Epidermal growth factor receptor expression correlates with poor prognosis in non-small cell lung cancer patients with p53 overexpression

Silencing kinase-interacting stathmin gene enhances erlotinib sensitivity by inhibiting Ser¹⁰ p27 phosphorylation in epidermal growth factor receptor-expressing breast cancer

The epidermal growth factor receptor (EGFR) signaling pathway has emerged as a promising target for cancer therapy. EGFR tyrosine kinase inhibitors (TKI) such as erlotinib have been approved for cancer treatment but have shown very limited activity in breast cancer patients. Clarifying the molecular mechanism underlying resistance to EGFR TKIs could lead to more effective treatment against breast cancer. We previously reported that the sensitivity of breast cancer cells to erlotinib is partially dependent on p27 and that cytoplasmic localization of p27 is associated with erlotinib resistance. In the present study, we found that erlotinib induces p27 phosphorylation at Ser¹⁰ (S10), and S10 p27 phosphorylation leads to erlotinib resistance in EGFR-expressing breast cancer. Inhibiting S10 phosphorylation of p27 by knocking down human kinase-interacting stathmin (KIS), a nuclear protein that can phosphorylate p27 at S10, led to p27 accumulation in the nucleus and enhanced erlotinib-mediated cytotoxicity. Further, in vivo KIS gene silencing enhanced the antitumor activity of erlotinib in an orthotopic breast cancer xenograft model. KIS depletion also enhanced erlotinib sensitivity in erlotinib-resistant EGFR-expressing triple-negative breast cancer cells. Our study provides a rationale for the development of combinations of erlotinib with KIS inhibition to overcome EGFR TKI resistance in EGFR-expressing breast cancer.

Prognostic value of epidermal growth factor receptor expression in operable non-small cell lung carcinoma

Background and aim

Increased expression of the epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC), supporting the tumor growth by a possible endocrine mechanism, affects patient survival negatively. We designed a study to test EGFR expression by immunohistochemistry (IHC) in resected stage I-II NSCLC and to correlate its overexpression with survival.

Methods

EGFR expression was evaluated in 98 consecutive NSCLC patients after complete resection (53 squamous cell carcinomas, 40 adenocarcinomas, 5 large cell carcinomas: stage I, 57 (58%) and stage II, 41 (42%). IHC was used to examine the expression of EGFR in resected lung tumor samples obtained from these patients, who had no pre- or post-operative chemotherapy or radiotherapy. Univariate and multivariate analyses were performed for factors influencing patient survival.

Results

EGFR was expressed in 51 (52%) of 98 NSCLC samples. More squamous tumors (61%) were EGFR-positive than adenocarcinomas (38%) (p = 0.038). There was a statistically significant correlation between EGFR expression and stage (p = 0.04). No difference was found between EGFR positive and negative tumors in the 5-year overall survival (57% vs. 73%, p = 0.13).

Conclusion

The level of EGFR expression in tumors was not a successful predictor of survival in resected NSCLC.

Novel insights into the molecular origins and treatment of lung cancer

Lung cancer is the most common and most deadly cancer worldwide. Because of the aggressive and metastatic nature of many forms of the disease, it is frequently diagnosed late and responds poorly to the therapies currently available. Although our understanding of the molecular origins and evolution of lung cancer is still incomplete, recent research has yielded several developments that may offer opportunities for new, targeted and effective therapy. In this review we first discuss the prevalence and origins of lung cancer, with emphasis on non-small-cell lung cancer and adenocarcinoma, together with current treatments and their efficacy. We then look at a selection of recent papers which between them shed new light on possible therapeutic opportunities, including a novel synthetic interaction with the Kras gene and genomic or proteomic profiling studies that may pave the way for personalized treatment for lung cancer based on specific "signatures" of protein and gene expression. Lung cancer remains the foremost cause of cancer deaths worldwide. Despite advances in both detection and treatment, diagnosis is often late and the prognosis for patients poor. Our understanding of the molecular basis and progression of lung cancer remains incomplete, hampering the design and development of more effective diagnostic tools and therapies for this devastating disease. However, the last twelve months have witnessed the publication of several studies that represent significant advances in our knowledge of lung cancer, and may represent important steps on the road to effective new therapies. In this review we aim to summarize these recent developments, and give our perspectives on the therapeutic possibilities they may offer in the future.

[The predictive value of EGFR status in non-small cell lung cancer patients treated with EGFR-TKIs]

Epidermal growth factor receptor (EGFR) is a major molecular for target therapy. The epidermal growth factor receptor tyrosine kinase inhibitors (TKIs), gefitinib (Iressa) and erlotinib (Tarceva), are two prospective agents towards non-small cell lung cancer (NSCLC). Multi-center clinical studies showed that there were obvious differences between individuals by the treatment of EGFR-TKIs. EGFR status is the major factor that influences the outcome for the treatment by TKI. Exon mutations and amplification of EGFR molecule are the critical factors that predict good response to TKIs. On the other hand, KRAS mutations indicate the resistant to the TKIs.

Rapid detection of epidermal growth factor receptor mutations with multiplex PCR and primer extension in lung cancer

Epidermal growth factor receptor (EGFR) kinase domain mutations hyperactivate the kinase and confer kinase addiction of the non-small-cell lung cancer (NSCLC) tumor cells. Almost all of these mutations are located within exons 18-21. The -216 single nucleotide polymorphism in the promoter region is associated with increased EGFR production. We present a method for detecting these common mutations in 81 cases of NSCLC. The protocol is based on the multiplex amplification of promoter region and exons 18-21 of the EGFR genes in a single tube, followed by primer extension of the PCR products using various sizes of primers to detect base changes at -216 promoter region and codons 719, 746-750, 790, 858 of the EGFR gene. We compared the results with that from direct sequencing for detecting EGFR mutations in 81 cases of NSCLC. The two methods identified the same 26 mutations, but our method is superior to direct sequencing in terms of the amount of work and time required. We presented a simple and fast method to detect mutations of EGFR genes in NSCLC.

Biomarkers in bronchopulmonary cancer

Non-small-cell lung cancer (NSCLC) ranks among the neoplasms with the worst prognoses and the highest mortality rates. Several factors, mainly clinical, are known that provide a predictive value on the course of the disease. In the era in which we live, the molecular basis of cancer is studied in depth and several molecular markers have been described that could play a prognostic role or that could predict the probability of responding to the different treatments used. Moreover, some mechanisms have been proposed that could explain primary or acquired resistance to treatment with chemotherapy and to targeted therapies. Knowing all these pathways is very important, as it allows the development of selective therapeutic strategies that minimise toxicity and optimise treatment effectiveness. However, the data obtained yield results that are at times contradictory, prospective studies with biomarkers thus being necessary so that their role can be established with the necessary evidence.

Epidermal growth factor receptor inhibition in lung cancer: the evolving role of individualized therapy

Non-small cell lung cancer (NSCLC) is the major cause of cancer-related deaths in the USA and worldwide. Most patients present with advanced disease, and treatment options for these patients are generally limited to platinum-based chemotherapy and a few targeted therapies. Targeted agents currently in use for NSCLC inhibit oncogenic receptor tyrosine kinase pathways, such as the epidermal growth factor receptor (EGFR) pathway. While current EGFR-targeted agents, including erlotinib and gefitinib, may result in dramatic responses, they demonstrate efficacy in only a fraction of patients, and resistance to these agents frequently develops. In order to select patients most likely to benefit from blockade of EGFR pathways, investigators have focused on identifying molecular correlates of response to anti-EGFR therapy. New strategies to minimize the risk of resistance to EGFR inhibition have been employed in the development of next-generation EGFR tyrosine kinase inhibitors, such as PF00299804 and BIBW 2992; these include irreversibility of target binding, inhibition of multiple EGFR family receptors, and/or simultaneous inhibition of EGFR and other oncogenic pathways.

Epidermal growth factor receptor tyrosine kinase inhibitor reverses mesenchymal to epithelial phenotype and inhibits metastasis in inflammatory breast cancer

PURPOSE

Inflammatory breast cancer (IBC) is a rare but aggressive type of advanced breast cancer. Epidermal growth factor receptor (EGFR) expression is an independent poor prognostic factor in IBC. The purpose of this study was to determine the effect on IBC tumorigenicity and metastasis of blocking the EGFR pathway.

EXPERIMENTAL DESIGN

IBC cell lines, which express high level of EGFR, were treated with EGFR small interfering RNA and with the EGFR tyrosine kinase inhibitor erlotinib. The role of EGFR in IBC cell proliferation, motility, invasiveness, and change of the expression levels of epithelial-mesenchymal transition markers was examined. The role of extracellular signal-regulated kinase (ERK)-1/2 in erlotinib activity was also studied. The activity of erlotinib in tumor growth and metastasis was examined in an orthotopic xenograft model of IBC.

RESULTS

Erlotinib inhibited proliferation and anchorage-independent growth of IBC cells, and this inhibition was ERK dependent. Erlotinib inhibited cell motility and invasiveness and reversed the mesenchymal phenotype of IBC cells to epithelial phenotype in three-dimensional culture. Erlotinib dramatically inhibited IBC tumor growth in a xenograft model. Interestingly, erlotinib inhibited spontaneous lung metastasis, even at a low dose that had no significant effect on primary tumor growth. These erlotinib-treated tumors were converted to epithelial phenotype from mesenchymal phenotype.

CONCLUSIONS

The EGFR pathway is involved in tumor growth and metastasis of IBC. Targeting EGFR through the ERK pathway may represent an effective therapeutic approach to suppress tumorigenicity and prevent metastasis in EGFR-expressing IBC.

Refinement of the population pharmacokinetic model for the monoclonal antibody matuzumab: external model evaluation and simulations

OBJECTIVES

A developed population pharmacokinetic model of the humanized monoclonal antibody (mAb) matuzumab was evaluated by external evaluation. Based on the estimates of the final model, simulations of different dosing regimens and the covariate effect were performed.

METHODS

The development dataset included 90 patients, and the evaluation dataset included 81 patients; the two sets of patients were from three different studies. In all studies, the patients had different types of advanced carcinoma - mainly colon, rectal and pancreatic cancer. They received matuzumab as multiple 1-hour intravenous infusions in a wide range of dosing regimens (development dataset: from 400 mg every 3 weeks to 2000 mg in the first week followed by 1600 mg weekly; evaluation dataset: from 100 mg weekly to 800 mg weekly). In addition to 1256 serum mAb concentrations for model development, there were 1124 concentrations available for model evaluation. Serum concentration-time data were simultaneously fitted using NONMEM software. The developed two-compartment model - with the parameters central volume of distribution (V(1)) and peripheral volume of distribution (V(2)), intercompartmental clearance and linear clearance (CLL), an additional nonlinear elimination pathway (Michaelis-Menten constant: the concentration with the half-maximal elimination rate and V(max): the maximum elimination rate) and covariate relations - was evaluated by an external dataset. Different simulation scenarios were performed to demonstrate the impact of the incorporated covariate effect and the influence of different dosing regimens and dosing strategies on the concentration-time profiles.

RESULTS

The developed model included the covariate fat-free mass (FFM) on V(1) and on CLL. The evaluation did not support the covariate FFM on V(1) and, after deletion of this covariate, the model parameters of the refined model were estimated. The model showed good precision for all parameters: the relative standard errors (RSEs) were <42% for the development dataset and < or = 51% for the evaluation dataset (excluding the higher RSEs for the correlation between V(2) and V(max) and the interindividual variability on V(2) for the evaluation dataset). The model showed good robustness for the ability to estimate highly precise parameters for the combined dataset of 171 patients (RSE <29%). Simulations revealed that variability in concentration-time profiles for minimum and maximum steady-state concentrations was reduced to a marginal extent by a proposed dose adaptation.

CONCLUSION

The population pharmacokinetic model for matuzumab was improved by evaluation with an external dataset. The new model obtained precise parameter estimates and demonstrated robustness. After correlation with efficacy data simulation results in particular could serve as a tool to guide dose selection for this 'targeted' cancer therapy.

The Role of Gefitinib in Lung Cancer Treatment

Gefitinib (Iressa) is a novel targeted therapy that inhibits the tyrosine kinase activity of the epidermal growth factor receptor by competitively blocking the ATP binding site. In preclinical studies gefitinib has shown potent activity in a number of tumor models, including several lung cancer cell lines and xenografts. Two large randomized Phase II studies (IDEAL 1 and IDEAL 2) in pretreated non-small cell lung cancer reported a response rate approaching 20% in second-line patients and approximately 10% in those pretreated with two or more chemotherapy regimens. The median survival in these two studies approached 6-8 months. As a first-line therapy, gefitinib has been assessed in combination with two different chemotherapy regimens in two large randomized studies (INTACT 1 and INTACT 2). Both studies failed to show an improvement in survival on a total patient accrual of >1000 patients in each study. Other end points (e.g., time to progression and response rate) were also not improved by the addition of gefitinib. Additional studies are indicated to assess the possible role of gefitinib in the maintenance of patients who received chemotherapy or chemoradiotherapy. Studies investigating gefitinib as first-line monotherapy are also required.

Hydrogel-based protein array for quantifying epidermal growth factor receptor activity in cell lysates

Epidermal growth factor receptor (EGFR) signaling plays an important role in a majority of solid tumors, and therapeutics targeted against EGFR has demonstrated promise in slowing growth of these tumors. However, many of these drugs either have failed to reproduce promising preclinical model results in clinical settings or have been successful in only a subgroup of cancer patients due partly to incomplete assessment of EGFR status in cancer. A patient-customized, predictive diagnostic for the effects of specific anti-EGFR therapies may improve outcomes. Here we report the development of a hydrogel-based protein array for quantitative and reproducible determination of the activity of EGFR directly from cellular extracts. In this study, we used glutathione S-transferase-fused Eps15 (GST-Eps15) fusion proteins immobilized within a polyacrylamide hydrogel as a substrate for quantifying EGFR kinase activity from the extracts of EGFR-expressing cell lines. Significant EGFR up-regulation was detected in a mixture containing 7% EGFR-overexpressing cell lysate diluted in lysate from a cell line expressing low levels of EGFR. In addition, the GST-Eps15 protein array was capable of detecting inhibition of EGFR activity when incubated with different tyrosine kinase inhibitors. These findings establish the potential of this protein-acrylamide copolymer hydrogel array not only to evaluate EGFR status in cancer cell lysates but also to screen for the most promising therapeutics for individual patients and monitor treatment progression.

Autocrine production of amphiregulin predicts sensitivity to both gefitinib and cetuximab in EGFR wild-type cancers

PURPOSE

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, gefitinib and erlotinib, lead to significant tumor regressions in 10% to 15% of non-small cell lung cancer (NSCLC) patients with EGFR activating mutations. However, 30% to 40% of NSCLC patients, majority of whom are EGFR wild-type, develop stable disease following EGFR tyrosine kinase inhibitor therapy. EGFR-directed antibodies (cetuximab) are effective treatments for head and neck squamous cell carcinomas, which seldom contain EGFR mutations. The determinant(s) of efficacy of EGFR-targeted therapies in EGFR wild-type cancers is not well defined.

EXPERIMENTAL DESIGN

We examined the relationship of EGFR ligands, EGF, transforming growth factor-alpha,and amphiregulin and the efficacy of gefitinib and cetuximab in EGFR wild-type NSCLC (n=10) and head and neck squamous cell carcinoma (n=4) cell lines. We compared amphiregulin expression using immunohistochemistry in EGFR wild-type NSCLC patients (n=24) that developed either stable or progressive disease following erlotinib or gefitinib treatment.

RESULTS

Cell lines which produced >or=20 pmol/L amphiregulin, as detected by an ELISA, were significantly more likely to be growth inhibited by both gefitinib and cetuximab than those that produced minimal or no amphiregulin. In these cell lines, both cetuximab and gefitinib led to cell cycle arrest at the G(1)-S boundary and was associated with preferential inhibition of extracellular signal-regulated kinase 1/2 but not Akt signaling. Amphiregulin expression was significantly higher in NSCLC patients that developed stable disease compared with those that developed disease progression following gefitinib or erlotinib treatment.

CONCLUSIONS

Amphiregulin expression may help select EGFR wild-type patients who are likely to develop stable disease from EGFR-targeted therapies.

Serum levels of epidermal growth factor and HER-2 neu in non small-cell lung cancer: prognostic correlation

Lung cancer is still a leading cause of cancer related mortality all over the world with the majority of cases are discovered at a late stage. Various panels of molecular prognostic markers are being studied to map the association of these markers with response and survival. The aim of this study is to study levels of epidermal growth factor receptor (EGFR), HER-2 neu in both serum and bronchoalveolar lavage (BAL) in patients with non small-cell lung cancer (NSCLC), correlate their levels with clinical, pathological characters as well as prognosis. A total of 30 patients with pathologically proven NSCLC were enrolled in this study in addition to ten normal controls subjects and ten cases with benign pulmonary diseases as broncheicatsis, chronic obstructive pulmonary disease. Results revealed significantly increased levels of EGFR and HER-2 neu in both serum and bronco-alveolar lavage compared with controls. The levels were significantly higher in those with stages III, IV compared with I, II, and in those with higher grades of the tumor. There was no statistically significant correlation with performance status or survival. In conclusion, serum measurement of these markers is a promising noninvasive technique which needs correlation with other methods of determination, measurement at different chronological points during disease evolution to explore its full potential. Standardization of techniques for determination of EGFR and HER-2 neu over-expression must become a priority in future studies that should also include larger number of patients, conducted in a prospective manner together with comparisons of various methods and correlation of protein expression with gene copy numbers.

EGFR Inhibition in the Treatment of Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) inhibitors have introduced the concept of targeted therapy to the treatment of non-small cell lung cancer (NSCLC). These agents appear most effective in patients with tumors that are highly dependent on EGFR signaling pathways, a population that disproportionately includes females, nonsmokers, individuals of East Asian origin, and patients with adenocarcinoma histology. Currently available EGFR-inhibiting drugs include the tyrosine kinase inhibitors (TKIs) erlotinib, gefitinib, and lapatinib, which are administered orally and interfere with the intracellular tyrosine kinase domain, and the monoclonal antibodies (mAbs) cetuximab and panitumumab, which are administered intravenously and interfere with extracellular ligand binding. While the use of EGFR TKIs as monotherapy prolongs survival in metastatic NSCLC, they have demonstrated no benefit when added to conventional, cytotoxic chemotherapy. In contrast, the anti-EGFR mAb cetuximab appears most effective when combined with chemotherapy or radiation. Despite dramatic initial responses to treatment in some cases, NSCLC eventually becomes resistant to EGFR inhibition. Possible mechanisms include secondary mutations that interfere with drug binding, oncogenic pathways driven by other receptor tyrosine kinases, and independent activity of downstream signaling molecules. Efforts to overcome such resistance include irreversibly binding EGFR TKIs, multi-targeted TKIs, and combinations with chemotherapy, radiation, and other targeted therapies.

Biomarkers in lung cancer: from early detection to novel therapeutics and decision making

Lung cancer remains a significant cause of mortality worldwide. While advances in therapy continue to be made, the overall prognosis for patients diagnosed with lung cancer remains poor. Historically, markers such as age, performance status and disease stage have been used to risk-stratify patients and guide therapeutic decisions. These parameters provide some useful information, but more sensitive markers are clearly needed. Molecular and genetic studies have identified several such markers, which appear to play critical roles in carcinogenesis and affect patient outcomes. This article reviews a number of biomarkers that have been identified in lung cancer, and their prognostic and predictive roles.

Epidermal growth factor receptor expression analysis in chemotherapy-naive patients with advanced non-small-cell lung cancer treated with gefitinib or placebo in combination with platinum-based chemotherapy

PURPOSE

Two large, randomized, placebo-controlled trials (IRESSA NSCLC Trial Assessing Combination Therapy; INTACT 1 and 2) in non-small-cell lung cancer (NSCLC) failed to show survival benefit for gefitinib (IRESSA) in combination with first-line platinum-based chemotherapy. Epidermal growth factor receptor (EGFR) staining was assessed retrospectively in relation to survival response to gefitinib in combination with chemotherapy.

METHODS

Tumor biopsies obtained prior to start of therapy were assessed by immunohistochemistry for EGFR using the Dako EGFR pharmDx assay (Dako, Denmark). Analyses were stratified by trial and performed independently for patients randomized to placebo and gefitinib as well as for both treatment groups combined. A restricted backwards elimination Cox regression analysis was conducted to identify independent EGFR factors that were statistically significant (P < 0.10), and these were also tested for treatment interaction to assess if they served as predictive factors.

RESULTS

Analyses found two statistically significant EGFR-based prognostic factors representing growth pattern and percent membrane staining in patients treated with gefitinib (P = 0.0023), placebo (P = 0.0128), and both combined (P < 0.0001). The prognostic effect was independent of other known prognostic factors. There was no predictive effect of either the growth pattern or membrane staining variable.

CONCLUSIONS

While some previous studies indicate that higher EGFR expression correlates with poor survival, our analyses provide statistically significant evidence that the combination of EGFR expression and growth pattern is a strong prognostic indicator for improved survival within this setting. The effects of membrane staining and growth pattern are still significant when adjusting for mutation.

Targeting of AKT1 enhances radiation toxicity of human tumor cells by inhibiting DNA-PKcs-dependent DNA double-strand break repair

We have already reported that epidermal growth factor receptor/phosphatidylinositol 3-kinase/AKT signaling is an important pathway in regulating radiation sensitivity and DNA double-strand break (DNA-dsb) repair of human tumor cells. In the present study, we investigated the effect of AKT1 on DNA-dependent protein kinase catalytic subunit (DNA-PKcs) activity and DNA-dsb repair in irradiated non-small cell lung cancer cell lines A549 and H460. Treatment of cells with the specific AKT pathway inhibitor API-59 CJ-OH (API; 1-5 micromol/L) reduced clonogenic survival between 40% and 85% and enhanced radiation sensitivity of both cell lines significantly. As indicated by fluorescence-activated cell sorting analysis (sub-G(1) cells) and poly(ADP-ribose) polymerase cleavage, API treatment or transfection with AKT1-small interfering RNA (siRNA) induced apoptosis of H460 but not of A549 cells. However, in either apoptosis-resistant A549 or apoptosis-sensitive H460 cells, API and/or AKT1-siRNA did not enhance poly(ADP-ribose) polymerase cleavage and apoptosis following irradiation. Pretreatment of cells with API or transfection with AKT1-siRNA strongly inhibited radiation-induced phosphorylation of DNA-PKcs at T2609 and S2056 as well as repair of DNA-dsb as measured by the gamma-H2AX foci assay. Coimmunoprecipitation experiments showed a complex formation of activated AKT and DNA-PKcs, supporting the assumption that AKT plays an important regulatory role in the activation of DNA-PKcs in irradiated cells. Thus, targeting of AKT enhances radiation sensitivity of lung cancer cell lines A549 and H460 most likely through specific inhibition of DNA-PKcs-dependent DNA-dsb repair but not through enhancement of radiation-induced apoptosis.

Molecular predictors of EGFR-TKI sensitivity in advanced non-small cell lung cancer

The epidermal growth factor receptor (EGFR) is overexpressed in the majority of non-small cell lung cancers (NSCLC) and is a major target for new therapies. Specific EGFR tyrosine kinase inhibitors (TKIs) have been developed and used for the treatment of advanced NSCLC. The clinical response, however, varies dramatically among different patient cohorts. Females, East Asians, non-smokers, and patients with adenocarcinoma usually show higher response rates. Meanwhile, a number of biological factors are also associated with EGFR-TKIs responsiveness. In order to better understand the predictive value of these biomarkers and their significance in clinical application we prepared this brief review. Here we mainly focused on EGFR somatic mutations, MET amplification, K-ras mutations, EGFRvIII mutation, EGFR gene dosage and expression, HER2 gene dosage and expression, and Akt phosphorylation. We think EGFR somatic mutation probably is the most effective molecular predictor for EGFR-TKIs responsiveness and efficacy. Mutation screening test can provide the most direct and valuable guidance for clinicians to make decision on EGFR-TKIs therapy.

High resolution melting analysis for rapid and sensitive EGFR and KRAS mutation detection in formalin fixed paraffin embedded biopsies

BACKGROUND

Epithelial growth factor receptor (EGFR) and KRAS mutation status have been reported as predictive markers of tumour response to EGFR inhibitors. High resolution melting (HRM) analysis is an attractive screening method for the detection of both known and unknown mutations as it is rapid to set up and inexpensive to operate. However, up to now it has not been fully validated for clinical samples when formalin-fixed paraffin-embedded (FFPE) sections are the only material available for analysis as is often the case.

METHODS

We developed HRM assays, optimised for the analysis of FFPE tissues, to detect somatic mutations in EGFR exons 18 to 21. We performed HRM analysis for EGFR and KRAS on DNA isolated from a panel of 200 non-small cell lung cancer (NSCLC) samples derived from FFPE tissues.

RESULTS

All 73 samples that harboured EGFR mutations previously identified by sequencing were correctly identified by HRM, giving 100% sensitivity with 90% specificity. Twenty five samples were positive by HRM for KRAS exon 2 mutations. Sequencing of these 25 samples confirmed the presence of codon 12 or 13 mutations. EGFR and KRAS mutations were mutually exclusive.

CONCLUSION

This is the first extensive validation of HRM on FFPE samples using the detection of EGFR exons 18 to 21 mutations and KRAS exon 2 mutations. Our results demonstrate the utility of HRM analysis for the detection of somatic EGFR and KRAS mutations in clinical samples and for screening of samples prior to sequencing. We estimate that by using HRM as a screening method, the number of sequencing reactions needed for EGFR and KRAS mutation detection can be reduced by up to 80% and thus result in substantial time and cost savings.

A phase II study of gefitinib monotherapy in advanced esophageal adenocarcinoma: evidence of gene expression, cellular, and clinical response

PURPOSE

At presentation, most cases of adenocarcinoma of the esophagus (ACE) are inoperable. Although chemotherapy can prolong survival, patients eventually die as a result of refractory disease. Epidermal growth factor receptor (EGFR) is almost universally expressed in ACE and is a negative prognostic factor.

EXPERIMENTAL DESIGN

This open-label, two-center, noncomparative, two-part phase II trial assessed the EGFR tyrosine kinase inhibitor gefitinib (500 mg/d) in patients with advanced, inoperable ACE. The primary end point was tumor response. The effect of EGFR inhibition was also evaluated by gene expression analysis of tumor biopsies taken before gefitinib treatment and 28 days after.

RESULTS

Twenty-seven patients were recruited and evaluable for tumor response and safety. Three patients had a partial response and seven had stable disease, giving a disease control rate (partial response + stable disease) of 37%. Drug-related adverse events were generally mild: diarrhea in 19 (grade 3 in three) and rash in 19 (grade 3 in five) patients, and there were no grade 4 drug-related adverse events. Microarray experiments on tumor biopsies showed that gefitinib also down-regulated oncogenes associated with tumor progression. Ki67 (a marker of tumor growth) expression decreased in five of seven biopsies taken before and after treatment.

CONCLUSION

Gefitinib (500 mg/d) is an active and generally well-tolerated treatment for ACE. Studies on endoscopic biopsies are feasible and indicate that gefitinib inhibits both gene expression and cellular biology at 500 mg/d, and these may provide surrogate end points for predictive biomarkers. Further trials of gefitinib are warranted, particularly as patient response seems to be durable and current second-line chemotherapy options have no proven ability to prolong life.

The presence of carboxypeptidase-M in tumour cells signifies epidermal growth factor receptor expression in lung adenocarcinomas: the coexistence predicts a poor prognosis regardless of EGFR levels

PURPOSE

Carboxypeptidase-M (CPM) is a membrane-bound peptidase that metabolizes peptides, and is present in pneumocytes. CPM hydrolyses the C-terminal arginine of epidermal growth factor (EGF) resulting in des-Arg53-EGF which binds to the EGF receptor (EGFR) with an equal or greater affinity than native EGF. Therefore, this study focused on the possible presence of CPM in human lung adenocarcinomas (ADC) and evaluated the relationship between CPM and EGFR by assessing the impact of expressions on patient clinical outcome.

METHODS

This is a retrospective study of 110 patients who underwent resection of the primary tumour (92) or metastatic tissues (18) for treatment or diagnosis. Immunohistochemistry (IHC) for CPM and EGFR was made in serial sections using standard methods.

RESULTS

This study demonstrates for the first time that 23.6% of ADCs express carboxypeptidase-M (26/110), mainly in membrane-bound forms. The amounts and the extent of CPM within tumours vary from low levels to obviously overexpressed forms. The immunohistochemical positivity (+) for CPM in ADCs negatively correlated with disease survival. In addition, 80% of CPM+ adenocarcinomas (21/26) showed a coexpression with EGFR suggesting a high prevalence for coexistence. The follow up data indicated a significantly shorter 5-year survival time for patients with CPM+-EGFR+ (double-positive) tumours compared to those harbouring neoplasias negative for both proteins (9.5 vs. 60.4% survivals, P < 0.001).

CONCLUSION

The fact that CPM+ ADCs often co-express with EGFR suggests a functional-regulatory link between these proteins which might have therapeutical consequences. The present novel data could lead to improved IHC tests in lung adenocarcinomas for EGFR expression.

Somatic mutations of the epidermal growth factor receptor and non-small-cell lung cancer

Frequent overexpression of epidermal growth factor receptor (EGFR) in non-small-cell lung cancer (NSCLC) makes EGFR a new therapeutic target. Two specific EGFR tyrosine kinase inhibitors, gefitinib (ZD1839, Iressa) and erlotinib (OSI-774, Tarceva), have been developed and approved by the US Food and Drug Administration for second-line and third-line treatment of advanced NSCLC. Clinical trials have shown considerable variability in the response rate between different patients with NSCLC, which led to the discovery of somatic EGFR-activating mutations. This brief review summarises the discovery and functional consequences of the mutations, their clinicopathological features and significant implications in the treatment and prognosis of NSCLC.

Significance of EGFR protein expression and gene amplification in non-small cell lung carcinoma

We evaluated epidermal growth factor receptor (EGFR) protein expression by immunohistochemical analysis and EGFR gene amplification by fluorescence in situ hybridization in 199 consecutive newly diagnosed and surgically treated patients with primary non-small cell lung carcinoma (NSCLC) and correlated results with clinicopathologic findings. EGFR protein expression was more common in squamous cell carcinoma (SCC; 17 [26.2%]) than in adenocarcinoma (14 [11.1%]; (P = .0076) and more frequently associated with EGFR amplification (8 [14.5%] vs 4 [3.6%] cases; P = .0208). Poor differentiation was associated with a higher average number of EGFR gene copies per cell (mean, 4.18; P = .0322) and a higher EGFR/chromosome 7 ratio (mean, 1.84; P = .0324). N0 disease showed a higher number of EGFR gene copies (mean, 4.196; P = .0163). SCCs demonstrated a higher EGFR/chromosome 7 ratio than adenocarcinomas (mean, 1.95 vs 1.47; P = .0324), particularly T1 tumors (mean, 1.79; P = .0243). Statistical analysis failed to show correlation between outcome and EGFR protein expression and gene amplification in early NSCLC. EGFR protein expression was uncoupled from gene amplification in most cases, although good correlation occurred in a subset of SCCs.

Survival impact of epidermal growth factor receptor overexpression in patients with non-small cell lung cancer: a meta-analysis

BACKGROUND

It is thought that overexpression of epidermal growth factor receptor (EGFR) in non-small cell lung cancer (NSCLC) might compromise patient survival, presumably by promoting tumour growth by an autocrine mechanism. However, conflicting results have been reported from various laboratories, and the clinical importance of EGFR overexpression remains unsettled.

METHODS

A meta-analysis of previous studies was performed to quantitatively review the effects of EGFR overexpression on survival in patients with NSCLC using a DerSimonian-Laird random effects model. Eighteen studies including 2972 patients were subjected to final analysis.

RESULTS

Overall, positivity for EGFR overexpression differed between histological types: 39% in adenocarcinomas, 58% in squamous cell carcinomas, 38% in large cell carcinomas, and 32% in cancers in a miscellaneous category (p<0.0001). The combined hazard ratio (HR) was 1.14 (95% CI 0.97 to 1.34; p = 0.103), indicating that EGFR overexpression has no significant impact on survival. When only the 15 immunohistochemistry based studies were considered, the combined HR was 1.08 (95% CI 0.92 to 1.28; p = 0.356), again suggesting that EGFR overexpression has no impact on survival. Heterogeneity testing indicated that there was heterogeneity between studies but publication bias was absent, which suggests that the summary statistics obtained may approximate the actual average.

CONCLUSIONS

EGFR overexpression was not associated with poorer survival in patients with NSCLC. Specific mutations of the EGFR gene will need further study in terms of survival implications.

Epidermal Growth Factor Receptor Mutations in Non–Small-Cell Lung Cancer: Implications for Treatment and Tumor Biology

The epidermal growth factor receptor (EGFR) has emerged as an attractive therapeutic target for patients with non–small-cell lung cancer (NSCLC). However, despite its almost universal presence in NSCLC tumors, therapeutic inhibition of EGFR has resulted in significant tumor regressions in only 10% to 20% of patients. Several investigations over the last 12 months have uncovered somatic mutations in EGFR that underlie the sensitivity to EGFR inhibitors. NSCLC tumors and cell lines with EGFR mutations are exquisitely sensitive to the EGFR tyrosine kinase inhibitors (TKIs), erlotinib and gefitinib, and are biologically distinct from other forms of NSCLC. Somatic mutations in EGFR are found more frequently in patients with adenocarcinomas, nonsmokers, patients of Asian ethnicity, and in females. EGFR mutation detection is now becoming clinically available and is being incorporated into clinical treatment decisions and into the design of future clinical trials. Mutations in K-ras, a mediator of EGFR signaling, are mutually exclusive with EGFR mutations, and are associated with resistance to EGFR TKIs. In addition, secondary mutations, conferring resistance to EGFR TKIs, in patients with primary EGFR mutations once sensitive to EGFR TKIs, are beginning to be identified. The frequency of EGFR mutations, their impact on NSCLC biology, clinical treatment, and clinical trial design, as well as methods and limitations for mutation detection, will be reviewed.

Phase I/II trial evaluating the anti-vascular endothelial growth factor monoclonal antibody bevacizumab in combination with the HER-1/epidermal growth factor receptor tyrosine kinase inhibitor erlotinib for patients with recurrent non-small-cell lung cancer

PURPOSE

Bevacizumab (Avastin; Genentech, South San Francisco, CA) is a recombinant, humanized anti-vascular endothelial growth factor monoclonal antibody. Erlotinib HCl (Tarceva, OSI-774; OSI Pharmaceuticals, New York, NY) is a potent, reversible, highly selective and orally available HER-1/epidermal growth factor receptor tyrosine kinase inhibitor. Preclinical data in various xenograft models produced greater growth inhibition than with either agent alone. Additionally, both agents have demonstrated benefit in patients with previously treated non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

A phase I/II study in two centers examined erlotinib and bevacizumab (A+T) in patients with nonsquamous stage IIIB/IV NSCLC with > or = one prior chemotherapy. In phase I, erlotinib 150 mg/day orally plus bevacizumab 15 mg/kg intravenously every 21 days was established as the phase II dose, although no dose-limiting toxicities were observed. Phase II assessed the efficacy and tolerability of A+T at this dose. Pharmacokinetic parameters were evaluated. ResultsForty patients were enrolled and treated in this study (34 patients at phase II dose); the median age was 59 years (range, 36 to 72 years), 21 were female, 30 had adenocarcinoma histology, nine were never-smokers, and 22 had > or = two prior regimens (three patients had > or = four prior regimens). The most common adverse events were mild to moderate rash, diarrhea, and proteinuria. Preliminary data showed no pharmacokinetic interaction between A + T. Eight patients (20.0%; 95% CI, 7.6% to 32.4%) had partial responses and 26 (65.0%; 95% CI, 50.2% to 79.8%) had stable disease as their best response. The median overall survival for the 34 patients treated at the phase II dose was 12.6 months, with progression-free survival of 6.2 months.

CONCLUSION

Encouraging antitumor activity and safety of A + T support further development of this combination for patients with advanced NSCLC and other solid tumors.

Coexpression of epidermal growth factor receptor with related factors is associated with a poor prognosis in non-small-cell lung cancer

The epidermal growth factor receptor (EGFR) is commonly expressed in non-small-cell lung cancer (NSCLC) and promotes a host of mechanisms involved in tumorigenesis. However, EGFR expression does not reliably predict prognosis or response to EGFR-targeted therapies. The data from two previous studies of a series of 181 consecutive surgically resected stage I-IIIA NSCLC patients who had survived in excess of 60 days were explored. Of these patients, tissue was available for evaluation of EGFR in 179 patients, carbonic anhydrase (CA) IX in 177 patients and matrix metalloproteinase-9 (MMP-9) in 169 patients. We have previously reported an association between EGFR expression and MMP-9 expression. We have also reported that MMP-9 (P=0.001) and perinuclear (p)CA IX (P=0.03) but not EGFR expression were associated with a poor prognosis. Perinuclear CA IX expression was also associated with EGFR expression (P<0.001). Multivariate analysis demonstrated that coexpression of MMP-9 with EGFR conferred a worse prognosis than the expression of MMP-9 alone (P<0.001) and coexpression of EGFR and pCA IX conferred a worse prognosis than pCA IX alone (P=0.05). A model was then developed where the study population was divided into three groups: group 1 had expression of EGFR without coexpression of MMP-9 or pCA IX (number=21); group 2 had no expression of EGFR (number=75); and group 3 had coexpression of EGFR with pCA IX or MMP-9 or both (number=70). Group 3 had a worse prognosis than either groups 1 or 2 (P=0.0003 and 0.027, respectively) and group 1 had a better prognosis than group 2 (P=0.036). These data identify two cohorts of EGFR-positive patients with diametrically opposite prognoses. The group expressing either EGFR and or both MMP-9 and pCA IX may identify a group of patients with activated EGFR, which is of clinical relevance with the advent of EGFR-targeted therapies.

Receptor Imaging in Oncology by Means of Nuclear Medicine: Current Status

To date, our understanding of the role of receptors and their cognate ligands in cancer is being successfully translated into the design and development of an arsenal of new, less toxic, and more specific anticancer drugs. Because most of these novel drugs are cytostatic, objective response as measured by morphologic imaging modalities (eg, computed tomography or magnetic resonance imaging) cannot be used as a surrogate marker for drug development or for clinical decision making. Positron emission tomography (PET) can be used to image and quantify the in vivo distribution of positron-emitting radioisotopes such as oxygen-15, carbon-11, and fluorine-18 that can be substituted or added into biologically relevant and specific receptor radioligands. Similarly, single-photon emission computed tomography (SPECT) can be used to image and quantify the in vivo distribution of receptor targeting compounds labeled with indium-111, technetium-99m, and iodine-123. By virtue of their whole-body imaging capacity and the absence of errors of sampling and tissue manipulation as well as preparation, both techniques have the potential to address locoregional receptor status noninvasively and repetitively. This article reviews available data on the in vivo evaluation of receptor systems by means of PET or SPECT for identifying and monitoring patients with sufficient receptor overexpression for tailored therapeutic interventions, and also for depicting tumor tissue and determining the currently largely unknown heterogeneity in receptor expression among different tumor lesions within and between patients.

Analysis of epidermal growth factor receptor expression as a predictive factor for response to gefitinib ('Iressa', ZD1839) in non-small-cell lung cancer

Gefitinib ('Iressa', ZD1839) is an orally active epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated antitumour activity and favourable tolerability in Phase II studies. We investigated whether EGFR expression levels could predict for response to gefitinib in patients with advanced non-small-cell lung cancer (NSCLC), who received gefitinib (250 mg day(-1)) as part of a worldwide compassionate-use programme. Tissue samples were analysed by immunohistochemistry to assess membrane EGFR immunoreactivity. Of 147 patients enrolled in our institution, 50 patients were evaluable for assessment of both clinical response and EGFR expression. The objective tumour response rate was 10% and disease control was achieved in 50% of patients. Although high EGFR expression was more common in squamous-cell carcinomas than adenocarcinomas, all objective responses were observed in patients with adenocarcinoma. Response and disease control with gefitinib were not associated with high EGFR expression. Overall, median survival was 4 months, and the 1-year survival rate was 18%. Strong EGFR staining correlated with shorter survival time for all patients. Gefitinib demonstrated promising clinical activity in this group of patients with NSCLC. These results have also shown that EGFR expression is not a significant predictive factor for response to gefitinib.

Lung cancer. 9: Molecular biology of lung cancer: clinical implications

It has been hypothesised that clinically evident lung cancers have accumulated many different genetic or epigenetic abnormalities in oncogenes and/or tumour suppressor genes. This notion has important clinical ramifications. Recent developments in our knowledge of the molecular biology of lung cancer are reviewed, with particular reference to genetic abnormalities in tumour suppressor gene inactivation and overactivity of growth promoting oncogenes. These changes lead to the "hallmarks of lung cancer". These hallmarks are the new rational targets for early detection, prevention, and treatment of lung cancer.

Epidermal growth factor receptor in non-small-cell lung carcinomas: correlation between gene copy number and protein expression and impact on prognosis

PURPOSE

The epidermal growth factor receptor (EGFR) is frequently overexpressed in non-small-cell lung carcinoma (NSCLC), and EGFR inhibitors are promising new therapeutic agents. The molecular mechanisms responsible for EGFR overexpression are poorly understood.

MATERIALS AND METHODS

Gene copy number and protein status of EGFR were investigated in microarrayed tumors from 183 NSCLC patients, including squamous cell carcinoma (SCC; 89 patients) and non-SCC (94 patients) histologies. Protein expression was assessed by immunohistochemistry on a scale from 0 to 400 (percentage of positive cells x staining intensity). Gene and chromosome 7 copy numbers were identified by fluorescent in situ hybridization (FISH).

RESULTS

EGFR protein overexpression was observed in 62% of the NSCLC (25% scored 201 to 300; 37% scored 301 to 400), more frequently in SCC than non-SCC (82% v 44%; P <.001), and in 80% of the bronchioloalveolar carcinomas. The prevalent FISH patterns were balanced disomy (40%) and trisomy (38%) for EGFR gene and chromosome 7 (40%), whereas balanced polysomy was seen in 13% and gene amplification was seen in 9% of the patients. Gene copy number correlated with protein expression (r = 0.4; P <.001). EGFR overexpression or high gene copy numbers had no significant influence on prognosis.

CONCLUSION

EGFR overexpression is frequent in NSCLC, is most prominent in SCC, and correlates with increased gene copy number per cell. High gene copy numbers per cell showed a trend toward poor prognosis. It will be important to evaluate EGFR gene and EGFR protein status and signal protein expression to properly interpret future clinical trials using EGFR inhibitors.

The role of epidermal growth factor receptor in head and neck squamous cell carcinoma

Growth factor receptors play a crucial role in the cell proliferation pathways involved in the development of cancer. One such receptor, the epidermal growth factor receptor (EGFR), is upregulated in many types of human tumors, particularly head and neck squamous cell carcinoma (HNSCC). EGFR overexpression in HNSCC has been the basis for investigation of therapeutic strategies that target EGFR. EGFR-blocking methods under evaluation involve immunotoxins, monoclonal antibodies, EGFR-specific tyrosine kinase inhibitors, and antisense approaches. These molecular targeting tactics have produced a number of agents that are currently in various stages of preclinical investigation, along with clinical trials to assess their potential as anticancer treatments.

Selective oral epidermal growth factor receptor tyrosine kinase inhibitor ZD1839 is generally well-tolerated and has activity in non-small-cell lung cancer and other solid tumors: results of a phase I trial

PURPOSE

To investigate safety, tolerability, dose-related pharmacologic properties, and pharmacodynamics of ZD1839 (gefinitib, Iressa; AstraZeneca Pharmacueticals, Wilmington, DE), an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in patients with solid tumor types known to express or highly express EGFR.

METHODS

This was an open-label, phase I, dose escalation safety/tolerability trial of oral ZD1839 (150 to 1,000 mg/d), administered once daily for 28-continuous-day cycles until disease progression or undue toxicity.

RESULTS

Of 71 (69 assessable for safety; 58 for efficacy) patients at seven dose levels, most had non-small-cell lung (n = 39) or head and neck (n = 18) cancer, and 68 of 71 patients received prior cancer therapy (two or more regimens in 54 patients [78%]). Diarrhea and rash, the primary dose-limiting toxicities (DLTs), occurred at 800 mg. Frequent treatment-related grade 1/2 adverse events were diarrhea (55%), asthenia (44%), and acne-like follicular rash (46%). At doses >or= 800 mg, 45% of patients required dose reductions. No increased or cumulative toxicity was observed over 250 patient-months of exposure. Pharmacokinetic analysis showed that steady-state occurred by day 7, interpatient exposure was more variable than intrapatient exposure, and variability of exposure did not change with dose. One patient experienced a partial response, but antitumor activity manifested mainly as prolonged stable disease (45% of patients >or= 3 months, 22% >or= 6 months, and 7.2% >or= 1 year). No relationship between dose, response, or duration on study was observed.

CONCLUSION

Rash and diarrhea, generally mild and tolerable at doses <or= 600 mg/d, were DLTs at 800 mg/d (maximum-tolerated dose). Antitumor activity was observed at all doses. Pharmacokinetic analyses confirmed suitability of once-daily oral dosing.