Predicting gefitinib responsiveness in lung cancer by fluorescence in situ hybridization/chromogenic in situ hybridization analysis of EGFR and HER2 in biopsy and cytology specimens

Template-Assisted Plasmonic Nanogap Shells for Highly Enhanced Detection of Cancer Biomarkers

We present a template-assisted method for synthesizing nanogap shell structures for biomolecular detections based on surface-enhanced Raman scattering. The interior nanogap-containing a silver shell structure, referred to as a silver nanogap shell (Ag NGS), was fabricated on silver nanoparticles (Ag NPs)-coated silica, by adsorbing small aromatic thiol molecules on the Ag NPs. The Ag NGSs showed a high enhancement factor and good signal uniformity, using 785-nm excitation. We performed in vitro immunoassays using a prostate-specific antigen as a model cancer biomarker with a detection limit of 2 pg/mL. To demonstrate the versatility of Ag NGS nanoprobes, extracellular duplex surface-enhanced Raman scattering (SERS) imaging was also performed to evaluate the co-expression of cancer biomarkers, human epidermal growth factor-2 (HER2) and epidermal growth factor receptor (EGFR), in a non-small cell lung cancer cell line (H522). Developing highly sensitive Ag NGS nanoprobes that enable multiplex biomolecular detection and imaging can open up new possibilities for point-of-care diagnostics and provide appropriate treatment options and prognosis.

Mechanisms of resistance to irreversible epidermal growth factor receptor tyrosine kinase inhibitors and therapeutic strategies in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) T790M mutation is the most frequent mechanism which accounts for about 60% of acquired resistance to first-generation EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) patients harboring EGFR activating mutations. Irreversible EGFR-TKIs which include the second-generation and third-generation EGFR-TKIs are developed to overcome T790M mediated resistance. The second-generation EGFR-TKIs inhibit the wide type (WT) EGFR combined with dose-limiting toxicity which limits its application in clinics, while the development of third-generation EGFR-TKIs brings inspiring efficacy either in vitro or in vivo. The acquired resistance, however, will also occur and limit their response. Understanding the mechanisms of resistance to irreversible EGFR-TKIs plays an important role in the choice of subsequent treatment. In this review, we show the currently known mechanisms of resistance which can be summarized as EGFR dependent and independent mechanisms and potential therapeutic strategies to irreversible EGFR-TKIs.

EGFR copy number alterations in primary tumors, metastatic lymph nodes, and recurrent and multiple primary tumors in oral cavity squamous cell carcinoma

Background

The EGFR and downstream signaling pathways play an important role in tumorigenesis in oral squamous cell carcinoma (OSCC). Gene copy number alteration is one mechanism for overexpressing the EGFR protein and was also demonstrated to be related to lymph node metastasis, tumor invasiveness and perineural invasion. Therefore, we hypothesized that EGFR gene copy number alteration in the primary tumor could predict amplification in recurrent tumors, lymph node metastatic foci or secondary primary tumors.

Methods

We recruited a group of newly diagnosed OSCC patients (n = 170) between Mar 1997 and Jul 2004. Metastatic lymph nodes were identified from neck dissection specimens (n = 57). During follow-up, recurrent lesions (n = 41) and secondary primary tumors (SPTs, n = 17) were identified and biopsied. The EGFR gene amplifications were evaluated by fluorescence in situ hybridization (FISH) assay in primary tumors, metastatic lymph nodes, recurrences and SPTs.

Results

Of the 170 primary OSCCs, FISH showed low EGFR amplification/polysomy in 19 (11.4%) patients and amplification in 33 (19.8%) patients. EGFR gene amplification was related to lymph node metastasis (χ2 trend test: p = 0.018). Of 57 metastatic lymph nodes, nine (15.8%) had EGFR polysomy and 14 (24.6%) had EGFR gene amplification. The concordance rate of EGFR gene copy number in primary tumors and lymph node metastasis was 68.4% (McNemar test: p = 0.389). Of 41 recurrent tumors, five (12.2%) had EGFR polysomy and five (12.2%) had gene amplification. The concordance rate of EGFR gene copy number between primary tumors and recurring tumors was 65.9% (McNemar test: p = 0.510). The concordance rate between primary tumors and SPTs was 70.6%. EGFR amplification in either primary tumors, metastatic lymph nodes or recurrent tumors had no influence on patient survival.

Conclusion

We can predict two-thirds of the EGFR gene copy number alterations in lymph node metastasis or recurrent tumors from the analysis of primary tumors. For OSCC patients who are unable to provide lymph node or recurrent tumor samples for EGFR gene copy number analysis, examining primary tumors could provide EGFR clonal information in metastatic, recurrent or SPT lesions.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3586-9) contains supplementary material, which is available to authorized users.

Epidermal Growth Factor Receptor (EGFR) Pathway Biomarkers in the Randomized Phase III Trial of Erlotinib Versus Observation in Ovarian Cancer Patients with No Evidence of Disease Progression after First-Line Platinum-Based Chemotherapy

BACKGROUND

In this work, we aimed to identify molecular epidermal growth factor receptor (EGFR) tissue biomarkers in patients with ovarian cancer who were treated within the phase III randomized European Organisation for Research and Treatment of Cancer-Gynaecological Cancer Group (EORTC-GCG) 55041 study comparing erlotinib with observation in patients with no evidence of disease progression after first-line platinum-based chemotherapy.

METHODS

Somatic mutations in KRAS, BRAF, NRAS, PIK3CA, EGFR, and PTEN were determined in 318 (38 %) and expression of EGFR, pAkt, pMAPK, E-cadherin and Vimentin, and EGFR and HER2 gene copy numbers in 218 (26 %) of a total of 835 randomized patients. Biomarker data were correlated with progression-free survival (PFS) and overall survival (OS).

RESULTS

Only 28 mutations were observed among KRAS, BRAF, NRAS, PIK3CA, EGFR, and PTEN (in 7.5 % of patients), of which the most frequent were in KRAS and PIK3CA. EGFR mutations occurred in only three patients. When all mutations were pooled, patients with at least one mutation in KRAS, NRAS, BRAF, PIK3CA, or EGFR had longer PFS (33.1 versus 12.3 months; HR 0.57; 95 % CI 0.33 to 0.99; P = 0.042) compared to those with wild-type tumors. EGFR overexpression was detected in 93 of 218 patients (42.7 %), and 66 of 180 patients (36.7 %) had EGFR gene amplification or high levels of copy number gain. Fifty-eight of 128 patients had positive pMAPK expression (45.3 %), which was associated with inferior OS (38.9 versus 67.0 months; HR 1.81; 95 % CI 1.11 to 2.97; P = 0.016). Patients with positive EGFR fluorescence in situ hybridization (FISH) status had worse OS (46.1 months) than those with negative status (67.0 months; HR 1.56; 95 % CI 1.01 to 2.40; P = 0.044) and shorter PFS (9.6 versus 16.1 months; HR 1.57; 95 % CI 1.11 to 2.22; P = 0.010). None of the investigated biomarkers correlated with responsiveness to erlotinib.

CONCLUSIONS

In this phase III study, increased EGFR gene copy number was associated with worse OS and PFS in patients with ovarian cancer. It remains to be determined whether this association is purely prognostic or is also predictive.

[Role of HER2 in NSCLC]

过去几年中, 随着分子靶向药物的引入, 非小细胞肺癌(non-small cell lung cancer, NSCLC)的药物治疗策略发生了巨大变化, 向基于组织学和分子水平的治疗手段转变。表皮生长因子受体(epidermal growth factor receptor, EGFR)突变、Kirsten鼠肉瘤(Kirsten rat sarcoma, KRAS)癌基因突变、间变淋巴瘤激酶(anaplastic lymphoma kinase, ALK)重排等的发现, 影响着NSCLC治疗的发展。最近, 对人表皮生长因子受体2(human epidermal growth factor receptor 2, HER2)研究重燃兴趣, 这一基因改变与NSCLC对不同酪氨酸激酶抑制剂(tyrosine kinase inhibitors, TKIs)的敏感性相关, 其具有可能的预测作用, HER2扩增可能是EGFR突变肿瘤对EGFR-TKIs获得性耐药的机制之一。其次, HER2突变可能阐明一条新的靶向治疗NSCLC的策略。本文将对NSCLC中HER2异常调节发挥的作用做一简要介绍。

NSCLC and HER2: between lights and shadows

The therapeutic landscape of non-small-cell lung cancer (NSCLC) has dramatically changed in the last few years with the introduction of molecularly targeted agents, leading to unprecedented results in lung tumors with a paradigmatic shift from a "one size fits all" approach to an histologic and molecular-based approach. The discovery of epidermal growth factor receptor (EGFR) mutations in NSCLC in 2004 and the marked response to the EGFR tyrosine kinase inhibitor gefitinib, in a small subset of patients harboring these genetic abnormalities, stimulated the study of other kinase mutants involvement in NSCLC. The incredible story of ALK rearranged tumors, with the rapid Food and Drug Administration approval of Crizotinib after only 4 years from the discovery of EML4-ALK translocation in NSCLC, has profoundly influenced the concept of drug development in NSCLC, paving the way to a novel series of molecularly selected studies with specific inhibitors. The identification of these oncogenic drivers has dramatically changed the genetic landscape of NSCLC moving away from the old concept of a large indistinct histological entity to a combination of rare clinically relevant molecular subsets. Recently, a renewed interest has been emerging on the human epidermal growth factor-2 (HER2) pathway. Genetic aberrations of this signaling pathway have been reported over time to be associated in NSCLC with different sensitivity to the EGFR tyrosine kinase inhibitors, to have a possible prognostic role and more recently HER2 amplification has been emerged as a possible mechanism in EGFR-mutated tumors of acquired resistance to the EGFR tyrosine kinase inhibitors. In addition, dysregulation of the HER2 pathway, in particular HER2 mutations (mostly, in-frame exon 20 insertions), may represent a possible novel therapeutic target in NSCLC, paving the way for a new generation of targeted agents in NSCLC. Since anecdotal case reports of clinical activity of anti-HER2 agents in NSCLC patients with HER2 mutations, several targeted agents have been evaluated in HER2-mutated patients, generating a growing interest upon this oncogenic driver, leading to the design of molecularly selected trials with anti-HER2 compounds and the rediscover of hastily thrown out drugs, such as neratinib. The aim of this article is to provide an overview of the role of HER2 dysregulation in NSCLCs, trying to throw a light not only on the strengths but also the weaknesses of the studies conducted so far. It is a long way to the clinical implementation of these biomarkers and probably the increasing use of next generation sequencing techniques, the creation of large multi-institutional molecular testing platforms and the design of rationally based trials can get closer personalized medicine in NSCLC.

HER2 gene copy number status may influence clinical efficacy to anti-EGFR monoclonal antibodies in metastatic colorectal cancer patients

BACKGROUND

In metastatic colorectal cancer (mCRC), KRAS is the only validated biomarker used to select patients for administration of epidermal growth factor receptor (EGFR)-targeted therapies. To identify additional predictive markers, we investigated the importance of HER2, the primary EGFR dimerisation partner, in this particular disease.

METHODS

We evaluated the HER2 gene status by fluorescence in situ hybridisation (FISH) in 170 KRAS wild-type mCRC patients treated with cetuximab or panitumumab.

RESULTS

Depending on HER2 gene copy number status, patients showed three distinct cytogenetic profiles: 4% of patients had HER2 gene amplification (R:HER2/CEP17 ≥ 2) in all neoplastic cells (HER2-all-A), 61% of patients had HER2 gain due to polysomy or to gene amplification in minor clones (HER2-FISH+*), and 35% of patients had no or slight HER2 gain (HER2-FISH-). These subgroups were significantly correlated with different clinical behaviours, in terms of response rate (RR; P=0.0006), progression-free survival (PFS; P<0.0001) and overall survival (OS; P<0.0001). Patients with HER2-all-A profile experienced the worst outcome, patients with HER2-FISH- profile showed an intermediate behaviour and patients with HER2-FISH+* profile were related to the highest survival probability (median PFS in months: 2.5 vs 3.9 vs 7.6, respectively; median OS in months: 4.2 vs 9.7 vs 13, respectively).

CONCLUSION

HER2 gene copy number status may influence the clinical response to anti-EGFR-targeted therapy in mCRC patients.

Molecular modeling and description of a newly characterized activating mutation of the EGFR gene in non-small cell lung cancer

Abstract

Lung cancer is the leading cause of death among malignant diseases in humans worldwide. In the last decade development of new targeted drugs for the treatment of non-small cell lung cancer proved to be a promising approach to prolong the otherwise very poor prognosis of patients with advanced UICC stages. Epidermal growth factor receptor (EGFR) has been in the focus of this lung cancer science and specific activating mutations are eligible for the treatment with specific tyrosine kinase inhibitors like gefitinib or erlotinib. Beside typical deletions in exon 19 and point mutations in exons 18 and 21 several insertions in exon 19 have been described and attributed activating properties as well. This is the first European and overall the 5^th description in English literature of one of these specific insertions. To elucidate its structural changes leading to the activating properties we performed molecular modeling studies. These revealed conformational and electrostatic force field changes in the kinase domain of EGFR. To not miss uncommon mutations thorough and precise characterization of EGFR hotspots, i. e. at least exons 18, 19 and 21, should therefore be conducted to provide best medical care and to offer lung cancer patients appropriate cancer treatment.

Virtual slides

The vistual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2209889658102062

Recent understanding of the molecular mechanisms for the efficacy and resistance of EGF receptor-specific tyrosine kinase inhibitors in non-small cell lung cancer

INTRODUCTION

The epidermal growth factor receptor (EGFR) and its family members are involved in many aspects of tumor biological processes. Aberrant activation of the EGFR tyrosine kinase by mutations or protein overexpression is observed in various types of human cancer, including lung cancer. EGFR tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, are highly effective in lung cancer patients who harbor active mutations in the EGFR gene. However, patients who are initially sensitive to EGFR-TKIs eventually relapse within few years.

AREAS COVERED

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and is associated with a high frequency of EGFR mutations. This review describes the EGFR mutations that determine the sensitivity to EGFR-TKIs and the current understanding of the molecular mechanisms of acquired resistance to EGFR-TKIs in NSCLC. Furthermore, the authors describe recent strategies developed to overcome acquired resistance using second-generation EGFR-TKIs and combination therapies with several molecular-targeting drugs.

EXPERT OPINION

Although recent findings have contributed to our understanding of the mechanism of acquired resistance and helped the development of novel strategies to overcome such resistance, the underlying mechanisms are complex and additional research is necessary to develop effective therapeutic strategies for individual patients with lung cancer.

Emerging concepts in the pathology and molecular biology of advanced non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is traditionally classified histologically, but until recently, the histologic subtype has had little impact on the selection of therapy. Drugs such as pemetrexed and bevacizumab are indicated for specific NSCLC subtypes, and this type of stratification represents the first step toward individualizing therapy in NSCLC. Beyond histologic features, the status of molecular targets, such as the epidermal growth factor receptor (EGFR) gene, has been shown to correlate with response to treatment with EGFR tyrosine kinase inhibitors in patients with relapsed or refractory disease and in the first-line therapy setting. New therapies targeting the EGFR and other molecular aberrations are under way to help define specific subsets of patients responsive to certain molecularly targeted treatments. The role of pathologists in guiding treatment decisions will increase because molecular profiling, together with pathologic and histologic analysis, represents the future of personalizing medicine for patients with NSCLC.

EGFR gene status in cytological samples of nonsmall cell lung carcinoma: controversies and opportunities

BACKGROUND

In nonsmall cell lung cancer (NSCLC), the development and clinical application of tyrosine kinase inhibitors (TKIs) targeting the epidermal growth factor receptor (EGFR) has required the investigation of EGFR status by gene copy number and/or mutation analysis. This review aimed to present the current knowledge of the use of cytological specimens for EGFR testing in lung cancer.

METHODS

A systematic computerized search was performed of the MEDLINE(R) and EMBASE databases to identify articles reporting the use of cytological samples for determining EGFR status in NSCLC.

RESULTS

Data were extracted from 30 original articles. An additional 19 reviews, consensus statements, and editorials were selected from 175 retrieved papers. Different techniques using cell blocks, scraped cells from archival slides, and fresh cells have shown promising results and include fluorescent in situ hybridization (FISH), direct sequencing, and quantitative polymerase chain reaction (PCR), with similar or higher accuracy and sensitivity than surgical specimens. Preservation and quality of the extracted DNA seem to matter more than the actual number of tumor cells present in the samples. However, major issues still reside in the amount of material, the interference from background non-neoplastic cells, and standardization of parameters for cytological samples.

CONCLUSIONS

This analysis provided evidence that cytological material is suitable for detecting EGFR status using several different methodologies and preparations. New prospective, clinical studies are encouraged for collection and handling of cytological samples as well as for validation of novel techniques in large cohorts.

Chromogenic in situ hybridization to detect EGFR gene copy number in cell blocks from fine-needle aspirates of non small cell lung carcinomas and lung metastases from colo-rectal cancer

Background

Several studies demonstrated that epidermal growth factor receptor (EGFR) gene copy number (GCN) correlates to the response to tyrosine kinase inhibitors in non small cell lung cancer (NSCLC) and to anti-EGFR monoclonal antibodies (MoAbs) in metastatic colorectal cancer (CRC). In the presence of lung nodules, cytology is often the only possible diagnostic approach. Chromogenic in situ hybridization (CISH) is an alternative technique to fluorescence in situ hybridization (FISH), but its feasibility in detecting EGFR GCN in cell blocks from fine-needle aspiration cytology (FNAC) of lung nodules has not yet been established.

Methods

We evaluated the feasibility of CISH on 33 FNAC from 20 primary NSCLC (5 squamous carcinomas, 8 large cell carcinomas and 7 adenocarcinomas) and 13 lung metastases from CRC.

Results

Of the 33 FNAC analyzed by CISH, 27 (82%) presented a balanced increase in EGFR gene and chromosome 7 number: 10 cases (30%) showed a low polysomy, 15 (45%) a high polysomy and 2 (6%) NSCLC were amplified. No significant differences between NSCLC and CRC lung metastases were found in relation to disomic or polysomic status. In addition, no correlation between EGFR GCN and EGFR immunohistochemical overexpression was found. Furthermore, we compared CISH results with those obtained by FISH on the same samples and we found 97% overall agreement between the two assays (k = 0.78, p < 0.0001). Two cases were amplified with both assays, whereas 1 case of NSCLC was amplified by FISH only. CISH sensitivity was 67%, the specificity and positive predictive value (PPV) was 100%, and the negative predictive value (NPV) was 97%.

Conclusions

Our study shows that CISH is a valid method to detect EGFR GCN in cell blocks from FNAC of primary NSCLC or metastatic CRC to the lung.

EGFR gene copy number as a predictive biomarker for patients receiving tyrosine kinase inhibitor treatment: a systematic review and meta-analysis in non-small-cell lung cancer

INTRODUCTION

We conducted a systematic review and meta-analysis to assess epidermal growth factor receptor (EGFR) gene copy number as a potential biomarker of survival for patients with advanced non-small-cell lung cancer (NSCLC) receiving single-agent treatment with EGFR tyrosine kinase inhibitors (TKIs).

METHODS

We systematically identified articles investigating EGFR gene copy number by fluorescent or chromogenic in situ hybridization in patients with advanced or recurrent NSCLC treated with the TKIs erlotinib or gefitinib, (last search: 31 June 2009). Eligible studies had to report on overall survival (OS), progression-free survival (PFS) or time-to-progression (TTP), stratified by EGFR gene copy number. Summary hazard ratios (HRs) were calculated using random-effects models.

RESULTS

Among 255 identified studies, 20 (1689 patients, 594 with increased gene copy number), 10 (822 patients, 290 with increased gene copy number) and 5 (294 patients, 129 with increased gene copy number) were eligible for the OS, PFS and TTP meta-analyses, respectively. Increased EGFR gene copy number was associated with increased OS (HR = 0.77; 95% CI 0.66-0.89; P = 0.001), PFS (HR = 0.60; 95% CI 0.46-0.79; P<0.001) and TTP (HR = 0.50; 95% CI 0.28-0.91; P = 0.02). Among predominantly white populations, increased EGFR gene copy number was strongly associated with improved survival (HR = 0.70; 95% CI 0.59-0.82; P<0.001), whereas it did not influence survival in East Asians (HR = 1.11; 95% CI 0.82-1.50; P=0.50). This difference was statistically significant (P=0.02).

CONCLUSION

Among TKI-treated patients, increased EGFR gene copy number appears to be associated with improved survival outcomes. The effect on OS appears to be limited to patients of non-Asian descent.

Detection of SYT and EWS gene rearrangements by dual-color break-apart CISH in liquid-based cytology samples of synovial sarcoma and Ewing sarcoma/primitive neuroectodermal tumor

To improve cytologic diagnostic accuracy for translocation-associated sarcomas, we explored dual-color break-apart (dc) chromogenic in situ hybridization (CISH) on liquid-based cytology (LBC) samples of 2 prototypic sarcomas: synovial sarcoma (SS) and Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET). LBC samples of 10 cases of SS and 9 cases of ES/PNET were subjected to dc-CISH using probes for the specifically rearranged genes in each tumor entity: SYT in SS and EWS in ES/PNET. Rearranged SYT was successfully detected in all SSs but not in any ES/PNETs. In contrast, EWS rearrangement was identified in all ES/PNETs but not in any SSs. These results were validated by dc-fluorescence in situ hybridization and reverse transcription-polymerase chain reaction. dc-CISH on LBC samples is a reliable modality to detect gene rearrangements in sarcomas. This system has a clear advantage over other methods, enabling simultaneous visualization of the genetic abnormality and well-preserved, nonoverlapping cytomorphologic features with clear background under bright-field microscope.

Clinicopathological predictors of EGFR/KRAS mutational status in primary lung adenocarcinomas

Screening for EGFR and KRAS mutations in patients with lung adenocarcinomas can be used to predict the patient's response to EGFR tyrosine kinase inhibitors, but there is a lack of guidelines for testing in clinical practice. We analyzed the morphological and clinicopathological characteristics, including tumor stage, size, presence of scar, inflammatory response, angiolymphatic and pleural invasion, of 345 surgically treated primary lung adenocarcinomas with respect to their EGFR and KRAS mutational profile and EGFR FISH. EGFR and KRAS mutations were found in 33 (10%) and 78 (23%) of lung adenocarcinomas, respectively, whereas 226 (67%) cases were negative for both mutations. There was a large overlap in the analyzed clinicopathological characteristics among the three study groups. Statistically significant predictors for the presence of EGFR mutations included history of never smoking (OR 5.939; 95% Wald confidence limit 1.662-21.223, P=0.0149), mild lymphocytic host response (OR 4.724; 95% Wald confidence limit 1.33-1.776; P=0.0163), female gender (OR 2.571; 95% Wald confidence limit 1.015-6.511, P=0.0463) and absence of solid growth pattern. Statistically significant predictors for the presence of KRAS mutations included older age (OR 1.034; 95% Wald confidence limit 1.007-1.062, P=0.0132), history of smoking (OR 0.617, 95% Wald confidence limit 0.357-1.066, P=0.0412) and mucinous differentiation. EGFR FISH positivity as defined by the Colorado criteria was a significant predictor of EGFR mutations, with high polysomy as the strongest predictive criteria. Despite statistically significant differences among the study groups and because of the large overlap in the analyzed clinicopathological criteria, none of these could be implemented as the selection criteria for molecular testing in clinical practice. The cost-effectiveness of lung carcinoma mutational testing would be improved by initial determination of KRAS mutational status as negative predictor of the patient's response to EGFR tyrosine kinase inhibitors, followed by EGFR mutational analysis, if necessary.

Clinical efficacy of erlotinib in patients previously treated for advanced non-small cell lung cancer

BACKGROUND AND OBJECTIVE

Erlotinib is one of the standard second/third line treatments for patients with advanced non-small cell lung cancer (NSCLC). This study investigated the efficacy of erlotinib in a Chinese population with advanced NSCLC and compared the predictive value of serum vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-alpha for the efficacy of erlotinib.

METHODS

Patients with advanced, previously treated NSCLC received 150 mg of erlotinib once daily orally until disease progression or intolerable toxicity. Serum levels of VEGF and TGF-alpha were measured by ELISA at baseline and 1 month after treatment commenced.

RESULTS

There were 112 patients enrolled during the period October 2005 to February 2008 and followed until July 2008. Serum samples were available in 50 patients. Tumour response to erlotinib was partial in 35.7% of patients and 41.1% of patients had stable disease. The severity of skin rash (P < 0.001) had a significant positive correlation with the response to erlotinib. Median progression-free survival (PFS) and overall survival were 6.3 months and 12.5 months, respectively. After erlotinib treatment, serum VEGF levels did not change significantly, while serum TGF-alpha levels increased in patients who had partial response (P = 0.075) or stable disease (P = 0.055), but not in patients with progressive disease (P = 0.155). In patients with measurable serum TGF-alpha levels at baseline the PFS and median survival were 5 and 9.9 months respectively, and in patients with no measurable TGF-alpha at baseline the PFS and median survival were 11 and 21 months, respectively. Overall survival was significantly longer in patients with negative baseline serum TGF-alpha (P = 0.002).

CONCLUSIONS

Oral erlotinib was effective as a second/third line treatment for patients with advanced NSCLC. Baseline serum TGF-alpha levels may be a predictor for the efficacy of erlotinib treatment.

Predictive value of EGFR and HER2 overexpression in advanced non-small-cell lung cancer

Epidermal growth factor receptor (EGFR) and HER2 are cell surface receptor tyrosine kinases (TKs) that transduce growth signals through dimerization with HER family receptors. The heterodimerization of EGFR with HER2 induces a more potent activation of EGFR TK than does EGFR homodimerization. When tumor cells overexpress both EGFR and HER2, they exhibit aggressive tumor cell growth, owing to the increased potential for EGFR/HER2 heterodimerization and signaling. Gefitinib and erlotinib are EGFR TK inhibitors (EGFR TKIs) and have antitumor activity in 8-18% of patients with advanced non-small-cell lung cancer (NSCLC). Certain patient subsets are particularly responsive to EGFR TKIs. Analyses of biomarkers from patients in clinical studies of EGFR TKIs show correlations between objective tumor response and EGFR overexpression, as detected by immunohistochemistry and increased gene copy number measured by fluorescence in situ hybridization analysis. Furthermore, NSCLC tumors that overexpress both EGFR and HER2 are more sensitive to EGFR TKIs than are tumors that overexpress EGFR but are HER2 negative. Therefore, the measurement of EGFR and HER2 protein expression and the gene copy number in NSCLC tumors may have a prognostic value in NSCLC and a predictive value for identifying patients likely to benefit from an EGFR TKI. These considerations suggest that the simultaneous inhibition of EGFR and HER2 may warrant further study in patients with NSCLC.

Overview of molecular testing in non-small-cell lung cancer: mutational analysis, gene copy number, protein expression and other biomarkers of EGFR for the prediction of response to tyrosine kinase inhibitors

Most patients with non-small-cell lung cancer (NSCLC) present with advanced disease. Current treatment paradigms are shifting from cytotoxic chemotherapies alone to single-agent and combination biological and targeted therapies. As patient responses to these therapies vary, predictive biomarkers will be an important facet of a patient's diagnostic workup in personalized medicine, as there is accumulating evidence that they may enable the prognostication and prediction of therapeutic response. Potential biomarkers for the selection of patients with NSCLC most likely to benefit from epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, include mutations, gene copy number increase and single-nucleotide polymorphisms of the EGFR gene, EGFR protein expression and oncogenic mutation on the KRAS gene. Many techniques are available to assay for these biomarkers. In this review, we present the current weight of evidence for using these methods as biomarkers for anti-EGFR therapy in patients with NSCLC.

EGFR and HER2 genomic gain in recurrent non-small cell lung cancer after surgery: impact on outcome to treatment with gefitinib and association with EGFR and KRAS mutations in a Japanese cohort

BACKGROUND

Sensitivity to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) and frequency of activation mutations in EGFR is lower in Caucasian than Asian non small-cell lung cancer (NSCLC) patients. Increased EGFR gene copy numbers evaluated by fluorescence in situ hybridization (FISH) has been reported as predictor of clinical benefit from EGFR-TKIs in Caucasian NSCLC patients. This study was carried out to verify whether EGFR FISH had similar performance in Japanese patients.

METHODS

A cohort of 44 Japanese patients with recurrent NSCLC after surgery was treated with gefitinib 250 mg daily. The cohort included 48% females and 52% never-smokers; 73% had prior chemotherapy and 57% had stage III-IV at the time of surgery. Adenocarcinoma was the most common histology (86%). FISH was performed using the EGFR/Chromosome Enumeration Probe 7 and PathVysion DNA probes (Abbott Molecular). Specimens were classified as FISH positive when showing gene amplification or high polysomy (> or = 4 copies of the gene in > or = 40% of tumor cells). Tumor response to gefitinib was assessed by RECIST for 33 patients with measurable diseases.

RESULTS

Twenty-nine tumors (66%) were EGFR FISH+ and 23 (53%) were HER2 FISH+. Overall response rate was 52%, representing 65% of EGFR FISH+ patients and 29% of EGFR FISH- patients (p = 0.0777). Survival was not impacted by the EGFR FISH (p = 0.9395) or the HER2 FISH (p = 0.0671) status. EGFR FISH+ was significantly associated with HER2 FISH+ (p = 0.015) and presence of EGFR mutation (p = 0.0060). EGFR mutation significantly correlated with response (p < 0.0001) and survival after gefitinib (p = 0.0204). EGFR and HER2 FISH status were not associated with KRAS mutation.

CONCLUSION

Frequency of EGFR FISH+ status was higher and its predictive power for TKI sensitivity was lower in this Japanese cohort than in Western NSCLC cohorts. These findings support differences in the mechanisms of EGFR pathway activation in NSCLC between Asian and Caucasian populations. Confirmation of these results in larger cohorts is warranted.

Theme: Oncology - Molecular mechanisms determining the efficacy of EGF receptor-specific tyrosine kinase inhibitors help to identify biomarker candidates

Non-small-cell lung cancer is a major subtype of lung cancer, which is the most common and fatal cancer in the world. Gefitinib (Iressa™) and later erlotinib (Tarceva™), specific tyrosine kinase inhibitors for EGF receptors (EGFRs), have been demonstrated to be effective for some non-small-cell lung cancer patients and used in clinics as pioneers of molecule-based targeted drugs for cancer. There has been an urgent need to develop biomarkers and to select appropriate patients who should benefit from treatment with these drugs because of the high sensitivity of target cancer cells. However, problems of acquired resistance after long-term treatment with these drugs have been recognized. Emerging evidence indicates that the efficacy of these drugs is partly dependent on somatic mutations in the EGFR. In this review, we summarize recent understandings of the molecular mechanisms that determine the efficacy of EGFR–tyrosine kinase inhibitors. Towards the end of this article, we discuss recent ongoing projects validating potential biomarkers and future prospects.

Utility of chromogenic in situ hybridization (CISH) for detection of EGFR amplification in glioblastoma: comparison with fluorescence in situ hybridization (FISH)

In this study, we test the reliability of chromogenic in situ hybridization (CISH) for the detection of epidermal growth factor receptor (EGFR) gene amplification in glioblastoma. Earlier reports have described EGFR CISH in glioblastoma multiforme, but a comparison of CISH with a "gold standard" testing method, such as fluorescence in situ hybridization (FISH), has not been described. Therapies targeting the EGFR-signaling pathway might increase the importance of assessment of EGFR-amplification status. CISH is a potential alternative to FISH as a testing method. To test its reliability, EGFR-amplification status by CISH was assessed in 89 cases of glioblastoma and compared with FISH results, and correlated with the protein expression using immunohistochemistry (IHC) for EGFR. FISH was scored as being EGFR-amplified in 47/89 tumors, CISH as being amplified in 43/89 tumors. The CISH and FISH results were in agreement in 83/89 cases (93%). Four glioblastomas were scored as being amplified by FISH, but not by CISH; whereas amplification was detected in 2 tumors by CISH that were not amplified using FISH. Forty-eight of the 89 cases were positive for EGFR expression by IHC. EGFR amplification was highly correlated with protein expression by IHC, as 40/48 (83%) EGFR IHC-positive cases were found to be EGFR-amplified. The high concordance of CISH and FISH for the assessment of EGFR gene-amplification status indicates that CISH is a viable alternative to FISH for the detection of EGFR gene amplification in glioblastoma. Detectable EGFR expression by IHC can occur in the absence of gene amplification, but is uncommon.

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.

Lung adenocarcinoma: modification of the 2004 WHO mixed subtype to include the major histologic subtype suggests correlations between papillary and micropapillary adenocarcinoma subtypes, EGFR mutations and gene expression analysis

The histologic heterogeneity of lung adenocarcinoma creates a variety of complex challenges to pathologists in analyzing the various subtypes. Current classification schemas do not take into account the major subtype. We analyzed 100 cases for clinical, pathologic, and molecular features using a modification of the 2004 World Health Organization (WHO) classification to record the major component in the mixed subtype tumors. The tumors were analyzed for KRAS mutation and epidermal growth factor receptor (EGFR) by mutation, chromogenic in situ hybridization, and immunohistochemistry for EGFR and phosphorylated EGFR. Gene expression analysis was performed using HG-U133A Affymetrix oligonucleotide microarrays revealing 3 gene clusters. The most common major histologic subtype was papillary (37%) followed by acinar (30%), solid (25%) and bronchioloalveolar (7%) carcinoma (BAC), although no pure BACs were seen. Sixteen tumors harbored EGFR mutations and 14 KRAS mutations. Papillary adenocarcinoma strongly correlated with EGFR mutation (P<0.001) and gene profile Cluster 1 (P=0.006) with weaker correlations with low grade (P=0.038) and favorable behavior in Stage 1 patients (P=0.047). Micropapillary subtype correlated strongly with EGFR mutation (P<0.001) and weakly with Cluster 1 (P=0.030). Solid adenocarcinoma strongly correlated with gene profile Cluster 3 (P=0.001) and worse survival (P=0.001). BAC as a major component strongly correlated with gene Cluster 2 (P=0.001). Cluster 1 correlated strongly with less smoking (P<0.001), papillary histology (P<0.001), and EGFR mutations (P<0.001). Cluster 3 strongly correlated with heavier smoking (P<0.001), larger tumor size (P<0.001), solid subtype (P<0.001), and poor grade (P=0.004); weak correlations were found with KRAS mutation (P=0.025). No correlation was found with BAC and EGFR by mutation, chromogenic in situ hybridization or immunohistochemistry. Higher stage (P<0.001), grade (P<0.001), and solid subtype (P=0.001) correlated with shorter survival. Our data suggest that EGFR mutations are associated with papillary adenocarcinoma and gene profile Cluster 1. We discovered this only because we used a comprehensive approach examining in detail all histologic subtypes and we modified the 2004 WHO mixed subtype to include the major histologic subtype. As we do not know the major genetic pathways of 30% to 70% of lung adenocarcinomas, the comprehensive histologic subtyping we propose gives advantage for recognition of unanticipated histologic-genetic correlations that might not be detected using classification systems that focus primarily on specific aspects of adenocarcinomas such as BAC or EGFR mutations. Such an approach should be considered in future studies for validation in other datasets.

EGFR assays in lung cancer

The development of small-molecule inhibitors of the epidermal growth factor receptor (EGFR) resulted in new therapeutic options for patients with advanced lung cancer. It was clear from the experience with targeted therapy for breast cancer that a new standardized assay procedure for assessing and predicting the effects of therapeutic agents must be developed. Three academic groups almost simultaneously reported the discovery of somatic mutations in the exons 18 to 21 of the tyrosine kinase (TK) domain of EGFR that correlated with a high likelihood of response to EGFR TK inhibitors. This observation revolutionized understanding of EGFR in lung carcinogenesis and resulted in numerous retrospective studies that correlated patient's response and molecular profile of the lung adenocarcinoma. The results of these studies indicate that clinical benefits from treatment with EGFR TK inhibitors are variable between the different subsets of patients. Multiple methodologic approaches were used including mutational analysis, fluorescence in situ hybridization, and immunohistochemistry. Conflicting results reflect the lack of standardization of the methodology and interpretation. Sample types, sample processing, and storage should also be taken into consideration as another potentially confounding factor. Therefore, it is important to standardize the approach and decide which assays are best to predict patient response to targeted therapies. It is also essential to determine the most cost-effective way to integrate EGFR molecular assays into clinical practice. This review will address practical aspects of each of the currently proposed assays. Difficulties in standardization of these assays in a clinical practice will be discussed.

Phosphorylated epidermal growth factor receptor on tumor-associated endothelial cells is a primary target for therapy with tyrosine kinase inhibitors

We determined whether phosphorylated epidermal growth factor receptor (EGFR) expressed on tumor-associated endothelial cells is a primary target for therapy with EGFR tyrosine kinase inhibitors (TKIs). Human colon cancer cells SW620CE2 (parental) that do not express EGFR or human epidermal growth factor receptor 2 (HER2) but express transforming growth factor alpha (TGF-alpha) were transduced with a lentivirus carrying nontargeting small hairpin RNA (shRNA) or TGF-alpha shRNA. The cell lines were implanted into the cecum of nude mice. Two weeks later, treatment began with saline, 4-[R]-phenethylamino-6-[hydroxyl] phenyl-7H-pyrrolo [2,3-D]-pyrimidine (PKI166), or irinotecan. Endothelial cells in parental and nontargeting shRNA tumors expressed phosphorylated EGFR. Therapy with PKI166 alone or with irinotecan produced apoptosis of these endothelial cells and necrosis of the EGFR-negative tumors. Endothelial cells in tumors that did not express TGF-alpha did not express EGFR, and these tumors were resistant to treatment with PKI166. The response of neoplasms to EGFR antagonists has been correlated with EGFR mutations, HER2 expression, Akt activation, and EGFR gene copy number. Our present data using colon cancer cells that do not express EGFR or HER2 suggest that the expression of TGF-alpha by tumor cells leading to the activation of EGFR in tumor-associated endothelial cells is a major determinant for the susceptibility of neoplasms to therapy by specific EGFR-TKI.

Gefitinib (ZD1839): therapy in selected patients with non-small cell lung cancer (NSCLC)?

PURPOSE

To evaluate response rate, toxicity and epidermal growth factor (EGFR) mutations and gene copy number as outcome predictive factors in Italian patients with non-small cell lung cancer (NSCLC) treated with gefitinib (Iressa) in an expanded access program (EAP).

PATIENTS AND METHODS

A total of 137 patients with advanced NSCLC received gefitinib as first line treatment or after failure of chemotherapy. In 43 cases, tissue specimens were available for EGFR status evaluation: immunohistochemical (IHC) for EGFR, fluorescence in situ hybridisation (FISH) or Chromogenic in situ hybridisation (CISH)-(ISH) analysis for EGFR and HER2 gene copy number, and PCR-DNA sequencing for mutational analysis of EGFR were performed.

RESULTS

In the study population, response rate (PR) was 13%; disease stabilization (DS) 26%; overall disease control rate 39%; median survival 6.3 months and time to progression 2.7 months. Toxicity was mild (G3 skin toxicity in 3% and G3 liver toxicity in 4% of patients). An EGFR-mutation was detected in 9/43 patients: Eight deletions in exon 19 and 1 missense mutation in exon 21. Increased gene copy number for EGFR and/or HER2 was detected in 17/43 patients. Response rate was significantly higher in women, non-smokers, in mutation carriers than in wild type carriers, in EGFR-trisomy/polysomy carriers and HER2-trisomy/polysomy carriers.

CONCLUSIONS

In this study, response rate and toxicity to gefitinib treatment were consistent with previously reported data for whites. Female gender, absence of smoking history, EGFR-mutations, EGFR and HER2-polysomy were significantly associated with response to gefitinib therapy in NSCLC patients.

Expression of epidermal growth factor (EGF)/transforming growth factor-alpha by human lung cancer cells determines their response to EGF receptor tyrosine kinase inhibition in the lungs of mice

Epidermal growth factor receptor (EGFR) has been extensively targeted in the treatment of non-small cell lung cancer, producing responses in a small number of patients. To study the role of ligand expression in mediating response to EGFR antagonism, we injected NCI-H441 [EGFR and EGF/transforming growth factor-alpha (TGF-alpha) positive] or PC14-PE6 (EGFR positive and EGF/TGF-alpha negative) human lung adenocarcinoma cells into the lungs of nude mice. We randomized the mice to receive treatment with the EGFR tyrosine kinase inhibitors gefitinib or AEE788 or vehicle. Treatment of mice bearing NCI-H441 but not PC14-PE6 lung tumors resulted in a significant reduction in primary tumor growth, pleural effusion, and lymph node metastasis. Immunohistochemical analyses revealed that NCI-H441 and PC14-PE6 cells expressed EGFR but that the expression of EGF/TGF-alpha was high in NCI-H441 cells and very low in PC14-PE6 cells. Consequently, EGFR was activated in both tumor and tumor-associated endothelial cells in the NCI-H441 tumors but not in the PC14-PE6 tumors. Antagonism of EGFR signaling by treatment of mice with AEE788 decreased proliferation and increased apoptosis of both tumor cells and tumor-associated endothelial cells in NCI-H441 tumors but not in PC14-PE6 tumors. However, after transfection of PC14-PE6 cells with TGF-alpha, lung tumors derived from the transfected cells expressed and activated EGFR in both tumor and tumor-associated endothelial cells and tumors responded to treatment with AEE788. Collectively, these results strongly suggest that the response of human lung cancers growing orthotopically in mice to the inhibition of EGFR signaling is determined by ligand (EGF/TGF-alpha) expression by tumor cells. Our findings provide an additional explanation for the susceptibility of lung cancers to treatment with EGFR tyrosine kinase inhibitors.