Biomarker analysis of cetuximab plus oxaliplatin/leucovorin/5-fluorouracil in first-line metastatic gastric and oesophago-gastric junction cancer: results from a phase II trial of the Arbeitsgemeinschaft Internistische Onkologie (AIO)

Novel Biomarkers of Gastric Adenocarcinoma: Current Research and Future Perspectives

Simple Summary

Gastric cancer is characterized by poor survival rates despite surgery and chemotherapy. Current research focuses on biomarkers to improve diagnosis and prognosis, and to enable targeted treatment strategies. The aim of our review was to give an overview over the wide range of novel biomarkers in gastric cancer. These biomarkers are targets of a specific treatment, such as antibodies against human epidermal growth factor receptor 2. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are vascular endothelial growth factor, programmed cell death protein 1, and Claudin 18.2. There is a vast number of biomarkers based on DNA, RNA, and protein expression, as well as detection of circulating tumor cells and the immune tumor microenvironment.

Abstract

Overall survival of gastric cancer remains low, as patients are often diagnosed with advanced stage disease. In this review, we give an overview of current research on biomarkers in gastric cancer and their implementation in treatment strategies. The HER2-targeting trastuzumab is the first molecular targeted agent approved for gastric cancer treatment. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are VEGF and Claudin 18.2. Expression of MET has been shown to be a negative prognostic factor in gastric cancer. Targeting the PD-1/PD-L1 pathway with immune checkpoint inhibitors has proven efficacy in advanced gastric cancer. Recent technology advances allow the detection of circulating tumor cells that may be used as diagnostic and prognostic indicators and for therapy monitoring in gastric cancer patients. Prognostic molecular subtypes of gastric cancer have been identified using genomic data. In addition, transcriptome profiling has allowed a comprehensive characterization of the immune and stromal microenvironment in gastric cancer and development of novel risk scores. These prognostic and predictive markers highlight the rapidly evolving field of research in gastric cancer, promising improved treatment stratification and identification of molecular targets for individualized treatment in gastric cancer.

Genomic Analysis of Response to Neoadjuvant Chemotherapy in Esophageal Adenocarcinoma

Neoadjuvant therapy followed by surgery is the standard of care for locally advanced esophageal adenocarcinoma (EAC). Unfortunately, response to neoadjuvant chemotherapy (NAC) is poor (20-37%), as is the overall survival benefit at five years (9%). The EAC genome is complex and heterogeneous between patients, and it is not yet understood whether specific mutational patterns may result in chemotherapy sensitivity or resistance. To identify associations between genomic events and response to NAC in EAC, a comparative genomic analysis was performed in 65 patients with extensive clinical and pathological annotation using whole-genome sequencing (WGS). We defined response using Mandard Tumor Regression Grade (TRG), with responders classified as TRG1-2 (n = 27) and non-responders classified as TRG4-5 (n =38). We report a higher non-synonymous mutation burden in responders (median 2.08/Mb vs. 1.70/Mb, p = 0.036) and elevated copy number variation in non-responders (282 vs. 136/patient, p < 0.001). We identified copy number variants unique to each group in our cohort, with cell cycle (CDKN2A, CCND1), c-Myc (MYC), RTK/PIK3 (KRAS, EGFR) and gastrointestinal differentiation (GATA6) pathway genes being specifically altered in non-responders. Of note, NAV3 mutations were exclusively present in the non-responder group with a frequency of 22%. Thus, lower mutation burden, higher chromosomal instability and specific copy number alterations are associated with resistance to NAC.

Objective Quantitation of EGFR Protein Levels using Quantitative Dot Blot Method for the Prognosis of Gastric Cancer Patients

Purpose

An underlying factor for the failure of several clinical trials of anti-epidermal growth factor receptor (EGFR) therapies is the lack of an effective method to identify patients who overexpress EGFR protein. The quantitative dot blot method (QDB) was used to measure EGFR protein levels objectively, absolutely, and quantitatively. Its feasibility was evaluated for the prognosis of overall survival (OS) of patients with gastric cancer.

Materials and Methods

Slices of 2×5 μm from formalin-fixed paraffin-embedded gastric cancer specimens were used to extract total tissue lysates for QDB measurement. Absolutely quantitated EGFR protein levels were used for the Kaplan-Meier OS analysis.

Results

EGFR protein levels ranged from 0 to 772.6 pmol/g (n=246) for all gastric cancer patients. A poor correlation was observed between quantitated EGFR levels and immunohistochemistry scores with ρ=0.024 and P=0.717 in Spearman's correlation analysis. EGFR was identified as an independent negative prognostic biomarker for gastric cancer patients only through absolute quantitation, with a hazard ratio of 1.92 (95% confidence interval, 1.05–3.53; P=0.034) in multivariate Cox regression OS analysis. A cutoff of 208 pmol/g was proposed to stratify patients with a 3-year survival probability of 44% for patients with EGFR levels above the cutoff versus 68% for those below the cutoff based on Kaplan-Meier OS analysis (log rank test, P=0.002).

Conclusions

A QDB-based assay was developed for gastric cancer specimens to measure EGFR protein levels absolutely, quantitatively, and objectively. This assay should facilitate clinical trials aimed at evaluation of anti-EGFR therapies retrospectively and prospectively for gastric cancer.

Targeting EGFR in Esophagogastric Cancer

Esophagogastric cancer (EGC) remains a major cause of cancer-related mortality. Overall survival in the metastatic setting remains poor, with few molecular targeted approaches having been successfully incorporated into routine care to-date: only first line anti-HER2 therapy in ERBB2-expressing tumors, second line anti-VEGFR2 therapy with ramucirumab in unselected patients, and pembrolizumab in PD-L1 expressing or MSI-H patients. EGFR inhibitors were extensively studied in EGC, including phase III trials with cetuximab (EXPAND), panitumumab (REAL3), and gefitinib (COG). All three trials were conducted in unselected populations, and therefore, failed to demonstrate clinical benefit. Here, we review previous attempts at targeting EGFR in EGC and potential future biomarkers for targeting this pathway in patients with EGFR-amplified tumors.

Targeted Molecular Therapies in the Treatment of Esophageal Adenocarcinoma, Are We There Yet?

Esophageal adenocarcinoma is one of the leading causes of cancer-related deaths worldwide. The incidence of esophageal adenocarcinoma has increased at an alarming rate in the Western world and long-term survival remains poor. Current treatment approaches involve a combination of surgery, chemotherapy, and radiotherapy. Unfortunately, standard first-line approaches are met with high rates of recurrence and metastasis. More recent investigations into the distinct molecular composition of these tumors have uncovered key genetic and epigenetic alterations involved in tumorigenesis and progression. These discoveries have driven the development of targeted therapeutic agents in esophageal adenocarcinoma. While many agents have been studied, therapeutics targeting the human epidermal growth factor receptor (HER2) and vascular endothelial growth factor (VEGF) pathways have demonstrated improved survival. More recent advances in immunotherapies have also demonstrated survival advantages with monoclonal antibodies targeting the programmed death ligand 1 (PD-L1). In this review we highlight recent advances of targeted therapies, specifically agents targeting receptor tyrosine kinases, small molecule kinase inhibitors, and immune checkpoint inhibitors. While targeted therapeutics and immunotherapies have significantly improved survival, the benefits are limited to patients whose tumors express biomarkers such as PD-L1 and HER2. Survival remains poor for the remainder of patients with esophageal adenocarcinoma, underscoring the critical need for development of novel treatment strategies.

Histone Lysine Methylation Dynamics Control EGFR DNA Copy-Number Amplification

Acquired chromosomal DNA copy gains are a feature of many tumors; however, the mechanisms that underpin oncogene amplification are poorly understood. Recent studies have begun to uncover the importance of epigenetic states and histone lysine methyltransferases (KMT) and demethylases (KDM) in regulating transient site-specific DNA copy-number gains (TSSG). In this study, we reveal a critical interplay between a myriad of lysine methyltransferases and demethylases in modulating H3K4/9/27 methylation balance to control extrachromosomal amplification of the EGFR oncogene. This study further establishes that cellular signals (hypoxia and EGF) are able to directly promote EGFR amplification through modulation of the enzymes controlling EGFR copy gains. Moreover, we demonstrate that chemical inhibitors targeting specific KMTs and KDMs are able to promote or block extrachromosomal EGFR amplification, which identifies potential therapeutic strategies for controlling EGFR copy-number heterogeneity in cancer, and, in turn, drug response. SIGNIFICANCE: This study identifies a network of epigenetic factors and cellular signals that directly control EGFR DNA amplification. We demonstrate that chemical inhibitors targeting enzymes controlling this amplification can be used to rheostat EGFR copy number, which uncovers therapeutic opportunities for controlling EGFR DNA amplification heterogeneity and the associated drug response.This article is highlighted in the In This Issue feature, p. 161.

Epidermal Growth Factor Receptor Family and its Role in Gastric Cancer

Despite the gradual decrease in incidence, gastric cancer is still the third leading cause of cancer death worldwide. Although chemotherapy enhances overall survival and quality of life in advanced disease, the median overall survival is < 12 months. In recent years, the human epidermal growth factor receptor (ErbB) family has been extensively investigated in gastric cancer. The ErbB family is composed of four closely-related members: ErbB-1 (HER1 or epidermal growth factor receptor, EGFR), ErbB-2 (HER2), ErbB-3 (HER3), and ErbB-4 (HER4), all of which play a critical role in regulating cell growth, proliferation and migration of tumors. It is well known that gastric cancer overexpresses HER in a heterogeneous pattern, especially EGFR, and HER2. HER3 is another important member of the ErbB family that preferentially activates the phosphatidylinositol 3-kinase (PI3K) pathway. Furthermore, its heterodimerization with HER2 seems fundamental for steering HER2-overexpressing breast cancer tumor growth. Less is known about the impact of HER4 on gastric cancer. Improved survival from the use of trastuzumab has paved the way for ErbB receptor family-targeted treatments in gastric cancer. However, unlike trastuzumab, ErbB receptor-targeted drugs have not consistently maintained the encouraging results obtained in preclinical and early clinical trials. This may be attributable to the intrinsic heterogeneity of gastric cancer and/or to the lack of standardized test quality for established biomarkers used to evaluate these biological targets. This review presents an overview of the most recent clinical studies on agents targeting the ErbB family in gastric cancer.

Neoadjuvant chemotherapy followed by chemoradiation and surgery with and without cetuximab in patients with resectable esophageal cancer: a randomized, open-label, phase III trial (SAKK 75/08)

Background

This open-label, phase III trial compared chemoradiation followed by surgery with or without neoadjuvant and adjuvant cetuximab in patients with resectable esophageal carcinoma.

Patients and methods

Patients were randomly assigned (1 : 1) to two cycles of chemotherapy (docetaxel 75 mg/m2, cisplatin 75 mg/m2) followed by chemoradiation (45 Gy, docetaxel 20 mg/m2 and cisplatin 25 mg/m2, weekly for 5 weeks) and surgery, with or without neoadjuvant cetuximab 250 mg/m2 weekly and adjuvant cetuximab 500 mg/m2 fortnightly for 3 months. The primary end point was progression-free survival (PFS).

Results

In total, 300 patients (median age, 61 years; 88% male; 63% adenocarcinoma; 85% cT3/4a, 90% cN+) were assigned to cetuximab (n = 149) or control (n = 151). The R0-resection rate was 95% for cetuximab versus 97% for control. Postoperative treatment-related mortality was 6% in both arms. Median PFS was 2.9 years [95% confidence interval (CI), 2.0 to not reached] with cetuximab and 2.0 years (95% CI, 1.5-2.8) with control [hazard ratio (HR), 0.79; 95% CI, 0.58-1.07; P = 0.13]. Median overall survival (OS) time was 5.1 years (95% CI, 3.7 to not reached) versus 3.0 years (95% CI, 2.2-4.2) for cetuximab and control, respectively (HR, 0.73; 95% CI, 0.52-1.01; P = 0.055). Time to loco-regional failure after R0-resection was significantly longer for cetuximab (HR 0.53; 95% CI, 0.31-0.90; P = 0.017); time to distant failure did not differ between arms (HR, 1.01; 95% CI, 0.64-1.59, P = 0.97). Cetuximab did not increase adverse events in neoadjuvant or postoperative settings.

Conclusion

Adding cetuximab to multimodal therapy significantly improved loco-regional control, and led to clinically relevant, but not-significant improvements in PFS and OS in resectable esophageal carcinoma.

Clinical trial information

NCT01107639.

Targeted therapies in metastatic gastric cancer: Current knowledge and future perspectives

Gastric cancer (GC) represents a leading cause of cancer related morbidity and mortality worldwide accounting for more than 1 million of newly diagnosed cases and thousands of deaths every year. In the last decade, the development of targeted therapies and the optimization of already available chemotherapeutic drugs has expanded the available treatment options for advanced GC and granted better survival expectations to the patients. At the same time, global efforts have been undertaken to investigate in detail the genomic and epigenomic heterogeneity of this disease, resulting in the identification of new specific and sensitive predictive and prognostic biomarkers and in innovative molecular classifications based on gene expression profiling. Nonetheless, several randomized studies aimed at exploring new innovative agents, such as immune checkpoint inhibitors, failed to demonstrate clinically meaningful survival advantages. Therefore, it is essential to further improve the molecular characterization of GC subgroups in order to provide researchers and medical oncologists with new tools for patients’ selection and stratification in future clinical development programs and subsequent trials. The aim of the present manuscript is to provide a global overview of the recent molecular classifications from The Cancer Genome Atlas and the Asian Cancer Research Group and to present key promising developments in the field of immunotherapy and targeted therapies in metastatic GC.

EGFR Amplification as a Target in Gastroesophageal Adenocarcinoma: Do Anti-EGFR Therapies Deserve a Second Chance?

<b/> Anti-EGFR therapies have failed to improve survival for unselected patients with metastatic gastroesophageal cancer, but in a subset of patients, EGFR amplification may predict treatment benefit. Maron and colleagues report the clinical activity of anti-EGFR therapies in a cohort of patients with EGFR-amplified metastatic gastroesophageal cancer and utilize serial blood and tumor tissue collection to identify molecular drivers of treatment sensitivity and resistance. Their insights offer a path to overcome technical limitations associated with EGFR amplification and facilitate molecularly targeted therapeutic strategies. Cancer Discov; 8(6); 679-81. ©2018 AACRSee related article by Maron et al., p. 696.

A PLK1 kinase inhibitor enhances the chemosensitivity of cisplatin by inducing pyroptosis in oesophageal squamous cell carcinoma

BACKGROUND

Targeting PLK1 has recently been proven as a viable therapeutic strategy against oesophageal squamous cell carcinom (ESCC). Therefore, this study aimed to explore whether the PLK1 inhibitor BI2536 is able to sensitize ESCC cells to cisplatin (DDP) and determine the underlying mechanisms.

METHODS

Viability, clonogenicity, cell cycle distribution and apoptosis were assessed in ESCC cells treated with BI2536 or DDP alone or in combination. Checkpoint activation was examined by immunoblotting and immunohistochemistry. Xenograft model was used to assess the efficacy of the co-treatment. The expression level of GSDME in tissue samples were examined by immunohistochemistry.

FINDINGS

We found that the combination of BI2536 and DDP was synergistic in ESCC cells, which induced pyroptosis in ESCC cells at low doses. Mechanistic studies revealed that BI2536 significantly induced DNA damage and impaired the DNA damage repair pathway in DDP-treated cells both in vitro and in vivo. Interestingly, we found that co-treatment with BI2536 and DDP induced pyroptosis in ESCC cells depending on the caspase-3/GSDME pathway. Importantly, our study found that GSDME was more highly expressed in tumour tissue than that in normal adjacent tissues, and could serve as a prognostic factor.

INTERPRETATION

BI2536 sensitizes ESCC cells to DDP by inhibiting the DNA damage repair pathway and inducing pyroptosis, which provides new information for understanding pyroptosis. Our study also reveals that the PLK1 inhibitor BI2536 may be an attractive candidate for ESCC targeted therapy, especially when combined with DDP for treating the GSDME overexpression subtype. FUND: National 973 Program and National Natural Science Fundation of China.

EGFR and MET Amplifications Determine Response to HER2 Inhibition in ERBB2-Amplified Esophagogastric Cancer

The anti-HER2 antibody trastuzumab is standard care for advanced esophagogastric (EG) cancer with ERBB2 (HER2) amplification or overexpression, but intrinsic and acquired resistance are common. We conducted a phase II study of afatinib, an irreversible pan-HER kinase inhibitor, in trastuzumab-resistant EG cancer. We analyzed pretreatment tumor biopsies and, in select cases, performed comprehensive characterization of postmortem metastatic specimens following acquisition of drug resistance. Afatinib response was associated with coamplification of EGFR and ERBB2. Heterogeneous 89Zr-trastuzumab PET uptake was associated with genomic heterogeneity and mixed clinical response to afatinib. Resistance to afatinib was associated with selection for tumor cells lacking EGFR amplification or with acquisition of MET amplification, which could be detected in plasma cell-free DNA. The combination of afatinib and a MET inhibitor induced complete tumor regression in ERBB2 and MET coamplified patient-derived xenograft models established from a metastatic lesion progressing on afatinib. Collectively, differential intrapatient and interpatient expression of HER2, EGFR, and MET may determine clinical response to HER kinase inhibitors in ERBB2-amplified EG cancer. SIGNIFICANCE: Analysis of patients with ERBB2-amplified, trastuzumab-resistant EG cancer who were treated with the HER kinase inhibitor afatinib revealed that sensitivity and resistance to therapy were associated with EGFR/ERBB2 coamplification and MET amplification, respectively. HER2-directed PET imaging and cell-free DNA sequencing could help guide strategies to overcome the emergence of resistant clones.See related commentary by Klempner and Catenacci, p. 166.This article is highlighted in the In This Issue feature, p. 151.

Advances in molecular, genetic and immune signatures of gastric cancer: Are we ready to apply them in our patients' decision making?

In the last few years we have witnessed a vast expansion of our knowledge regarding the molecular and genetic profile of gastric cancer. The molecular subtypes described have shed light on the pathogenesis of the disease, thus prompting the development of new therapeutic strategies and favoring a more individualized approach for treatment. Most of the clinical trials for so called targeted therapies could be considered, at best, partially successful. In addition, checkpoint inhibitors have recently been added to our armamentarium in later stages of the disease, and combinations with chemotherapy and targeted agents are currently under development. In view of the rapid advances of molecular oncology, a new challenge for the clinical oncologist arises: The appropriate patient selection for each new therapy, which can be made possible only through the implementation of predictive biomarkers in our therapy decision making.

Targeted Therapies for Targeted Populations: Anti-EGFR Treatment for EGFR-Amplified Gastroesophageal Adenocarcinoma

Previous anti-EGFR trials in unselected patients with gastroesophageal adenocarcinoma (GEA) were resoundingly negative. We identified EGFR amplification in 5% (19/363) of patients at the University of Chicago, including 6% (8/140) who were prospectively screened with intention-to-treat using anti-EGFR therapy. Seven patients received ≥1 dose of treatment: three first-line FOLFOX plus ABT-806, one second-line FOLFIRI plus cetuximab, and three third/fourth-line cetuximab alone. Treatment achieved objective response in 58% (4/7) and disease control in 100% (7/7) with a median progression-free survival of 10 months. Pretreatment and posttreatment tumor next-generation sequencing (NGS), serial plasma circulating tumor DNA (ctDNA) NGS, and tumor IHC/FISH for EGFR revealed preexisting and/or acquired genomic events, including EGFR-negative clones, PTEN deletion, KRAS amplification/mutation, NRAS, MYC, and HER2 amplification, and GNAS mutations serving as mechanisms of resistance. Two evaluable patients demonstrated interval increase of CD3+ infiltrate, including one who demonstrated increased NKp46+, and PD-L1 IHC expression from baseline, suggesting an immune therapeutic mechanism of action. EGFR amplification predicted benefit from anti-EGFR therapy, albeit until various resistance mechanisms emerged.Significance: This paper highlights the role of EGFR inhibitors in EGFR-amplified GEA-despite negative results in prior unselected phase III trials. Using serial ctDNA and tissue NGS, we identified mechanisms of primary and acquired resistance in all patients, as well as potential contribution of antibody-dependent cell-mediated cytotoxicity to their clinical benefit. Cancer Discov; 8(6); 696-713. ©2018 AACR.See related commentary by Strickler, p. 679This article is highlighted in the In This Issue feature, p. 663.

New agents on the horizon in gastric cancer

Background

Conventional cytotoxic chemotherapy has been the backbone of advanced gastric cancer treatment for decades and still represents a key element of the therapeutic armamentarium. However, only small increments in survival outcomes have been reached. A better understanding of genetic alterations and molecular signatures of gastric cancer has been reached in the last years. It will serve as a roadmap for better treatment stratification and future drug development.

Materials and methods

We reviewed preclinical and clinical studies that assessed novel treatment targets and emerging drug therapies in gastric cancer. We performed research via PubMed, and the congress webpages of the American Society of Clinical Oncology, European Society of Medical Oncology and the Japanese Society of Medical Oncology.

Results

HER2-targeting with trastuzumab is effective in HER2-positive metastatic gastric cancer; combined HER2 targeting strategies are being investigated. Studies assessing the role of HER2 targeting in the perioperative setting are ongoing. Novel treatment targets include inhibition of cancer stemness-related signaling pathways like STAT3. DNA damage repair and Claudin 18.2, a tight junction protein with high expression in gastric cancers are also novel molecular drug targets. Modification of the tumor microenvironment, including activation of immune response by PD-1/PD-L1 checkpoint inhibitors and stroma modification by matrix metalloproteinase-9 inhibition, led to first promising treatment results.

Conclusion

Novel treatment options for gastric cancer patients are emerging. They involve novel mechanisms of action, and are based on our constantly increasing understanding of tumor biology and better molecular stratification of gastric cancer patients.

Novel Targeted Therapies for Esophagogastric Cancer

Gastroesophageal cancer (GEC) remains a major cause of cancer-related mortality worldwide. Although the incidence of distal gastric adenocarcinoma (GC) is declining in the United States, proximal esophagogastric junction adenocarcinoma (EGJ) is increasing in incidence. GEC, including GC and EGJ, is treated uniformly in the metastatic setting. Overall survival in the metastatic setting remains poor. Molecular characterization of GEC has identified mutations and copy number variations, along with other oncogenes, biomarkers, and immuno-oncologic checkpoints that may serve as actionable therapeutic targets. This article reviews these key aberrations, their impact on protein expression, therapeutic implications, and clinical directions within each pathway.

Novel metastatic models of esophageal adenocarcinoma derived from FLO-1 cells highlight the importance of E-cadherin in cancer metastasis

There is currently a paucity of preclinical models available to study the metastatic process in esophageal cancer. Here we report FLO-1, and its isogenic derivative FLO-1LM, as two spontaneously metastatic cell line models of human esophageal adenocarcinoma. We show that FLO-1 has undergone epithelial-mesenchymal transition and metastasizes following subcutaneous injection in mice. FLO-1LM, derived from a FLO-1 liver metastasis, has markedly enhanced proliferative, clonogenic, anti-apoptotic, invasive, immune-tolerant and metastatic potential. Genome-wide RNAseq profiling revealed a significant enrichment of metastasis-related pathways in FLO-1LM cells. Moreover, CDH1, which encodes the adhesion molecule E-cadherin, was the most significantly downregulated gene in FLO-1LM compared to FLO-1. Consistent with this, repression of E-cadherin expression in FLO-1 cells resulted in increased metastatic activity. Importantly, reduced E-cadherin expression is commonly reported in esophageal adenocarcinoma and independently predicts poor patient survival. Collectively, these findings highlight the biological importance of E-cadherin activity in the pathogenesis of metastatic esophageal adenocarcinoma and validate the utility of FLO-1 parental and FLO-1LM cells as preclinical models of metastasis in this disease.

Characterization and validation of potential therapeutic targets based on the molecular signature of patient-derived xenografts in gastric cancer

Background

Patient-derived xenograft (PDX) models with definite molecular signature are attractive preclinical models for development of novel targeted drugs. Here, we profiled and explored potential therapeutic targets based on characterized PDX models for advanced gastric cancer (AGC).

Methods

The genomic variation and molecular profile of 50 PDX models from AGC patients were analyzed by targeted next-generation sequencing, in situ hybridization, and immunohistochemistry. The antitumor activities of several targeted drugs were investigated in the PDX models. Furthermore, response biomarkers were explored.

Results

Each PDX model had individual histopathological and molecular features, and recurrent alterations in the MAPK, ErbB, VEGF, mTOR, and cell cycle signaling pathways were major events in these PDX models. Several potential drug targets, such as EGFR, MET, and CCNE1, were selected and validated in this study. Volitinib demonstrated strong antitumor activity in PDX models with MET and phosphorylated MET (pMET) overexpression. The EGFR monoclonal antibodies BK011 and cetuximab inhibited tumor growth in a PDX model with EGFR amplification. Afatinib inhibited tumor growth in the PDX models with EGFR amplification, EGFR overexpression, or HER2 amplification. Apatinib was more sensitive in the PDX models with high microvessel density. The CDK1/2/9 inhibitor AZD5438 had superior anti-tumor activity in two models with higher copy number of CCNE1.

Conclusions

PDX models with defined molecular signature are useful for preclinical studies with targeted drugs, and the results should be validated in larger studies with PDX models or in clinical trials.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0563-y) contains supplementary material, which is available to authorized users.

The role of anti-EGFR agents in the first-line treatment of advanced esophago-gastric adenocarcinoma: a meta-analysis

The role of anti-epidermal growth factor receptor (EGFR) therapy is controversial in patients with esophago-gastric adenocarcinoma. We performed this meta-analysis to evaluate whether the addition of an anti-EGFR agent to chemotherapy can produce survival benefits in patients with advanced esophageal adenocarcinoma, gastric adenocarcinoma, or gastroesophageal junction adenocarcinoma. Electronic databases were searched for eligible randomized studies. From six studies, 1,817 patients were included in the meta-analysis of hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS). Compared with chemotherapy alone, anti-EGFR agents in combination with chemotherapy were significantly associated with shorter PFS (HR = 1.14 [95% confidence interval {CI}, 1.01-1.28], P = 0.03). In terms of OS, the addition of an anti-EGFR agent to chemotherapy showed no advantage (HR = 1.10 [95% CI, 0.98-1.23], P = 0.11). In addition, the combination of an anti-EGFR agent with chemotherapy significantly increased some grade 3/4 toxicities including diarrhea (risk ratio {RR} = 1.42, [95% CI, 1.03-1.94], P = 0.03), mucositis (RR = 3.30 [95% CI, 1.54-7.07], P = 0.002), and skin rash (RR = 6.82 [95% CI, 3.15-14.78], P < 0.00001). In conclusion, this meta-analysis indicates that the addition of an anti-EGFR agent to chemotherapy conveys no additional benefit for patients with advanced esophago-gastric adenocarcinoma. As of now, anti-EGFR agents should not be used in the first-line treatment of adenocarcinoma of the upper gastrointestinal tract.

Insights into next developments in advanced gastric cancer

PURPOSE OF REVIEW

The purpose of the review is to delineate novel approaches for biology-based treatment in advanced gastric cancer. We reviewed the latest translational and clinical research articles and congress presentations.

RECENT FINDINGS

A new molecular classification of gastric cancer based on histology, genetic and proteomic alterations has evolved. It provides a roadmap for development of new drugs and combinations and for patient stratification. Anti-HER2 treatment, which is an effective strategy in metastatic gastric cancer, is now also being studied in the perioperative setting. However, resistance mechanisms in advanced disease are poorly understood and optimal patient selection remains challenging. Targeting angiogenesis is an emerging concept in the management of advanced gastric cancer, and ramucirumab has prolonged survival in the second line either as a monotherapy or in combination with paclitaxel. Biomarkers for selecting patients who benefit from ramucirumab are still lacking. Immune checkpoint blockade and inhibition of cancer stemness targets are other emerging directions for the medical treatment of gastric cancer. Large-scale international studies are ongoing.

SUMMARY

Promising biology-based treatment strategies are evolving. But tumor heterogeneity which is an inherent feature of gastric cancer challenges the development of molecularly targeted and personalized treatment strategies.

Update on Gastroesophageal Adenocarcinoma Targeted Therapies

Gastroesophageal cancer (GEC) remains a major cause of cancer-related mortality worldwide. Although the incidence of distal gastric adenocarcinoma (GC) is declining in the United States, proximal esophagogastric junction adenocarcinoma (EGJ) incidence is rising. GC and EGJ, together, are treated uniformly in the metastatic setting as GEC. Overall survival in the metastatic setting remains poor, with few molecular targeted approaches having been successfully incorporated into routine care to date-only first-line anti-HER2 therapy for ERBB2 amplification and second-line anti-VEGFR2 therapy. This article reviews aberrations in epidermal growth factor receptor, MET, and ERBB2, their therapeutic implications, and future directions in targeting these pathways.

p-Akt as a potential poor prognostic factor for gastric cancer: a systematic review and meta-analysis

To understand the relationship between p-Akt expression and the prognosis of patients with gastric cancer, we searched six databases, Pubmed, EMBASE, Cochrane Library, CNKI, Wanfang and CBM for relevant articles in order to conduct this metaanalysis. The pooled hazard ratios and corresponding 95%CI of overall survival were calculated to evaluate the prognostic value of p-Akt expression in patients with gastric cancer. With 2261 patients combined from 13 available studies, the pooled HR showed a poor prognosis in patients with gastric cancer in the univariate analysis (HR=1.88, 95%CI:1.45-2.43, P<0.00001), and the group "univariate analysis+estimate" (HR=1.41, 95%CI: 1.01-1.97, P=0.04), but not in multivariate analysis (HR=0.66, 95%CI: 0.29-1.52, P=0.33) and estimate (HR=1.13, 95%CI: 0.65-1.95, P=0.67). In conclusion, our results indicated that p-Akt was likely to be an indicator of poor prognosis in patients with gastric cancer.

A multi-center phase II study and biomarker analysis of combined cetuximab and modified FOLFIRI as second-line treatment in patients with metastatic gastric cancer

BACKGROUND

To evaluate the efficacy of cetuximab combined with modified FOLFIRI (mFOLFIRI) as a second-line treatment in metastatic gastric cancer patients and to identify potential biomarkers of clinical outcomes.

METHODS

All 61 patients received an initial intravenous (IV) dose of cetuximab (400 mg/m²) and weekly doses (250 mg/m²) thereafter, starting on day 1. On day 2 of each 14-day period, patients received IV irinotecan (180 mg/m²), leucovorin (200 mg/m²), and an IV bolus dose of 5-FU (400 mg/m²) followed by a continuous infusion of 5-FU (2400 mg/m²) for 46 h. The primary endpoint was time-to-progression (TTP).

RESULTS

The response rate (RR) was 33.3% among 54 evaluable patients. In the intention-to-treat analysis, median TTP was 4.6 months (95% confidential interval [CI]: 3.6-5.6 months) and median overall survival (OS) was 8.6 months (95% CI: 7.3-9.9 months). In univariate analyses, plasma vascular endothelial growth factor (VEGF) levels were correlated with clinical outcome. In patients with low (≤12.6 pg/ml) and high (>12.6 pg/ml) baseline plasma VEGF levels, RR values were 55.0% and 5.3%, respectively (P = 0.001); median TTP values were 6.9 months and 2.8 months, respectively (P = 0.0005); and median OS values were 12 months and 5 months, respectively (P <0.0001). None of these patients exhibited KRAS, BRAF, or PIK3CA mutations.

CONCLUSIONS

Combination therapy comprising cetuximab and mFOLFIRI was well tolerated and active as a second-line treatment for patients with metastatic gastric cancer. Patients with low baseline plasma VEGF levels were associated with better clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT00699881 . Registered 17 June 2008 (retrospectively registered).

Clinical impact of tumour biology in the management of gastroesophageal cancer

The characterization of oesophageal and gastric cancer into subtypes based on genotype has evolved in the past decade. Insights into the molecular landscapes of gastroesophageal cancer provide a roadmap to assist the development of new drugs and their use in combinations, for patient stratification, and for trials of targeted therapies. Trastuzumab is the only approved treatment for gastroesophageal cancers that overexpress HER2. Acquired resistance usually limits the duration of response to this treatment, although a number of new agents directed against HER2 have the potential to overcome or prolong the time until resistance occurs. Beyond that, anti-VEGFR2 therapy with ramucirumab was the first biological treatment strategy to produce a survival benefit in an unselected population of patients with chemotherapy-refractory gastroesophageal cancer. Large initiatives are starting to address the role of biomarker-driven targeted therapy in the metastatic and in the perioperative setting for patients with this disease. Immunotherapy also holds promise, and our understanding of subsets of gastroesophageal cancer based on patterns of immune response continues to evolve. Efforts are underway to identify more relevant genomic subsets through genomic screening, functional studies, and molecular characterization. Herein, we provide an overview of the key developments in the treatment of gastroesophageal cancer, and discuss potential strategies to further optimize therapy by targeting disease subtypes.

High EGFR and low p-Akt expression is associated with better outcome after nimotuzumab-containing treatment in esophageal cancer patients: preliminary clinical result and testable hypothesis

The epidermal growth factor receptor (EGFR) is widely overexpressed in esophageal squamous cell carcinoma (ESCC) and it results is associated with a poor prognosis. Identifying the subgroup of ESCC patients who are sensitive to EGFR-targeted therapy is a key point to facilitate its medical use.

We retrospectively analyzed 32 ESCC patients treated with the combination of nimotuzumab (h-R3) and radiotherapy (RT) or chemoradiotherapy (CRT). Expression of EGFR and phosphorylated proteins associated with EGFR signaling pathway, i.e. p-Akt and p-Erk, were assessed with immunohistochemistry (IHC) for all patients. Correlations between these proteins' expression levels and overall survival (OS) were assessed.

High expression of EGFR, p-Akt and p-Erk was detected in 53.1% (17/32), 54.8% (17/31) and 59.4% (19/32) of tumors respectively. No significant differences in OS were found between high EGFR, p-Akt and p-Erk expression groups and their respective counterparts. Of note, significantly better overall survival was observed in patients with coexistence of high EGFR expression and low p-Akt expression (p = 0.030).

Our data allowed us to put forward a hypothesis that high EGFR and low p-Akt expression may predict a clinical benefit of EGFR antagonists such as nimotuzumab combined with RT or CRT. This can be discussed in the terms of oncogene addiction and synthetic lethality concepts. This hypothesis can be further tested in larger groups of patients.

Expression and Prognostic Significance of Human Epidermal Growth Factor Receptors 1 and 3 in Gastric and Esophageal Adenocarcinoma

Background

Gastric and esophageal adenocarcinomas are major global cancer burdens. These cancer forms are characterized by a poor prognosis and a modest response to chemo- radio- and targeted treatment. Hence there is an obvious need for further enhanced diagnostic and treatment strategies. The aim of this study was to examine the expression and prognostic impact of human epidermal growth factor receptor 1 (HER1/EGFR) and 3 (HER3), as well as the occurrence of EGFR and KRAS mutations in gastric and esophageal adenocarcinoma.

Methods

Immunohistochemical expression of EGFR and HER3 was analysed in all primary tumours and a subset of lymph node metastases in a consecutive cohort of 174 patients with adenocarcinoma of the stomach, cardia and esophagus. The anti-HER3 antibody used was validated by siRNA-mediated knockdown, immunohistochemistry and quantitative real-time PCR. EGFR and KRAS mutation status was analysed by pyrosequencing tecchnology.

Results and Discussion

High EGFR expression was an independent risk factor for shorter overall survival (OS), whereas high HER3 expression was associated with a borderline significant trend towards a longer OS. KRAS mutations were present in only 4% of the tumours and had no prognostic impact. All tumours were EGFR wild-type. These findings contribute to the ongoing efforts to decide on the potential clinical value of different HERs and druggable mutations in gastric and esophageal adenocarcinomas, and attention is drawn to the need for more standardised investigational methods.

Monoclonal antibodies-based treatment in gastric cancer: current status and future perspectives

Gastric cancer (GC) is the second leading cause of cancer-related death, and despite having improved treatment modalities over the last decade, for most patients, only modest improvements have been seen in overall survival. Recent progress in understanding the molecular biology of GC and the related signaling pathways offers, from the clinical point of view, promising advances for selected groups of patients. In the past, targeted therapies have significantly impacted the treatment strategy of several common solid tumors such as breast, colorectal, and lung cancers. Unfortunately, translational and clinical research shows fewer encouraging targeted treatments with regards to the GC. To date, only two monoclonal antibodies (mAb), named trastuzumab and ramucirumab, are approved for the treatment of advanced GC, suggesting that in GC, maybe more than in other cancers, effective targeted therapy requires patient selection based on precise predictive molecular biomarkers. The aim of this review is to summarize the available data on the clinical advantages offered by the use of mAbs in the treatment of advanced/metastatic GC. Future perspective is also discussed.

Gene copy number gain of EGFR is a poor prognostic biomarker in gastric cancer: evaluation of 855 patients with bright-field dual in situ hybridization (DISH) method

BACKGROUND

EGFR overexpression is a prognostic biomarker and is expected to be a predictive biomarker for anti-EGFR therapies in gastric cancer. However, few studies have reported the clinical impact of EGFR gene copy number (GCN) and its correlation with EGFR overexpression.

METHODS

We used dual in situ hybridization (DISH) to detect EGFR GCN and chromosome 7 centromere (CEN7) in a set of tissue microarrays representing 855 patients with gastric cancer. These data were compared with those of immunohistochemical (IHC) analysis of EGFR expression to evaluate prognostic value.

RESULTS

EGFR GCN gain (≥ 2.5 EGFR signals per cell) was detected in 194 patients (22.7%) and indicated poor prognosis. Among 194 patients, EGFR amplification (EGFR/CEN7 ≥ 2.0) was observed in 29 patients (14.9%), which was almost identical to the IHC 3+ subgroup and worst prognostic subgroup. Patients with EGFR GCN gain but not amplification, including those exhibiting polysomy, also exhibited poorer prognosis than GCN non-gain patients and were distributed between IHC 0/1+ and 2+ subgroups. GCN gain was frequently observed in patients with more advanced disease, but served as an independent prognostic factor regardless of the pathological stage.

CONCLUSIONS

EGFR GCN gain is a more accurate prognostic biomarker than EGFR overexpression in patients with gastric cancer.

Relevance of MET activation and genetic alterations of KRAS and E-cadherin for cetuximab sensitivity of gastric cancer cell lines

PURPOSE

The therapeutic activity of the epidermal growth factor receptor (EGFR)-directed monoclonal antibody cetuximab in gastric cancer is currently being investigated. Reliable biomarkers for the identification of patients who are likely to benefit from the treatment are not available. The aim of the study was to examine the drug sensitivity of five gastric cancer cell lines towards cetuximab as a single agent and to establish predictive markers for chemosensitivity in this cell culture model. The effect of a combination of cetuximab with chemotherapy was compared between a sensitive and a nonsensitive cell line.

METHODS

EGFR expression, activation and localisation, the presence and subcellular localisation of the cell adhesion molecule E-cadherin as well as MET activation were examined by Western blot analysis, flow cytometry and immunofluorescence staining. Cells were treated with varying concentrations of cetuximab and cisplatin and 5-fluorouracil in tumour-relevant concentrations. The biological endpoint was cell viability, which was measured by XTT cell proliferation assay. Response to treatment was evaluated using statistical methods.

RESULTS

We assessed the activity of cetuximab in five gastric cancer cell lines (AGS, KATOIII, MKN1, MKN28 and MKN45). The viability of two cell lines, MKN1 and MKN28, was significantly reduced by cetuximab treatment. High EGFR expression and low levels of receptor activation were associated with cetuximab responsiveness. MET activation as well as mutations of KRAS and CDH1 (gene encoding E-cadherin) was associated with cetuximab resistance.

CONCLUSION

These data indicate that our examinations may be clinically relevant, and the candidate markers should therefore be tested in clinical studies.

Epidermal growth factor receptor immunohistochemistry: new opportunities in metastatic colorectal cancer

The treatment of cancer is becoming more precise, targeting specific oncogenic drivers with targeted molecular therapies. The epidermal growth factor receptor has been found to be over-expressed in a multitude of solid tumours. Immunohistochemistry is widely used in the fields of diagnostic and personalised medicine to localise and visualise disease specific proteins. To date the clinical utility of epidermal growth factor receptor immunohistochemistry in determining monoclonal antibody efficacy has remained somewhat inconclusive. The lack of an agreed reproducible scoring criteria for epidermal growth factor receptor immunohistochemistry has, in various clinical trials yielded conflicting results as to the use of epidermal growth factor receptor immunohistochemistry assay as a companion diagnostic. This has resulted in this test being removed from the licence for the drug panitumumab and not performed in clinical practice for cetuximab. In this review we explore the reasons behind this with a particular emphasis on colorectal cancer, and to suggest a way of resolving the situation through improving the precision of epidermal growth factor receptor immunohistochemistry with quantitative image analysis of digitised images complemented with companion molecular morphological techniques such as in situ hybridisation and section based gene mutation analysis.

Current status of novel agents in advanced gastroesophageal adenocarcinoma

Gastroesophageal (GE) adenocarcinomas are highly lethal malignancies and despite multiple chemotherapy options, 5-year survival rates remain dismal. Chemotherapy is the mainstay of treatment but patients are often limited by toxicity and poor performance status. Because of molecular heterogeneity, it is essential to classify tumors based on the underlying oncogenic pathways and develop targeted therapies that act on individual tumors. Trastuzumab, a human epidermal growth factor receptor type 2 (HER2) monoclonal antibody, was the first such agent shown to improve response rate, progression free survival (PFS), and overall survival (OS) when added to cisplatin based chemotherapy in patients with HER2 over-expressing GE junction (GEJ) and gastric adenocarcinomas. However, HER2 over expressing GE tumors are in the minority and the need for additional targeted agents is urgent. Though many agents are in development, incorporating targeted therapy in the treatment of GE cancers comes with a unique set of challenges. In this review, we outline oncogenic pathways relevant to GE adenocarcinomas, including HER2, epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and c-Met, and discuss recent trials with agents targeting these pathways.

Proteomic and metabolic prediction of response to therapy in gastric cancer

Several new treatment options for gastric cancer have been introduced but the prognosis of patients diagnosed with gastric cancer is still poor. Disease prognosis could be improved for high-risk individuals by implementing earlier screenings. Because many patients are asymptomatic during the early stages of gastric cancer, the diagnosis is often delayed and patients present with unresectable locally advanced or metastatic disease. Cytotoxic treatment has been shown to prolong survival in general, but not all patients are responders. The application of targeted therapies and multimodal treatment has improved prognosis for those with advanced disease. However, these new therapeutic strategies do not uniformly benefit all patients. Predicting whether patients will respond to specific therapies would be of particular value and would allow for stratifying patients for personalized treatment strategies. Metabolic imaging by positron emission tomography was the first technique with the potential to predict the response of esophago-gastric cancer to neoadjuvant therapy. Exploring and validating tissue-based biomarkers are ongoing processes. In this review, we discuss the status of several targeted therapies for gastric cancer, as well as proteomic and metabolic methods for investigating biomarkers for therapy response prediction in gastric cancer.

A systematic review and meta-analysis of somatic and germline DNA sequence biomarkers of esophageal cancer survival, therapy response and stage

Recent advances in next generation sequencing reinforce the potential for DNA sequence markers to guide esophageal cancer management. We report the first systematic review and meta-analysis, identifying 94 markers of outcome and 41 of stage. Overall, evidence was poor. Meta-analyses demonstrated outcome associations for 6 tumor and 9 germline variants: priorities for prospective evaluation.

Introduction

There is an urgent need for biomarkers to help predict prognosis and guide management of esophageal cancer. This review identifies, evaluates and meta-analyses the evidence for reported somatic and germline DNA sequence biomarkers of outcome and stage.

Methods

A systematic review was carried out of the PubMed, EMBASE and Cochrane databases (20 August 2014), in conjunction with the ASCO Level of Evidence scale for biomarker research. Meta-analyses were carried out for all reported markers associated with outcome measures by more than one study.

Results

Four thousand and four articles were identified, 762 retrieved and 182 studies included. There were 65 reported markers of survival or recurrence 12 (18.5%) were excluded due to multiple comparisons. Following meta-analysis, significant associations were seen for six tumor variants (mutant TP53 and PIK3CA, copy number gain of ERBB2/HER2, CCND1 and FGF3, and chromosomal instability/ploidy) and seven germline polymorphisms: ERCC1 rs3212986, ERCC2 rs1799793, TP53 rs1042522, MDM2 rs2279744, TYMS rs34743033, ABCB1 rs1045642 and MTHFR rs1801133. Twelve germline markers of treatment complications were reported; 10 were excluded. Two tumor and 15 germline markers (11 excluded) of chemo (radio)therapy response were reported. Following meta-analysis, associations were demonstrated for mutant TP53, ERCC1 rs11615 and XRCC1 rs25487. There were 41 tumor/germline reported markers of stage; 27 (65.9%) were excluded.

Conclusions

Numerous DNA markers of outcome and stage have been reported, yet few are backed by high-quality evidence. Despite this, a small number of variants appear reliable. These merit evaluation in prospective trials, within the context of high-throughput sequencing and gene expression.

Correlation Between E-cadherin Immunoexpression and Efficacy of First Line Platinum-Based Chemotherapy in Advanced High Grade Serous Ovarian Cancer

To analyze correlation between immunoexpression of E-cadherin and efficacy of first line platinum-based chemotherapy in patients with advanced-stage high-grade serous ovarian carcinoma. The expression of E-cadherin was analyzed immunohistochemically in formalin-fixed, paraffin-embedded samples from 98 patients with advanced-stage high-grade serous ovarian cancer and related to clinical features (stage according to the International Federation of Gynecology and Obstetrics (FIGO) and residual tumors after initial cytoreductive surgery), response to platinum-based chemotherapy (according to Response Evaluation Criteria in Solid tumors (RECIST 1.1 criteria)), platinum sensitivity (according to platinum free interval (PFI) as platinum-refractory, platinum-resistant and platinum-sensitive) and patients progression free survival (PFS) and overall survival (OS). E-cadherin immunostaining was positive in 74 and negative in 24 serous ovarian carcinomas. E-cadherin immunoreactivity was not associated with FIGO stage, residual tumor after initial cytoreductive surgery and number of chemotherapy cycles. Positive E-cadherin expression predict significantly better response to first line platinum-based chemotherapy (p < 0.001) and platinum sensitivity (p < 0.001). Moreover, positive E-cadherin expression predict significantly longer PFS (p < 0.001) and OS (p < 0.001). The multivariate analysis for OS showed that positive E-cadherin expression is predictor to platinum sensitivity (p < 0.001) and longer OS (p = 0.01). Positive E-cadherin expression seems to be a predictor of better response to first line platinum-based chemotherapy, platinum sensitivity and favorable clinical outcome in patients with advanced-stage serous ovarian cancer. Negative E-cadherin expression was shown to be significant, independent predictor of poorer PFS and OS. E-cadherin as a marker has predictive and prognostic value.

Investigational therapies targeting the ErbB family in oesophagogastric cancer

INTRODUCTION

The prognosis for patients with oesophagogastric (OG) cancer remains poor, with a median survival of approximately 9 - 11 months for patients with metastatic disease. However, a more personalised approach to treatment, using drugs tailored to the molecular characteristics of patients' tumours, has the potential to improve patient outcomes. Drugs targeting the ErbB family of receptors have been developed, but these have had varying degrees of success in clinical practice.

AREAS COVERED

The authors provide an overview of the ErbB receptor family with regard to OG cancers. Furthermore, they evaluate the evidence from preclinical and clinical trials of therapeutics targeting this family, including monoclonal antibodies, tyrosine kinase inhibitors and novel agents.

EXPERT OPINION

Drugs targeting the ErbB family have been evaluated in OG cancer, with a notable success story in the case of trastuzumab, although there have been disappointing failures with anti-EGFR therapy. The response to targeted treatment remains variable and further biomarker research is essential to identify patients most likely to benefit from these therapies. The treatment of OG cancer remains challenging, but new anti-HER2 therapies and combination therapies hold promise for the future.

Innovative personalized medicine in gastric cancer: time to move forward

Globally, gastric cancer (GC) is the second leading cancer cause of death. To date, only one targeted therapy trial generated positive survival outcomes in a selected population among many targeted therapy trials. This trial showed the addition of trastuzumab to fluoropyrimidine/platinum chemotherapy as first-line chemotherapy for human epidermal growth factor receptor 2 (HER2)-positive GC that resulted in an overall survival (OS) benefit. The increasing use of next generation sequencing approach to genomically profile GC patients allows the identification of many more GC patients who could benefit from specific targeted agents. Here we provide a comprehensive review of targeted therapy trials in GC and discuss future potential actionable driver mutations in GC.

EGFR, HER2 and HER3 dimerization patterns guide targeted inhibition in two histotypes of esophageal cancer

Receptor tyrosine kinases (RTKs) are in the focus of targeted therapy for epithelial tumors. Our study addressed the role of EGFR, HER2 and HER3 expression and dimerization in esophageal cancers in situ and in vitro in the context of therapeutic EGFR and HER2 inhibitors. In archival pretreatment biopsies of esophageal carcinomas (n = 110), EGFR was preferentially expressed in esophageal squamous cell carcinomas (ESCCs) (22.4%; p = 0.088) and HER2 (34.4%; p < 0.001) with HER3 (91.5%; p < 0.001) in esophageal (Barrett's) adenocarcinomas (EACs). In situ proximity ligation assays revealed mainly EGFR and HER2 homodimers in ESCC and EAC cases, respectively. However, EAC cases also exhibited HER2/HER3 heterodimers. In vitro ESCC (OE21) cells displayed a significant response to erlotinib, gefitinib and lapatinib, with loss of AKT phosphorylation, G0/G1 cell cycle arrest and induction of apoptosis. In EAC cells (OE19, OE33 and SK-GT-4), lapatinib was similarly effective in strongly HER2-positive (mainly HER2 homodimers and some HER2/EGFR heterodimers) OE19 and OE33 cells. The HER2-targeting antibodies (trastuzumab and pertuzumab) given alone were largely ineffective in ESCC and EAC cells. However, both antibodies significantly induced antibody-dependent cellular cytotoxicity in EAC (OE19 and OE33) cells upon co-culture with peripheral blood mononuclear cells. The study reveals that overexpression of EGFR and HER2 predominantly results in homodimers in ESCCs and EACs, respectively. Still, some EACs also show HER2 dimerization plasticity, e.g., with HER3. Such RTK dimerization patterns affect responses to EGFR and HER2 targeting inhibitors in ESCC and EAC cells in vitro and hence may influence future prediction for particularly HER2-targeting inhibitors in EACs.

Optimal chemotherapy for advanced gastric cancer: is there a global consensus?

The optimal medical treatment for advanced gastric cancer is currently the source of debate. Cytotoxic treatment has been shown to prolong survival and provide improved symptom control compared with best supportive care alone, but a global standard has not yet been defined. A literature research was undertaken. Results were evaluated by an international author team. The conclusions of this are presented in this paper. Combination chemotherapy with cisplatin and 5-fluorouracil was the preferred first-line chemotherapy, but oxaliplatin has shown equivalent efficacy to cisplatin. Oral fluoropyrimidines, especially S-1 and capecitabine, can substitute for 5-fluorouracil. Modern doublet regimens are preferred in the majority of patients on the basis of a balanced benefit-to-risk ratio. In selected fit and compliant patients, especially those with a high tumor burden or potential secondary resectability, a third drug may be added because triplet chemotherapy led to higher responses rates and enhanced efficacy. However, docetaxel also adds a significant increase in side effects. Monotherapy and early dose modifications should be considered in elderly and infirm patients. Beyond that, our understanding of gastric cancer tumor biology is increasing. In HER2-positive gastric cancer, the addition of the monoclononal anti-HER2 antibody trastuzumab to cisplatin and fluoropyrimidines has prolonged survival duration. Second-line chemotherapy with single agents has now become a proven treatment option. Alternatively, anti-angiogenic treatment with ramucirumab is on the horizon. In conclusion, combination chemotherapy is regarded as the global standard of care for the first-line treatment of advanced gastric cancer. Molecularly targeted treatments are being explored, preferably in combination with a backbone of chemotherapy doublets.

Esophageal carcinoma: are modern targeted therapies shaking the rock?

PURPOSE OF REVIEW

Our current review aims to outline recent progress in the development of modern targeted therapeutic regimens for esophageal cancer.

RECENT FINDINGS

Esophageal cancers demonstrate marked molecular heterogeneity. Modern technology increasingly allows us to identify subgroups of patients whose tumors fit particular molecular profiles. Tumor-based human epidermal growth factor receptor 2 (HER-2) analysis has become a standard part of the work-up for patients with tumors of the esophagogastric junction. The anti-HER-2 antibody, trastuzumab, when added to a chemotherapeutic regimen combining a fluoropyrimidine and platinum, provides a survival benefit for those patients with HER-2 overexpression and/or amplification. Despite large coordinated efforts to establish the efficacy of additional targeted therapeutics, to this point minimal additional benefit has been realized in affecting prominent molecular targets, such as vascular endothelial growth factor and epidermal growth factor receptor, in esophageal cancer. Multiple targets of interest remain under investigation with some early encouraging data. These targets include mammalian target of rapamycin, c-MET, insulin like growth factor 1 receptor and cytotoxic T-lymphocyte antigen 4. Additional improvements in therapy may stem from improved patient selection for combinations of standard cytotoxic regimens, such as platinum-based regimens.

SUMMARY

Targeted therapeutics have yielded early benefit, but further progress will require a deeper understanding of this disease, improved identification of subpopulations who may derive greater benefit, and continued multicenter efforts to conduct the necessary clinical investigations.

A subset of gastric cancers with EGFR amplification and overexpression respond to cetuximab therapy

A preclinical trial identified 4 of 20 (20%) gastric cancer (GC) patient-derived xenografts responded to cetuximab. Genome-wide profiling and additional investigations revealed that high EGFR mRNA expression and immunohistochemistry score (3+) are associated with tumor growth inhibition. Furthermore, EGFR amplification were observed in 2/4 (50%) responders with average copy number 5.8 and >15 respectively. Our data suggest that a GC subtype with EGFR amplification and overexpression benefit from cetuximab treatment.

Capecitabine and cisplatin with or without cetuximab for patients with previously untreated advanced gastric cancer (EXPAND): a randomised, open-label phase 3 trial

BACKGROUND

Patients with advanced gastric cancer have a poor prognosis and few efficacious treatment options. We aimed to assess the addition of cetuximab to capecitabine-cisplatin chemotherapy in patients with advanced gastric or gastro-oesophageal junction cancer.

METHODS

In our open-label, randomised phase 3 trial (EXPAND), we enrolled adults aged 18 years or older with histologically confirmed locally advanced unresectable (M0) or metastatic (M1) adenocarcinoma of the stomach or gastro-oesophageal junction. We enrolled patients at 164 sites (teaching hospitals and clinics) in 25 countries, and randomly assigned eligible participants (1:1) to receive first-line chemotherapy with or without cetuximab. Randomisation was done with a permuted block randomisation procedure (variable block size), stratified by disease stage (M0 vs M1), previous oesophagectomy or gastrectomy (yes vs no), and previous (neo)adjuvant (radio)chemotherapy (yes vs no). Treatment consisted of 3-week cycles of twice-daily capecitabine 1000 mg/m(2) (on days 1-14) and intravenous cisplatin 80 mg/m(2) (on day 1), with or without weekly cetuximab (400 mg/m(2) initial infusion on day 1 followed by 250 mg/m(2) per week thereafter). The primary endpoint was progression-free survival (PFS), assessed by a masked independent review committee in the intention-to-treat population. We assessed safety in all patients who received at least one dose of study drug. This study is registered at EudraCT, number 2007-004219-75.

FINDINGS

Between June 30, 2008, and Dec 15, 2010, we enrolled 904 patients. Median PFS for 455 patients allocated capecitabine-cisplatin plus cetuximab was 4.4 months (95% CI 4.2-5.5) compared with 5.6 months (5.1-5.7) for 449 patients who were allocated to receive capecitabine-cisplatin alone (hazard ratio 1.09, 95% CI 0.92-1.29; p=0.32). 369 (83%) of 446 patients in the chemotherapy plus cetuximab group and 337 (77%) of 436 patients in the chemotherapy group had grade 3-4 adverse events, including grade 3-4 diarrhoea, hypokalaemia, hypomagnesaemia, rash, and hand-foot syndrome. Grade 3-4 neutropenia was more common in controls than in patients who received cetuximab. Incidence of grade 3-4 skin reactions and acne-like rash was substantially higher in the cetuximab-containing regimen than in the control regimen. 239 (54%) of 446 in the cetuximab group and 194 (44%) of 436 in the control group had any grade of serious adverse event.

INTERPRETATION

Addition of cetuximab to capecitabine-cisplatin provided no additional benefit to chemotherapy alone in the first-line treatment of advanced gastric cancer in our trial.

FUNDING

Merck KGaA.

Biomarker analysis in oesophagogastric cancer: Results from the REAL3 and TransMAGIC trials

BACKGROUND

REAL3 (Randomised ECF for Advanced or Locally advanced oesophagogastric cancer 3) was a phase II/III trial designed to evaluate the addition of panitumumab (P) to epirubicin, oxaliplatin and capecitabine (EOC) in untreated advanced oesophagogastric adenocarcinoma, or undifferentiated carcinoma. MAGIC (MRC Adjuvant Gastric Infusional Chemotherapy) was a phase III study which demonstrated that peri-operative epirubicin, cisplatin and infused 5-fluorouracil (ECF) improved survival in early oesophagogastric adenocarcinoma.

PATIENTS AND METHODS

Analysis of response rate (RR; the primary end-point of phase II) and biomarkers in the first 200 patients randomised to EOC or modified dose (m) EOC+P in REAL3 was pre-planned to determine if molecular selection for the on-going study was indicated. KRAS, BRAF and PIK3CA mutations and PTEN expression were assessed in pre-treatment biopsies and results correlated with response to mEOC+P. Association between these biomarkers and overall survival (OS) was assessed in MAGIC patients to determine any prognostic effect.

RESULTS

RR was 52% to mEOC+P, 48% to EOC. Results from 175 assessable biopsies: mutations in KRAS (5.7%), BRAF (0%), PIK3CA (2.5%) and loss of PTEN expression (15.0%). None of the biomarkers evaluated predicted resistance to mEOC+P. In MAGIC, mutations in KRAS, BRAF and PIK3CA and loss of PTEN (phosphatase and tensin homolog) were found in 6.3%, 1.0%, 5.0% and 10.9%, respectively, and were not associated with survival.

CONCLUSIONS

The RR of 52% in REAL3 with mEOC+P met pre-defined criteria to continue accrual to phase III. The frequency of the mutations was too low to exclude any prognostic or predictive effect.

Prognostic role of E-cadherin in patients with advanced serous ovarian cancer

PURPOSE

To analyse correlation between expression of E-cadherin and clinical and pathological features and overall survival in advanced-stage serous ovarian carcinoma.

METHODS

The expression of E-cadherin was analysed immunohistochemically in formalin-fixed, paraffin-embedded samples from 54 patients with advanced-stage serous ovarian cancer and related to clinicopathological characteristics and patients survival. The clinicopathological characteristics included the stage according to the International Federation of Gynecology and Obstetrics (FIGO), tumour differentiation, number of mitoses per 10 high-power fields (HPF), residual tumour size, and vascular invasion. Only patients with serous ovarian cancer FIGO stages III-IV were included. Overall survival (OS) was defined as time from surgery to the last follow-up date on 01.10.2010. OS was evaluated using Kaplan-Meier method, and log-rank test was used to asses the differences between the positive and E-cadherin negative group. Multivariate analysis was completed using the Cox proportional hazard regression model.

RESULTS

E-cadherin immunoreactivity was not associated with FIGO stage, tumour grade, number of mitotic figures per 10 HPF, residual tumour volume or vascular invasion. Negative E-cadherin expression significantly predicted shorter OS (p < 0.001). The multivariate analyses showed that negative E-cadherin (p < 0.001), FIGO stage (p = 0.012) and residual tumour size >1 cm after the initial cytoreductive surgery (p < 0.001) were predictors of shorter OS.

CONCLUSION

Negative E-cadherin expression like presence of residual tumour after primary cytoreductive surgery and higher FIGO stage seem to predict unfavourable clinical outcome in patients with advanced-stage serous ovarian cancer. Negative expression of E-cadherin was shown to be a significant independent predictor of poorer OS. E-cadherin as marker has prognostic value.

Epidermal growth factor receptor, phosphatidylinositol-3-kinase catalytic subunit/PTEN, and KRAS/NRAS/BRAF in primary resected esophageal adenocarcinomas: loss of PTEN is associated with worse clinical outcome

Alterations of the epidermal growth factor receptor (EGFR) can be observed in a significant subset of esophageal adenocarcinomas (EACs), and targeted therapy against EGFR may become an interesting approach for the treatment of these tumors. Mutations of KRAS, NRAS, BRAF, and phosphatidylinositol-3-kinase catalytic subunit (PIK3CA) and deregulation of PTEN expression influence the responsiveness against anti-EGFR therapy in colorectal carcinomas. We investigated the prevalence of these events in a collection of 117 primary resected EACs, correlated the findings with EGFR expression and amplification, and determined their clinicopathologic impact. KRAS mutations were detected in 4 (3%) of 117 tumors (3× G12D and 1 G12V mutation). One tumor had a PIK3CA E545K mutation. Neither NRAS nor BRAF mutations were detected. Sixteen (14%) of 117 cases were negative for PTEN expression, determined by immunohistochemistry. Loss of PTEN was observed predominantly in advanced tumor stages (P = .004). There was no association between PTEN and EGFR status. Loss of PTEN was associated with shorter overall and disease-free survival (P < .001 each) and also an independent prognostic factor in multivariate analysis (P = .015). EGFR status had no prognostic impact in this case collection. In summary, loss of PTEN can be detected in a significant subset of EAC and is associated with an aggressive phenotype. Therefore, PTEN may be useful as a prognostic biomarker. In contrast, mutations of RAS/RAF/PIK3CA appear only very rarely, if at all, in EAC. A possible predictive role of PTEN in anti-EGFR treatment warrants further investigations, whereas determination of RAS/RAF/PIK3CA mutations may only have a minor impact in this context.

Multimodal treatment of esophageal cancer

BACKGROUND

The treatment of localized esophageal cancer has been debated controversially over the past decades. Neoadjuvant treatment was used empirically, but evidence was limited due to the lack of high-quality confirmatory studies. Meanwhile, data have become much clearer due to recently published well-conducted randomized controlled trials and meta-analyses.

METHODS

Neoadjuvant and perioperative platinum fluoropyrimidine-based combination chemotherapy has now an established role in the treatment of stage II and stage III esophageal adenocarcinoma and cancer of the esophago-gastric junction. Neoadjuvant chemoradiation is now the standard of care for treating stage II and stage III esophageal squamous cell cancer and can also be considered for treating esophageal adenocarcinoma.

RESULTS

Patients with esophageal squamous cell cancer treated with definitive chemoradiation achieve comparable long-term survival compared with surgery. Short-term mortality is less with chemoradiation alone, but local tumor control is significantly better with surgery.

CONCLUSION

This expert review article outlines current data and literature and delineates recommendable treatment guidelines for localized esophageal cancer.

Impact of expression of human epidermal growth factor receptors EGFR and ERBB2 on survival in stage II/III gastric cancer

PURPOSE

EGF receptor (EGFR) and HER2 positivity are considered to be negative prognostic factors in gastric cancer. Biomarker analysis was conducted to evaluate the impact of EGFR and HER2 expression on the outcome of patients enrolled in the Adjuvant Chemotherapy Trial of TS-1 for Gastric Cancer (ACTS-GC), a randomized controlled trial comparing postoperative adjuvant S-1 therapy with surgery alone in 1,059 patients with stage II/III gastric cancer.

EXPERIMENTAL DESIGN

Formalin-fixed, paraffin-embedded surgical specimens were retrospectively examined in 829 patients (78.3%). The effects of EGFR and HER2 positivity on survival were analyzed on the basis of the 5-year survival data from the study. EGFR positivity was defined as an immunohistochemistry (IHC) score of 3+, and HER2 positivity as an IHC score of 3+ or an IHC score of 2+ with a positive dual-color in situ hybridization status.

RESULTS

EGFR and HER2 were positive in 75 (9.0%) and 113 (13.6%) patients, respectively. The overall and relapse-free survival rates were significantly lower in EGFR-positive patients than in EGFR-negative patients, whereas they were similar in HER2-positive and HER2-negative patients. Multivariate analysis showed that EGFR positivity correlated with poor outcomes [HR = 1.504; 95% confidence interval (CI) = 1.020-2.149; P = 0.040]. Treatment with S-1 improved survival compared with surgery alone, irrespective of EGFR and HER2 status.

CONCLUSIONS

EGFR positivity, but not HER2 positivity, was associated with poor patient outcomes after curative resection of stage II/III gastric cancer. There was no interaction between S-1 and EGFR or HER2 status with respect to survival outcome.