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Does the EGFR and VEGF expression predict the prognosis in colon cancer?

BACKGROUND/AIM: Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) are frequently encountered with aggressive tumor phenotype and poor prognosis, but the relationship between EGFR/VEGF expression and survival remains unclear. The aim of our study was to further investigate the prognostic value of EGFR and VEGF expression in colon cancer. MATERIALS AND METHODS: The pathological specimens of 60 colon carcinoma patients were retrospectively evaluated and grouped according to EGFR and VEGF staining intensity and percentage of stained neoplastic cells. A final score was assigned to each case by multiplying percentage and staining score. The patients were stratified into the following categories: negative (score 0), low expression (score 1 or 2), and high expression (score 4). The remaining patient data were filtered out from the institutional cancer database. RESULTS: The mean survival time was 28.93 +/- 14.1 (range 2-52) months in the EGFR-negative group, 23.92 +/- 14.0 (range 6-46) months in the group with a low EGFR expression, and 17.00 +/- 12.8 (range 10-40) months in the group with a high EGFR expression. The median survival time was 27.50 +/- 14.7 (range 4-52) months in the VEGF-negative group, 29.33 +/- 12.8 (range 6-48) months in the group with a low VGEF expression, and 14.50 +/- 14.2 (range 2-40) months in the group with a high VGEF expression. The expression of EGFR and VEGF was not an independent factor that affects survival. CONCLUSIONS: The EGFR and VEGF expression rates of colon tumors do not predict the survival. In addition, the EGFR expression in the primary tumor was not predictive of metastatic lymph nodes. The prognostic value of EGFR/VEGF staining may be further questioned.

Aged↗

Senseless represses nuclear transduction of Egfr pathway activation.

The Epidermal growth factor receptor (Egfr) pathway controls cell fate decisions throughout phylogeny. Typically, binding of secreted ligands to Egfr on the cell surface initiates a well-described cascade of events that ultimately invokes transcriptional changes in the nucleus. In contrast, the mechanisms by which autocrine effects are regulated in the ligand-producing cell are unclear. In the Drosophila eye, Egfr signaling, induced by the Spitz ligand, is required for differentiation of all photoreceptors except for R8, the primary source of Spitz. R8 differentiation is instead under the control of the transcription factor Senseless. We show that high levels of Egfr activation are incompatible with R8 differentiation and describe the mechanism by which Egfr signaling is actively prevented in R8. Specifically, Senseless does not affect cytoplasmic transduction of Egfr activation, but does block nuclear transduction of Egfr activation through transcriptional repression of pointed, which encodes the nuclear effector of the pathway. Thus, Senseless promotes normal R8 differentiation by preventing the effects of autocrine stimulation by Spitz. An analogous relationship exists between Senseless and Egfr pathway orthologs in T-lymphocytes, suggesting that this mode of repression of Egfr signaling is conserved.

Animals↗

Genetic and biochemical analysis of the role of Egfr in the morphogenetic furrow of the developing Drosophila eye.

A key event in patterning the developing Drosophila compound eye is the progressive restriction of the transcription factor Atonal in the morphogenetic furrow. The Atonal pattern evolves from expression in all cells to an over-dispersed pattern of single founder cells (the future R8 photoreceptors). This restriction involves Notch-mediated lateral inhibition. However, there have been inconsistent data on a similar proposed role for the Egf receptor (Egfr). Experiments using a conditional Egfr mutation (Egfr(tsla)) suggested that Egfr does not regulate Atonal restriction, whereas experiments using Egfr-null mosaic Minute+ clones suggested that it does. Here, we have re-examined both approaches. We report that the lesion in Egfr(tsla) is a serine to phenylalanine change in a conserved extracellular ligand-binding domain. We show by biochemical and genetic approaches that the Egfr(tsla) protein is rapidly and completely inactivated upon shift to the non-permissive temperature. We also find that on temperature shift the protein moves from the cell surface into the cell. Finally, we report a flaw in the Egfr-null mosaic Minute+ clone approach. Thus, we demonstrate that Egfr does not play a role in the initial specification or spacing of ommatidial founder cells.

Animals↗

Rational design of potent and selective EGFR tyrosine kinase inhibitors as anticancer agents.

Increasing knowledge of the structure and function of the Epidermal Growth Factor Receptor (EGFR) subfamily of tyrosine kinases, and of their role in the initiation and progression of various cancers has led to the search for inhibitors of signaling molecules that may prove to be important in cancer therapy. The complex nature of EGFR biology allows for potential opportunities for EGFR inhibitors in a number of areas of cancer therapy, including proliferative, angiogenic, invasive, and metastatic aspects. Different approaches have been used to target either the extracellular ligand-binding domain of the EGFR or the intracellular tyrosine kinase region that results in interference with its signaling pathways that modulate cancer-promoting responses. Examples of these include a number of monoclonal antibodies, immunotoxins and ligand-binding cytotoxic agents that target the extracellular ligand binding region of EGFR, and small molecule inhibitors that target the intracellular kinase domain and act by interfering with ATP binding to the receptor. During the past 3 years, significant progress has been made towards the identification of new structural classes of small molecule inhibitors that show high potency and specificity towards EGFR. The search for new small molecules that inhibit kinases has included traditional approaches like the testing of natural products, random screening of chemical libraries, the use of classical structure-activity-relationship studies, and the incorporation of structure-based drug design and combinatorial chemistry techniques. There has been a significant improvement in the development of selective EGFR inhibitors with the use of a structure-based design approach employing a homology model of the EGFR kinase domain. Molecular modeling procedures have been used to generate novel molecules that are complementary in shape and electrostatics to the EGFR kinase domain topography. This review focuses on some examples of the successful use of this method.

Antineoplastic Agents↗

The prognostic value of epidermal growth factor receptor (EGFR) in breast cancer patients. Results of a follow-up study on 149 patients.

The expression of epidermal growth factor receptor (EGFR) in breast cancer patients was correlated to the disease-free survival. The study included 149 breast cancer patients. The mean follow-up time was 4.2 years. There was an inverse correlation between EGFR and estrogen receptor (p < 0.003) and progesterone receptor (p < 0.013). Subdivision of EGFR showed that patients with EGFR > or = 0.60%, regarded as EGFR positive, had a worse prognosis than patients with EGFR binding < 0.60%, regarded as EGFR negative (p = 0.004). In the ER negative group, EGFR positive patients had a shorter relapse-free time than patients with EGFR negative cancer (p < 0.009). The same subdivision among ER positive patients showed no statistically significant difference.

Adult↗

Overexpression of p53, EGFR, c-erbB2 and c-erbB3 in endometrioid carcinoma of the ovary.

OBJECTIVES: To determine overexpression of p53, EGFR, c-erbB-2 and c-erbB-3 in endometrioid carcinoma of the ovary and to evaluate the prognostic significance of these results, especially, coexisting overexpression of p53 and one of the member of type I growth factor receptor family. METHODS: Overexpressions of the p53, EGFR, c-erbB-2 and c-erbB-3 protein were studied by immunohistochemistry in paraffin-embedded tumor tissue from 28 patients with endometrioid carcinoma of the ovary. RESULTS: 11 (39.3%), 13 (46.4%), and 14 (50.0%) were stained positively with p53, c-erbB-2 and c-erbB-3 monoclonal antibodies. 13 (46.4%) was stained positively with EGFR polyclonal antibody. There were no relationship between p53, EGFR, C-erbB-2, c-erbB-3 and histologic grade, lymph node metastasis. The percentage of tumors with over expression of p53, EGFR, C-erbB-2 and c-erbB-3 was higher in those with stage II-III tumors compared with those with stage I, in patients with residual tumor after initial surgery compared with those without. A high survival rate was observed in patients without p53, EGFR, c-erbB-2 and c-erbB-3 overexpression respectively than those with. A highest survival rate was observed in patients with both p53 and one of EGFR, c-erbB-2 and c-erbB-3 negative compared with those both positive or either of both positive. CONCLUSION: Overexpression of p53, EGFR, c-erbB-2 and C-erbB-3 resulted in a poorer prognosis respectively. Overexpression of both p53 and one of the EGFR, c-erbB-2 and c-erbB-3 is a worse prognostic indicator in patients with endometrioid carcinoma of the ovary.

Adult↗

The CNS midline cells control the spitz class and Egfr signaling genes to establish the proper cell fate of the Drosophila ventral neuroectoderm.

The spitz class genes, pointed (pnt), rhomboid frho), single-minded (sim), spitz (spi)and Star (S), as well as the Drosophila epidermal growth factor receptor (Egfr) signaling genes, argos (aos), Egfr, orthodenticle (otd) and vein (vn), are required for the proper establishment of ventral neuroectodermal cell fate. The roles of the CNS midline cells, spitz class and Egfr signaling genes in cell fate determination of the ventral neuroectoderm were determined by analyzing the spatial and temporal expression patterns of each individual gene in spitz class and Egfr signaling mutants. This analysis showed that the expression of all the spitz class and Egfrsignaling genes is affected by the sim gene, which indicates that sim acts upstream of all the spitz class and Egfr signaling genes. It was shown that overexpression of sim in midline cells fails to induce the ectodermal fate in the spi and Egfr mutants. On the other hand, overexpression of spi and Draf causes ectopic expression of the neuroectodermal markers in the sim mutant. Ectopic expression of sim in the en-positive cells induces the expression of downstream genes such as otd, pnt, rho, and vn, which clearly demonstrates that the sim gene activates the EGFR signaling pathway and that CNS midline cells, specified by sim, provide sufficient positional information for the establishment of ventral neuroectodermal fate. These results reveal that the CNS midline cells are one of the key regulators for the proper patterning of the ventral neuroectoderm by controlling EGFR activity through the regulation of the expression of spitz class genes and Egfr signaling genes.

Animals↗

Distinct amplification of an untranslated regulatory sequence in the egfr gene contributes to early steps in breast cancer development.

Overexpression of the epidermal growth factor receptor (egfr) gene is a common feature in breast cancer. We demonstrated recently that the expression of EGFR in breast cancer strongly correlates with the length of a CA simple sequence repeat within the first 2000 bases in intron 1 of the egfr gene [CA simple sequence repeat (CA-SSR) I; H. Buerger et al., Cancer Res., 60: 854-857, 2000]. Using a standardized semiautomated method of microsatellite analysis for loss of heterozygosity detection, we identified an allelic imbalance (AI) at the egfr locus in 55 of 163 primary breast cancer cases. Fine mapping of the chromosomal region at 7p12-15 around the egfr gene using 10 CA-SSR markers showed that mutations of egfr in breast cancer are frequently restricted to the first intron of egfr. Thereby, the simple sequence repeat CA-SSR I in intron 1 was affected in 84% of the patients with AI. Reverse transcription-PCR analysis of 23 breast cancer tissues with AI excluded the presence of in-frame deletions between exon 2 and exon 7. For additional characterization of the underlying phenomenon leading to the detection of an AI in microsatellite analysis, a quantitative 5'-nuclease assay for the first CA-SSR I in intron 1 was established. In breast cancer cases with AI the presence of amplifications of this sequence was shown. Kaplan-Meier analysis revealed a statistically significant worse prognosis for patients with AI in the cancer tissue at the egfr locus compared with patients without AI. Interestingly, 75% of the patients bearing AI of CA-SSR I in the tumor also showed AI at normal, nontumorous breast tissue. Our data strongly support the assumption that distinct amplifications in intronic sequences of the egfr gene, which enhance the basic transcription activity of the gene, represent one of the first steps in breast carcinogenesis. Furthermore, they point to the presence of prognosis-associated markers for breast cancer already in morphological normal breast tissue.

Adult↗

Expression of cytoplasmic-domain substituted epidermal growth factor receptor inhibits tumorigenicity of EGFR-overexpressed human glioblastoma multiforme.

The accumulated results of recent clinical studies have indicated that aberrant epidermal growth factor receptor (EGFR) activation due to gene amplification and/or rearrangement contributes to increased malignancy and poor prognosis in many human cancers, especially in human glioblastoma multiforme (GBM). The elevated EGFR signaling in GBM has been correlated with shorter interval to relapse and lower survival rates, even in patients treated with surgery, radiation therapy, and/or chemotherapy. Therefore, the blockade of EGFR signaling in GBM may provide an ideal alternative therapeutic strategy. In this study, two EGFR-overexpressing human GBM cell lines (i.e., DBTRG and GBM 8901) were used as a model system. We demonstrated that expression of a human EGFR (EGFRt-EGFP) chimera protein in which the cytoplasmic domain is substituted by EGFP significantly reduced the EGF-induced endogenous EGFR autophosphorylation, EGF-induced downstream extra-cellular signal-regulated kinase (ERK) and Akt signaling, and the proportion of internalized receptors in EGF stimulated cells. Furthermore, these cells' anchorage-independent growth in vitro was decreased and their tumorigenicity in vivo abrogated or strongly suppressed. Our data suggest that EGFRt-EGFP abrogates tumor growth by disrupting receptor activation via competing for EGF-like ligands, forming non-activated heterodimers with endogenous EGFR, and inhibiting the EGFR endosomal signaling by substantially diminishing receptor internalization. This treatment modality (termed 'dominant-negative EGFR therapy') and its efficacy for gliomas or other tumors are under scrutiny.

Animals↗

Activated Akt expression has significant correlation with EGFR and TGF-alpha expressions in stage I NSCLC.

BACKGROUND: In vitro studies have indicated that epidermal growth factor receptor (EGFR) may intensify signaling output by the receptor's overexpression, heterodimerization with HER-2, or autocrine expression of ligands. The purpose of the present study was to evaluate the correlation between EGFR and its related proteins and to explore the prognostic value of the proteins. MATERIALS AND METHODS: Immunohistochemical staining of transforming growth factor alpha (TGF-alpha), EGFR, HER-2, and phosphorylated (p-)Akt was performed in specimens surgically excised from 91 consecutive patients with p-stage I non-small cell lung cancer (NSCLC). Expression or coexpression of TGF-alpha and the receptors were related to expression of p-Akt. The prognostic impact of these peptides was also tested. RESULTS: TGF-alpha, EGFR and HER-2 overexpressions were detected in 32%, 79% and 13% of tumors, respectively. Coexpressions of TGF-alpha & EGFR and EGFR & HER-2 were observed in 29% and 11% of tumors, respectively. P-Akt expression was found in 73% of tumors. Significant correlations between EGFR TGF-alpha or coexpression of TGF-alpha & EGFR and p-Akt expression were found (p=0.006, 0.008 and 0.010, respectively). No proteins examined had an impact on relapse-free survival. CONCLUSION: The Akt pathway is frequently involved in NSCLC and overexpression of EGFR and autocrine expression of TGF-alpha may increase the potency of Akt activation.

Carcinoma, Non-Small-Cell Lung↗

EGFR LI and Ki-67 LI are independent prognostic parameters influencing survivals of surgically treated squamous cell lung cancer patients.

In literature there are still opinion differences concerning the prognostic significance of epidermal growth factor receptor (EGFR) expression and proliferative potential in patients with non small cell lung cancer (NSCLC). This prompted us to study those parameters. The Ki-67 labeling index (Ki-67 LI), EGFR labeling index (EGFR LI), and mitotic index (MI) were analyzed in the group of 78 consecutive, surgically treated squamous cell lung cancer (SqCLC) patients. The expression of Ki-67 and EGFR protein was visualized on formalin fixed, paraffin embedded sections using immunohistochemistry (IHC). Mitotic index was assessed on formalin fixed, paraffin embedded sections, stained with hematoxylin and eosin using morphological criteria. Mean values of Ki-67 LI and MI were higher for G2+G3 tumors than for G1 tumors. EGFR LI was higher for G1+G2 than for G3 tumors, and for pT3 than for pT1+pT2 tumors. Patients having tumors with Ki-67 < or =28% or (EGFR LI < or =13% or EGFR LI >80%) survived significantly shorter than those having tumors with Ki-67 LI >28% or 13%< EGFR LI < or =80%. In multivariate analysis, 13%> or = EGFR LI <80% and Ki-67 LI < or =28% were independent negative prognostic parameters influencing survivals of SqCLC patients.

Adult↗

Relationship between EGFR overexpression and gene amplification status in central nervous system gliomas.

OBJECTIVE: To correlate epidermal growth factor receptor (EGFR) protein overexpression, as assessed by immunohistochemistry, with EGFR gene amplification determined by fluorescence in situ hybridization in a series of gliomas. STUDY DESIGN: Forty-seven central nervous system gliomas, including 34 cases of glioblastoma multiforme, 3 oligodendrogliomas, 4 juvenile pilocytic astrocytomas and 5 low grade astrocytomas, were obtained from the files of the University of Utah Pathology Department. In each case a representative paraffin block was selected, and EGFR protein expression was quantified using immunohistochemistry. EGFR gene amplification status was determined by fluorescence in situ hybridization. RESULTS: EGFR protein overexpression was detected in 9 cases of glioblastoma multiforme. EGFR gene amplification was present in 7 of these cases. Both nonamplified glioblastomas demonstrated only 2+ overexpression of EGFR protein. None of the low grade, pilocytic or anaplastic astrocytomas demonstrated either EGFR protein overexpression or gene amplification. CONCLUSION: EGFR protein overexpression is closely associated with gene amplification. Seventy-eight percent of cases showing protein overexpression demonstrated gene amplification. All cases of central nervous system neoplasms showing protein overexpression but lacking gene amplification were associated with only 2+ protein overexpression. All central nervous system neoplasms demonstrating gene amplification and/or overexpression were high grade neoplasms.

Adult↗

[Expressions of Her-2, EGFR, PS-2 and ER in breast cancer and their clinical implications].

OBJECTIVE: To detect the expressions of human epidermal growth factor receptor 2 (Her-2), epidermal growth factor receptor (EGFR), presenilin 2 (PS-2) and estrogen receptor (ER) in breast cancer and discuss their clinical implications. METHODS: The expressions of Her-2, EGFR, PS-2 and ER were measured immunohistochemically in 108 patients with breast cancer. RESULTS: The positive expression rates of Her-2, EGFR, PS-2 and ER were 37.0%, 40.7%, 57.4% and 53.7% respectively in the breast cancer patients. The expression of Her-2 was not correlated with EGFR, but inversely correlated with PS-2 and ER. The expressions of Her-2 and EGFR, PS-2, ER were correlated with the histological grades (P<0.05), and Her-2, EGFR and ER expressions with lymph node metastasis (P<0.05). The expressions of Her-2, EGFR, PS-2 and ER did not correlate to the pathological types, patient's age and tumor size (P>0.05). CONCLUSION: Expressions of Her-2 and EGFR often suggests an unfavorable prognosis while expressions of PS-2 and ER suggest a more favorable one. Expressions of Her-2, EGFR, PS-2 and ER are useful prognostic factors in breast cancer patients.

Adult↗

Anti-EGFR therapies: clinical experience in colorectal, lung, and head and neck cancers.

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.

Antibodies, Monoclonal↗

Uniform MDM2 overexpression in a panel of glioblastoma multiforme cell lines with divergent EGFR and p53 expression status.

BACKGROUND: Overexpression and deletion mutation of the epidermal growth factor receptor (EGFR) gene, as well as murine double minute 2 (MDM2) overexpression have been linked to the absence of p53 gene mutations in human glioblastoma multiforme (GBM). MATERIALS AND METHODS: EGFR and MDM2 messenger (m)RNA expression profiles and p53 status were examined by reverse transcription-polymerase chain rection (RT-PCR) and gene sequencing, respectively, in a set of human wild-type (wt) p53 GBM cell lines (U-87MG, U-87MG.wtEGFR and U-87MG.deltaEGFR) that exclusively differ in EGFR expression (endogenous wt EGFR expression, exogenous wt EGFR overexpression and exogenous 801-bp deletion-mutant [delta] EGFR overexpression, respectively), as well as in two human mutant p53 GBM cell lines that differ approximately two-fold in endogenous wt EGFR mRNA expression. RESULTS: Regardless of the underlying heterogeneity in EGFR mRNA expression and p53 status, MDM2 was similarly overexpressed among the cell lines. CONCLUSION: These data suggest that in human GBM (i) overexpression of wt or deltaEGFR and of MDM2 may constitute independent genetic events, (ii) overexpression of wt EGFR and mutation of p53 in GBM, although considered mutually exclusive in vivo, are not reciprocally prohibitive per se, and (iii) p53 mutations do not necessarily preclude MDM2 overexpression. In addition, this set of human GBM cell lines may constitute a suitable model for evaluating MDM2-targeted therapies in the context of various accompanying genetic alterations.

Brain Neoplasms↗

Inhibition of pancreatic and lung adenocarcinoma cell survival by curcumin is associated with increased apoptosis, down-regulation of COX-2 and EGFR and inhibition of Erk1/2 activity.

BACKGROUND: Several studies suggested that curcumin inhibits growth of malignant cells via inhibition of cyclooxygenase-2 (COX-2) activity. Other studies indicated that epidermal growth factor receptor (EGFR) is also inhibited by curcumin in vitro and in vivo. Moreover, recent investigations revealed an intracellular cross-talk between EGFR signaling and the COX-2 pathway. Our aim was to evaluate whether the curcumin inhibitory effect on the survival of cancer cells is associated with simultaneous down-regulation of COX-2 and EGFR and inhibition of Erk1/2 (extra-cellular signal regulated kinase) signaling pathway. MATERIALS AND METHODS: Lung and pancreas adenocarcinoma cell lines co-expressing COX-2 and EGFR (PC-14 and p34, respectively) and those expressing EGFR but deficient in COX-2 (H1299 and Panc-1, respectively) were exposed for 72 h to curcumin (0-50 microM). Cell viability was assessed by the XTT assay. Apoptosis was determined by FACS analysis. COX-2, EGFR, ErbB-2 and p-Erk1/2 expressions were measured by Western blot analysis. RESULTS: Curcumin's inhibitory effect on survival and apoptosis of lung and pancreatic adenocarcinoma cell lines was significantly higher in the COX-2-expressing cells than in the COX-2-deficient cells. In the p34 and PC-14 cells, curcumin decreased COX-2, EGFR and p-Erk1/2 expressions in a dose-dependent manner. However, in the Panc-1 and H1299 cell lines, which did not express COX-2, curcumin did not affect EGFR levels. CONCLUSION: Curcumin co-inhibited COX-2 and EGFR expression and decreased Erk1/2 activity. This inhibition was associated with decreased survival and enhanced induction of apoptosis in lung and pancreatic adenocarcinoma cells.

Adenocarcinoma↗

EGFRvIII mutation in lung cancer correlates with increased EGFR copy number.

Overexpression of the epidermal growth factor receptor (EGFR) is caused by EGFR gene amplification and is sometimes associated with expression of a variant EGFR (deletion exon 2-7 or EGFRvIII). EGFRvIII mutation has oncogenic potential and is investigated as a potential therapeutic target. We genotyped the EGFRvIII mutation status in 252 surgically treated lung cancer cases. The presence or absence of EGFRvIII mutation was analyzed by real-time quantitative polymerase chain reaction (PCR) with mutation specific sensor and anchor probes. EGFR copy number was evaluated with PCR-based assay. EGFR mutation status at kinase domain has been examined and reported. EGFRvIII mutation was found on 8 of 252 patients. All patients were male, smokers, and 7 had squamous cell carcinoma. The mutation status was significantly correlated with pathological subtypes (squamous cell carcinoma vs. adenocarcinoma, p=0.0114). Sixty EGFR mutations at kinase domain exclusively existed with EGFRvIII mutations. EGFR gene copy number was significantly higher in EGFRvIII mutant (4.711+/-4.968) than in non-EGFRvIII mutant (2.284+/-1.224) (p=0.0001). EGFRvIII gene mutation might be one of the mechanisms of increased EGFR copy number. Further studies are needed to confirm the mechanisms of EGFRvIII mutations for possible anti-EGFR therapy for lung cancer.

Adenocarcinoma↗

[Analysis of EGFR gene transcription in rat embryo and adult tissues].

EGFR gene transcription in rat embryo and adult tissues were analysed by RNA Northern and Dot hybridization using 2.4 Kb human EGFR cDNA pE 7 as probe. In Northern hybridization (Fig. 1), the normal rat liver RNA showed a major 5.6 Kb RNA band which was a common EGFR mRNA present in human normal and cancer cells. For the comparison of EGFR gene transcription in embryo of different stages and different tissues, the density scanning data of dot hybridization signals are shown as bars in accompanying figures. The results indicated that the highest level of EGFR transcription was seen in rat embryo at 10th to 12th day during neonatal development (Fig. 2 and Fig. 3). In adult rat tissues, EGFR gene was commonly expressed with some variation in different tissues, for example, much more expressed in kidney than in liver, heart, brain and spleen, and moderately expressed in testis and lung (Fig. 4). The EGFR gene transcription could be induced in liver by hepatectomy. Fig. 5 showed the increase of EGFR gene transcripts at the 2-8 th hour of liver regeneration and the decrease after the 8th hour, even reaching a value lower than that of normal liver after the 24th hour. The results suggest that EGFR gene transcripts are commonly present in a wide range of normal tissues and may be involved in the control of proliferation and differentiation in embryo and adult tissues.

Animals↗