• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제35권5호
• /
• pp.287-293
• /
• 2009

Cell survival is the result of a balance between programmed cell death and cellular proliferation. Cell membrane receptors and their associated signal transducing proteins control these processes. Of the numerous receptors and signaling proteins, epidermal growth factor receptor (EGFR) is one of the most important receptors involved in signaling pathways implicated in the proliferation and survival of cancer cells. EGFR is often highly expressed in human tumors including oral squamous cell carcinomas, and there is increasing evidence that high expression of EGFR is correlated with poor clinical outcome of common human cancers. Therefore, we examined the antiproliferative activity of gefitinib, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), in head and neck cancer cell lines. SCC-9, KB cells were cultured and growth inhibition activity of gefitinib was measured with MTT assay. To study influence of gefitinib in cell cycle, we performed cell cycle analysis with flow cytometry. Western blot was done to elucidate the expression of EGFR in cell lines and phosphorylation of EGFR and downstream kinase protein, Erk and Akt. Significant growth inhibition was observed in SCC-9 cells in contrast with KB cells. Also, flow cytometric analysis showed G1 phase arrest only in SCC-9 cells. In Western blot analysis for investigation of EGFR expression and downstream molecule phosphorylation, gefitinib suppressed phosphorylation of EGFR and downstream protein kinase Erk, Akt in SCC-9. However, in EGFR positive KB cells, weak expression of active form of Erk and Akt and no inhibitory activity of phosphorylation in Erk and Akt was observed. The antiproliferative activity of gefitinib was not correlated with EGFR expression and some possibility of phosphorylation of Erk and Akt as a predictive factor of gefitinib response was emerged. Further investigations on more reliable predictive factor indicating gefitinib response are awaited to be useful gefitinib treatment in head and neck cancer patients.

• 대한두경부종양학회지
• /
• 제15권2호
• /
• pp.156-161
• /
• 1999

Objectives: The epidermal growth factor receptor(EGFR) family has been increasingly recognized as an important component in the control of normal cell proliferation and the pathogenesis of cancer. To confirm the usefulness of epidermal growth factor receptor as a tumor marker, we initiated this study. Materials and Methods: EGFR was measured by immunohistochemical staining using EGFR antibody. It was performed on section from paraffin blocks of 65 thyroid tissue including 33 paillary carcinoma, 11 follicular carcinoma, 11 nodular hyperplasia, 5 follicular adenoma and 5 normal thyroid tissue. We evaluated morphologic characteristic of various thyroid neoplasms, and the relationship between EGFR and other prognostic factors in papillary thyroid carcinomas. Results: The expression of EGFR was commonly found in neoplasms of thyroid, with trend for stronger staining in the more malignant tumor(p=0.000). Also the expression of EGFR in papillary thyroid cancer related to tumor characters including tumor size(p=0.042), extent(p=0.024) and prognostic features including AMES scores(p=0.019). The strong EGFR staining in papillary carcinoma was significantly associated with tumor recurrence(p=0.003). Conclusions: EGFR may have a role in the regulation of normal and neoplastic thyroid cell growth. EGFR status may help predict the clinical course of patients with malignant thyroid neoplasms. However, the study of more cases will be needed for significance of the information about the EGFR as an independent prognostic factor.

• 한국임상약학회지
• /
• 제18권2호
• /
• pp.75-83
• /
• 2008

Purpose: Currently lung cancer ranks second in cancer for incidence rate and is a disease that ranks first for a death rate by cancerous growth because it is already advanced at the time of diagnosis. The purpose of this paper was to analyze the factors that affect the effectiveness of and rash occurrence by Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor (EGFR TKI) in patients with non-small cell lung cancer. Methods: A retrospective chart review of 100 patients, who took EGFR TKI (erlotinib, gefitinib) among patients who were diagnosed with non-small cell lung cancer in a Hospital in Korea between May 2005 and February 2008, was conducted. The drug effectiveness was evaluated by Response Evaluation Criteria In Solid Tumor. Results: EGFR mutation was the only factor associated with drug response (complete response and partial response). When stable disease was added to drug response as the evaluation parameter, ECOG and rash as well as EGFR mutation were found to be important factors. Survival, however, was not affected by EGFR mutation. The factors influenced on survival were older age (${\geq}65$), low ECOG ($1{\sim}2$), adenocarcinoma and rash. In the case of rash, group with EGFR mutation or low ECOG showed significantly higher chance of occurrence. There was no significant difference in rash occurrence between gefitinib and erlotinib groups. Conclusions: Based on the results, EGFR mutation positive and low ECOG ($1{\sim}2$) were significantly important factors for both effectiveness of EGFR TKI and rash occurrence. Also, rash itself was found to be an independently significant factor for the disease control and survival. Therefore, while administering EGFR TKI, patients who have the factors associated with rash occurrence should be closely monitored for effective and safe drug therapy.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제28권3호
• /
• pp.193-201
• /
• 2006

Squamous cell carcinoma(SCC) of head and neck(SCCHN) is the sixth most common human malignant tumor. However, despite advances in prevention and treatment of SCC, the five-year survival rates for patients remain still low. To improve the outcome for patients with SCCHN, novel treatment strategies are needed. Overexpression of the epidermal growth factor(EGF) and activation of its receptor(EGFR) are associated with progressive growth of SCCHN. Vascular endothelial growth factor(VEGF) signaling molecules are related with neoangiogenesis and vascular metastasis of SCC. In this study, we determined the therapeutic effect of AEE788(Novartis Pharma AG, Basel, Switzerland), which is a dual inhibitor of EGFR/ErbB2 and VEGFR tyrosine kinases, on human oral SCC. At first, we screened the expression of EGFR, c-ErbB2(HER-2) and VEGFR-2 in a series of human oral SCC cell lines. And then we evaluated the effects of AEE788 on the phosphorylation of EGFR and VEGFR-2 in a oral SCC cell line expressing EGFR/HER-2 and VEGFR-2. We also evaluated the effects of AEE788 alone, or with paclitaxel(Taxol) on the oral SCC cell growth and apoptosis. As a result, all oral SCC cells expressed EGFR and VEGFR-2. Treatment of oral SCC cells with AEE788 led to dose-dependent inhibition of EGFR and VEGFR-2 phosphorylation, growth inhibition, and induction of apoptosis. Moreover, AEE788 sensitizes the cells to paclitaxel-mediated toxicity and apoptosis. These data mean EGFR and VEGFR-2 can be reliable targets for molecular therapy of oral SCC, and therefore warrant clinical use of EGFR/VEGFR inhibition in the treatment of patients with recurrent or metastatic oral SCC.

• Nuclear Medicine and Molecular Imaging
• /
• 제42권3호
• /
• pp.185-191
• /
• 2008

While indirect targeting strategies using reporter-genes are taking center stage in current molecular imaging research, another vital strategy has long involved direct imaging of specific receptors using radiolabeled ligands. Recently, there is renewal of immense interest in this area with particular attention to the epidermal growth factor receptor (EGFR), a transmembrane glycoprotein critically involved in the regulation of many cellular functions and malignancies. Recently, two novel classes of EGFR-targeting anticancer drugs have entered clinical trials with great expectations. These are monoclonal antibodies such as cetuximab that target the extracellular domain, and small molecule tyrosine kinase inhibitors such as gefitinib (lressa) and erlotinib (Tarceva) that target the catalytic domain of the receptor. However, early results have showed disappointing survival benefits, disclosing a major challenge for this therapeutic strategy; namely, the need to identify tumors that are most likely to respond to the agents. To address this important clinical issue, several noninvasive imaging techniques are under investigation including radiolabeled probes based on small molecule tyrosine kinase inhibitors, anti-EGFR antibodies, and EGF peptides. This review describes the current status, limitations, and future prospects in the development of radiotracer methods for EGFR imaging.

• Journal of Gastric Cancer
• /
• 제4권4호
• /
• pp.268-271
• /
• 2004

Purpose: Most gastrointestinal stromal tumors (GISTs) have gain-of-function mutations of the KIT or the platelet-derived growth factor receptor alpha (PDGFRA) genes, but approximately $10\%$ of the GISTs are wild types for both the KIT and the PDGFRA genes. The purpose of this study was to investigate the possibility that epidermal growth factor receptor (EGFR) gene mutation might be responsible for the pathogenesis of GIST. Materials and Methods: We analyzed the EGFR gene in 60 GISTs for the detection of somatic mutations by using the polymerase chain reaction (PCR), the single strand conformation polymorphism (SSCP), and DNA sequencing in exon 18, 19, and 21 encoding the kinase domain. Results: The SSCP analysis revealed no evidence of EGFR mutations in exon 18, 19, and 21 in GISTs. Conclusion: The data indicate that the EGFR gene may not be mutated in human GIST and suggest that therapies targeting the mutated EGFR gene products might not be useful in the treatment of GISTs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제37권5호
• /
• pp.396-402
• /
• 2011

Introduction: Epidermal growth factor is a single-chain polypeptide consisting of 53 amino acids with potent mitogenic activity that stimulates the proliferation of a range of normal and neoplastic cells through an interaction with its specific receptor (epidermal growth factor receptor, EGFR). This interaction plays a key role in tumor progression including the induction of tumor cell proliferation. An increased EGFR copy number have been associated with a favorable response to EGFR tyrosine kinase inhibitors therapy. In contrast, K-ras mutations tend to predict a poor response to such therapy. The aim of this study was to determine the correlation between the clinicopathological factors and the up-regulation of EGFR expression and Kras mutations in oral squamous cell carcinoma. Materials and Methods: This study examined the immunohistochemical staining of EGFR, K-ras mutation detection with peptide nucleic acid (PNA)-based real-time polymerase chain reaction (PCR) clamping in 20 specimens from 20 patients with oral squamous cell carcinoma. Results: 1. In the immunohistochemical study of poorly differentiated and invasive oral squamous cell carcinoma, a high level of EGFR staining was observed. The correlation between immunohistochemical EGFR expression and histological differentiation, as well as the tumor size of the specimens was significant (Pearson correlation analysis, significance [r] >0.5, P<0.05). 2. In PNA-based real-time PCR clamping analysis, a K-ras mutation was not detected in all specimens. Conclusion: These findings suggest that the up-regulation of the EGFR may play a role in the progression and invasion of oral squamous cell carcinoma that is, independent of a K-ras mutation.

• BMB Reports
• /
• 제48권6호
• /
• pp.342-347
• /
• 2015

The expression of epidermal growth factor receptor (EGFR) is an important diagnostic marker for triple-negative breast cancer (TNBC) cells, which lack three hormonal receptors: estrogen and progesterone receptors as well as epidermal growth factor receptor 2. EGFR transactivation can cause drug resistance in many cancers including TNBC, but the mechanism underlying this phenomenon is poorly defined. Here, we demonstrate that insulin treatment induces EGFR activation by stimulating the interaction of EGFR with insulin-like growth factor receptor 1 (IGF-1R) in the MDA-MB-436 TNBC cell line. These cells express low levels of EGFR, while exhibiting high levels of IGF-1R expression and phosphorylation. Low-EGFRexpressing MDA-MB-436 cells show high sensitivity to insulinstimulated cell growth. Therefore, unexpectedly, insulin stimulation induced EGFR transactivation by regulating its interaction with IGF-1R in low-EGFR-expressing TNBC cells. [BMB Reports 2015; 48(6): 342-347]

• 한국컴퓨터정보학회논문지
• /
• 제21권9호
• /
• pp.101-106
• /
• 2016

The epidermal growth factor receptor(EGFR) protein kinase signaling is an important pathway in cancer development and recently reported that EGFR and its kinase domain molecules are mutated in various of cancers including head and neck cancer. Functional deregulation of EGFR due to mutations in coding exons and copy number amplification is the most common event in cancers, especially among receptor tyrosine kinases(TK). We have analyzed Korean oral squamous cell carcinomas (OSCC) cell lines for mutations in EGFRTK. Exons encoding the hot-spot regions in the TK domain of EGFR (exons 17 to 23) were amplified by using polymerase chain reaction(PCR) and sequenced directly. EGFR expression was also analyzed in 8 OSCC cell lines using western blotting. Data analysis of the EGFR exons 17 to 23 coding sequences did not show any mutations in the 8 OSCC cell lines that were analyzed. The absence of mutations indicate that protein overexpression might be responsible for activation rather than mutation.

• Tuberculosis and Respiratory Diseases
• /
• 제75권5호
• /
• pp.188-198
• /
• 2013

Over the past decade, several kinase inhibitors have been approved based on their clinical benefit in cancer patients. Unfortunately, in many cases, patients develop resistance to these agents via secondary mutations and alternative mechanisms. To date, several major mechanisms of acquired resistance, such as secondary mutation of the epidermal growth factor receptor (EGFR) gene, amplification of the MET gene and overexpression of hepatocyte growth factor, have been reported. This review describes the recent findings on the mechanisms of primary and acquired resistance to EGFR tyrosine kinase inhibitors and acquired resistance to anaplastic lymphoma kinase inhibitors, primarily focusing on non-small cell lung carcinoma.