scholarly journals Heterogeneity of Epidermal Growth Factor Receptor Status and Mutations of KRAS/PIK3CA in Circulating Tumor Cells of Patients with Colorectal Cancer

2013 ◽  
Vol 59 (1) ◽  
pp. 252-260 ◽  
Author(s):  
Christin Gasch ◽  
Thomas Bauernhofer ◽  
Martin Pichler ◽  
Sabine Langer-Freitag ◽  
Matthias Reeh ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Egfr Gene ◽  
Egfr Expression ◽  
Epidermal Growth ◽  
Viral Oncogene Homolog

BACKGROUND Molecular characterization of circulating tumor cells (CTCs) is pivotal to increasing the diagnostic specificity of CTC assays and investigating therapeutic targets and their downstream pathways on CTCs. We focused on epidermal growth factor receptor (EGFR) and genes relevant for its inhibition in patients with colorectal cancer (CRC). METHODS We used the CellSearch® system for CTC detection in peripheral blood samples from 49 patients with metastatic CRC (mCRC) and 32 patients with nonmetastatic CRC (nmCRC). We assessed EGFR expression in 741 CTCs from 27 patients with mCRC and 6 patients with nmCRC using a fluorescein-conjugated antibody with the CellSearch Epithelial Cell Kit. DNA of a single CTC isolated by micromanipulation was propagated by whole-genome amplification and analyzed by quantitative PCR for EGFR gene amplification and sequencing for KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog), BRAF (v-raf murine sarcoma viral oncogene homolog B1), and PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α) mutations. RESULTS At least 2 CTCs were detected in 24 of 49 patients with mCRC and 7 of 32 patients with nmCRC. In 7 of 33 patients, CTCs with increased EGFR expression were identified. Heterogeneity in EGFR expression was observed between CTCs from the same patient. EGFR gene amplification was found in 7 of 26 CTCs from 3 patients. The investigated BRAF gene locus was not mutated in 44 analyzed CTCs, whereas KRAS mutations were detected in 5 of 15 CTCs from 1 patient and PIK3CA mutations in 14 of 36 CTCs from 4 patients. CONCLUSIONS Molecular characterization of single CTCs demonstrated considerable intra- and interpatient heterogeneity of EGFR expression and genetic alterations in EGFR, KRAS, and PIK3CA, possibly explaining the variable response rates to EGFR inhibition in patients with CRC.

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.

Cetuximab Shows Activity in Colorectal Cancer Patients With Tumors That Do Not Express the Epidermal Growth Factor Receptor by Immunohistochemistry

2005 ◽  
Vol 23 (9) ◽  
pp. 1803-1810 ◽  
Author(s):  
Ki Young Chung ◽  
Jinru Shia ◽  
Nancy E. Kemeny ◽  
Manish Shah ◽  
Gary K. Schwartz ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cancer Patients ◽  
Growth Factor Receptor ◽  
Pathology Report ◽  
Egfr Expression ◽  
Epidermal Growth ◽  
Colorectal Cancer Patients

Purpose To establish evidence of activity, or lack thereof, of cetuximab-based therapy in patients with refractory colorectal cancer with tumors that do not demonstrate epidermal growth factor receptor (EGFR) expression by immunohistochemistry (IHC). Patients and Methods Pharmacy computer records were reviewed to identify all patients who received cetuximab at Memorial Sloan-Kettering Cancer Center in a nonstudy setting during the first 3 months of cetuximab's commercial availability. Medical records of these patients were then reviewed to identify colorectal cancer patients who had experienced failure with a prior irinotecan-based regimen and who had a pathology report indicating an EGFR-negative tumor by IHC. Pathology slides from these patients were reviewed by a reference pathologist to confirm EGFR negativity, and computed tomography scans during cetuximab-based therapy were reviewed by a reference radiologist. Response rates were reported using WHO criteria. Results Sixteen chemotherapy-refractory, EGFR-negative colorectal cancer patients who received cetuximab in a nonstudy setting were identified. Fourteen of these patients received cetuximab plus irinotecan, and two received cetuximab monotherapy. In the 16 patients, four major objective responses were seen (response rate, 25%; 95% CI, 4% to 46%). Conclusion Colorectal cancer patients with EGFR-negative tumors have the potential to respond to cetuximab-based therapies. EGFR analysis by current IHC techniques does not seem to have predictive value, and selection or exclusion of patients for cetuximab therapy on the basis of currently available EGFR IHC does not seem warranted.

scholarly journals Abnormal Epithelial Cell Polarity and Ectopic Epidermal Growth Factor Receptor (EGFR) Expression Induced in Emx2 KO Embryonic Gonads

Endocrinology ◽  
2010 ◽  
Vol 151 (12) ◽  
pp. 5893-5904 ◽  
Author(s):  
Masatomo Kusaka ◽  
Yuko Katoh-Fukui ◽  
Hidesato Ogawa ◽  
Kanako Miyabayashi ◽  
Takashi Baba ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Epithelial Cells ◽  
Tight Junction ◽  
Tyrosine Phosphorylation ◽  
Growth Factor Receptor ◽  
Egfr Expression ◽  
Epidermal Growth ◽  
Viral Oncogene Homolog

The gonadal primordium first emerges as a thickening of the embryonic coelomic epithelium, which has been thought to migrate mediodorsally to form the primitive gonad. However, the early gonadal development remains poorly understood. Mice lacking the paired-like homeobox gene Emx2 display gonadal dysgenesis. Interestingly, the knockout (KO) embryonic gonads develop an unusual surface accompanied by aberrant tight junction assembly. Morphological and in vitro cell fate mapping studies showed an apparent decrease in the number of the gonadal epithelial cells migrated to mesenchymal compartment in the KO, suggesting that polarized cell division and subsequent cell migration are affected. Microarray analyses of the epithelial cells revealed significant up-regulation of Egfr in the KO, indicating that Emx2 suppresses Egfr gene expression. This genetic correlation between the two genes was reproduced with cultured M15 cells derived from mesonephric epithelial cells. Epidermal growth factor receptor signaling was recently shown to regulate tight junction assembly through sarcoma viral oncogene homolog tyrosine phosphorylation. We show through Emx2 KO analyses that sarcoma viral oncogene homolog tyrosine phosphorylation, epidermal growth factor receptor tyrosine phosphorylation, and Egfr expression are up-regulated in the embryonic gonad. Our results strongly suggest that Emx2 is required for regulation of tight junction assembly and allowing migration of the gonadal epithelia to the mesenchyme, which are possibly mediated by suppression of Egfr expression.

scholarly journals Characterization of the Epidermal Growth Factor Receptor T790M Mutation in Colorectal Cancer

2018 ◽  
pp. 1-7
Author(s):  
Erdem Altunel ◽  
Abed Alhalim Aljamal ◽  
John Mantyh ◽  
Kristen Deak ◽  
Wayne Glover ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
T790m Mutation ◽  
Epidermal Growth
Sign in / Sign up

Export Citation Format

Share Document