The epidermal growth factor receptor as a prognostic marker: results of 370 patients and review of 3009 patients

Immunolocalization and Quantitation of Transforming Growth Factor Alpha in Hydatidiform Mole

Complete hydatidiform mole (CHM), a condition related to abnormal gestation, occurs predominantly in the young reproductive age group and has a high prevalence rate in the Trivandrum region, occurring in 1.2% of deliveries. Transforming growth factor alpha (TGF-α) is an important growth regulatory molecule, the location and function of which at the human fetomaternal interface in CHM remains to be determined. The present study examined the presence of TGF-α in the normal and complete molar placenta and decidua throughout gestation. A total of 149 complete molar placental tissue samples and 96 normal placental tissue samples were evaluated for TGF-α expression by immunohistochemistry and 50 each of CHM and normal placental tissue for TGF-α concentration by radioimmunoassay. The peptide was localized immunocytochemically with a monoclonal anti-TGF-α antibody on paraffin-embedded tissue using the avidin-biotin complex peroxidase technique with aminoethyl carbazole as the chromogen. In molar placenta, villous trophoblast cells (syncytiotrophoblasts and cytotrophoblasts) showed intense cytoplasmic staining at all gestational ages compared to normal placenta of the same gestational age. The tissue concentration of TGF-α was highly overexpressed in the molar placenta (10-1000 fold) compared to that in the normal placenta. The results indicate that TGF-α is present in trophoblasts throughout human gestation and may provide additional growth advantage to maintenance of the hyperproliterative condition in trophoblastic tumors.

Protein tyrosine phosphatase SHP-1 sensitizes EGFR/HER-2 positive breast cancer cells to trastuzumab through modulating phosphorylation of EGFR and HER-2

Background

Trastuzumab resistance in HER-2 positive breast cancer cells is closely related to overexpression of both epidermal growth factor receptor (EGFR) and human epidermal receptor (HER-2). SHP-1 has been demonstrated to downregulate tyrosine kinase activity including EGFR via its phosphatase function, but its effect on HER-2 activity is still unknown. Here, we examined the hypothesis that SHP-1 enhances the anticancer efficacy of trastuzumab in EGFR/HER-2 positive breast cancer cells through combining dual inhibition of EGFR and HER-2.

Methods

Trastuzumab-resistant breast cancer SKBr-3 cells were generated by long-term in vitro culture of SKBr-3cells in the presence of trastuzumab. The SHP-1 was ectopically expressed by stable transfection. The activity and expression of EGFR, HER-2, and downstream signaling pathways were tested by Western blot. Cell viability was examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and apoptosis was examined by flow cytometry. The binding between SHP-1 and EGFR/HER-2 was evaluated by immunoprecipitation assay and bimolecular fluorescence complementation. The effects of SHP-1 on tumorigenicity and trastuzumab sensitivity were confirmed via in vivo xenograft model.

Results

Trastuzumab-resistant SKBr-3 cells showed aberrant co-expression of EGFR and HER-2. Introduction of wild-type SHP-1 inhibited cell proliferation, clone formation, and promoted the apoptosis induced by trastuzumab. Meanwhile, SHP-1 overexpression reduced phosphorylation levels of EGFR and HER-2 both in parental and trastuzumab-resistant SKBr-3 cells. In vivo study showed an increased antitumor effect of trastuzumab in SHP-1 overexpressed xenografts. At last, we discovered that SHP-1 can make complexes with both EGFR and HER-2, and both phospho-EGFR and phosphor-HER-2 levels in wild-type SHP-1 immunoprecipitates were less than those in phosphatase-inactive SHP-1 (C453S) immunoprecipitates, indicating that EGFR and HER-2 are potential substrates of SHP-1.

Conclusion

Taken together, we have demonstrated that the SHP-1 is a negative regulatory factor of the tyrosine kinase activity of HER-2 and EGFR through inhibiting phosphorylation. Dual targeting of EGFR and HER-2, by combining trastuzumab with SHP-1 overexpression, may improve response in HER-2 overexpressing breast cancer cells that also express high levels of EGFR.

A microfluidic device to select for cells based on chemotactic phenotype

In the search for biomarkers of metastasis, attention has been largely placed on ensemble-averaged measurements that screen for molecules or genes. However, individual molecular changes do not always result in disease, and population-based measurements can mask the molecular signatures of the cells responsible for disease. Here, we describe a device that selects for cells based on chemotactic behavior rather than based on molecular differences, enabling the most aggressive cells to be studied independently from the heterogeneous population.

The effects of cetuximab alone and in combination with endostatin on vascular endothelial growth factor and interleukin-8 expression in human lung adenocarcinoma cells

BACKGROUND

Angiogenesis, the growth of new blood vessels, plays an important role in tumor growth and metastasis. Both cetuximab and endostatin have been found to reduce the expression of endothelial-stimulating growth factors such as vascular endothelial growth factor (VEGF) and interleukin (IL)-8. However, the effects of cetuximab alone or in combination with endostatin on human lung adenocarcinoma cell growth remain unclear.

OBJECTIVE

The aim of this study was to evaluate the cellular and molecular effects of cetuximab alone and in combination with endostatin on human lung adenocarcinoma cell lines HI 299, SPC-A1, and H460 in vitro. Methods The epidermal growth factor receptor (EGFR) status of a panel of human lung adenocarcinoma cell lines was characterized using Western blot analysis. We used a modified tetrazolium salt assay to evaluate the growth-inhibitory effects of cetuximab and endostatin alone and in combination on the cell lines. We also determined the effects of these 2 drugs on VEGF and IL-8 expression using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Cells were treated for 4 days with cetuximab 12.5 μ/mL, endostatin 25 μ/mL, or cetuximab 12.5 μg/mL + endostatin 25 μg/mL. Untreated cells cultured for 4 days served as controls.

RESULTS

EGFR expression in the H1299 cells was higher than in the SPC-A1 and H460 cells. Varying concentrations of cetuximab alone were associated with a significant growth-inhibitory effect on all 3 cell lines in a dose-dependent manner after 4 days of exposure compared with controls (all, P < 0.05). Compared with controls, varying concentrations of endostatin alone were not associated with significant inhibition of cell growth in any of the 3 cell lines. The inhibitory ratio of cetuximab + endostatin at varying concentrations was significantly greater than that of cetuximab alone (all, P < 0.05). On ELISA, either drug alone was associated with significant reductions in secreted VEGF and IL-8 in the HI 299, SPC-A1, and H460 cell lines (all, P < 0.05), with the exception of IL-8 concentration in the H460 cells. Mean (SD) VEGF expression with combination treatment in the H1299 and SPC-A1 cell lines (687 [21] and 629 [23] pg/mL, respectively) was significantly lower than with cetuxi-mab alone (878 [31] and 708 [20] pg/mL; both, P < 0.001); in the H460 cell line, combination treatment was not associated with a significant further reduction in VEGF expression. IL-8 concentrations with cetuximab in the H1299, SPC-A1, and H460 cell lines were 628 (20), 484 (29), and 532 (28) pg/mL, respectively, while the IL-8 concentrations with the combination treatment were 516 (20), 480 (18), and 467 (30) pg/mL. An enhanced effect of endostatin on IL-8 was observed in the H1299 and H460 cell lines (P < 0.001 and P = 0.018, respectively); however, no enhanced effect in the SPC-A1 line was observed. Similar results for VEGF and IL-8 expression were found using Western blot analysis.

CONCLUSIONS

The results from this in vitro study suggest that cetuximab treatment might both inhibit human lung adenocarcinoma cell line growth and reduce the expression of VEGF and IL-8, which are the biomarkers of angiogenesis. Endostatin was not associated with inhibition of human lung adenocarcinoma cell line growth directly. Findings with the combination of cetuximab + endostatin suggest that endostatin might enhance the antiangiogenic and antitumor activity of cetuximab through an apparent effect on VEGF expression and, to a lesser degree, on IL-8 expression.

A novel discriminant score based on tumor-associated trypsin inhibitor for accurate diagnosis of metastasis in patients with breast cancer

Invasion and metastasis of solid tumors require proteolytic enzymes for degradation of the basal membrane and extracellular matrix. Currently, there are no reliable methodologies to predict the risk for metastatic disease. In this context, our aim has been focused on the development of a noninvasive score based on tumor-associated trypsin inhibitor (TATI) for the assessment of metastasis in patients with breast cancer. TATI, trypsin, and soluble epidermal growth factor receptor (sEGFR) were assayed by enzyme-linked immunosorbent assay. CA 15.3 serum level was assayed by microparticle enzyme immunoassay in 265 patients with breast cancer. Statistical analyses were performed by logistic regression and receiver operating characteristic analysis curves. Using multivariate discriminant analysis, a score is selected based on absolute values of the four biochemical markers: TATI-metastatic breast cancer score (TATI-MBCS) = [0.03 × CA 15.3 (U/L) + 0.039 × TATI (ng/ml) + 0.04 × trypsin (ng/ml) + 0.023 × sEGFR (ng/ml) - 6.49 (numerical constant)]. This function correctly classified 84% of metastatic breast cancer at cutoff value = 0.62 (i.e., greater than 0.62 indicates patients with metastatic breast cancer and less than 0.62 indicates patients with nonmetastatic breast cancer). In conclusion, TATI-MBCS is a novel, noninvasive, and simple score which can be applied to discriminate patients with metastatic breast cancer.

P53 mutations in triple negative breast cancer upregulate endosomal recycling of epidermal growth factor receptor (EGFR) increasing its oncogenic potency

There is no available targeted therapy for triple-negative or its more aggressive subtype, basal-like breast cancer. Multiple therapeutic strategies based on translational knowledge have not improved the treatment options for triple negative patients. As understanding of molecular pathways that drive tumor development is rapidly increasing, it is imperative to adapt our treatment strategies to perturbations in molecular pathways driving the malignant process. Basal-like breast cancers over-express EGFR (without mutations or EGFR gene amplifications) and have p53 mutations. While EGFR drives the malignant behavior in triple negative breast cancer (TNBC), anti-EGFR therapies have fallen short of the expected results in clinical trials. Here we bring evidence that the less than optimal results of the anti-EGFR therapies may be explained in part by the increased potency of the EGFR signaling due to increased endosomal recycling. The functional connection between EGFR and endosomal trafficking in TNBC is mutant p53 found in the most aggressive forms of TNBC. Mutant p53 acquires oncogenic functions and binds p63 protein, a member of p53 family with tumor suppressor activities. In the absence of functional p63 there is an upregulation of endosomal recycling EGFR and integrin to the membrane with increased proinvasive abilities of cancer cells. Blocking endosomal trafficking combined with anti-EGFR treatments may result in better clinical outcomes in TNBC.

The next generation of biologic agents: therapeutic role in relation to existing therapies in metastatic breast cancer

The use of more active cytotoxic agents (eg, anthracyclines and taxanes) in the adjuvant setting has impacted treatment options in metastatic breast cancer (MBC). Various new approaches to combination therapy are being investigated, including classic and novel cytotoxic agents and targeted therapies. The heterogeneous molecular pathways involved in the development of breast cancer provide numerous potential targets for therapeutic intervention. Molecular technologies have facilitated the development of various new therapies targeted at disrupting processes as diverse as angiogenesis and DNA repair. Targeted therapies have the potential to improve outcomes in MBC, and their use has increased dramatically over recent years after the introduction of human epidermal growth factor receptor 2 (EGFR2)-targeted therapy with trastuzumab. Lapatinib and bevacizumab have recently been approved for patients with MBC. Numerous other targeted agents are undergoing preclinical investigation or are being evaluated in clinical trials. The maximum benefit of targeted therapies has been realized by their combined use with cytotoxic agents. Overall, single-agent use of targeted therapies has failed to produce dramatic benefit in patients with advanced breast cancer. This article reviews the data from studies of established and emerging targeted therapies in the treatment of MBC and describes how best to incorporate these agents into current treatment paradigms.

Novel targeted agents for the treatment of advanced breast cancer

The discovery of the molecular processes involved in cancer development has led to the design of an array of targeted agents. These agents, directed to specific proteins in the machinery of cancer cells, interfere with vital cascades involved in cell invasion, metastasis, apoptosis, cell-cycle control and angiogenesis. In breast cancer, the main pathways studied and targeted by drugs are the HER2 pathway, EGFR, VEGF, PI3K/Akt/mammalian target of rapamycin (PI3K-M-Tor), IGF/IGFR, poly(ADP ribose) polymerase 1, HDAC and many others. In this review, we present the most promising studies of these new targeted therapies and novel combination of targeted therapies with cytotoxic agents for the treatment of breast cancer patients.

EGFR soluble isoforms and their transcripts are expressed in meningiomas

The EGFR (epidermal growth factor receptor) is involved in the oncogenesis of many tumors. In addition to the full-length EGFR (isoform a), normal and tumor cells produce soluble EGFR isoforms (sEGFR) that lack the intracellular domain. sEGFR isoforms b, c and d are encoded by EGFR variants 2 (v2), 3 (v3) and 4 (v4) mRNA resulting from gene alternative splicing. Accordingly, the results of EGFR protein expression analysis depend on the domain targeted by the antibodies. In meningiomas, EGFR expression investigations mainly focused on EGFR isoform a. sEGFR and EGFRvIII mutant, that encodes a constitutively active truncated receptor, have not been studied. In a 69 meningiomas series, protein expression was analyzed by immunohistochemistry using extracellular domain targeted antibody (ECD-Ab) and intracellular domain targeted antibody (ICD-Ab). EGFRv1 to v4 and EGFRvIII mRNAs were quantified by RT-PCR and EGFR amplification revealed by MLPA. Results were analyzed with respect to clinical data, tumor resection (Simpson grade), histological type, tumor grade, and patient outcome.Immunochemical staining was stronger with ECD-Ab than with ICD-Ab. Meningiomas expressed EGFRv1 to -v4 mRNAs but not EGFRvIII mutant. Intermediate or high ECD-Ab staining and high EGFRv1 to v4 mRNA levels were associated to a better progression free survival (PFS). PFS was also improved in women, when tumor resection was evaluated as Simpson 1 or 2, in grade I vs. grade II and III meningiomas and when Ki67 labeling index was lower than 10%.Our results suggest that, EGFR protein isoforms without ICD and their corresponding mRNA variants are expressed in meningiomas in addition to the whole isoform a. EGFRvIII was not expressed. High expression levels seem to be related to a better prognosis. These results indicate that the oncogenetic mechanisms involving the EGFR pathway in meningiomas could be different from other tumor types.

Mammary tumorigenesis induced by fibroblast growth factor receptor 1 requires activation of the epidermal growth factor receptor

Fibroblast growth factor receptor 1 (FGFR1) is an oncoprotein with known involvement in mammary tumorigenesis. To understand how FGFR1 signaling promotes mammary tumorigenesis, an inducible FGFR1 (iFGFR1) system was created previously. Previous studies have demonstrated that upon iFGFR1 activation in vivo, the epidermal growth factor (EGF) ligands amphiregulin (AREG) and epiregulin (EREG) are upregulated. Both AREG and EREG interact with the EGF receptor (EGFR). Here, we investigated whether the FGFR1-induced increase in AREG and EREG expression might coordinately increase EGFR signaling to promote mammary tumorigenesis. Treatment of mouse mammary epithelial cells with either AREG or EREG conferred a greater migratory potential, increased cellular proliferation and increased extracellular regulated kinase 1/2 (ERK1/2) activation. These effects could be blocked with the EGFR-specific inhibitor erlotinib, suggesting that they are EGFR-dependent. In transgenic mice with iFGFR1 under the control of the mouse mammary tumor virus (MMTV) promoter, iFGFR1 activation also led to increased mammary epithelial cell proliferation that was inhibited with erlotinib. Taken together, these data suggest that AREG and EREG mediate tumorigenic phenotypes by activating EGFR signaling, and that the oncogenic potential of FGFR1 requires EGFR activation to promote mammary tumorigenesis.

Epidermal growth factor enhances the malignant phenotype in canine mammary carcinoma cell lines

Canine mammary gland tumours (CMTs) are the most common malignancies in female dogs. The receptor tyrosine kinase EGFR (erbb1), a receptor for epidermal growth factor (EGF) and related factors, mediates multiple oncogenic functions in human epithelial neoplasms. While previous studies have demonstrated EGFR expression in canine tumours, its function has not been studied in canine cancer. The purpose of this study was to determine the in vitro effects of EGF and vandetanib (ZD6474), a small molecule inhibitor of VEGFR-2, EGFR and RET tyrosine kinases, on proliferation, invasion, survival and chemosensitivity in CMT cells. In low serum, EGF enhanced proliferation and chemotaxis, attenuated apoptosis, and stimulated vascular endothelial growth factor (VEGF) production. Vandetanib dose-dependently inhibited EGFR phosphorylation as well as PI3K/Akt activation, and inhibited all EGF-induced phenotypic effects. In conclusion, EGF stimulates multiple features promoting the malignant phenotype in CMT. Thus, CMT may be an important translational model for the investigation of novel EGFR-directed therapies.

Vandetanib with docetaxel as second-line treatment for advanced breast cancer: a double-blind, placebo-controlled, randomized Phase II study

PURPOSE

The aim of this Phase II study was to assess the efficacy and safety of vandetanib in combination with docetaxel in patients with pretreated advanced breast cancer.

METHODS

The primary study objective was to compare the number of progression events in patients receiving once-daily oral vandetanib (100 mg) in combination with docetaxel (100 mg/m(2) iv every 21 days) versus placebo plus docetaxel. Sixty-four patients were randomized to receive study treatment (n = 35, vandetanib; n = 29, placebo).

RESULTS

A slightly greater number of patients had experienced a progression event by the data cut-off in the vandetanib group (24 [69%]) compared with the placebo group (18 [62%]); HR = 1.19, two-sided 80% CI: 0.79-1.81; two-sided P = 0.59), suggesting that the addition of vandetanib to docetaxel did not affect the risk of disease progression compared with placebo plus docetaxel. The safety and tolerability profile of the combination therapy reflected those of both drugs as monotherapy agents.

CONCLUSIONS

In patients with advanced breast cancer, vandetanib plus docetaxel was generally well tolerated. Clinical benefit was not different to that observed with placebo plus docetaxel. However, due to the small patient number it was not possible to yield robust results, further research is required to identify predictive factors for patient selection.

A phase II study of erlotinib (OSI-774) given in combination with carboplatin in patients with recurrent epithelial ovarian cancer (NCIC CTG IND.149)

OBJECTIVES

Approximately 50% of ovarian cancers have elevated levels of epidermal growth factor receptor (EGFR) which correlates with a poor prognosis. Preclinical evidence suggests that EGFR tyrosine kinase inhibitors (TKIs), such as erlotinib (OSI-774), may potentiate the anti-tumour effects of cytotoxic agents, including carboplatin. Blocking EGFR could thus potentially reverse drug resistance. The primary objective of the study was to assess the response rate to the addition of erlotinib in patients with recurrent ovarian cancer who were receiving carboplatin.

METHODS

Patients enrolled on this study had either local or advanced recurrent ovarian cancer with measurable disease. They may have had up to 2 prior chemotherapy regimens, one of which must have contained platinum, and they must have responded to prior platinum therapy. Patients were stratified by platinum sensitivity and were treated with erlotinib 150 mg daily on a continuous dosing schedule, and carboplatin at an AUC of 5 every 21 days.

RESULTS

Fifty patients with recurrent ovarian cancer entered the study, 33 in the platinum-sensitive arm and 17 in the platinum-resistant arm. Of patients evaluable for response, there were 14 partial responses (PR) of 30 evaluable for response (57% objective response rate (ORR)) in the platinum-sensitive arm, and 1 PR of 14 evaluable for response (7% ORR) in the platinum-resistant arm.

CONCLUSIONS

The combination of erlotinib and carboplatin was active in patients with platinum-sensitive disease, but not in platinum-resistant disease. The toxicities seen were those expected with carboplatin and erlotinib.

Emerging targeted therapies for breast cancer

Increased understanding of the molecular events involved in cancer development has led to the identification of a large number of novel targets and, in parallel, to the development of multiple approaches to anticancer therapy. Targeted therapy focuses on specific molecules in the malignant cell signal transduction machinery, including crucial molecules involved in cell invasion, metastasis, apoptosis, cell-cycle control, and tumor-related angiogenesis. In breast cancer, two new targeted agents have recently been approved: lapatinib, directed against the human epidermal growth factor receptor 2 (HER2); and bevacizumab, directed against vascular endothelial growth factor (VEGF). Multiple other targeted agents are under evaluation in clinical trials, including inhibitors of the epidermal growth factor receptor (EGFR), dual EGFR and HER2 inhibitors, other VEGF or VEGF-receptor inhibitors, and agents that alter crucial signaling pathways, such as RAS/MEK/ERK; phosphatidylinositol-3-kinase/Akt/ mammalian target of rapamycin; insulin-like growth factor/insulin-like growth factor receptor; poly (ADP-ribose) polymerase 1; and others. In this review, we present the most promising studies of these new targeted therapies and novel combinations of targeted therapies with traditional cytotoxic agents.

Synergistic interaction between trastuzumab and EGFR/HER-2 tyrosine kinase inhibitors in HER-2 positive breast cancer cells

Overexpression of HER-2 in breast cancer is frequently associated with expression of EGFR, and EGFR expression influences response to HER-2 inhibition. The aim of this study was to examine the effects of combining dual inhibition of EGFR and HER-2, using trastuzumab, gefitinib and lapatinib, in HER-2 overexpressing breast cancer cells. Combination proliferation assays were performed in two HER-2 positive breast cancer cell lines, SKBR-3 and BT-474. Trastuzumab combined with lapatinib was also tested in BT-474 xenografts. In proliferation assays, dual targeting with trastuzumab and gefitinib or lapatinib showed synergy or additivity in both SKBR-3 and BT-474 cells. Trastuzumab (10 nM) or gefitinib (5 µM) alone did not induce significant apoptosis, whereas lapatinib (0.75 µM) induced significant apoptosis in SKBR-3 cells. Trastuzumab combined with lapatinib further enhanced apoptosis induction. Trastuzumab (10 nM) and gefitinib (5 µM) induced apoptosis comparable to lapatinib alone (0.75 µM), suggesting that inhibition of both EGFR and HER-2 may be required to induce apoptosis in these cells. Pre-treatment with trastuzumab and gefitinib or lapatinib enhanced response to chemotherapy in vitro. The combination of trastuzumab and lapatinib also effectively blocked tumour growth in vivo. Dual targeting of EGFR and HER-2, by combining trastuzumab with EGFR/HER-2 tyrosine kinase inhibitors, may improve response in HER-2 overexpressing breast cancer cells that also express EGFR.

Hierarchical clustering of immunohistochemical analysis of the activated ErbB/PI3K/Akt/NF-kappaB signalling pathway and prognostic significance in prostate cancer

Background:

The PI3K/Akt signalling pathway, induced by epidermal growth factor receptor (EGFR) and Her-2, is involved in the constitutive activation of NF-κB in prostate cancer cell lines. In this study, we extended the in vitro observation using an ex vivo model of prostate cancer tissues and assessed the prognostic significance of the PI3K/Ak/NF-κB signalling determinants.

Methods:

We analysed a prostate cancer tissue microarray of 63 patients for the expression of total and activated EGFR, Her-2 receptors and the signalling molecules PTEN, phospho-PTEN, Akt, phospho-Akt and the NF-κB subunit p65. Data were analysed using Spearman's rho test, Kaplan–Meier curves and multivariate Cox regression analysis. In addition, a non-supervised hierarchical clustering analysis was applied to stratify patients according to prognostic groups in terms of risk of recurrence.

Results:

The concomitant overexpression of activated EGFR and Her-2 was correlated with the nuclear expression of NF-κB. EGFR, phospho-EGFR, phospho-Her-2, ErbB3 and nuclear NF-κB were associated with the overall biochemical recurrence (BCR) of patients. The non-supervised hierarchical clustering analysis resulted in the separation of patients into five groups according to BCR.

Conclusions:

These results validate the previous in vitro data on ErbB involvement in NF-κB activation and shows evidence for a significant role of ErbB/PI3K/Akt/NF-κB signalling in the progression of prostate cancer.

Inhibition of epidermal growth factor receptor-overexpressing cancer cells by camptothecin, 20-(N,N-diethyl) glycinate

The epidermal growth factor receptor (EGFR) represents a prognostic marker for short survival of patients and therapy resistance of tumors. Despite clinical usefulness of EGFR tyrosine kinase inhibitors, resistance can develop. Therefore, there is an urgent need for novel EGFR inhibitors. Camptothecins have been characterized as inhibitors of DNA topoisomerase I (TOP1), although a correlation between TOP1 expression and activity is not well established in clinical biopsies. Hence, other targets may also be relevant. By molecular docking, we found that camptothecin 20-N,N-glycinate (CPTg) and camptothecin (CPT) bind to the same pharmacophore at EGFR as erlotinib, albeit to partly different amino acids. To validate the in silico results, CPT and CPTg were evaluated for their cytotoxic activity and downstream signaling mechanisms in U87MG glioblastoma cell lines transduced with different expression vectors for EGFR. All transduced cell lines were more susceptible to CPTg or CPT than the non-transduced cells, indicating a preferential activity towards EGFR-expressing tumor cells. Microarray-based mRNA hybridizations were performed in treated a non-treated cell lines. Subsets of genes were commonly regulated between the cell lines. By pathway analyses, we ranked canonical pathways according to differential gene expression after drug treatment. The pathways for G2/M DNA damage checkpoint regulation, aryl hydrocarbon receptor signaling, and xenobiotic metabolism and endoplasmatic reticulum stress were top ranked. In conclusion, binding of CPTg and CPT to the erlotinib pharmacophore and preferential cytotoxicity towards EGFR-overexpressing cells indicate susceptibility towards erlotinib-resistant tumors. Multiple mechanisms may account for cytotoxicity of these camptothecins.

Epidermal growth factor receptor expression in breast cancer association with biologic phenotype and clinical outcomes

BACKGROUND

Epidermal growth factor receptor (EGFR) expression is associated with aggressive phenotypes in preclinical breast cancer models, but in clinical studies, EGFR has been inconsistently linked to poor outcome. We hypothesized that EGFR expression in human breast tumors, when centrally and uniformly assessed, is associated with an aggressive phenotype and resistance to systemic therapy.

METHODS

In a database of 47,286 patients with breast cancer, EGFR status was known on 2567 tumors. EGFR levels were measured centrally by ligand binding assay, and tumors with > or =10 fmol/mg were prospectively deemed positive. Clinical and biological features of EGFR-positive and EGFR-negative tumors were compared. Clinical outcomes were assessed by systemic therapy status.

RESULTS

Of 2567 tumors, 475 (18%) were EGFR positive. EGFR-positive tumors were more common in younger and in black women, were larger, had a higher S-phase fraction, and were more likely to be aneuploid. EGFR-positive tumors were more likely to be HER2-positive (26% vs 16%, P < .0001), but less likely to be estrogen receptor-positive (60% vs 88%, P < .0001) or progesterone receptor-positive (26% vs 65%, P < .0001). In multivariate analyses, EGFR expression independently correlated with worse disease-free survival (hazard ratio [HR] = 1.66; 95% confidence interval [CI], 1.4-2.41, P = .007) and overall survival (HR = 1.98, 95% CI, 1.36-2.88, P = .0004) in treated patients, but not in untreated patients.

CONCLUSIONS

EGFR expression is more common in breast tumors in younger and black women. It is associated with lower hormone receptor levels, higher proliferation, genomic instability, and HER2 overexpression. It is correlated with higher risk of relapse in patients receiving adjuvant treatment. Blocking EGFR may improve outcome in selected patients.

Epidermal growth factor receptor-mediated membrane type 1 matrix metalloproteinase endocytosis regulates the transition between invasive versus expansive growth of ovarian carcinoma cells in three-dimensional collagen

The epidermal growth factor receptor (EGFR) is overexpressed in ovarian carcinomas and promotes cellular responses that contribute to ovarian cancer pathobiology. In addition to modulation of mitogenic and motogenic behavior, emerging data identify EGFR activation as a novel mechanism for rapid modification of the cell surface proteome. The transmembrane collagenase membrane type 1 matrix metalloproteinase (MT1-MMP, MMP-14) is a major contributor to pericelluar proteolysis in the ovarian carcinoma microenvironment and is subjected to extensive posttranslational regulation. In the present study, the contribution of EGFR activation to control of MT1-MMP cell surface dynamics was investigated. Unstimulated ovarian cancer cells display caveolar colocalization of EGFR and MT1-MMP, whereas EGFR activation prompts internalization via distinct endocytic pathways. EGF treatment results in phosphorylation of the MT1-MMP cytoplasmic tail, and cells expressing a tyrosine mutated form of MT1-MMP (MT1-MMP-Y(573)F) exhibit defective MT1-MMP internalization. As a result of sustained cell surface MT1-MMP activity, a phenotypic epithelial-mesenchymal transition is observed, characterized by enhanced migration and collagen invasion, whereas growth within three-dimensional collagen gels is inhibited. These data support an EGFR-dependent mechanism for regulation of the transition between invasive and expansive growth of ovarian carcinoma cells via modulation of MT1-MMP cell surface dynamics.

Immunohistochemical expression of Epidermal Growth Factor Receptor (EGFR) in canine mammary tissues

Epidermal Growth Factor Receptor (EGFR) has been extensively studied in human breast cancer; however, systematic studies of EGFR protein expression in canine mammary gland tumours are lacking. Therefore, we evaluated its immunohistochemical expression in a series of 136 canine mammary tumours and representative areas of adjacent normal and hyperplastic mammary tissue and investigated a possible correlation between EGFR overexpression and several clinicopathological parameters and survival. In normal and hyperplastic canine mammary glands, EGFR expression was consistently observed in myoepithelial cells, with luminal cells usually negative. In tumour tissues, EGFR overexpression was found in 9 benign (19.6%) and 38 malignant (42.2%) lesions, with EGFR positivity significantly related with malignancy. Besides animal age and tumour size, there were no significant associations between other clinicopathological parameters and EGFR overexpression. On survival analysis, tumours with EGFR overexpression showed a reduced disease-free and overall survival; however these associations failed to reach statistically significant levels.

The EGFR-GEP100-Arf6-AMAP1 signaling pathway specific to breast cancer invasion and metastasis

Tumors are tissue-specific diseases, and their mechanisms of invasion and metastasis are highly diverse. In breast cancer, biomarkers that specifically correlate with the invasive phenotypes have not been clearly identified. A small GTPase Arf6 primarily regulates recycling of plasma membrane components. We have shown that Arf6 and its effector AMAP1 (DDEF1, DEF1, ASAP1 and centaurin β4) are abnormally overexpressed in some breast cancers and used for their invasion and metastasis. Overexpression of these proteins is independent of the transcriptional upregulation of their genes, and occurs only in highly malignant breast cancer cells. We recently identified GEP100 (BRAG2) to be responsible for the Arf6 activation to induce invasion and metastasis, by directly binding to ligand-activated epidermal growth factor receptor (EGFR). A series of our studies revealed that for activation of the invasion pathway of EGFR, it is prerequisite that Arf6 and AMAP1 both are highly overexpressed, and that EGFR is activated by ligands. Pathological analyses indicate that a significant large population of human ductal cancers may utilize the EGFR-GEP100-Arf6-AMAP1 pathway for their malignancy. Microenvironments have been highly implicated in the malignancy of mammary tumors. Our results reveal an aspect of the precise molecular mechanisms of some breast cancers, in which full invasiveness is not acquired just by intracellular alterations of cancer cells, but extracellular factors from microenvironments may also be necessary. Possible translation of our knowledge to cancer therapeutics will also be discussed.

Expression of EGFR and c-kit is associated with the basal-like phenotype in breast carcinomas of African women

Epidermal growth factor receptor (EGFR) and c-kit are tyrosine kinase growth factor receptors which are frequently expressed in basal-like breast carcinomas, and tyrosine kinase inhibition is now a promising strategy in treatment of breast cancer. The aim of this study was to evaluate the expression of EGFR and c-kit in breast cancer with special focus on the basal-like phenotype (BLP) and other prognostic factors in an African population. We analyzed 65 archival tissues immunohistologically. EGFR and/or c-kit were expressed in 55% of basal-like tumors. Expression of EGFR and/or c-kit was strongly associated with high histologic grade (P=0.001), high nuclear grade (P=0.017), high mitotic counts (P=0.002), ER negativity (P=0.003), PR negativity (P=0.007), and HER2 negativity (P=0.014). EGFR and/or c-kit positive tumors were more likely to express the BLP (OR 9.1, CI 2.6-32.0, P<0.0005) than the negative tumors. In conclusion, there is a high expression of EGFR and/or c-kit in basal-like breast carcinoma in this series from Uganda and their expression is associated with features of poor prognosis. More studies are required to assess the clinical significance of EGFR and c-kit in breast cancer patients in Uganda.

The epidermal growth factor receptor family in breast cancer

THE HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR (HER) FAMILY COMPRISES FOUR HOMOLOGOUS MEMBERS: EGFR, HER-2, HER-3, and HER-4. The activation of these receptors triggers a complex series of signal transduction pathways which affect pivotal tumorigenic processes. The deregulation of HER signaling is seen in several human malignancies. HER-2 is now recognized as a key oncogene in breast cancer pathogenesis. Assessment of HER-2 status is of central importance in the prognosis of breast cancer patients. In the light of clinical data suggesting that HER-2 can also be useful as a predictive marker both for trastuzumab and chemotherapy, standardized determination of the HER-2 status in tumors has become more important. Moreover, current data provide evidence for the significance of HER-3 and HER-4 alterations in breast carcinogenesis. Because of the complex interactions among the HER receptors, it is likely that the effect on cell proliferation and tumor growth depends on receptor trans-signaling and thus, the evaluation of the combined expression pattern of all family members is of particular interest. This review presents the current evidence highlighting the role of the family as a whole panel and an update on the role of HER-3 and HER-4 receptors in breast cancer. Moreover, we provide updated data regarding the prognostic value of HER family members giving emphasis to novel methods for the determination of their status, such as real-time polymerase chain reaction. In addition, we review recent therapeutic approaches aimed at targeting the HER family in breast cancer patients.

Jab1 is a target of EGFR signaling in ERalpha-negative breast cancer

Introduction

c-Jun activation domain-binding protein-1 (Jab1) is a multifunctional signaling protein that previously has been shown to be a master regulator of a poor prognostic gene signature in invasive breast cancer and to mediate the action of S100A7. Since epidermal growth factor receptor (EGFR), like S100A7, is often expressed in estrogen receptor-alpha-negative (ERα^-) breast cancer, we set out to investigate the role of Jab1 in mediating EGFR signaling, another facet of the ERα^- phenotype.

Methods

MDA-MB-231 and MDA-MB-468 ERα^-/EGFR⁺ cell lines were assessed for localization of Jab1 and levels of downstream genes by immunofluorescence and nuclear protein extract assay following treatment with epidermal growth factor (EGF) and extracellular signal-regulated kinase (ERK) pathway inhibitor. A cohort of 424 human breast tumors was also assessed by immunohistochemistry.

Results

EGF treatment of cell lines resulted in increased Jab1 nuclear expression. This effect was inhibited by the ERK pathway inhibitor, PD98059. EGF treatment was also associated with colocalization of pERK (phosphorylated ERK) and Jab1 as well as regulation of the Jab1 downstream target gene, p27. When Jab1 activity was knocked down, p27 levels were restored to pre-EGF treatment level. Analysis of EGFR and Jab1 expression in a cohort of invasive breast tumors by tissue microarray and immunohistochemistry confirmed a relationship between EGFR and increased nuclear Jab1 within the ERα^- subset (n = 154, P = 0.019). The same association was also confirmed for S100A7 and Jab1 (P = 0.036), and high Jab1 nuclear expression was most frequent in tumors that were positive for both EGFR and S100A7 (P = 0.004).

Conclusion

Jab1 is a target of EGFR signaling in ERα^- cell lines and breast tumors and therefore may be a common central factor and potential therapeutic target for important cell signaling pathways in ERα^- breast cancer.

Interaction between the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor (VEGF) pathways: a rational approach for multi-target anticancer therapy

Over the last decade, the concept of targeted biological therapy for the treatment of cancer has emerged. However, a better understanding of these targets and their role in tumor cells and in the surrounding stromal cells is required. Two interesting biological targets are the epidermal growth factor receptor (EGFR) and the vascular endothelia growth factor (VEGF) and its receptors. A number of agents that target these pathways have been described. Many of these are currently in clinical trials and a few have recently been approved by the regulatory authorities in USA and in the European Union. The molecular pathways involved in the proliferation of cancer cells and in tumor-related angiogenesis are very complex and the interference with only a single step of these pathways may often reveal an insufficient therapeutic approach. Moreover, cancer cells have an inherent ability to harness different growth factor signaling pathways for growth advantage and cell survival, a process that may even be facilitated by the use of selective targeted agents. Because of these escape mechanisms, monotherapy with selective targeted agents is unlikely to be a fully effective cancer treatment. For these reasons, targeting different pathways is an attractive and effective therapeutic strategy with a strong rationale for investigating this approach in the clinic. This review focuses on the preclinical rationale of combining targeted agents such as EGFR and VEGF inhibitors in the treatment of cancer and on the clinical trials that have emerged from these studies.

Evaluation of the prognostic and predictive value of HER-1/EGFR in breast cancer patients participating in a randomized study with dose-dense sequential adjuvant chemotherapy

BACKGROUND

To assess the prognostic and predictive significance of HER-1/EGFR protein levels in high-risk patients with breast cancer treated with dose-dense sequential adjuvant chemotherapy.

METHODS

595 high-risk breast cancer patients were treated with adjuvant anthracycline-based dose-dense sequential chemotherapy (E-CMF vs. E-T-CMF). Disease-free survival (DFS) was the primary end point. HER-1/EGFR was assessed by immunohistochemistry (IHC) in 312 patients.

RESULTS

HER-1/EGFR expression was detected in 54 of 312 patients (17%). Positive expression of HER-1/EGFR was significantly associated with negative receptor status (52 vs. 17%, p < 0.001), worse histological grade (70 vs. 45%, p = 0.001), HER-2 overexpression (46 vs. 27%, p = 0.01) and positive p53 expression (48 vs. 19%, p < 0.001). With a median follow-up of 7 years, the total number of relapses was 105 (34%), and the total number of deaths 69 (22%). The analysis for DFS provides significant evidence that the HER-1/EGFR effect on the risk of disease progression was different according to treatment (interaction p = 0.02). Regarding overall survival, a trend towards a significant difference for an interaction of HER-1/EGFR and treatment was found (p = 0.07).

CONCLUSION

The present study demonstrated a differential effect of positive HER-1/EGFR expression in the two treatment groups, with HER-1/EGFR being a negative prognostic marker in the absence of paclitaxel.

Conventional and new emerging prognostic factors in breast cancer: an update

This article reviews the conventional clinicopathological, as well as the principal new emerging prognostic factors of breast cancer and proposes a tumor marker utility grading system for their use. In spite of the many advances in molecular biology toward better defining the biological aggressiveness of the primary malignancy, the conventional node-negative status, tumor size and grade are still the strongest predictors of relapse-free survival and/or overall survival. Microvessel count and bone-marrow micrometastases, among the more recently studied clinicopathological prognostic factors, and amplification and/or p53 mutation and S-phase fraction among the biological ones must be considered investigational, although, with enough documentation recommending their usefulness. Estrogen and/or progesterone expression, c-erbB-2 amplification and/or mutation are the prognostic factors currently included in the principal clinical guidelines. They also enable probable forecast of the response to endocrine treatment or chemotherapy. In particular, c-erbB-2 is used to define the different risk categories of node-negative operated breast cancer patients. In recent years, microarray and quantitative reverse-transcription PCR technologies have enabled the study of multiple genetic alterations and computer algorithms have been developed for visual recognition of tumors that share so-called ‘signatures’. So far, different gene-expression patterns with different prognoses have been identified but methodological problems remain to be solved prior to routine use.

Progressive loss of epidermal growth factor receptor in a subpopulation of breast cancers: implications in target-directed therapeutics

Understanding the molecular etiology and heterogeneity of disease has a direct effect on cancer therapeutics. To identify novel molecular changes associated with breast cancer progression, we conducted phosphoproteomics of the MCF10AT model comprising isogenic, ErbB2- and ErbB3-positive, xenograft-derived cell lines that mimic different stages of breast cancer. Using in vitro animal model and clinical breast samples, our study revealed a marked reduction of epidermal growth factor receptor (EGFR) expression with breast cancer progression. Such diminution of EGFR expression was associated with increased resistance to Gefitinib/Iressa in vitro. Fluorescence in situ hybridization showed that loss of EGFR gene copy number was one of the key mechanisms behind the low/null expression of EGFR in clinical breast tumors. Statistical analysis on the immunohistochemistry data of EGFR expression from 93 matched normal and breast tumor samples showed that (a) diminished EGFR expression could be detected as early as in the preneoplastic lesion (ductal carcinoma in situ) and this culminated in invasive carcinomas; (b) EGFR expression levels could distinguish between normal tissue versus carcinoma in situ and invasive carcinoma with high statistical significance (P < 0.001, n = 81). However, no significant correlation of EGFR expression with disease-free survival and overall survival was observed. This is the first time EGFR expression has been tracked meaningfully and developmentally from the normal condition through disease progression using in vitro, xenograft, and matched normal and tumor samples. Thus, our study provides a new insight into the role of EGFR in breast cancer development. Although no value of EGFR expression in prognosis was found, our findings are likely to have implications in the design of clinical trials targeting the EGFR family of proteins in breast cancer.

A phase II clinical trial of ZD1839 (Iressa) in combination with docetaxel as first-line treatment in patients with advanced breast cancer

This was a phase II multi-institutional trial to determine the efficacy and tolerability of gefitinib (Iressatrade) and docetaxel as first-line treatment in patients with metastatic breast cancer. All patients had histologically confirmed breast cancer with metastatic disease. They were permitted to have received adjuvant chemotherapy, but no prior docetaxel or prior chemotherapy for metastatic disease. Patients received gefitinib 250 mg once daily and docetaxel 75 mg/m(2) every 3 weeks, until tumor progression, toxicity or other reasons for discontinuation. Thirty-three patients were enrolled and received a median of 5 cycles of treatment. The clinical benefit rate was 51.5% (95% CI: 33.5-69.2%). There were 1 confirmed complete response and 12 confirmed partial responses, and the overall objective response rate was 39.4% (95% CI: 22.9-57.9%). Four patients had stable disease for > or =24 weeks. The median duration of clinical benefit was 10.9 months (95% CI: 6.0-17.6 months). The most common reason for study discontinuation was disease progression (16 patients), followed by toxicity (ten patients). Toxicities were mainly attributable to docetaxel, including > or =grade 3 neutropenia in 43% of patients. The combination of gefitinib and docetaxel is an active regimen in patients with previously untreated metastatic breast cancer, with a clinical benefit rate and toxicity profile in the range of that reported for docetaxel alone.

EGFR expression: associations with outcome and clinicopathological variables in malignant pleural mesothelioma

Malignant mesothelioma (MM) is a fatal tumour of increasing incidence which is related to asbestos exposure. This work evaluated expression in MM of Epidermal Growth Factor Receptor (EGFR) by immunohistochemistry in 168 tumour sections and its correlations with clinicopathological and biological factors. The microvessel density (MVD) was derived from CD34 immunostained sections. Hematoxylin and eosin stained sections were examined for intratumoural necrosis. COX-2 protein expression was evaluated with semi-quantitative Western blotting of homogenised tumour supernatants (n=45). EGFR expression was correlated with survival by Kaplan-Meier and log rank analysis. Univariate and multivariate Cox proportional hazards models were used to compare the effects of EGFR with clinicopathological and biological prognostic factors and prognostic scoring systems. EGFR expression was identified in 74 cases (44%) and correlated with epithelioid cell type (p<0.0001), good performance status (p<0.0001), the absence of chest pain (p<0.0001) and the presence of TN (p=0.004), but not MVD or COX-2. EGFR expression was a good prognostic factor in univariate analysis (p=0.01). Independent indicators of poor prognosis in multivariate analysis were non-epithelioid cell type (p=0.0001), weight loss, performance status and WBC>8.3x10(9)L(-1). EGFR status was not an independent prognostic factor. EGFR expression in MM correlates with epithelioid histology and TN. EGFR may be a target for selective therapies in MM.

Phase II study of gefitinib in combination with docetaxel as first-line therapy in metastatic breast cancer

We have evaluated the activity and safety of gefitinib, a small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in combination with docetaxel as first-line treatment of women with metastatic breast cancer (MBC). In total, 41 patients with MBC were enrolled in a first-line combination therapy study with oral gefitinib (250 mg day⁻¹) and intravenous docetaxel (75 mg m⁻², the first 14 patients; or 100 mg m⁻², the following 27 patients, on day 1 of a 3-week cycle). Out of 41 patients, 38 received at least one cycle of therapy. There were no differences in activity or tolerability between the two docetaxel doses. G3/4 toxicities were neutropenia (49%), diarrhoea (10%), acne-like rash (5%), and anaemia (2%). Complete plus partial responses (CR+PR) were observed in 22 out of 41 patients with a 54% response rate (95% confidence interval (CI) 45–75%). The 22 patients that achieved a response following six cycles of docetaxel plus gefitinib continued gefitinib monotherapy (median duration, 24 weeks; range, 2–108+ weeks). Two patients with PR following combination therapy achieved a CR during gefitinib monotherapy. Complete plus partial responses correlated with oestrogen receptor (ER) status, since they occurred in 19 out of 27 (70%) patients with ER-positive tumours as compared to three out of 14 (21%) patients with ER-negative tumours (P=0.01).

Radiobiology of Breast Cancer

Advances in molecular and cellular biology are transforming our understanding of breast cancer and promise the same for radiotherapy over the next few years. At the clinical level, the molecular basis of fractionation dependency and other tumour and normal tissue responses are likely to become clearer. More importantly, they will become useful in the clinic, where molecular characterisation of the patient and tumour will start to determine therapeutic options. Although many of the fundamental processes are only amenable to study in laboratory systems, the power of array-based technologies makes it possibly to address highly relevant questions in the clinic, using functional imaging and/or tissue biopsies. To help clinical oncologists exploit these opportunities in translational research, some aspects of the molecular and cellular basis of radiotherapy are described below in their relation to breast cancer.

La expresión del receptor del factor de crecimiento epidérmico (EGFR) en carcinomas mamarios hormonoindependientes

OBJECTIVE

To determine the expression of epidermal growth factor receptor (EGFR) in ER-negative and Pg-R negative infiltrating ductal carcinomas of the breast (IDC) and to analyze the possible relationship between the EGFR positivity and some clinico-biological parameters of tumors.

MATERIAL AND METHODS

EGFR was measured by a single point radioligand assay in the cell surfaces of 115 ER-negative and Pg-R-negative (< 10 fmol/mg prot.) IDC. We measured also the cytosolic concentrations of pS2, cathepsin D, tissue-type plasminogen activator (t-PA) and hyaluronic acid (AH), as well as the levels of AH in cell surfaces. Tumor size, axillary involvement, distant metastasis, histological grading, ploidy and S-phase (SP) were taken account.

RESULTS

Using as cut-off for EGFR a value of 5 fmol/mg prot., we can observed that IDCs -EGFR + had greater global values of S-phase (p: 0.005) and were more frequently metastastatic (p: 0.004), SP > 7 % (p < 0.001) and SP > 14 % (p: 0.077); likewise, they were lower frequently pS2-positive (p < 0.01) and t-PA-positive (p < 0.01). During the follow up time (median 85 months), the number of recurrences was higher in EGFR-positive than in EGFR- negative tumors (14/41 frente a 1/29; p: 0.002), but there was not differences in the number of deaths by the tumor.

CONCLUSIONS

1) The EGFR-positivity in ER-negative and PgR-negative IDCs is associated with distant metastasis, greater cellular proliferation (SP), lower positivity for pS2 and t-PA and greater number of recurrences. 2) Using 10 fmol/mg prot. as cut-off, we observed the same findings, except the change in cellular proliferation. 3) Our findings support the possible use of EGFR as a prognostic parameter in those breast carcinomas.

The role of the epidermal growth factor receptor in breast cancer

Recent trials of drug therapy targeting the erbB receptor HER2 have met with success in breast cancer. The epidermal growth factor receptor or EGFR is a closely related receptor from this same family that is involved in cellular signal transduction and tumor cell growth and survival. Emerging evidence indicates that EGFR is implicated in the development of hormone-resistant breast cancer, and that its activity is intertwined with estrogen receptor. Here, the role of EGFR in breast cancer is reviewed, and data from selected clinical trials of signal transduction inhibition of this cellular target are summarized.

Prognostic role of epidermal growth factor receptor in localized breast cancer: 15 Years of follow-up

Background: The expression of epidermal growth factor receptor (EGF-R) in breast cancer (BC) is generally considered as an unfavorable event during tumor progression. Its predictive role has been fairly well defined: EGF-R expression predicts tamoxifen unresponsiveness. EGF-R role in autocrine growth regulation was confirmed. However, reported results on its prognostic role in BC patients were conflicting. The prognostic role of EGF-R after 15 years of follow-up is analyzed in a group of 70 localized BC patients, presented at diagnosis in clinical stages I-III. Methods: BC patients newly diagnosed from December 1990 until March 1991, treated in accordance to the National Protocol, were selected for EGF-R analysis. Steroid receptors and EGF-R were determined at diagnosis in same frozen tissue samples, using biochemical methods. Except 6 patients who were lost from follow-up in the interval shorter than 60 months, the remaining patients were followed-up from 60-188 months. The total number of events was 32 relapses (46%), and 27 deaths (38.5%). Results: EGF-R expression was found in 28/70 patients (40%), and the EGF-R content higher than 26 fmol - in 15/70 patients (21%). Neither the expression, nor the high content of EGF-R showed any influence on disease-free or overall survival. Levels of EGF-R were similar in relapsing and relapse-free patients. Nodal status had the strongest infuence on prognosis. Conclusion: Our results suggest that the controversial findings, regarding the EGF-R prognostic role, might be the consequence of a genuine weak influence of EGF-R expression on disease outcome. .

Gefitinib, a selective EGFR tyrosine kinase inhibitor, induces apoptosis through activation of Bax in human gallbladder adenocarcinoma cells

Although gefitinib, a selective inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, has been clinically demonstrated to be effective for certain cancer cell types, the molecular mechanisms of the anti-tumor activity have not been fully elucidated. In this study, we investigated the mechanism of gefitinib-induced growth inhibition and apoptosis in HAG-1 human gallbladder adenocarcinoma cells. Treatment of gefitinib at a dose of 1 microM resulted in a significant growth inhibition, and the cell number irreversibly declined after 72-h incubation, with a progressive expansion of apoptotic cell population over 120-h. Following 2-h treatment, gefitinib significantly inhibited EGFR autophosphorylation and subsequent downstream signaling pathway through Erk and Akt, and induced accumulation of cells in the G0/G1 phase of the cell cycle at 24-h, accompanied by a concomitant increase in p21 transcript and increased expression of p27. Gefitinib did not affect the amount of total and phosphorylated p53 at serine 15, but upregulated the expression of total Bax, with subsequent increase in p18 Bax, an active form of Bax. The expression of Bcl-2 and Bad was unchanged. An increase in gefitinib-induced expression of total Bax might be due to the decreased degradation of Bax, because the level of Bax mRNA has not been altered by gefitinib treatment. Gefitinib promoted the cleavage of full-length p21 Bax into p18 Bax in mitochondrial-enriched fraction, a characteristic feature of Bax activation toward apoptosis. Moreover, blockade of Bax by using anti-Bax small interfering double stranded RNA (siRNA) significantly reduced gefitinib-induced apoptosis. Taken together, these data suggest a critical role of p18 Bax in gefitinib-induced apoptosis.

EGFR overexpression in malignant pleural mesothelioma. An immunohistochemical and molecular study with clinico-pathological correlations

The epidermal growth factor receptor (EGFR) is overexpressed in many epithelial malignancies, against which some antitumoral drugs have been developed. There is a lack of information as to EGFR expression in malignant pleural mesothelioma (MPM), an aggressive and fatal cancer poorly responsive to current oncological treatments. Our aim was to: (a) compare EGFR immunohistochemical expression with mRNA levels measured by real time PCR; (b) assess the relationships between EGFR expression and clinico-pathological data including survival; (c) analyze the EGFR mutations. We developed an immunohistochemical method of EGFR evaluation based on the number of immunoreactive cells and staining intensity in 61 MPMs. EGFR immunoreactivity was documented in 34/61 (55.7%) cases. A significant correlation between EGFR protein and mRNA levels (p = 0.0077) was found, demonstrating the reliability of our quantification method of EGFR membrane expression. Radically resected patients (p = 0.005) and those with epithelial histotype (p = 0.048) showed an increased survival. No statistical correlation between EGFR immunoreactivity and patients survival was observed. No EGFR mutation was documented. This study documents EGFR overexpression in MPM at the protein and the transcriptional levels; it proposes a reliable method for EGFR expression evaluation in MPM. EGFR levels are not associated with clinico-pathological features of patients, including survival.

Clinical value of epidermal growth factor receptor expression in primary breast cancer

EGFR expression in primary breast cancer has been extensively investigated for its prognostic and predictive value. However overall there is no consensus on its potential to guide such prognostication. This is largely because of the great heterogeneity in study designs and methods used to assay the EGFR protein. The impetus to standardize such studies is much needed as there are now several tyrosine kinase inhibitors directed against the EGF receptor and phase II trials are showing significant promise.

Phase 1 clinical and pharmacokinetics evaluation of oral CI-1033 in patients with refractory cancer

PURPOSE

To determine the tolerability and pharmacokinetics of oral CI-1033, a pan-erbB tyrosine kinase inhibitor, administered over 14 consecutive days of a 21-day cycle.

DESIGN

Phase 1, multicenter trial involving patients with solid tumors that are refractory to standard therapy. CI-1033 was administered initially at 300 mg/day to a minimum cohort of three patients. Dose escalation proceeded at </=40% increments. Patients were evaluated for toxicity, pharmacokinetic profile, and evidence of response.

RESULTS

Thirty-two patients entered the trial and were evaluable for safety assessment. Dose-limiting toxicity (diarrhea, rash, and/or anorexia) occurred at the 560 mg dose level; the maximum tolerated dose was 450 mg. No patients achieved objective responses and six patients achieved stable disease. Plasma CI-1033 concentrations increased with increasing dose. CI-1033 was not eliminated in urine to any appreciable extent.

CONCLUSIONS

CI-1033 is suitable for phase 2 testing at the 450 mg/day dose level when administered for 14 days in a 21-day cycle. The pharmacokinetic profile is consistent with biologically relevant plasma concentrations over the dosing interval.

EGFR gene amplification in breast cancer: correlation with epidermal growth factor receptor mRNA and protein expression and HER-2 status and absence of EGFR-activating mutations

The human epidermal growth factor receptor (HER) family of receptor tyrosine kinase has been extensively studied in breast cancer; however, systematic studies of EGFR gene amplification and protein overexpression in breast carcinoma are lacking. We studied EGFR gene amplification by chromogenic in situ hybridization (CISH) and protein expression by immunohistochemistry in 175 breast carcinomas, using tissue microarrays. Tumors with >5 EGFR gene copies per nucleus were interpreted as positive for gene amplification. Protein overexpression was scored according to standardized criteria originally developed for HER-2. EGFR mRNA levels, as measured by Affymetrix U133 Gene Chip microarray hybridization, were available in 63 of these tumors. HER-2 gene amplification by fluorescence in situ hybridization (FISH) and protein overexpression by immunohistochemistry were also studied. EGFR gene amplification (copy number range: 7-18; median: 12) was detected in 11/175 (6%) tumors, and protein overexpression was found in 13/175 (7%) tumors. Of the 11 tumors, 10 (91%) with gene amplification also showed EGFR protein overexpression (2+ or 3+ by immunohistochemistry). The EGFR mRNA level, based on Affymetrix U133 chip hybridization data, was increased relative to other breast cancer samples in three of the five tumors showing gene amplification. Exons 19 and 21 of EGFR, the sites of hotspot mutations in lung adenocarcinomas, were screened in the 11 EGFR-amplified tumors but no mutations were found. Three of these 11 tumors also showed HER-2 overexpression and gene amplification. Approximately 6% of breast carcinomas show EGFR amplification with EGFR protein overexpression and may be candidates for trials of EGFR-targeted antibodies or small inhibitory molecules.

Metaplastic breast carcinomas are negative for Her-2 but frequently express EGFR (Her-1): potential relevance to adjuvant treatment with EGFR tyrosine kinase inhibitors?

BACKGROUND

Metaplastic carcinomas (MCs) of the breast rarely express steroid receptors and Her-2, which minimises the options for adjuvant treatment in patients with advanced disease.

AIMS

To investigate the possible eligibility of patients with MCs for epidermal growth factor receptor (EGFR) targeted treatment.

METHODS

Immunohistochemical assessment of the expression of steroid receptors and four members of the EGFR/Her family (EGFR/Her-1-4) in 20 MCs (eight with heterologous elements, seven spindle cell MCs, four carcinosarcomas, and one matrix producing carcinoma). Fourteen of the 20 MCs were positive for EGFR (Her-1). Among these cases, 1+, 2+, and 3+ reactivity were seen in two, four, and eight cases, respectively. Her-2 was only present in one MC with 1+ reactivity. Her-3 (1+ reactivity), Her-4 (2+ reactivity), and the androgen receptor (2+ reactivity) were also expressed by one tumour. Oestrogen and progesterone receptors (3+ reactivity each) were detected in the epithelial component only of two carcinosarcoma-type MCs.

CONCLUSIONS

MCs express EGFR considerably more frequently than the types of breast carcinomas that have been investigated previously. Although molecular analyses for possible genetic alterations in the EGFR might be required, these results suggest that women suffering from this aggressive form of breast carcinoma might benefit from treatment with protein kinase inhibitors, such as gefitinib.

Administration of CI-1033, an irreversible pan-erbB tyrosine kinase inhibitor, is feasible on a 7-day on, 7-day off schedule: a phase I pharmacokinetic and food effect study

PURPOSE

To determine the maximum tolerated dose of administrating CI-1033, an oral 4-anilinoquinazoline that irreversibly inhibits the tyrosine kinase domain of all erbB subfamilies, on an intermittent schedule, and assess the interaction of CI-1033 with food on the pharmacokinetic behavior.

EXPERIMENTAL DESIGN

Escalating doses of CI-1033 from a dose level of 300 mg/day for 7 days every other week were administered to patients with advanced solid malignancies. Plasma concentration-time data sets from all evaluable patients were used to develop a population pharmacokinetic model. Noncompartmental methods were used to independently assess the effect of a high-fat meal on CI-1033 absorption and bioavailability.

RESULTS

Twenty-four patients were treated with 69 twenty-eight day courses. The incidence of unacceptable toxicity, principally diarrhea and skin rash, was observed at the 300 mg/day dose level. At the 250 mg/day level, toxicity was manageable, and protracted administration was feasible. A one-compartment linear model with first-order absorption and elimination adequately described the pharmacokinetic disposition. CL/F, apparent volume of distribution (Vd/F), and ka (mean +/- relative SD) were 280 L/hour +/- 33%, 684 L +/- 20%, and 0.35 hour(-1)+/- 69%, respectively. Cmax values were achieved in 2 to 4 hours. Systemic CI-1033 exposure was largely unaffected by administration of a high-fat meal. At 250 mg, concentration values exceeded IC50 values required for prolonged pan-erbB tyrosine kinase inhibition in preclinical assays.

CONCLUSIONS

The recommended dose on this schedule is 250 mg/day. Its tolerability and the biological relevance of concentrations achieved at the maximal tolerated dose warrant consideration of disease-directed evaluations. This intermittent treatment schedule can be used without regard to meals.

Inhibition of proliferation, migration, and matrix metalloprotease production in malignant mesothelioma cells by tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) is expressed in a variety of human solid tumors, including malignant mesothelioma. EGFR has been implicated in regulation of cell proliferation, survival, angiogenesis, and metastasis, making it an ideal target for drug development. ZD1839 (gefitinib) and OSI-774 (erlotinib) are new, low-molecular-weight, EGFR-selective tyrosine kinase (TK) inhibitors, whereas CI-1033 is a pan-EGFR family TK inhibitor. In the present study, we used ZD1839, OSI-774, and CI-1033 and investigated the effect of these drugs on proliferation, migration, and matrix metalloprotease (MMP) production in three malignant mesothelioma cell lines (M14K, ZL34, and SPC212). Using [3H]thymidine incorporation, DNA synthesis assay, we found that all three drugs inhibited transforming growth factor-alpha (TGF-alpha)-induced cellular proliferation in a dose-dependent manner. In addition, all three drugs induced apoptosis in ZL34 cells as determined by flow cytometry using annexin-V staining. Furthermore, all three drugs inhibited TGF-alpha-induced cell migration (chemotaxis) in a dose-dependent manner as determined by Boyden chamber assay. TGF-alpha-induced MMP-9 production was also inhibited in a dose-dependent manner as determined by gelatin zymography in three cell lines tested. In conclusion, our study demonstrates inhibitory effectiveness of EGFR-TK inhibitors in malignant mesothelioma cells and suggests that these drugs may be an effective treatment strategy for malignant mesothelioma.

Early phase I data on an irreversible pan-erb inhibitor: CI-1033. What did we learn?

CI-1033 (Canertinib dihydrochloride) is an orally available pan-erbB receptor tyrosine kinase inhibitor that, unlike the majority of receptor inhibitors, effectively blocks signal transduction through all four members of the erbB family. In addition, it blocks the highly tumorigenic, constitutively activated variant of erbB-1, EGFRvIII, and inhibits downstream signaling through both the Ras/ MAP kinase, and PI-3 kinase/AKT pathways (Figure 1). CI-1033 is also unique in that it is an irreversible inhibitor; thereby providing prolonged suppression of erbB receptor-mediated signaling. Preclinical data show CI-1033 to be efficacious against a variety of human tumors in mouse xenograft models, including breast carcinomas.