurrent/metastatic disease, with little enhancement of toxicity profiles. Limited clinical experience with TKIs in SCCHN suggests similar degrees of single-agent activity and dermatologic toxicities. Levels of EGFR expression and the presence of EGFR mutations correlate with responsiveness to TKI therapy, while it remains unclear whether a relationship exists between level of EGFR expression and cetuximab efficacy in colorectal cancer. Anti-EGFR therapies are good candidates for combination with other treatment modalities, including chemotherapy and radiotherapy, due to their tolerable safety profile and nonoverlapping toxicities. In addition, these agents represent important treatment options in patients ineligible for chemotherapy due to refractory or resistant disease. Ongoing trials continue to investigate both the monoclonal antibodies and TKIs in various treatment settings.
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PMID:Anti-EGFR therapies: clinical experience in colorectal, lung, and head and neck cancers. 1673 79

New cancer-specific therapies are based on specific molecular alterations of malignant tumors which are targeted by small inhibitory molecules or specific antibodies. During the development of these agents potential molecular targets are characterized for their expression and importance for pathogenesis and clinical course of the disease. Frequently the assumption is made that the degree of expression of the target protein or the molecular alteration of the target gene allows a prediction if a certain patient will profit from the therapy against this specific protein or not. The first example was that breast cancer patients with overexpression and/or amplification of Her-2 respond to a Her-2-specific antibody (Herceptin) therapy. The expression or activation of the Epidermal Growth Factor Receptor (EGFR, Her-1) are altered in many epithelial tumours and clinical studies indicate that they have important roles in tumor aetiology and progression. Several EGFR-specific monoclonal antibodies and specific tyrosine kinase inhibitors were developed in the last years. Cetuximab is approved for the treatment of metastatic colorectal cancer and advanced squamous cell carcinoma of the head and neck and is investigated in numerous trials for other tumors. The expression of EGFR in the tumor was a prerequisite for the therapy in the first trials, giving the pathologist a central role in treatment decision. However, recent data clearly demonstrate that the degree of EGFR expression does not correlate with therapy response. Therefore a therapy should be not denied to a individual patient solely because of lack of EGFR expression in the tumor. Tyrosine kinase inhibitors (e. g. Gefitinib, Erlotinib) are effective in the treatment of non small cell lung cancer and also investigated in ongoing trials in many cancer types. The correlation of therapy response with both specific molecular alterations (EGFR tyrosine kinase domain mutations) and clinicopathological features (Asian ethnicity, women, non-smokers, bronchioloalveolar differentation) is a good example of the potential role of predictive molecular pathology in the future.
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PMID:[Role of predictive pathology in oncology--example of new therapies targeting EGFR]. 1786 89


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