Molecular analysis of the epidermal growth factor receptor (EGFR) gene and protein expression in patients treated with erlotinib in National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) trial BR.21

2005 ◽  
Vol 23 (16_suppl) ◽  
pp. 7007-7007 ◽  
Author(s):  
M. S. Tsao ◽  
A. Sakurada ◽  
I. Lorimer ◽  
J.-C. Cutz ◽  
S. Kamel-Reid ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Protein Expression ◽  
National Cancer Institute ◽  
Growth Factor Receptor ◽  
Egfr Gene ◽  
Gene And Protein Expression ◽  
Epidermal Growth

Critical Update and Emerging Trends in Epidermal Growth Factor Receptor Targeting in Cancer

2005 ◽  
Vol 23 (11) ◽  
pp. 2445-2459 ◽  
Author(s):  
José Baselga ◽  
Carlos L. Arteaga
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinase ◽  
Kinase Inhibitors ◽  
Growth Factor Receptor ◽  
Egfr Gene ◽  
Epidermal Growth ◽  
Egfr Tkis ◽  
Receptor Family

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase of the ErbB receptor family that is abnormally activated in many epithelial tumors. The aberrant activation of the EGFR leads to enhanced proliferation and other tumor-promoting activities, which provide a strong rationale to target this receptor family. There are two classes of anti-EGFR agents: monoclonal antibodies (MAbs) directed at the extracellular domain of the receptor and small molecule, adenosine triphosphate–competitive inhibitors of the receptor's tyrosine kinase. Anti-EGFR MAbs have shown antitumor activity in advanced colorectal carcinoma, squamous cell carcinomas of the head and neck, non–small-cell lung cancer (NSCLC) and renal cell carcinomas. The tyrosine kinase inhibitors (TKIs) have a partially different activity profile. They are active against NSCLC, and a specific EGFR inhibitor has shown improvement in survival. Recently, mutations and amplifications of the EGFR gene have been identified in NSCLC and predict for enhanced sensitivity to anti-EGFR TKIs. In addition to specific anti-EGFR TKIs, there are broader acting inhibitors such as dual EGFR HER-2 inhibitors and combined anti-pan-ErbB and antivascular endothelial growth factor receptor inhibitors. Current research efforts are directed at selecting the optimal dose and schedule and identifying predictive factors of response and resistance beyond EGFR gene mutations and/or amplifications. Finally, there is a need for improved strategies to integrate anti-EGFR agents with conventional therapies and to explore combinations with other molecular targeted approaches including other antireceptor therapies, receptor-downstream signaling transduction inhibitors, and targeted approaches interfering with other essential drivers of cancer, such as angiogenesis.

scholarly journals Loss of Phosphatase and Tensin Homolog or Phosphoinositol-3 Kinase Activation and Response to Trastuzumab or Lapatinib in Human Epidermal Growth Factor Receptor 2–Overexpressing Locally Advanced Breast Cancers

2011 ◽  
Vol 29 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Bhuvanesh Dave ◽  
Ilenia Migliaccio ◽  
M. Carolina Gutierrez ◽  
Meng-Fen Wu ◽  
Gary C. Chamness ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Single Agent ◽  
Growth Factor Receptor ◽  
Breast Cancers ◽  
Trastuzumab Resistance ◽  
Epidermal Growth

Purpose Phosphatase and tensin homolog (PTEN) loss or activating mutations of phosphoinositol-3 (PI3) kinase (PIK3CA) may be associated with trastuzumab resistance. Trastuzumab, the humanized human epidermal growth factor receptor 2 (HER2) monoclonal antibody, and lapatinib, an epidermal growth factor receptor/HER2 tyrosine kinase inhibitor, are both established treatments for HER2-overexpressing breast cancers. Understanding of the cellular response to HER2-targeted therapies is needed to tailor treatments and to identify patients less likely to benefit. Methods We evaluated the effect of trastuzumab or lapatinib in three HER2-overexpressing cell lines. We confirmed the in vitro observations in two neoadjuvant clinical trials in patients with HER2 overexpression; 35 patients received trastuzumab as a single agent for the first 3 weeks, then docetaxel every 3 weeks for 12 weeks (trastuzumab regimen), whereas 49 patients received lapatinib as a single agent for 6 weeks, followed by trastuzumab/docetaxel for 12 weeks before primary surgery (lapatinib regimen). Apoptosis, Ki67, p-MAPK, p-AKT, and PTEN were assessed by immunohistochemistry. Genomic DNA was sequenced for PIK3CA mutations. Results Under low PTEN conditions, in vitro data indicate that lapatinib alone and in combination with trastuzumab was effective in decreasing p-MAPK and p-AKT levels, whereas trastuzumab was ineffective. In the clinical trials, we confirmed that low PTEN or activating mutation in PIK3CA conferred resistance to the trastuzumab regimen (P = .015), whereas low PTEN tumors were associated with a high pathologic complete response rate (P = .007). Conclusion Activation of PI3 kinase pathway is associated with trastuzumab resistance, whereas low PTEN predicted for response to lapatinib. These observations support clinical trials with the combination of both agents.

scholarly journals Modulation of EGFR Gene Transcription by a Polymorphic Repetitive Sequence – a Link between Genetics and Epigenetics

2000 ◽  
Vol 15 (1) ◽  
pp. 105-110 ◽  
Author(s):  
F. Gebhardt ◽  
H. BÜrger ◽  
B. Brandt
Keyword(s):  
Breast Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Model Calculations ◽  
Ca Repeat ◽  
Egfr Gene ◽  
Egfr Expression ◽  
Epidermal Growth

The epidermal growth factor receptor (EGFR) plays a crucial role in growth, differentiation and motility of normal as well as tumor cells. The transduction of extracellular signals to the cytoplasm via the receptor not only depends on ligand binding, but is also determined by the receptor density on the cell surface. Therefore, with regard to cancer diagnosis and therapeutic approaches targeting EGFR it is important to know how the expression level of EGFR is controlled. We found that transcription activity declines with increasing numbers of CA dinucleotides of a highly polymorphic CA repeat in the first intron of the epidermal growth factor receptor gene. In vivo data from cultured cell lines support these findings, although other regulation mechanisms can compensate this effect. In addition, we showed that RNA elongation terminates at a site closely downstream of the simple sequence repeat (SSR) and that there are two separate major transcription start sites. Model calculations for the helical DNA conformation revealed a high bendability in the EGFR polymorphic region, especially if the CA stretch is extended. These data suggest that the CA-SSR can act like a joint, bringing the promoter in proximity to a putative repressor protein bound downstream of the CA-SSR. The data indicate that this polymorphism may be a marker for cancer, linking genetic and epigenetic risk factors. Furthermore, in breast cancer, heterozygous tumors with short CA-SSR showed an elevated EGFR-expression in contrast to tumours with longer CA-SSR. Tumours with loss of heterozygosity in intron 1 of egfr revealed an increased EGFR expression if the longer allele was lost. Moreover, decreased EGFR gene levels were significantly correlated with poor prognosis in breast cancer.

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