Pharmacodynamic studies of gefitinib in tumor biopsy specimens from patients with advanced gastric carcinoma

Molecular pathogenesis and emerging targets of gastric adenocarcinoma

Gastric adenocarcinoma (GC) is a devastating disease and is the third leading cause of cancer deaths worldwide. This heterogeneous disease has several different classification systems that consider histological appearance and genomic alterations. Understanding the etiology of GC, including infection, hereditary conditions, and environmental factors, is of particular importance and is discussed in this review. To improve survival in GC, we also must improve our therapeutic strategies. Here, we discuss new targets that warrant further exploration.

Molecularly Targeted Therapies for Gastric Cancer. State of the Art

Many phase III trials failed to demonstrate a survival benefit from the addition of molecular therapy to conventional chemotherapy for advanced and metastatic gastric cancer, and only three agents were approved by the FDA. We examined the efficacy and safety of novel drugs recently investigated. PubMed, Embase and Cochrane Library were searched for phase III randomized controlled trials published from January 2016 to December 2020. Patients in the experimental arm received molecular therapy with or without conventional chemotherapy, while those in the control arm had conventional chemotherapy alone. The primary outcomes were overall and progression-free survival. The secondary outcomes were the rate of tumor response, severe adverse effects, and quality of life. Eight studies with a total of 4223 enrolled patients were included. The overall and progression-free survival of molecular and conventional therapy were comparable. Most of these trials did not find a significant difference in tumor response rate and in the number of severe adverse effects and related deaths between the experimental and control arms. The survival benefits of molecular therapies available to date for advanced and metastatic gastric cancer are rather unclear, mostly due to inaccurate patient selection, particularly concerning oncogene amplification and copy number.

Deregulated expression of Elastin Microfibril Interfacer 2 (EMILIN2) in gastric cancer affects tumor growth and angiogenesis

Gastric cancer is a frequent human tumor and often a lethal disease. Targeted therapy for gastric carcinomas is far behind vis-à-vis other solid tumors, primarily because of the paucity of cancer-driving mutations that could be efficiently and specifically targeted by current therapy. Thus, there is a need to discover actionable pathways/proteins and new diagnostic and prognostic biomarkers. In this study, we explored the role of the extracellular matrix glycoprotein EMILIN2, Elastin Microfibril Interfacer 2, in a cohort of gastric cancer patients. We discovered that EMILIN2 expression was consistently suppressed in gastric cancer and high expression levels of this glycoprotein were linked to abnormal vascular density. Furthermore, we found that EMILIN2 had a dual effect on gastric carcinoma cells: on one hand, it decreased tumor cell proliferation by triggering apoptosis, and on the other hand, it evoked the production of a number of cytokines involved in angiogenesis and inflammation, such as IL-8. Collectively, our findings posit EMILIN2 as an important onco-regulator exerting pleiotropic effects on the gastric cancer microenvironment.

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EMILIN2 is localized in the gastric lamina propria and its expression is down-regulated in gastric cancer.

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High levels of EMILIN2 associate with elevated vascular density.

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EMILIN2 impairs the proliferation of gastric cancer cells by evoking apoptosis.

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Surprisingly, EMILIN2 triggers the expression of pro-angiogenic and pro-inflammatory cytokines.

Comprehensive pharmacogenomic characterization of gastric cancer

BACKGROUND

Gastric cancer is among the most lethal human malignancies. Previous studies have identified molecular aberrations that constitute dynamic biological networks and genomic complexities of gastric tumors. However, the clinical translation of molecular-guided targeted therapy is hampered by challenges. Notably, solid tumors often harbor multiple genetic alterations, complicating the development of effective treatments.

METHODS

To address such challenges, we established a comprehensive dataset of molecularly annotated patient derivatives coupled with pharmacological profiles for 60 targeted agents to explore dynamic pharmacogenomic interactions in gastric cancers.

RESULTS

We identified lineage-specific drug sensitivities based on histopathological and molecular subclassification, including substantial sensitivities toward VEGFR and EGFR inhibition therapies in diffuse- and signet ring-type gastric tumors, respectively. We identified potential therapeutic opportunities for WNT pathway inhibitors in ALK-mutant tumors, a significant association between PIK3CA-E542K mutation and AZD5363 response, and transcriptome expression of RNF11 as a potential predictor of response to gefitinib.

CONCLUSIONS

Collectively, our results demonstrate the feasibility of drug screening combined with tumor molecular characterization to facilitate personalized therapeutic regimens for gastric tumors.

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.

Loss of Multimerin-2 and EMILIN-2 Expression in Gastric Cancer Associate with Altered Angiogenesis

Gastric cancer is a deadly tumor and a relatively common disease worldwide. Surgical resection and chemotherapy are the main clinical options to treat this type of disease, however the median overall survival rate is limited to one year. Thus, the development of new therapies is a highly necessary clinical need. Angiogenesis is a promising target for this tumor type, however clinical trials with the use of anti-angiogenic drugs have so far not met expectations. Therefore, it is important to better characterize the expression of molecules whose expression levels may impact on the efficacy of the treatments. In this study the characteristics of the gastric tumor associated blood vessels were first assessed by endomicroscopy. Next, we analyzed the expression of Multimerin-2, EMILIN-2 and EMILIN-1, three molecules of the EMI Domain ENdowed (EDEN) protein family. These molecules play important functions in the tumor microenvironment, affecting cancer progression both directly and indirectly impinging on angiogenesis and lymphangiogenesis. All the molecules were highly expressed in the normal mucosa whereas in a number of patients their expression was altered. We consider that better characterizing the gastric tumor microenvironment and the quality of the vasculature may achieve effective patient tailored therapies.

Gefitinib enhances sensitivity of endometrial cancer cells to progestin therapy via dual-specificity phosphatase 1

In this study, we investigated if Gefitinib, an epidermal growth factor receptor (EGFR) inhibitor, augments endometrial cancer (EC) therapy with medroxyprogesterone acetate (MPA). Combined treatment with Gefitinib plus MPA decreased the proliferation and invasiveness of the Ishikawa and RL952 EC cell lines more effectively than MPA treatment alone. Moreover, combined treatment with Gefitinib plus MPA reduced growth of EC xenografts in Balb/c nude mice more than either Gefitinib or MPA alone. The therapeutic efficacy of combined Gefitinib plus MPA treatment was dependent on expression of dual-specificity phosphatase 1 (DUSP1). DUSP1 knockdown in Ishikawa cells treated with Gefitinib plus MPA showed greater proliferation and invasiveness than parental Ishikawa cells treated similarly. EC cells treated with the combination of Gefitinib plus MPA also showed DUSP1-dependent reductions in phospho-ERK1/2 and increases in E-Cadherin. Thus, Gefitinib appears to DUSP1-dependently enhance the therapeutic efficacy of progestin in EC cells.

OncoBinder facilitates interpretation of proteomic interaction data by capturing coactivation pairs in cancer

High-throughput methods such as co-immunoprecipitationmass spectrometry (coIP-MS) and yeast 2 hybridization (Y2H) have suggested a broad range of unannotated protein-protein interactions (PPIs), and interpretation of these PPIs remains a challenging task. The advancements in cancer genomic researches allow for the inference of "coactivation pairs" in cancer, which may facilitate the identification of PPIs involved in cancer. Here we present OncoBinder as a tool for the assessment of proteomic interaction data based on the functional synergy of oncoproteins in cancer. This decision tree-based method combines gene mutation, copy number and mRNA expression information to infer the functional status of protein-coding genes. We applied OncoBinder to evaluate the potential binders of EGFR and ERK2 proteins based on the gastric cancer dataset of The Cancer Genome Atlas (TCGA). As a result, OncoBinder identified high confidence interactions (annotated by Kyoto Encyclopedia of Genes and Genomes (KEGG) or validated by low-throughput assays) more efficiently than co-expression based method. Taken together, our results suggest that evaluation of gene functional synergy in cancer may facilitate the interpretation of proteomic interaction data. The OncoBinder toolbox for Matlab is freely accessible online.

MiR-26a performs converse roles in proliferation and metastasis of different gastric cancer cells via regulating of PTEN expression

Gastric cancer is the second leading cause of cancer-related death in the world. The exact molecular pathways in gastric cancer need for further study. We herein indicated miR-26a performed converse roles on oncogenicity in different gastric cancer cells. In gastric cancer cells MKN-28, miR-26a promoted cell proliferation, migration and invasion. However, in gastric cancer cells AGS, miR-26a reduced cell proliferation and metastasis. PTEN was identified as a direct target of miR-26a. In MKN-28 cells, PTEN was suppressed by miR-26a through 3'-UTR, and PTEN mediated miR-26a promoting oncogenicity including cell proliferation and metastasis. On the other hand, in AGS cells, the expression of PTEN was enhanced by miR-26a, and PTEN mediated miR-26a reducing oncogenicity. The mechanism in AGS cells may be the indirect regulation of PTEN by miR-26a overcame the direct targeting regulation. The model like MKN-28 cells was concordant with patients with a high level of miR-26a and a low level of PTEN and patients with a low level of miR-26a and a high level of PTEN which showed lower overall survival (OS); the model like AGS cells was concordant with patients with both high level of miR-26a and PTEN and both low level of miR-26a and PTEN which showed higher OS. These findings will facilitate a better understanding of the functions and mechanisms about miR-26a, miR-26a and PTEN are potential combined biomarkers in patients with gastric cancer.

Epirubicin-based compared with docetaxel-based chemotherapy for advanced gastric carcinoma: A systematic review and meta-analysis

Docetaxel or Epirubicin-based regimens are both approved for the treatment of metastatic gastric cancer. We perform a systemic review with metanalysis to evaluate the efficacy and toxicities of docetaxel-based chemotherapy compared with epirubicin-containing regimens. A metaanalysis of randomized studies in accordance with the preference guidelines for reported items in systematic reviews and meta-analyses is performed in which the databases of PubMed, the Cochrane Library, and the ASCO University Meeting were searched for relevant publications. The primary outcome was efficacy, the secondary toxicities. A total of 553 cases were included in the meta-analysis; 278 received epirubicin-based treatment and 313 received docetaxel. The pooled risk ratio to achieve an objective response and a disease control rate were 1.08 (95% CI 0.85-1.37; P=0.52) and 0.90 (95% CI 0.75-1.08; P=0.27) respectively. EPI arm showed a decrease in the risk of neutropenia, anemia, fatigue, asthenia and diarrhea, paraesthesia; docetaxel arm showed a decrease in the risk of leucopenia, thrombocytopenia, anorexia, nausea, nausea-vomiting, stomatitis and neutropenic fever. The results of our study suggest a similar activity of docetaxel and epirubicin-based chemotherapeutic regimens in metastatic gastric cancer. Other parameters as, comorbidity, concomitant diseases and prior therapies should be taken into account to address the clinician's choice in selecting the best therapeutical approach for any single patient.

Epidermal growth factor receptor expression and gene copy number analysis in gastric carcinoma samples from Chinese patients

Epidermal growth factor receptor (EGFR) expression and gene copy number have been observed to be associated with a positive clinical response to EGFR inhibitors. The present study aimed to evaluate EGFR expression and gene copy number in samples of gastric carcinoma (GC) from Chinese patients. EGFR expression and gene copy number were detected using immunohistochemistry and fluorescence in situ hybridization, in tissue array slides containing 150 individual samples of GC tissue. The association between EGFR status, clinicopathological features and overall patient survival was analyzed. Out of the 150 cases of GC evaluated, 63 (42.00%) demonstrated weak EGFR expression and 20 (13.33%) demonstrated EGFR overexpression. EGFR expression was observed to be associated with tumor location (P<0.05). Out of 104 cases of GC, which produced a clear FISH signal, 6 (5.77%) exhibited EGFR gene amplification and 5 (4.80%) exhibited balanced polysomy. Patients exhibiting GC, who demonstrated weak EGFR expression, EGFR overexpression or increased EGFR gene copy number, possessed an unfavorable prognosis. Multivariate analysis revealed that EGFR expression, tumor/node/metastasis stage and tumor location were potential independent unfavorable prognostic factors for GC patients. In conclusion, EGFR overexpression, gene amplification and polysomy were observed in GC patients and were associated with an unfavorable prognosis. Evaluation of EGFR status may therefore facilitate the identification of a subset of GC patients sensitive to treatment with EGFR-targeted therapies.

Current advances in targeted therapies for metastatic gastric cancer: improving patient care

In this article, we review the literature on the current advances in targeted therapies for metastatic gastric cancer aimed at improving patient care. We conclude that the key to guiding targeted therapy is individual biomarkers, which are not completely elucidated. HER2 overexpression is the only predictive biomarker currently in use. Furthermore, it is necessary to understand that gastric tumors are heterogeneous; therefore, is impossible to evaluate a novel biological compound without evaluating personal biomarkers. The selection of patients who are able to receive each treatment is paramount for improving advanced gastric cancer survival and reducing unnecessary costs.

Apatinib: A novel receptor tyrosine kinase inhibitor for the treatment of gastric cancer

Metastatic gastric cancer is a lethal disease characterized by a very short overall survival, underlining a critical need of new therapeutic options. Unfortunately, although several molecular targets have been investigated, only very few recently approved agents, such as trastuzumab in the HER2-positive setting and ramucirumab, led to a clinical improvement in the outcome of metastatic gastric cancer patients. VEGF (vascular endothelial growth factor) is one of the most potent angiogenic factors and is a signalling molecule secreted by many solid tumours. Since high VEGF expression is one of the characteristic features of gastric carcinomas, targeting VEGF is therefore considered as a promising therapeutic strategy for gastric cancer. In the scenario of possible new target therapies with particular regard to angiogenesis, apatinib is a novel receptor tyrosine kinase inhibitor selectively targeting VEGFR-2. It is an orally-bioavailable agent currently being studied in several solid tumour types showing a promising activity in gastric cancer. Due to the recent positive results as a third line of treatment for metastatic gastric cancer patients, apatinib may be an interesting and novel type of targeted treatment for metastatic gastric cancer in several lines of therapy. In this review, we summarize the available data of apatinib, mainly focused on the clinical aspect, in advanced/metastatic gastric cancer.

Molecular targeted therapy for the treatment of gastric cancer

Despite the global decline in the incidence and mortality of gastric cancer, it remains one of the most common malignant tumors of the digestive system. Although surgical resection is the preferred treatment for gastric cancer, chemotherapy is the preferred treatment for recurrent and advanced gastric cancer patients who are not candidates for reoperation. The short overall survival and lack of a standard chemotherapy regimen make it important to identify novel treatment modalities for gastric cancer. Within the field of tumor biology, molecular targeted therapy has attracted substantial attention to improve the specificity of anti-cancer efficacy and significantly reduce non-selective resistance and toxicity. Multiple clinical studies have confirmed that molecular targeted therapy acts on various mechanisms of gastric cancer, such as the regulation of epidermal growth factor, angiogenesis, immuno-checkpoint blockade, the cell cycle, cell apoptosis, key enzymes, c-Met, mTOR signaling and insulin-like growth factor receptors, to exert a stronger anti-tumor effect. An in-depth understanding of the mechanisms that underlie molecular targeted therapies will provide new insights into gastric cancer treatment.

Angiogenesis inhibitors in gastric and gastroesophageal junction cancer

Despite significant improvements in systemic chemotherapy during the past two decades, the prognosis of patients with advanced gastric and gastroesophageal junction adenocarcinoma remains poor. Because of molecular heterogeneity, it is essential to classify tumors based on the underlying oncogenic pathways and to develop targeted therapies acting on individual tumors. Unfortunately, although a number of molecular targets have been studied, very few of these agents can be used in a clinical setting. In this review, we summarize the available data on anti-angiogenic agents in advanced/metastatic gastric cancer.

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.

Advancing pharmacological treatment options for advanced gastric cancer

INTRODUCTION

Gastric cancer is the third most common cause of cancer-related deaths worldwide. Improvement of conventional chemotherapy has been modest in the past decades.

AREAS COVERED

We review recent important studies of metastatic or recurrent gastric cancer. For human epidermal growth factor receptors 2 (HER2) negative cancer, standard treatments are combinations of fluoropyrimidine and platinum with or without epirubicin or docetaxel in first-line therapy. Controversy exists regarding the use of triplet chemotherapies due to their toxicity. For HER2 positive cancer, standard treatments are combinations of fluoropyrimidine and cisplatin with trastuzumab. As second- or third-line treatment, taxanes or irinotecan prolonged survival compared with best supportive care alone, but the extension of overall survival was only 1 - 2 months. A recent study demonstrated that ramucirumab plus paclitaxel improved survival as a second-line therapy.

EXPERT OPINION

Most trials have failed to demonstrate a benefit of targeted agents. It is important to identify predictive biomarkers to enrich an appropriate patient population for targeted agents such as HER2 status for trastuzumab.

Molecular classification of gastric adenocarcinoma: translating new insights from the cancer genome atlas research network

Gastric cancer is a heterogenous cancer, which may be classified into several distinct subtypes based on pathology and epidemiology, each with different initiating pathological processes and each possibly having different tumor biology. A classification of gastric cancer should be important to select patients who can benefit from the targeted therapies or to precisely predict prognosis. The Cancer Genome Atlas (TCGA) study collaborated with previous reports regarding subtyping gastric cancer but also proposed a refined classification based on molecular characteristics. The addition of the new molecular classification strategy to a current classical subtyping may be a promising option, particularly stratification by Epstein-Barr virus (EBV) and microsatellite instability (MSI) statuses. According to TCGA study, EBV gastric cancer patients may benefit the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) antibodies or phosphoinositide 3-kinase (PI3K) inhibitors which are now being developed. The discoveries of predictive biomarkers should improve patient care and individualized medicine in the management since the targeted therapies may have the potential to change the landscape of gastric cancer treatment, moreover leading to both better understanding of the heterogeneity and better outcomes. Patient enrichment by predictive biomarkers for new treatment strategies will be critical to improve clinical outcomes. Additionally, liquid biopsies will be able to enable us to monitor in real-time molecular escape mechanism, resulting in better treatment strategies.

c-Met targeting in advanced gastric cancer: An open challenge

Despite significant improvements in systemic chemotherapy over the last two decades, the prognosis of patients with advanced gastric and gastroesophageal junction adenocarcinoma (GC) remains poor. Because of molecular heterogeneity, it is essential to classify tumors based on the underlying oncogenic pathways and to develop targeted therapies acting on individual tumors. High-quality research and advances in technology have contributed to the elucidation of molecular pathways underlying disease progression and have stimulated many clinical studies testing target therapies in an advanced disease setting. In particular, strong preclinical evidence for the aberrant activation of the HGF/c-Met signaling pathways in GC cancers exists. This review will cover the c-Met pathway, the mechanisms of c-Met activation and the different strategies of its inhibition. Next, we will focus on the current state of the art in the clinical evaluation of c-Met-targeted therapies and the description of ongoing randomized trials with the idea that in this disease, high quality translational research to identify and validate biomarkers is a priority task.

Emerging kinase inhibitors of the treatment of gastric cancer

INTRODUCTION

Gastric cancer (GC) is the fifth most common malignancy in the world. In the last years, for the first time in literature, the addition of a targeted therapy to standard chemotherapy has proved to prolong median overall survival. In this scenario, kinase inhibitors (KIs), smaller intracellular agents, could be an interesting and novel type of targeted treatment of metastatic GC both in first and further lines of therapy.

AREAS COVERED

Several KI have been evaluated in the preclinical setting. This review will underline the most relevant targeted pathways involved in GC tumorigenesis and disease progression including EGFR, VEGFR, c-MET, mTOR, fibroblast growth factor receptor, Src and Aurora kinases.

EXPERT OPINION

Despite the good results of TOGA, RAINBOW and REGARD trials about the addition of monoclonal antibodies to standard of care in GC, the addition of KI seems not to achieve comparable interesting results in management of GC. However, an improved patient selection before and during treatment according to molecular characteristics, as well as combination studies evaluating the synergistic effect of combination schedules of different KIs and standard chemotherapy, or KI plus KI or KI plus antibodies-based therapy may reveal interesting results and lead to understand mechanisms of multi-drug resistance.

Targeted therapy in gastric cancer

Gastric cancer is often diagnosed at an advanced stage. Although chemotherapy prolongs survival and improves quality of life, the survival of gastric cancer patients with advanced disease is short. Thanks to recent insights into the molecular pathways involved in gastric carcinogenesis, new targeted treatment options have become available for gastric cancer patients. Trastuzumab, an antibody targeted to HER-2, was shown to improve survival of advanced gastric cancer patients harboring HER-2 overexpression due to gene amplification in their tumor cells, and is currently also explored in adjuvant and neoadjuvant settings. Another agent with promising results in clinical trials is ramucirumab, an antibody targeting VEGFR-2. No clear survival benefit, however, were experienced with agents targeting EGFR (cetuximab, panitumumab), VEGF-A (bevacizumab), or mTOR (everolimus). Drugs targeting c-MET/HGF are currently under investigation in biomarker-selected cohorts, with promising results in early clinical trials. This review will summarize the current status of targeted treatment options in gastric cancer.

Identification of KRAS and PIK3CA but not BRAF mutations in patients with gastric cancer

Cetuximab, an immunoglobulin G1 chimeric monoclonal antibody directed against the epidermal growth factor receptor, is currently considered to be the strategy with the most potential for the treatment of gastric cancer due to the low frequency of KRAS mutations in patients with gastric cancer. However, the therapeutic success of cetuximab in colorectal cancer (CRC) has demonstrated that the clinical effect of cetuximab is closely dependent not only on KRAS mutations, but also BRAF and phosphoinositide-3-kinase, catalytic, α polypeptide (PIK3CA) mutations. In the present study, the status of KRAS, BRAF and PIK3CA mutations in gastric cancer were investigated concomitantly in order to aid the selection of patients eligible for treatment with cetuximab. Mutations in KRAS (exon 2), BRAF (exon 15) and PIK3CA (exon 9 and exon 20) were retrospectively evaluated by high resolution melting analysis and DNA direct sequencing in samples from 156 patients with gastric cancer. Mutations in either KRAS or PIK3CA were identified in 13 samples (8.3%), 7 samples with KRAS mutations and 6 samples with PIK3CA mutations. No mutations in the BRAF gene were identified. The frequency of mutations in either KRAS or PIK3CA were significantly higher in patients without lymph node metastasis than those with. Furthermore, KRAS and PIK3CA mutations were mutually exclusive. The present study, therefore, suggested that it may be necessary to evaluate KRAS and PIK3CA mutations concomitantly for the selection of patients eligible for treatment with cetuximab.

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.

Analysis of AKT and ERK1/2 protein kinases in extracellular vesicles isolated from blood of patients with cancer

Background

Extracellular vesicles (EVs) are small nanometre-sized vesicles that are circulating in blood. They are released by multiple cells, including tumour cells. We hypothesized that circulating EVs contain protein kinases that may be assessed as biomarkers during treatment with tyrosine kinase inhibitors.

Methods

EVs released by U87 glioma cells, H3255 and H1650 non-small-cell lung cancer (NSCLC) cells were profiled by tandem mass spectrometry. Total AKT/protein kinase B and extracellular signal regulated kinase 1/2 (ERK1/2) levels as well as their relative phosphorylation were measured by western blot in isogenic U87 cells with or without mutant epidermal growth factor receptor (EGFRvIII) and their corresponding EVs. To assess biomarker potential, plasma samples from 24 healthy volunteers and 42 patients with cancer were used.

Results

In total, 130 different protein kinases were found to be released in EVs including multiple drug targets, such as mammalian target of rapamycin (mTOR), AKT, ERK1/2, AXL and EGFR. Overexpression of EGFRvIII in U87 cells results in increased phosphorylation of EGFR, AKT and ERK1/2 in cells and EVs, whereas a decreased phosphorylation was noted upon treatment with the EGFR inhibitor erlotinib. EV samples derived from patients with cancer contained significantly more protein (p=0.0067) compared to healthy donors. Phosphorylation of AKT and ERK1/2 in plasma EVs from both healthy donors and patients with cancer was relatively low compared to levels in cancer cells. Preliminary analysis of total AKT and ERK1/2 levels in plasma EVs from patients with NSCLC before and after sorafenib/metformin treatment (n=12) shows a significant decrease in AKT levels among patients with a favourable treatment response (p<0.005).

Conclusion

Phosphorylation of protein kinases in EVs reflects their phosphorylation in tumour cells. Total AKT protein levels may allow monitoring of kinase inhibitor responses in patients with cancer.

Downregulation of c-Met expression does not enhance the sensitivity of gastric cancer cell line MKN-45 to gefitinib

The aim of the present study was to investigate the effect of downregulation of the c‑Met gene on signal transduction and apoptosis in gastric cancer MKN‑45 cells; furthermore, the study aimed to determine whether altered c‑Met gene expression affected MKN‑45 sensitivity to gefitinib. Three c‑Met‑specific small interfering RNAs (siRNAs) were synthesized and transfected into MKN‑45 cells. Messenger RNA (mRNA) and protein levels of c‑Met and its downstream signaling molecules [phosphoinositide 3‑kinase (PI3K) and AKT] were examined using reverse transcription polymerase chain reaction and western blot analysis 48 h following transfection. Cell apoptosis was evaluated using Annexin‑V/propidium iodide double staining and fluorescence‑activated cell sorting analysis. An MTT assay was performed in order to measure the 50% inhibitory concentration (IC50) of gefitinib on MKN‑45 cells. The results of the present study demonstrated that 48 h post‑transfection with c‑Met siRNA, MKN‑45 cells showed significantly downregulated expression of c‑Met mRNA and protein as well as an increased rate of apoptosis (P<0.05). In addition, following c‑Met siRNA transfection mRNA and protein levels of PI3K and AKT were not significantly altered in MKN‑45 cells (P>0.05); however, a marked decrease in the expression levels of phosphorylated (p)‑PI3K and p‑AKT was observed (P<0.05). Furthermore, the IC50 of gefitinib in MKN‑45 cells was not significantly decreased. In conclusion, knockdown of the c‑Met gene promoted gastric cancer cell apoptosis and inhibited downstream p‑PI3K and p‑AKT; however, the sensitivity of MKN‑45 cells to gefitinib was not increased.

Recent advances and future trends in the targeted therapy of metastatic gastric cancer

The better understanding of the molecular mechanisms behind gastric cancer has led to the development of new therapeutic strategies that are likely to improve patient outcomes in the near future. Recently, targeting the HER2 and the VEGF pathways with trastuzumab and ramucirumab, respectively, have been found to improve survival, while directed therapies against a number of other pathways are under clinical evaluation. These include the hepatocyte growth factor and its receptor c-MET, the insulin-like growth factor 1, the fibroblast growth factor, the mammalian target of rapamycin (mTOR), the epidermal growth factor receptor, and other pathways, as well as relevant immunotherapeutic strategies. This article reviews recent advances and future trends of these concepts for gastric cancer and adenocarcinoma of the gastroesophageal junction.

Gefitinib for oesophageal cancer progressing after chemotherapy (COG): a phase 3, multicentre, double-blind, placebo-controlled randomised trial

BACKGROUND

Evidence is scarce for the effectiveness of therapies for oesophageal cancer progressing after chemotherapy, and no randomised trials have been reported. We aimed to compare gefitinib with placebo in previously treated advanced oesophageal cancer.

METHODS

For this phase 3, parallel, randomised, placebo-controlled trial, eligible patients were adults with advanced oesophageal cancer or type I/II Siewert junctional tumours, histologically confirmed squamous-cell carcinoma or adenocarcinoma, who had progressed after chemotherapy, with WHO performance status 0-2, and with measurable or evaluable disease on CT scan. Participants were recruited from 48 UK centres and randomly assigned (1:1) to gefitinib (500 mg) or matching placebo by simple randomisation with no stratification factors. Patients, clinicians, and trial office staff were masked to treatment allocation. Treatment continued until disease progression, unacceptable toxicity, or patient choice. The primary outcome was overall survival, analysed by intention to treat. This trial is registered, number ISRCTN29580179.

FINDINGS

Between March 30, 2009, and Nov 18, 2011, 450 patients were randomly assigned to treatment groups (one patient withdrew consent; 224 patients allocated gefitinib and 225 allocated placebo included in analyses). Overall survival did not differ between groups (median 3·73 months, 95% CI 3·23-4·50, for gefitinib vs 3·67 months, 95% CI 2·97-4·37, for placebo; hazard ratio [HR] 0·90, 95% CI 0·74-1·09, p=0·29). Among the prespecified patient-reported outcomes (110 patients on gefitinib and 121 on placebo completed both baseline and 4 week questionnaires and were included in analyses), odynophagia was significantly better in the gefitinib group (adjusted mean difference -8·61, 95% CI -14·49 to -2·73; n=227; p=0·004), whereas the other outcomes were not significantly improved compared with placebo: global quality of life (2·69, 95% CI -2·33 to 7·72, n=231, p=0·293), dysphagia (-3·18, 95% CI -8·36 to 2·00, n=231, p=0·228), and eating (-4·11, 95% CI -9·96 to 1·75, n=229, p=0·168). Median progression-free survival was marginally longer with gefitinib than it was with placebo (1·57 months, 95% CI 1·23-1·90 in the gefitinib group vs 1·17 months, 95% CI 1·07-1·37 in the placebo group; HR 0·80, 95% CI 0·66-0·96, p=0·020). The most common toxicities were diarrhoea (36 [16%] of 224 patients on gefitinib vs six [3%] of 225 on placebo) and skin toxicity (46 [21%] vs two [1%]), both mostly grade 2. The commonest grade 3-4 toxicities were fatigue (24 [11%] vs 13 [6%] patients) and diarrhoea (13 [6%] vs two [1%]). Serious adverse events were reported in 109 (49%) of 224 patients assigned to gefitinib and 101 (45%) of 225 on placebo. 54 (24%) of patients in the gefitinib group achieved disease control at 8 weeks, as did 35 (16%) of patients on placebo (p=0·023).

INTERPRETATION

The use of gefitinib as a second-line treatment in oesophageal cancer in unselected patients does not improve overall survival, but has palliative benefits in a subgroup of these difficult-to-treat patients with short life expectancy. Future research should focus on identification of predictive biomarkers to identify this subgroup of benefiting patients.

FUNDING

Cancer Research UK.

The rugged road to targeted therapy for gastric cancer

Gastric cancer is the second leading cause of cancer related-death. Most patients with gastric cancer present with an advanced stage of the disease that has a poor prognosis. Molecularly targeted drugs combined with chemotherapy have been becoming the main treatment for advanced gastric cancer. A number of targeted agents modulating different signal transduction pathways are currently entering clinical trials, such as angiogenesis inhibitors and agents targeting epidermal growth factor receptor, hepatocyte growth factor, cell cycle, or matrix metalloproteinases. However, disappointing results were achieved in most phase III clinical trials, in which special patient selection by molecular biomarkers was not conducted. This systematic review synthesizes most of the data available from clinical trials, evaluates the efficacy and safety of molecularly targeted drugs and explores the rugged road to targeted therapy for advanced gastric cancer.

Clinicopathologic characteristics of YES-associated protein 1 overexpression and its relationship to tumor biomarkers in gastric cancer

Yes-associated protein 1 (YAP1), a downstream effector of the Hippo pathway, plays an important role in the development and progression of multiple malignancies, including human gastric cancer (GC). However, the clinical significance of YAP1 expression in GC needs to be comprehensively explored. Based on the pivotal role of YAP1 in the hippo pathway, we explored the clinicopathologic characteristics of YAP1 overexpression and its relationship to some tumor biomarkers in GC. Ninety cases of GC, chronic gastritis (CG) and CG with dysplasia samples were collected, and clinical data of all patients with GC were analyzed. The expression of YAP1 was assessed using immunohistochemical assay in biopsy samples. As a result, almost all the GC samples, but few CG and dysplasia samples showed YAP1 positive staining mainly in the nucleus. The expression of YAP1 was found in GC tissues with higher strong reactivity rate, compared with dysplasia and CG tissues (79.2 percent vs 47.1 percent and 15 percent, each P&#60;0.001), and its expression level was elevated with the ascending order of GC malignancy. However, no significant correlation was found between the expression of YAP1 and epidermal growth factor receptor (EGFR) with gender, age, gross stage, degree of differentiation, tumor size, TNM staging, perineural infiltration, vascular invasion, lymphatic vessel invasion and lymph node metastases in patients with GC (each P&#62;0.05). Furthermore, Spearman rank correlation analysis also showed no correlation of YAP1 with EGFR, Ki-67, CD34 and topoisomerase II (TOP II). Taken together, YAP1 is highly expressed in GC tissues compared with the dysplasia and CG tissues and its expression level is elevated with the ascending order of tumor malignancy; but, YAP1 expression does not correlate with the clinicopathologic characteristics and the expression of EGFR, Ki-67, CD34 and TOP II in GC.

MicroRNA-219-2-3p functions as a tumor suppressor in gastric cancer and is regulated by DNA methylation

Background & Aims

Gastric cancer is the most frequent gastrointestinal tumor in adults and is the most lethal form of human cancer. Despite of the improvements in treatments, the underlying mechanism of gastric carcinogenesis is not well known. To define novel modulators that regulate susceptibility to tumorgenesis, we focused on miR-219-2-3p.

Methods

Quantitative RT-PCR was employed to investigate the level of miR-219-2-3p in gastric cancer (GC) tissues (n = 113) and their matched adjacent normal tissues (n = 113). In vitro cell proliferation, apoptosis assays, cell migration, and invasion assays were performed to elucidate biological effects of miR-219-2-3p. Since silencing of miRNA by promoter CpG island methylation may be an important mechanism in tumorgenesis, GC cells were treated with 5-aza-2′-deoxycytidine and trichostatin A, and expression changes of miR-219-2-3p were subsequently examined by quantitative RT-PCR. Finally, the methylation status of CpG island upstream of miR-219-2-3p was analyzed by methylation-specific PCR in GC tissues (n = 22).

Results

miR-219-2-3p was down-regulated in GC and cell lines. In addition, the experiments documented the lower expression of miR-219-2-3p in GC specimens with higher grade and later stage tumors. Meanwhile, miR-219-2-3p exerted antiproliferative, proapoptotic, and antimetastatic roles and reduced levels of p-ERK1/2 in GC cells. Furthermore, 5-aza-2′-deoxycytidine and trichostatin A increased the expression (∼2 fold) of miR-219-2-3p in GC cells. By methylation-specific PCR, DNA methylation in the upstream region of miR-219-2-3p was detected in both adjacent normal tissues and cancer tissues. As expected, the methylation level was considerably higher in the miR-219-2-3p down-regulated group than up-regulated group.

Conclusions

miR-219-2-3p is potentially involved in gastric cancer progression and metastasis by regulating ERK1/2-related signal pathways, which may provide a novel therapeutic strategy for treatment of gastric cancer. Methylation mechanism may be involved in modulating the expression level of miR-219-2-3p in gastric cancer.

Molecular targeted therapy for advanced gastric cancer

Although medical treatment has been shown to improve quality of life and prolong survival, no significant progress has been made in the treatment of advanced gastric cancer (AGC) within the last two decades. Thus, the optimum standard first-line chemotherapy regimen for AGC remains debatable, and most responses to chemotherapy are partial and of short duration; the median survival is approximately 7 to 11 months, and survival at 2 years is exceptionally > 10%. Recently, remarkable progress in tumor biology has led to the development of new agents that target critical aspects of oncogenic pathways. For AGC, many molecular targeting agents have been evaluated in international randomized studies, and trastuzumab, an anti-HER-2 monoclonal antibody, has shown antitumor activity against HER-2-positive AGC. However, this benefit is limited to only ~20% of patients with AGC (patients with HER-2-positive AGC). Therefore, there remains a critical need for both the development of more effective agents and the identification of molecular predictive and prognostic markers to select those patients who will benefit most from specific chemotherapeutic regimens and targeted therapies.

Molecular targeted agents for gastric cancer: a step forward towards personalized therapy

Gastric cancer (GC) represents a major cancer burden worldwide, and remains the second leading cause of cancer-related death. Due to its insidious nature, presentation is usually late and often carries a poor prognosis. 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 its signaling pathways, offers the hope of clinically significant promising advances for selected groups of patients. Patients with Her-2 overexpression or amplification have experienced benefit from the integration of monoclonal antibodies such as trastuzumab to the standard chemotherapy. Additionally, drugs targeting angiogenesis (bevacizumab, sorafenib, sunitinib) are under investigation and other targeted agents such as mTOR inhibitors, anti c-MET, polo-like kinase 1 inhibitors are in preclinical or early clinical development. Patient selection and the development of reliable biomarkers to accurately select patients most likely to benefit from these tailored therapies is now key. Future trials should focus on these advances to optimize the treatment for GC patients. This article will review recent progress and current status of targeted agents in GC.

Molecular targeted therapies in advanced gastric cancer: does tumor histology matter?

It is increasingly recognized that gastric cancer is a heterogeneous disease which may be divided into subgroups based on histological, anatomical, epidemiological and molecular classifications. Distinct molecular drivers and tumor biology, and thus different treatment targets and predictive biomarkers, may be implicated in each subtype. However, there is little evidence in the literature regarding the correlation among these different classifications, and particularly the molecular aberrations present in each subtype. In this review, we approach advanced gastric cancer (AGC) by presenting aberrant molecular pathways and their potential therapeutic targets in gastric cancer according to histological and anatomical classification, dividing gastric cancer into proximal nondiffuse, distal nondiffuse and diffuse disease. Several pathways are involved predominantly, although not exclusively, in different subtypes. This may help to explain the disappointing results of many published AGC trials in which study populations were heterogeneous regardless of clinicopathological characteristics of the primary tumor. Histological and anatomical classification may provide insights into tumor biology and facilitate selection of an enriched patient population for targeted agents in future studies and in the clinic. However, some molecular pathways implicated in gastric cancer have not been studied in correlation with histological or anatomical subtypes. Further studies are necessary to confirm the suggestion that such classification may predict tumor biology and facilitate selection of an enriched patient population for targeted agents in future studies and in the clinic.

Alterations in the human epidermal growth factor receptor 2-phosphatidylinositol 3-kinase-v-Akt pathway in gastric cancer

AIM: To investigate human epidermal growth factor receptor 2 (HER2)-phosphatidylinositol 3-kinase (PI3K)-v-Akt murine thymoma viral oncogene homolog signaling pathway.

METHODS: We analyzed 231 formalin-fixed, paraffin-embedded gastric cancer tissue specimens from Japanese patients who had undergone surgical treatment. The patients’ age, sex, tumor location, depth of invasion, pathological type, lymph node metastasis, and pathological stage were determined by a review of the medical records. Expression of HER2 was analyzed by immunohistochemistry (IHC) using the HercepTest^TM kit. Standard criteria for HER2 positivity (0, 1+, 2+, and 3+) were used. Tumors that scored 3+ were considered HER2-positive. Expression of phospho Akt (pAkt) was also analyzed by IHC. Tumors were considered pAkt-positive when the percentage of positive tumor cells was 10% or more. PI3K, catalytic, alpha polypeptide (PIK3CA) mutations in exons 1, 9 and 20 were analyzed by pyrosequencing. Epstein-Barr virus (EBV) infection was analyzed by in situ hybridization targeting EBV-encoded small RNA (EBER) with an EBER-RNA probe. Microsatellite instability (MSI) was analyzed by polymerase chain reaction using the mononucleotide markers BAT25 and BAT26.

RESULTS: HER2 expression levels of 0, 1+, 2+ and 3+ were found in 167 (72%), 32 (14%), 12 (5%) and 20 (8.7%) samples, respectively. HER2 overexpression (IHC 3+) significantly correlated with intestinal histological type (15/20 vs 98 /205, P = 0.05). PIK3CA mutations were present in 20 cases (8.7%) and significantly correlated with MSI (10/20 vs 9/211, P < 0.01). The mutation frequency was high (21%) in T4 cancers and very low (6%) in T2 cancers. Mutations in exons 1, 9 and 20 were detected in 5 (2%), 9 (4%) and 7 (3%) cases, respectively. Two new types of PIK3CA mutation, R88Q and R108H, were found in exon1. All PIK3CA mutations were heterozygous missense single-base substitutions, the most common being H1047R (6/20, 30%) in exon20. Eighteen cancers (8%) were EBV-positive and this positivity significantly correlated with a diffuse histological type (13/18 vs 93/198, P = 0.04). There were 7 cases of lymphoepithelioma-like carcinomas (LELC) and 6 of those cases were EBV-positive (percent/EBV: 6/18, 33%; percent/all LELC: 6/7, 86%). pAkt expression was positive in 119 (53%) cases but showed no correlation with clinicopathological characteristics. pAkt expression was significantly correlated with HER2 overexpression (16/20 vs 103/211, P < 0.01) but not with PIK3CA mutations (12/20 vs 107/211, P = 0.37) or EBV infection (8/18 vs 103/211, P = 0.69). The frequency of pAkt expression was higher in cancers with exon20 mutations (100%) than in those with exon1 (40%) or exon9 (56%) mutations. One case showed both HER2 overexpression and EBV infection and 3 cases showed both PIK3CA mutations and EBV infection. However, no cases showed both PIK3CA mutations and HER2 overexpression. One EBV-positive cancer with PIK3CA mutation (H1047R) was MSI-positive. Three of these 4 cases were positive for pAkt expression. In survival analysis, pAkt expression significantly correlated with a poor prognosis (hazard ratio 1.75; 95%CI: 1.12-2.80, P = 0.02).

CONCLUSION: HER2 expression, PIK3CA mutations and EBV infection in gastric cancer were characterized. pAkt expression significantly correlates with HER2 expression and with a poor prognosis.

Phase I study of aurora A kinase inhibitor MLN8237 in advanced solid tumors: safety, pharmacokinetics, pharmacodynamics, and bioavailability of two oral formulations

PURPOSE

This phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of the investigational oral drug MLN8237 (alisertib), a small-molecule Aurora A kinase (AAK) inhibitor, in 87 adult patients with advanced solid tumors.

EXPERIMENTAL DESIGN

Sequential cohorts of patients received MLN8237 5 to 150 mg orally once daily or twice daily for 7, 14, or 21 days, followed by 14 days' rest per cycle. MLN8237 pharmacokinetics was characterized, and the relative bioavailability of an enteric-coated tablet (ECT) formulation was evaluated in reference to the original powder-in-capsule (PIC) formulation. Pharmacodynamic effects of MLN8237 on inhibition of AAK activity were evaluated in skin biopsies. Tolerability and response to treatment were assessed.

RESULTS

Common toxicities included fatigue, nausea, and neutropenia. Plasma exposures increased dose proportionally (5-150 mg/d), and were similar for PIC and ECT. The terminal half-life was 23 hours. At the maximum tolerated dose of 50 mg twice daily on the 7-day schedule, the mitotic index of the skin basal epithelium was increased within 24 hours after MLN8237 administration on days 1 and 7, a finding consistent with AAK inhibition. One (1%) patient achieved a partial response lasting for more than 1 year and received MLN8237 for 51 cycles; 20 (23%) patients achieved stable disease for ≥3 months.

CONCLUSIONS

This first-in-human trial of MLN8237 showed tolerability and favorable pharmacokinetics in this patient population. The recommended phase II dose of MLN8237 is 50 mg twice daily orally for 7 days in 21-day cycles, which is being evaluated further in the treatment of various solid tumors and hematologic malignancies.

First-in-human, phase I dose-escalation study of the safety, pharmacokinetics, and pharmacodynamics of RO5126766, a first-in-class dual MEK/RAF inhibitor in patients with solid tumors

PURPOSE

This phase I study assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety, pharmacokinetics, pharmacodynamics, and clinical activity of the first-in-class dual MEK/RAF inhibitor, RO5126766.

EXPERIMENTAL DESIGN

Initial dose-escalation was conducted using once daily dosing over 28 consecutive days in 4-week cycles. Further escalation was completed using 2 intermittent dosing schedules [7 days on treatment followed by 7 days off (7on/7off); 4 days on treatment followed by 3 days off (4on/3off)].

RESULTS

Fifty-two patients received RO5126766 at doses of 0.1 to 2.7 mg once daily, 2.7 to 4.0 mg (4 on/3 off), or 2.7 to 5.0 mg (7 on/7 off). The most common DLTs were elevated creatine phosphokinase (CPK) and blurred vision. The MTD for each dosing schedule was 2.25 mg once daily, 4.0 mg (4 on/3 off), and 2.7 mg (7 on/7 off). The dose/schedule recommended for phase II (RP2D) investigation was 2.7 mg (4 on/3 off). Frequent adverse events included rash-related disorders (94.2%), elevated CPK (55.8%), and diarrhea (51.9%). C(max) occurred 1 to 2 hours after dosing and mean terminal half-life was approximately 60 hours. Pharmacodynamic changes included reduced ERK phosphorylation, an increase in apoptosis in tumor tissue, and a reduction in fluorodeoxyglucose (FDG) uptake after 15 days of dosing. Three partial responses were seen: two in BRAF-mutant melanoma tumors and one in an NRAS-mutant melanoma.

CONCLUSION

This first-in-human study shows that oral RO5126766 has manageable toxicity, a favorable pharmacokinetic/pharmacodynamic profile, and encouraging preliminary antitumor activity in this population of heavily pretreated patients, achieving tumor shrinkage in around 40% of patients across all dose levels and all tumor types.

Phosphorylation of epidermal growth factor receptor and chromosome 7 polysomy in gastric adenocarcinoma

OBJECTIVE

To investigate the phosphorylation of epidermal growth factor receptor (EGFR) and its potentially associated chromosomal aberrations in gastric adenocarcinoma.

METHODS

Phosphorylated EGFR (pEGFR) was detected by immunohistochemistry on 145 specimens including 60 tumoral, 60 non-tumoral, 12 tumor-adjacent intramucosal dysplasia from patients with gastric adenocarcinoma and 13 mucosae from cancer-free patients. EGFR gene amplification and chromosome 7 (Chr-7) polysomy were detected by fluorescence in situ hybridization.

RESULTS

Positivity of pEGFR was found in 50 tumoral (83.3%) and 42 non-tumoral specimens (70.0%). There was an association between tumoral and non-tumoral zones on immunostains of pEGFR (r = 0.353, P = 0.006). Nuclear pEGFR usually presented in mucosae with Helicobacter pylori infection, stromal reaction or vascular invasion. Cytoplasmic pEGFR was correlated with local cancer extension (r = 0.337, P = 0.014) and inversely related with gastrokine 2, which had been previously detected in the same specimens. Eleven intramucosal dysplastic specimens were also positive for pEGFR while 13 mucosae from cancer-free patients were all negative. No EGFR gene amplification was observed. However, seven tumor specimens showed Chr-7 polysomy (11.7%) in which 5 were strongly positive for pEGFR.

CONCLUSIONS

EGFR phosphorylation may be one of the mechanisms that promote tumor initiation and expansion in gastric adenocarcinoma. Detection of pEGFR with analysis of its nuclear or cytoplasmic patterns could be clinicopathologically valuable. Chr-7 polysomy may partially contribute to EGFR activation in gastric adenocarcinoma, although its role does not predominate.

Metastatic gastric cancer - focus on targeted therapies

Gastric cancer (GC) is currently the second leading cause of cancer death worldwide; unfortunately, most patients will present with locally advanced or metastatic disease. Despite recent progress in diagnosis, surgery, chemotherapy, and radiotherapy, prognosis remains poor. A better understanding of GC biology and signaling pathways is expected to improve GC therapy, and the integration of targeted therapies has recently become possible and appears to be promising. This article focuses on anti-Her-2 therapy, specifically trastuzumab, as well as other epidermal growth factor receptor antagonists such as cetuximab, panitumub, matuzumab, nimotzumab, gefitinib, and erlotinib. Additionally, drugs that target angiogenesis pathways are also under investigation, particulary bevacizumab, ramucirumab, sorafenib, sunitinib, and cediranib. Other targeted agents in preclinical or early clinical development include mTOR inhibitors, anti c-MET, polo-like kinase 1 inhibitors, anti-insulin-like growth factor, anti-heat shock proteins, and small molecules targeting Hedgehog signaling.

Sequential research-related biopsies in phase I trials: acceptance, feasibility and safety

BACKGROUND

Sequential tumour biopsies are of potential interest for the rational development of molecular targeted therapies.

PATIENTS AND METHODS

From June 2004 to July 2009, 186 patients participated in 14 phase I clinical trials in which sequential tumour biopsies (13 trials) and/or sequential normal skin biopsies (6 trials) were optional. All patients had to sign an independent informed consent for the biopsies.

RESULTS

Tumour biopsies were proposed to 155 patients and 130 (84%) signed the consent while normal skin biopsies were proposed to 70 patients and 57 (81%) signed the consent. Tumour biopsies could not be carried out in 41 (31%) of the 130 consenting patients. Tumour biopsies were collected at baseline in 33 patients, at baseline and under treatment in 56 patients. Tumour biopsies were obtained using an 18-gauge needle, under ultrasound or computed tomography guidance. Only nine minor complications were recorded. Most tumour biopsy samples collected were intended for ancillary molecular studies including protein or gene expression analysis, comparative genomic hybridization array or DNA sequencing. According to the results available, 70% of the biopsy samples met the quality criteria of each study and were suitable for ancillary studies.

CONCLUSIONS

In our experience, the majority of the patients accepted skin biopsies as well as tumour biopsies. Sequential tumour and skin biopsies are feasible and safe during early-phase clinical trials, even when patients are exposed to anti-angiogenic agents. The real scientific value of such biopsies for dose selection in phase I trials has yet to be established.

Current status of targeted therapies in advanced gastric cancer

INTRODUCTION

In metastatic gastric cancer, chemotherapy is the standard treatment because it prolongs survival when compared to best supportive care alone. However, even after the use of more effective regimens, the overall survival remains disappointing, justifying the need for new treatment options.

AREAS COVERED

Areas covered in this review include the most common molecular pathways, which have provided novel targets in gastric cancer therapy. These therapeutic strategies include EGFR inhibitors, anti-angiogenic agents, cell cycle inhibitors and apoptosis promoters.

EXPERT OPINION

Several mAbs and kinase inhibitors, especially those targeting EGFR and VEGF/VEGFR, have already demonstrated promising activity in gastric cancer. The Phase III ToGA trial reported an increase in overall survival for patients with human EGF receptor (HER)2-positive gastric cancer treated with chemotherapy and trastuzumab compared to chemotherapy alone. This means that accurate HER2 testing in gastric cancer is necessary. Final data of ongoing trials with novel agents will be critical to further progress with this cancer.

Targeted therapies in the treatment of gastric cancer

Gastric cancer (GC) constitutes a major cause of cancer deaths worldwide. Recent improvements in both surgical techniques and adjuvant and neoadjuvant radiotherapy and chemotherapy approaches have increased the survival of patients with loco-regional disease. However most patients with GC have advanced disease either at diagnosis or at follow up. Despite recent advances in the treatment of advanced disease, these patients still have poor outcomes. An emerging understanding of the molecular pathways that characterize cell growth, cell cycle, apoptosis, angiogenesis and invasion has provided novel targets in cancer therapy. In this review we describe the current status of targeted therapies in the treatment of GC. These therapeutic strategies include epidermal growth factor receptor inhibitors, antiangiogenic agents, cell cycle inhibitors, apoptosis, promoters and matrix metalloproteinases inhibitors.

Nuclear translocation of pro-amphiregulin induces chemoresistance in gastric cancer

Amphiregulin (AR) is derived from a membrane-anchored form (proAR) by ectodomain shedding, and is a ligand that activates epidermal growth factor receptor (EGFR). We have recently shown that proAR translocates from the plasma membrane to the nucleus after truncation of 11 amino acids at the C-terminus, which is independent of the conventional EGFR signaling pathway. Although proAR immunoreactivity has reportedly been detected in the nucleus of cancer cells, its biological meaning has never been investigated. This study was performed to investigate the roles of proAR nuclear translocation in human gastric cancer. We constructed proAR truncated 11 amino acids at the C-terminus (proARΔC11) that spontaneously translocates to the nucleus, and established proARΔC11-expression regulatable gastric cancer cells (MKN45, MKN28) using the tet-off system. Using these cells, we found that proAR nuclear translocation significantly induced chemoresistance in vitro and in vivo. Analyzing the relationship between immunoreactive localization of proAR and the clinical outcome for 46 advanced gastric cancer cases treated with chemotherapy, median survival time was 311 days in 16 patients with AR-positive staining in the nucleus and 387 days in 30 patients with AR-negative staining (P < 0.05). The present study demonstrates that proAR nuclear translocation increases resistance to anti-cancer drugs, which might be associated with poor prognosis in human gastric cancer.

Targeted therapy in the management of advanced gastric cancer: are we making progress in the era of personalized medicine?

BACKGROUND

Gastric cancer is one of the leading causes of cancer death. With greater understanding of the molecular basis of carcinogenesis, targeted agents have led to a modest improvement in the outcome of advanced gastric cancer (AGC) patients.

METHODS AND RESULTS

We conducted an overview of the published evidence regarding the use of targeted therapy in AGC patients. Thus far, the human epidermal growth factor receptor (HER) pathway, angiogenic pathway, and phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin pathway have emerged as potential avenues for targeted therapy in AGC patients. The promising efficacy results of the Trastuzumab for Gastric Cancer trial led to the approved use of trastuzumab-based therapy as first-line treatment for patients with HER-2+ AGC. On the other hand, the Avastin® in Gastric Cancer trial evaluating bevacizumab in combination with chemotherapy did not meet its primary endpoint of a longer overall survival duration despite a significantly higher response rate and longer progression-free survival time in patients in the bevacizumab arm. Phase III data are awaited for other targeted agents, including cetuximab, panitumumab, lapatinib, and everolimus.

CONCLUSION

Recent progress in targeted therapy development for AGC has been modest. Further improvement in the outcome of AGC patients will depend on the identification of biomarkers in different patient populations to facilitate the understanding of gastric carcinogenesis, combining different targeted agents with chemotherapy, and unraveling new molecular targets for therapeutic intervention.