Expression of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) is an independent prognostic indicator of worse outcome in gastric cancer patients

Comparison of site-specific gene expression levels in primary tumors and synchronous lymph node metastases in advanced gastric cancer

BACKGROUND

Many malignant tumors consist of heterogeneous subpopulations of cells. This heterogeneity is associated with genetic characteristics. However, it remains unclear whether gene expression levels differ among specific sites of tumors in gastric cancer.

METHODS

We studied differences in gene expression levels among specific sites of primary tumors and synchronous lymph node metastases, using formalin-fixed, paraffin-embedded specimens resected surgically from 48 patients with previously untreated advanced gastric cancer. Specimens were obtained by laser-captured microdissection from five regions: (1) nonneoplastic mucosa, (2) surface layer (mucosa) of the primary tumor (surface sections), (3) middle layer (submucosa) of the primary tumor (middle sections), (4) the deepest layer of the primary tumor (muscularis propria or deeper) at the site of deepest invasion (deep sections), and (5) level 1 synchronous lymph node metastasis (lymph node metastases). Expression levels of the following target genes were determined by quantitative real-time polymerase chain reaction: thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-1α (HIF1α).

RESULTS

TP, DPD, EGFR, and HIF1α gene expression levels were significantly higher in deep sections than in surface sections. TP, EGFR, VEGF, and HIF1α gene expression levels were significantly higher in lymph node metastases than in surface sections. TP, DPD, EGFR, VEGF, and HIF1α gene expression levels were positively correlated with the specific samples harvested from the tumors.

CONCLUSIONS

Our results show that the expression levels of some genes in tumor cells can change in specific sites of tumors and can become higher in association with tumor progression.

The prognostic impact of EGFR, ErbB2 and MET gene amplification in human gastric carcinomas as measured by quantitative Real-Time PCR

PURPOSE

Identification of critical genes which play pivotal roles in controlling tumor growth and survival will establish the basis for developing therapeutic targets. In this study, we focused on frequencies of EGFR, ErbB2 and MET gene amplification in gastric cancer patients to develop personalized medicine to improve the treatment.

METHOD

EGFR, ErbB2 and MET gene amplification, and mRNA expression were analyzed by the quantitative Real-Time PCR in paraffin-embedded samples from 115 patients with gastric cancer.

RESULTS

EGFR, ErbB2 and MET genes were amplified in 11.3 % (13/115), 6.1 % (7/115) and 19.1 % (22/115) of cancerous specimens, respectively. The correlation coefficient test clearly indicated that gene amplification in these three genes was positively correlated with mRNA transcription (EGFR: R = 0.631, p = 0.009; ErbB2: R = 0.652, p = 0.023; MET: R = 0.715, p < 0.001). EGFR and MET gene amplification was significantly associated with Ki-67 MI (p = 0.022 and p = 0.015). MET amplification was also significantly associated with age of ≥60 years (p = 0.021) and tumor size of ≥5 cm (p = 0.032). MET amplification, but not EGFR and ErbB2, was a significant prognostic factor in poor survival among patients with gastric cancer.

CONCLUSIONS

EGFR, ErbB2 and MET genes are frequently amplified in gastric carcinoma. EGFR, ErbB2 and MET gene amplification is positively correlated with mRNA transcription. MET gene amplification correlates with a poor prognosis and poor survival in gastric carcinomas.

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.

Role of PI3K/Akt and SP1 in VEGF induced up-regulation of MRP1 in gastric cancer cell line BGC-823

AIM: To explore the mechanism by which vascular endothelial growth factor (VEGF) up-regulates multidrug resistance-associated protein 1 (MRP1) in gastric cancer cell line BGC-823.

METHODS: BGC-823 cells cultured in the absence or presence of VEGF for 24 h were pretreated with phosphatidylinositol 3 kinase, PI-3K/protein kinase B, and PKB (PI3K/Akt) inhibitor LY294002 for 1 h before stimulation with VEGF. Western blot assay was applied to assess the expression of MRP1, Akt, p-Akt and specificity protein 1 (SP1) proteins in the three groups of cells described above, and electrophoretic mobility shift assay (EMSA) was adopted to detect the DNA binding activity of transcriptional factor SP1. The sequences of MRP1 promoter and MRP1 promoter with SP1 binding site mutants were synthesized and cloned into the luciferase reporter gene vector PGL3-Basic to result in recombinant plasmids PGL3-Basic-MRP1w and PGL3-Basic-MRP1m, respectively. The recombinant plasmid was transiently co-transfected into BGC-823 cells using lipofectamine 2000 reagent, and the alteration of the mutant MRP1 promoter activity and the effect of VEGF on MRP1 promoter activity were then investigated.

RESULTS: Compared with the control group, the MRP1, p-Akt and SP1 proteins were all up-regulated, and the DNA binding activity of SP1 was significantly enhanced in BGC-823 cells treated with 32 ng/mL VEGF for 24 h. Contrarily, the protein levels of MRP1, p-Akt and SP1 were down-regulated, and the DNA binding activity of SP1 was remarkably decreased in the LY294002 pretreated group when compared with the VEGF 32 ng/mL group. The analysis of the luciferase reporter gene activity indicated that the recombinant plasmid PGL3-Basic-MRP1m possessed its promoter activity (110.000 ± 2.603) in BGC-823 cells, and compared with the control vector PGL3-Basic, its transcriptional activity was increased by 1.8-fold (t = -8.936, P < 0.01). On the contrary, the transcriptional activity of PGL3-Basic-MRP1m was reduced by 23.6% compared with PGL3-Basic-MRP1w (t = 4.617, P < 0.05), and this was dose-dependently enhanced at the 12-h time point after the transfected cells were treated with VEGF (r = 0.911, P < 0.01). When the concentration of VEGF was increased to 32 ng/mL to continuously stimulate the cells for 12 h, the transcriptional activity of PGL3-Basic-MRP1m (191.000 ± 14.799) was 0.7-fold increased than the control group (112.000 ± 11.358, t = -7.335, P < 0.01). Similarly, 24 h after the transfected cells were treated with VEGF, the mutant MRP1 promoter activity was also up-regulated in a dose-dependent manner (r = 0.945, P < 0.01). Compared with untreated cells (133.000 ± 6.083), the greatest activity (426.000 ± 7.000) of about 2.2-fold was observed (t = -56.032, P < 0.01).

CONCLUSION: The PI3K/Akt signaling pathway and transcriptional factor SP1 are two critical factors involved in VEGF-mediated augmentation of the activity of the MRP1 promoter; the transcriptional activity of the MRP1 promoter is decreased by SP1 binding site mutation, and the enhancing effect of VEGF on the promoter activity is weakened when compared with the wild type MRP1 promoter.

Causes and consequences of microsatellite instability in gastric carcinogenesis

Loss of DNA mismatch repair (MMR) function, due to somatic or germline epi/genetic alterations of MMR genes leads to the accumulation of numerous mutations across the genome, creating a molecular phenotype known as microsatellite instability (MSI). In gastric cancer (GC), MSI occurs in about 15% to 30% of the cases. This review summarizes the current knowledge on the molecular mechanisms underlying the acquisition of MSI in GC as well as on the clinic, pathologic and molecular consequences of the MSI phenotype. Additionally, current therapeutic strategies for GC and their applicability in the MSI subset are also discussed.

Angiogenic and growth factors in gastric cancer

BACKGROUND

Antiangiogenic treatment is at the horizon in the palliative treatment of gastric cancer (GC), but data on proangiogenic biomarkers are still limited. The aim of this study was to analyze five proteins with a function in tumor angiogenesis: vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang-2), follistatin, leptin, and platelet endothelial cell adhesion molecule 1 (CD31) in peripheral blood and corresponding tumor tissue.

MATERIAL AND METHODS

From 2008-2010, tumor tissue (n = 76) and corresponding preoperative serum (n = 69) of patients with localized GC were collected; 45 had perioperative chemotherapy. Protein serum or tumor lysate levels of these factors were measured by an angiogenesis multiplex immunoassay and correlated with response and survival.

RESULTS

Serum Ang-2 had prognostic relevance in the whole study population (P = 0.027). In subgroup analysis, serum VEGF and Ang-2 had prognostic relevance in primarily resected patients (P = 0.028; P = 0.048) but no association was found in neoadjuvantly treated patients. Follistatin concentration in the tumor tissue was associated with prognosis in all patients (P = 0.019). Tumor VEGF concentrations were correlated with histopathologic response (P = 0.011), with patients showing >50% remaining tumor having higher VEGF concentrations. The tissue Ang-2/VEGF ratio was significantly correlated with both clinical and histopathologic response (P = 0.029, P = 0.009). Additionally, the level of leptin in the tissue was associated with clinical response: nonresponding patients had higher leptin levels than those of responding patients (P = 0.032).

CONCLUSIONS

Our results show the importance of angiogenetic factors in serum and tumor tissue in GC for prognosis and treatment response. Further trials in larger patient populations are warranted for a further evaluation of proangiogenetic factors as biomarkers in gastrointestinal cancer.

How prognostic and predictive biomarkers are transforming our understanding and management of advanced gastric cancer

BACKGROUND

Gastric cancer (GC) is the second leading cause of cancer death worldwide. GC is a heterogeneous disease in terms of histology, anatomy, and epidemiology. There is also wide variability in how GC is treated in both the resectable and unresectable settings. Identification of prognostic and predictive biomarkers is critical to help direct and tailor therapy for this deadly disease.

METHODS

A literature search was done using Medline and MeSH terms for GC and predictive biomarkers and prognostic biomarkers. The search was limited to human subjects and the English language. There was no limit on dates. Published data and unpublished abstracts with clinical relevance were included.

RESULTS

Many potential prognostic and predictive biomarkers have been assessed for GC, some of which are becoming practice changing. This review is focused on clinically relevant biomarkers, including EGFR, HER2, various markers of angiogenesis, proto-oncogene MET, and the mammalian target of rapamycin.

CONCLUSION

GC is a deadly and heterogeneous disease for which biomarkers are beginning to change our understanding of prognosis and management. The recognition of predictive biomarkers, such as HER2 and vascular endothelial growth factor, has been an exciting development in the management of GC, validating the use of targeted drugs trastuzumab and ramucirumab. MET is another potential predictive marker that may be targeted in GC with drugs such as rilotumumab, foretinib, and crizotinib. Further identification and validation of prognostic and predictive biomarkers has the potential transform how this deadly disease is managed.

The concentrations of EGFR, LRG1, ITIH4, and F5 in serum correlate with the number of colonic adenomas in ApcPirc/+ rats

The development of noninvasive methods for early detection of colon cancer is critical for the successful management of this disease. Using a targeted quantitative proteomics technique, we assessed the ability of 12 serum proteins to detect the presence of colonic polyps in the Apc(Pirc) (/+) rat model of familial colon cancer. Serum protein candidates were selected from gene transcripts upregulated in colonic tumors of Apc(Pirc) (/+) rats and from a prior study of serum proteins differentially expressed in mice carrying intestinal adenomas. Proteins were quantified at early stages of polyp formation in a rat cohort monitored longitudinally by colonoscopy over a period of 75 days. Of the 12 proteins monitored at three distinct time points, seven showed differential expression in at least one time point in the serum from Apc(Pirc) (/+) rats compared with wild-type rats. Tumor multiplicity correlated with protein expression changes, and most tumors grew during the study. EGFR, LRG1, ITIH4, and F5 displayed the most robust tumor-associated protein expression changes over time. Receiver operator characteristic analysis using these four proteins resulted in a sensitivity of 100%, a specificity of 80%, and an area under the curve of 0.93 at 135 days of age, when the Pirc rats bore an average of 19 tumors in the colon and seven in the small intestine. The results of this study demonstrate that the quantitative analysis of a panel of serum proteins can detect the presence of early intestinal tumors in a rat model, and provides support for future measurements in humans.

Prognostic value of vascular endothelial growth factor A expression in gastric cancer: a meta-analysis

Vascular endothelial growth factor A (VEGF-A) is considered as a prime mediator of angiogenesis and has been implicated in carcinogenesis and metastasis. Various studies examined the relationship between VEGF-A overexpression with the clinical outcome in patients with gastric cancer, but yielded conflicting results. Electronic databases updated to September 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between VEGF-A overexpression and survival of patients with gastric cancer. Survival data were aggregated and quantitatively analyzed. We performed a meta-analysis of 20 studies that evaluated the correlation between VEGF-A overexpression and survival in patients with gastric cancer. Combined hazard ratios suggested that VEGF-A overexpression had an unfavorable impact on overall survival (OS) (hazard ratio [HR] = 1.57; 95% confidence interval [CI], 1.30–1.84) and disease-free survival (DFS) (HR = 1.85; 95% CI, 1.39–2.32) in patients with gastric cancer. No significant heterogeneity (P = 0.487) was observed among 16 studies for OS and among 7 studies for DFS (P = 0.435). VEGF-A overexpression indicates a poor prognosis for overall survival and disease-free survival in patients with gastric cancer.

Gastric Cancer: New Drugs - New Strategies

BACKGROUND

Gastric cancer is the second most common cause of cancer-related deaths worldwide. There are large geographic variations in the incidence of these tumors, with 60% occurring in East Asia. For patients with resectable disease, surgery and perioperative treatment can be effective. For patients with advanced gastric cancer, chemotherapy regimens result in a median survival of 9-11 months. In general, the prognosis for advanced disease is poor and 5-year overall survival rates are around 15%. Combination therapies yield better survival rates, albeit with increased toxicity. Therefore, more effective and less toxic treatment regimens are needed.

SUMMARY

The molecular aberrations that characterize the different subgroups of gastric cancer have been used as therapeutic targets. However, the heterogeneity and complexity of gastric cancers is a major challenge for the development of effective targeted therapies. This review examines the main molecular targets in the treatment of gastric cancer, namely the vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), hepatocyte growth factor (HGF)/c-Met, epidermal growth factor receptor (EGFR) and phosphoinositide 3-kinase (PI3K)/Akt pathways.

KEY MESSAGE

The molecular aberrations characteristic of gastric cancer are being explored for the development of targeted therapies, including the VEGF, HER2, HGF/c-Met, EGFR and PI3K/Akt signaling pathways.

PRACTICAL IMPLICATIONS

Trastuzumab, an antibody which targets HER2, is the first approved targeted therapy for the treatment of gastric cancer. However, trastuzumab is only effective in HER2-positive tumors (about 10-20% of all gastric cancers). Ramucirumab, which targets the VEGF receptor 2, has yielded benefits with respect to overall survival in a phase III trial and is an effective treatment for advanced gastric cancer with approval in second-line treatment. Apatinib and rilotumumab are another two promising new agents currently under development.

VEGF-A clinical significance in gastric cancers: immunohistochemical analysis of a wide Italian cohort

PURPOSE

The clinical significance of VEGF-A expression in gastric cancer (GC) has been reported with contradicting results. We analyzed the expression and clinical significance of VEGF-A in a wide Italian cohort of GC specimens.

METHODS

VEGF-A expression was tested by immunohistochemistry in 507 patients with GC of all clinical stages. The impact of VEGF-A on overall survival (OS) was evaluated in conjunction with clinical and pathological parameters.

RESULTS

In the Italian cohort we studied VEGF-A was not an independent prognostic factor neither at the univariate nor at multivariate analysis.

CONCLUSIONS

Although frequently expressed, in our study VEGF-A was not able to discriminate between groups of patients with different risk.

Unmet needs and challenges in gastric cancer: the way forward

Although the incidence of gastric cancer has fallen steadily in developed countries over the past 50 years, outcomes in Western countries remain poor, primarily due to the advanced stage of the disease at presentation. While earlier diagnosis would help to improve outcomes for patients with gastric cancer, better understanding of the biology of the disease is also needed, along with advances in therapy. Indeed, progress in the treatment of gastric cancer has been limited, mainly because of its genetic complexity and heterogeneity. As a result, there is an urgent need to apply precision medicine to the management of the disease in order to ensure that individuals receive the most appropriate treatment. This article suggests a number of strategies that may help to accelerate progress in treating patients with gastric cancer. Incorporation of some of these approaches could help to improve the quality of life and survival for patients diagnosed with the disease. Standardisation of care across Europe through expansion of the European Registration of Cancer Care (EURECCA) registry - a European cancer audit that aims to improve quality and decrease variation in care across the region - may also be expected to lead to improved outcomes for those suffering from this common malignancy.

miR-7 inhibits the invasion and metastasis of gastric cancer cells by suppressing epidermal growth factor receptor expression

The present study profiled differentially expressed microRNAs (miRs) in gastric cancer cell lines and then investigated miR-7 expression in gastric cancer tissue specimens and the effects of miR-7 on the growth, invasion and metastasis of gastric cancer cells and the underlying molecular events. A microRNA microarray was used to profile differentially expressed miRNAs in human gastric cancer cell lines relative to a normal stomach mucosal epithelial cell line. The miRNA miR-7 was selected for further investigation, which included real-time reverse-transcription PCR (qRT-PCR) analysis of miR-7 levels in different gastric cancer cell lines and tissues and distant non-tumor tissues from patient resections. Cell counting kit-8 (CCK-8), Transwell migration and invasion, and western blot assays were performed to assess tumor cell viability, invasion and gene expression, respectively, after miR-7 transfection. The miRNA microarray profiling revealed 14 upregulated miRNAs (including miR-21, miR-26b and miR-30b) and 19 downregulated miRNAs (including let-7i, miR-7 and miR-622) between gastric cancer and normal cell lines. The qRT-PCR analysis confirmed that reduced miR-7 expression occurred more frequently in poorly and moderately differentiated gastric cancer MGC-803, MKN-45 and SGC-7901 cell lines than in the well-differentiated gastric cancer NCI-N87 cell line, which was consistent with the results for gastric cancer tissues. Expression of miR-7 was downregulated in 86.9% (20/23) of the gastric cancer tissues compared with that in the distant non-tumor tissues. Restoration of miR-7 expression significantly inhibited tumor cell viability, invasiveness and migration when compared with the control cells. Luciferase assay confirmed the epidermal growth factor receptor (EGFR) as a target gene of mR-7, and expression of miR-7 significantly suppressed EGFR expression at both the mRNA and protein levels. The data from the present study demonstrated that reduced miR-7 expression contributes to gastric cancer development and progression. Further study will investigate miR-7 in the regulation of EGFR expression in vitro and in vivo.

Ramucirumab monotherapy for previously treated advanced gastric or gastro-oesophageal junction adenocarcinoma (REGARD): an international, randomised, multicentre, placebo-controlled, phase 3 trial

BACKGROUND

Vascular endothelial growth factor (VEGF) and VEGF receptor-2 (VEGFR-2)-mediated signalling and angiogenesis can contribute to the pathogenesis and progression of gastric cancer. We aimed to assess whether ramucirumab, a monoclonal antibody VEGFR-2 antagonist, prolonged survival in patients with advanced gastric cancer.

METHODS

We did an international, randomised, double-blind, placebo-controlled, phase 3 trial between Oct 6, 2009, and Jan 26, 2012, at 119 centres in 29 countries in North America, Central and South America, Europe, Asia, Australia, and Africa. Patients aged 24-87 years with advanced gastric or gastro-oesophageal junction adenocarcinoma and disease progression after first-line platinum-containing or fluoropyrimidine-containing chemotherapy were randomly assigned (2:1), via a central interactive voice-response system, to receive best supportive care plus either ramucirumab 8 mg/kg or placebo, intravenously once every 2 weeks. The study sponsor, participants, and investigators were masked to treatment assignment. The primary endpoint was overall survival. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00917384.

FINDINGS

355 patients were assigned to receive ramucirumab (n=238) or placebo (n=117). Median overall survival was 5·2 months (IQR 2·3-9·9) in patients in the ramucirumab group and 3·8 months (1·7-7·1) in those in the placebo group (hazard ratio [HR] 0·776, 95% CI 0·603-0·998; p=0·047). The survival benefit with ramucirumab remained unchanged after multivariable adjustment for other prognostic factors (multivariable HR 0·774, 0·605-0·991; p=0·042). Rates of hypertension were higher in the ramucirumab group than in the placebo group (38 [16%] vs nine [8%]), whereas rates of other adverse events were mostly similar between groups (223 [94%] vs 101 [88%]). Five (2%) deaths in the ramucirumab group and two (2%) in the placebo group were considered to be related to study drug.

INTERPRETATION

Ramucirumab is the first biological treatment given as a single drug that has survival benefits in patients with advanced gastric or gastro-oesophageal junction adenocarcinoma progressing after first-line chemotherapy. Our findings validate VEGFR-2 signalling as an important therapeutic target in advanced gastric cancer.

FUNDING

ImClone Systems.

Ramucirumab: targeting angiogenesis in the treatment of gastric cancer

Gastroesophageal cancer is responsible for over 1 million deaths annually worldwide; for patients with advanced disease treatment options are limited. Angiogenesis is an attractive therapeutic target that has been successfully exploited in other cancers. Ramucirumab, a fully humanized monoclonal antibody targeting VEGFR-2 has demonstrated efficacy as a single agent and in combination with paclitaxel in two large randomized trials (REGARD and RAINBOW) for the treatment of advanced previously treated gastroesophageal cancer. In combination with paclitaxel chemotherapy ramucirumab treated patients demonstrated increased rates of neutropenia, and ramucirumab is also associated with hypertension consistent with other antiangiogenic agents. Ramucirumab has been US FDA approved for patients with advanced gastroesophageal cancer who have progressed during or after treatment with fluoropyrimidine- or platinum-containing chemotherapy.

Prognostic value of epidermal growth factor receptors in gastric cancer: a survival analysis by Weibull model incorporating long-term survivors

BACKGROUND

There is no consensus about the prognostic role of HER2 expression and that of other members of the EGFR family in gastric cancer patients. The aim of this study was to evaluate the prognostic value of the EGFR family in gastric cancer.

METHODS

This retrospective study included 201 patients with gastric and esophagogastric junction adenocarcinoma stages 0-IV (AJCC 6th edition) who underwent primary tumor resection. Tissues from primary tumors were analyzed by tissue microarray technology and immunohistochemistry. Correlations between receptor expression and clinicopathological characteristics were performed according to the chi-square test. Survival analysis was calculated according to the Weibull model with a mixture model incorporating long-term survivors. Multivariate analysis of prognostic factors was performed by a regression model incorporating long-term survivors with the Weibull distribution.

RESULTS

Membrane expression of HER1, HER2, and HER4 were 9, 17, and 15 %, respectively. No membrane expression of HER3 was observed. Cytoplasmic expression of HER1, HER3, and HER4 were 45, 62, and 24 %, respectively. HER2 and HER3 expression were correlated (p < 0.001) and associated with intestinal-type histology (p = 0.001 and p < 0.001, respectively) and advanced age (p = 0.011 and p = 0.008, respectively). According to a regression model adjusted for age, surgical radicality, surgical modality, Laurén histology, adjuvant therapy, TNM stage, and receptor expressions, only TNM stage showed prognostic influence.

CONCLUSIONS

According to analysis by a parametric model, the EGFR family did not have prognostic influence in the gastric cancer population studied. The data presented showed a correlation between HER2 and HER3 expression, which might suggest a potential role for HER2-HER3 heterodimerization inhibitors.

The role of epidermal growth factor receptor in prognosis and treatment of gastric cancer

Despite tremendous efforts to reduce deaths due to gastric cancer, it represents the second leading cause of cancer-related deaths worldwide. EGF receptor (EGFR) plays important roles in gastric carcinogenesis by regulation of cell cycle, angiogenesis and apoptosis. This review evaluates the functions, mechanisms and clinical uses of EGFR in gastric cancer. Although EGFR targeted single therapy shows limited effect, the combination of EGFR targeted agents with traditional chemotherapy regimens may bring about important progress in cancer therapy. More clinical trials should be performed to clarify both the prognostic and therapeutic value of EGFR in gastric cancer.

A phase I study of sorafenib in combination with S-1 plus cisplatin in patients with advanced gastric cancer

BACKGROUND

Sorafenib inhibits several receptor tyrosine kinases involved in tumor progression and angiogenesis. S-1, an oral fluorouracil antitumor drug, plus cisplatin (CDDP) is the standard regimen for advanced gastric adenocarcinoma (AGC) in Japan. The purpose of this phase I study was to evaluate the safety, pharmacokinetics, and preliminary efficacy of sorafenib in combination with S-1 plus CDDP.

METHODS

Patients with histologically confirmed previously untreated AGC were evaluated for eligibility and treated with sorafenib (400 mg bid, days 1-35), S-1 (40 mg/m(2) bid, days 1-21), and CDDP (60 mg/m(2), day 8). Treatment was continued until disease progression or unacceptable toxicity. Pharmacokinetics for sorafenib, 5-FU, and CDDP were investigated in cycle 1.

RESULTS

Thirteen patients were enrolled and received at least one dose of the study treatment. No specific or serious adverse event was newly reported in this study. Five patients had partial response and 8 had stable disease as the best response. Pharmacokinetic analysis showed no significant differences in the exposures of sorafenib when administered alone or in combination with S-1 and CDDP.

CONCLUSIONS

The present phase I study demonstrates the acceptable toxicity and preliminary efficacy of combined treatment with S-1, CDDP, and sorafenib.

The prognostic values of EGFR expression and KRAS mutation in patients with synchronous or metachronous metastatic colorectal cancer

Background

The epidermal growth factor receptor (EGFR)/RAS/RAF/MEK/MAPK pathway is an important pathway in the carcinogenesis, invasion and metastasis of colorectal cancers (CRCs). We conducted a retrospective study to determine the prognostic values of EGFR expression and KRAS mutation in patients with metastatic CRC (mCRC) based on synchronous or metachronous status.

Methods

From October 2002 to March 2012, 205 patients with mCRC were retrospectively analyzed; 98 were found to have metachronous mCRC while 107 were found to have synchronous mCRC. The EGFR expressions were determinate by IHC (immunohistochemistry) analysis and categorized 1+ (weak intensity), 2+ (moderate intensity), and 3+ (strong intensity). Genomic DNA was isolated from frozen primary CRC tissues and direct sequencing of KRAS was performed. The clinicopathological features of these mCRC patients were retrospectively investigated according to EGFR expression and KRAS mutation status. Moreover, we analyzed the prognostic values of EGFR expression and KRAS mutation among these patients.

Results

Of the 205 patients with mCRC, EGFR expression was analyzed in 167 patients, and positive EGFR expression was noted in 140 of those patients (83.8%). KRAS mutation was investigated in 205 patients and mutations were noted in 88 of those patients (42.9%). In patients with metachronous mCRC, positive EGFR expression was significantly correlated with well-and moderately-differentiated tumors (P = 0.028), poorer disease-free survival (DFS) (P < 0.001), and overall survival (OS) (P < 0.001). Furthermore, positive EGFR expression was a significant independent prognostic factor of DFS (P = 0.006, HR: 4.012, 95% CI: 1.130–8.445) and OS (P = 0.028, HR: 3.090, 95% CI: 1.477–10.900) in metachronous mCRC patients. KRAS mutation status was not significantly related to DFS and OS of patients with metachronous mCRC; likewise, KRAS mutation status was not significantly different in the progression-free survival (PFS) and OS of patients with synchronous mCRC (all P > 0.05).

Conclusions

The present study demonstrated that EGFR expression has prognostic value only for patients with metachronous mCRC. However, KRAS mutation did not have prognostic value in patients with metachronous or synchronous mCRC.

The progress of targeted therapy in advanced gastric cancer

Although palliative chemotherapy has been shown to prolong survival and improve quality of life, the survival of advanced gastric cancer (AGC) patients remains poor. With the advent of targeted therapy, many molecular targeted agents have been evaluated in clinical studies. Trastuzumab, an anti-HER2 monoclonal antibody, has shown activity against HER2-positive AGC and becomes the first targeted agent approved in AGC. Drugs that target epidermal growth factor receptor, including monoclonal antibody and tyrosine kinase inhibitor, do not bring survival benefit to patients with AGC. Additionally, vascular endothelial growth factor inhibitors are also under investigation. Ramucirumab has shown promising result. Other targeted agents are in preclinical or early clinical development, such as mammalian target of rapamycinm inhibitors and c-MET inhibitors.

Effect of epidermal growth factor receptor status on the outcomes of patients with metastatic gastric cancer: A pilot study

The expression of epidermal growth factor receptor (EGFR) has been linked to clinical outcome in several solid tumors. However, the clinical significance of EGFR (c-erbB1) in gastric cancer remains unclear. The present study was designed to detect the clinical implications of EGFR in the Turkish population. Paraffin-embedded tissue microarrays containing gastric cancer tissue were obtained from 30 patients. EGFR expression was detected using immunohistochemistry. The correlation of this biomarker to the clinicopathological features and survival of patients with gastric cancer was studied. The overall positivity rate of EGFR was 63.3%. EGFR expression was significantly correlated with an improved progression-free survival (PFS) and overall survival (OS) rate (P=0.039 and 0.01, respectively). EGFR expression is a good prognostic marker for patients with gastric cancer.

Relationship between expression of EGFR in gastric cancer tissue and clinicopathological features

OBJECTIVE

To investigate the relationship between the expression of epidermal growth factor receptor (EGFR) in gastric cancer and the clinicopathological features and prognosis.

METHODS

A total of 78 paraffin specimens of gastric cancer operation were collected. The immunohistochemical method was used to detect the expression of EGFR in 78 cases of gastric cancer and 20 cases of adjacent normal tissue. The relationship between the high expression of EGFR and clinicopathological features was analyzed.

RESULTS

EGFR positive expression rate in the 78 cases of gastric cancer tissue was 57.7 % (45/78), while EGFR was not expressed in 20 cases of adjacent normal tissue. The high EGFR expression was positively correlated with the position of gastric cancer, tumor size, cell differentiation, invasive depth, lymph node metastasis and TNM staging, yet having no obvious relation with gender or age.

CONCLUSIONS

EGFR expression level in gastric cancer is closely related to the incidence and development of gastric cancer, which can provide a theoretical basis for the targeted therapy for gastric cancer with EGFR as the target.

Molecular diagnosis for personalized target therapy in gastric cancer

Gastric cancer is the second leading cause of cancer-related deaths worldwide. In advanced and metastatic gastric cancer, the conventional chemotherapy with limited efficacy shows an overall survival period of about 10 months. Patient specific and effective treatments known as personalized cancer therapy is of significant importance. Advances in high-throughput technologies such as microarray and next generation sequencing for genes, protein expression profiles and oncogenic signaling pathways have reinforced the discovery of treatment targets and personalized treatments. However, there are numerous challenges from cancer target discoveries to practical clinical benefits. Although there is a flood of biomarkers and target agents, only a minority of patients are tested and treated accordingly. Numerous molecular target agents have been under investigation for gastric cancer. Currently, targets for gastric cancer include the epidermal growth factor receptor family, mesenchymal-epithelial transition factor axis, and the phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathways. Deeper insights of molecular characteristics for gastric cancer has enabled the molecular classification of gastric cancer, the diagnosis of gastric cancer, the prediction of prognosis, the recognition of gastric cancer driver genes, and the discovery of potential therapeutic targets. Not only have we deeper insights for the molecular diversity of gastric cancer, but we have also prospected both affirmative potentials and hurdles to molecular diagnostics. New paradigm of transdisciplinary team science, which is composed of innovative explorations and clinical investigations of oncologists, geneticists, pathologists, biologists, and bio-informaticians, is mandatory to recognize personalized target therapy.

Prognostic value of epidermal growth factor receptor in patients with gastric cancer: a meta-analysis

BACKGROUND

The epidermal growth factor receptor (EGFR) plays important roles in the development of gastric cancer. This study aims to analyze the prognostic value of EGFR in patients with gastric cancer.

METHODS

A meta-analysis is performed by searching Cochrane Library, PubMed, EMBASE and Science Direct databases from Jan 1970 to May 2013. Data are extracted from studies evaluating the survival of gastric cancer patients with either positive or negative EGFR expression. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) are calculated.

RESULTS

Totally 1600 cases of gastric cancer patients from five studies are subjected to final analysis. The HR of post-operational survival of patients with positive EGFR expression is 1.16 (95% CI: 0.94-1.43) as compared with those with negative expression, indicating that positive EGFR expression does not significantly predict the poor survival of gastric cancer.

CONCLUSIONS

EGFR expression is not an independent predictor for the survival of gastric cancer patients.

Candidate serum biomarkers for early intestinal cancer using 15N metabolic labeling and quantitative proteomics in the ApcMin/+ mouse

Current screening procedures for colorectal cancer are imperfect and highly invasive and result in increased mortality rates due to low compliance. The goal of the experiments reported herein is to identify potential blood-based biomarkers indicative of early stage intestinal cancers using the ApcMin/+ mouse model of intestinal cancer as an experimental system. Serum proteins from tumor-bearing ApcMin/+ mice were quantitatively compared to tumor-free Apc+/+ wild-type mice via in anima metabolic labeling with 14N/15N-labeled Spirulina algae and an LTQ Orbitrap mass spectrometer. Out of 1116 total serum proteins quantified, this study identified 40 that were differentially expressed and correlated with the increase in intestinal neoplasms. A subset of these differentially expressed proteins underwent a secondary quantitative screen using selected reaction monitoring-mass spectrometry with stable isotope-labeled peptides. Using both quantitative techniques, we identified MGAM and COL1A1 as downregulated and ITIH3 and F5 as upregulated in serum. All but COL1A1 were similarly differentially expressed in the mRNA of neoplastic colonic tissues of ApcMin/+ mice compared to normal wild-type tissue. These differentially expressed proteins identified in the ApcMin/+ mouse model have provided a set of candidate biomarkers for future validation screens in humans.

Vascular endothelial growth factor induces multidrug resistance-associated protein 1 overexpression through phosphatidylinositol-3-kinase /protein kinase B signaling pathway and transcription factor specificity protein 1 in BGC823 cell line

Multidrug resistance (MDR) is one of the most important causes of chemotherapy failure and carcinoma recurrence. But the roles of the MDR-associated protein MRP1 in MDR remain poorly understood. Vascular endothelial growth factor (VEGF), one of the most active and specific vascular growth factors, plays a significant role in proliferation, differentiation, and metastasis of cancers. To explore the effect of VEGF on the expression of MRP1, we used recombinant human VEGF to stimulate K562 and BGC-823 cell lines. Quantitative real-time polymerase chain reaction and western blot analysis showed that the expression of MRP1 at both mRNA and protein levels was increased. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide results also showed that VEGF significantly enhanced the IC50 of the cells treated with adriamycin. To explore the underlying regulatory mechanisms, we constructed MRP1 promoter and the luciferase reporter gene recombinant vector. The luciferase reporter gene assay showed that the activity of the MRP1 promoter was markedly increased by VEGF stimulation, while LY294002, an inhibitor of the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, reduced this effect. Transcription factor specificity protein 1 (SP1) binding site mutation partially blocked the up-regulation of MRP1 promoter activity by VEGF. In summary, our results demonstrated that VEGF enhanced the expression of MRP1, and the PI3K/Akt signaling pathway and SP1 may be involved in this modulation.

Cancer stem cells: the 'heartbeat' of gastric cancer

Gastric cancer (GC) remains one of the most common cancers worldwide. Its prevalence is still on the rise in the developing countries due to the ageing population. The cancer stem cell (CSC) theory provides a new insight into the interpretation of tumor initiation, aggressive growth, recurrence, and metastasis of cancer, as well as the development of new strategies for cancer treatment. This review will focus on the progress of biomarkers and signaling pathways of CSCs, the complex crosstalk networks between the microenvironment and CSCs, and the development of therapeutic approaches against CSCs, predominantly focusing on GC.

Prognostic value of vascular endothelial growth factor expression in resected gastric cancer

BACKGROUND AND AIMS

Vascular endothelial growth factor (VEGF) is a potential prognostic biomarker for patients with resected gastric cancer. However, its role remains controversial. The objective of this study was to conduct a systematic review and meta-analysis of published literature.

METHODS

Relevant literature was identified using Medline and survival data from published studies were collected following a methodological assessment. Quality assessment of eligible studies and meta-analysis of hazard ratio (HR) were performed to review the correlation of VEGF overexpression with survival and recurrence in patients with gastric cancer.

RESULTS

Our meta-analysis included 44 published studies with 4,794 resected patients. VEGF subtype for the prediction of overall survival (OS) included tissue VEGF (HR=2.13, 95% CI 1.71-2.65), circulating VEGF (HR=4.22, 95% CI 2.47-7.18), tissue VEGF-C (HR=2.21, 95% CI 1.58-3.09), tissue VEGF-D (HR=1.73, 95% CI 1.25-2.40). Subgroup analysis showed that HRs of tissue VEGF for OS were, 1.78 (95% CI 0.90-3.51) and 2.31 (95% CI 1.82-2.93) in non-Asians and Asians, respectively. The meta-analysis was also conducted for disease free survival (DFS) and disease specific survival (DSS).

CONCLUSION

Positive expression of tissue VEGF, circulating VEGF, VEGF-C and VEGF-D were all associated with poor prognosis in resected gastric cancer. However, VEGF demonstrated no significant prognostic value for non-Asian populations. Circulating VEGF may be better than tissue VEGF in predicting prognosis.

Epirubicin, oxaliplatin, and capecitabine with or without panitumumab for patients with previously untreated advanced oesophagogastric cancer (REAL3): a randomised, open-label phase 3 trial

Background

EGFR overexpression occurs in 27–55% of oesophagogastric adenocarcinomas, and correlates with poor prognosis. We aimed to assess addition of the anti-EGFR antibody panitumumab to epirubicin, oxaliplatin, and capecitabine (EOC) in patients with advanced oesophagogastric adenocarcinoma.

Methods

In this randomised, open-label phase 3 trial (REAL3), we enrolled patients with untreated, metastatic, or locally advanced oesophagogastric adenocarcinoma at 63 centres (tertiary referral centres, teaching hospitals, and district general hospitals) in the UK. Eligible patients were randomly allocated (1:1) to receive up to eight 21-day cycles of open-label EOC (epirubicin 50 mg/m² and oxaliplatin 130 mg/m² on day 1 and capecitabine 1250 mg/m² per day on days 1–21) or modified-dose EOC plus panitumumab (mEOC+P; epirubicin 50 mg/m² and oxaliplatin 100 mg/m² on day 1, capecitabine 1000 mg/m² per day on days 1–21, and panitumumab 9 mg/kg on day 1). Randomisation was blocked and stratified for centre region, extent of disease, and performance status. The primary endpoint was overall survival in the intention-to-treat population. We assessed safety in all patients who received at least one dose of study drug. After a preplanned independent data monitoring committee review in October, 2011, trial recruitment was halted and panitumumab withdrawn. Data for patients on treatment were censored at this timepoint. This study is registered with ClinicalTrials.gov, number NCT00824785.

Findings

Between June 2, 2008, and Oct 17, 2011, we enrolled 553 eligible patients. Median overall survival in 275 patients allocated EOC was 11·3 months (95% CI 9·6–13·0) compared with 8·8 months (7·7–9·8) in 278 patients allocated mEOC+P (hazard ratio [HR] 1·37, 95% CI 1·07–1·76; p=0·013). mEOC+P was associated with increased incidence of grade 3–4 diarrhoea (48 [17%] of 276 patients allocated mEOC+P vs 29 [11%] of 266 patients allocated EOC), rash (29 [11%] vs two [1%]), mucositis (14 [5%] vs none), and hypomagnesaemia (13 [5%] vs none) but reduced incidence of haematological toxicity (grade ≥3 neutropenia 35 [13%] vs 74 [28%]).

Interpretation

Addition of panitumumab to EOC chemotherapy does not increase overall survival and cannot be recommended for use in an unselected population with advanced oesophagogastric adenocarcinoma.

Funding

Amgen, UK National Institute for Health Research Biomedical Research Centre.

Markers CD40, VEGF, AKT, PI3K, and S100 correlate with tumor stage in gastric cancer

BACKGROUND

To better understand gastric cancer occurrence and prognosis, we explored the expression of molecules in the CD40 pathway and their correlation with gastric cancer prognosis.

PATIENTS AND METHODS

We measured the expression of CD40, VEGF, AKT, PI3K, and S100 in gastric cancer tissues and adjacent normal tissues from 128 patients by immunohistochemistry.

RESULTS

The expression of CD40, VEGF, AKT, and PI3K were significantly higher in tumor tissue than in normal tissue, while S100 expression in dendritic cells (DC) was lower. Expression of CD40, VEGF, AKT, and PI3K significantly increased with T stage, while S100 expression decreased with T stage. Lymph node metastasis was associated with low or negative S100 expression. PI3K expression increased with clinical stage, while negative S100 expression was associated with higher clinical stages. Multivariate analysis did not indicate significant associations between any of these markers and recurrence or mortality.

CONCLUSION

The correlation between T stage of gastric cancer and the higher expression of CD40, VEGF, AKT, and PI3K, along with lower S100 expression in DC, may provide insights into future targets for more effective immunotherapy for cancer.

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.

Metastatic gastric cancer treatment: a little slow but worthy progress

Metastatic gastric cancer is incurable and remains one of the leading causes of cancer-related deaths around the world. Despite the significant progress in its systemic treatment, metastatic gastric cancer is still a major therapeutic challenge for oncologists. Newer chemotherapy regimens and the addition of molecularly targeted agents to chemotherapy seem to provide better clinical outcomes for patients with metastatic gastric cancer. The objective of this article is to review the current treatment approach for this formidable disease.

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.

The prognostic impact of epidermal growth factor receptor in patients with metastatic gastric cancer

Background

The epidermal growth factor receptor (EGFR) is a potential target of anticancer therapy in gastric cancer. However, its prognostic role in metastatic gastric or gastroesophageal junction (GE) cancer has not been established yet.

Methods

EGFR status was analyzed by immunohistochemistry (IHC) in paraffin-embedded samples from 357 patients who received chemotherapy in 4 first-line trials. Automated RNA extraction from paraffin and RT-quantitative PCR were additionally used to evaluate EGFR mRNA expression in 130 patients.

Results

EGFR protein expression (any grade) and overexpression (3+) were observed in 43% and 11% of patients, respectively. EGFR positivity correlated with intestinal type histology (p = 0.05), but not with other clinicopathologic characteristics. Median follow-up was 18.2 months. Median overall survival (OS) was similar in patients with EGFR positive vs. those with EGFR negative tumors, regardless whether positivity was defined as ≥1+ (10.6 vs. 10.9 months, p = 0.463) or as 3+ (8.6 vs. 10.8 months, p = 0.377). The multivariate analysis indicated that EGFR status is not an independent prognostic factor (hazard ratio 0.85, 0.56 to 1.12, p = 0.247). There were also no significant differences in overall survival when patients were categorized according to median (p = 0.116) or quartile (p = 0.767) distribution of EGFR mRNA gene expression. Similar distributions of progression-free survival according to EGFR status were observed.

Conclusions

Unlike different cancer types where EGFR-positive disease is associated with an adverse prognostic value, EGFR positivity is not prognostic of patient outcome in metastatic gastric or GE cancer.

Carcinoma of the stomach: A review of epidemiology, pathogenesis, molecular genetics and chemoprevention

Carcinoma of the stomach is still the second most common cause of cancer death worldwide, although the incidence and mortality have fallen dramatically over the last 50 years in many regions. The incidence of gastric cancer varies in different parts of the world and among various ethnic groups. Despite advances in diagnosis and treatment, the 5-year survival rate of stomach cancer is only 20 per cent. Stomach cancer can be classified into intestinal and diffuse types based on epidemiological and clinicopathological features. The etiology of gastric cancer is multifactorial and includes both dietary and nondietary factors. The major diet-related risk factors implicated in stomach cancer development include high content of nitrates and high salt intake. Accumulating evidence has implicated the role of Helicobacter pylori (H. pylori) infection in the pathogenesis of gastric cancer. The development of gastric cancer is a complex, multistep process involving multiple genetic and epigenetic alterations of oncogenes, tumor suppressor genes, DNA repair genes, cell cycle regulators, and signaling molecules. A plausible program for gastric cancer prevention involves intake of a balanced diet containing fruits and vegetables, improved sanitation and hygiene, screening and treatment of H. pylori infection, and follow-up of precancerous lesions. The fact that diet plays an important role in the etiology of gastric cancer offers scope for nutritional chemoprevention. Animal models have been extensively used to analyze the stepwise evolution of gastric carcinogenesis and to test dietary chemopreventive agents. Development of multitargeted preventive and therapeutic strategies for gastric cancer is a major challenge for the future.

Prognostic significance of vascular endothelial growth factor immunohistochemical expression in gastric cancer: a meta-analysis

Vascular endothelial growth factor (VEGF) is considered as a prime mediator of angiogenesis, and has been implicated in carcinogenesis and metastasis. Various studies examined the relationship between VEGF protein overexpression with the clinical outcome in patients with gastric cancer, but yielded conflicting results. The prognostic significance of VEGF overexpression in gastric cancer remains controversial. Electronic databases updated to July 2011 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between VEGF overexpression and survival of patients with gastric cancer. Survival data were aggregated and quantitatively analyzed. We performed a meta-analysis of 30 studies (n = 3,999 patients) that evaluated the correlation between VEGF overexpression detected by immunohistochemistry and survival in patients with gastric cancer. Combined hazard ratios suggested that VEGF-A overexpression had an unfavorable impact on overall survival (OS) (HR [hazard ratio] = 1.49, 95 % CI [confidence interval]: 1.22-1.77) and disease free survival (DFS) (HR = 1.85, 95 % CI: 1.38-2.32) in patients with gastric cancer. However, VEGF-C overexpression did not significantly correlate with OS (HR = 1.24, 95 % CI: 0.92-1.56) or DFS (HR = 1.15, 95 % CI: 0.78-1.52). VEGF-D is an unfavorable indicator of OS (HR = 1.68, 95 % CI: 1.02-2.34) and DFS (HR = 1.88, 95 % CI: 1.07-2.70) in patients with gastric cancer. VEGF-A and VEGF-D overexpression indicated a poor prognosis for patients with gastric cancer. VEGF-C overexpression was not associated with poor prognosis in patients with gastric cancer. The prognostic value of VEGF on survival still needs further larger prospective trials to be confirmed.

Novel targeted agents for gastric cancer

Contemporary advancements have had little impact on the treatment of gastric cancer (GC), the world’s second highest cause of cancer death. Agents targeting human epidermal growth factor receptor mediated pathways have been a common topic of contemporary cancer research, including monoclonal antibodies (mAbs) and receptor tyrosine kinase inhibitors (TKIs). Trastuzumab is the first target agent evidencing improvements in overall survival in HER2-positive (human epidermal growth factor receptor 2) gastric cancer patients. Agents targeting vascular epithelial growth factor (VEGF), mammalian target of rapamycin (mTOR), and other biological pathways are also undergoing clinical trials, with some marginally positive results. Effective targeted therapy requires patient selection based on predictive molecular biomarkers. Most phase III clinical trials are carried out without patient selection; therefore, it is hard to achieve personalized treatment and to monitor patient outcome individually. The trend for future clinical trials requires patient selection methods based on current understanding of GC biology with the application of biomarkers.

Increased serum level of epidermal growth factor receptor in liver cancer patients and its association with exposure to arsenic

Arsenic is a human carcinogen and can activate epidermal growth factor receptor (EGFR) in human cell lines. As EGFR is associated with the occurrence of cancers, we conducted a study to evaluate whether serum EGFR may increase in liver cancer patients, particularly in those with exposure to arsenic. We recruited 100 patients of liver cancer and 100 age- and sex-matched controls in Taiwan and determined EGFR levels in sera by enzyme-linked immunosorbent assay. The patients had higher EGFR levels (668.1 vs. 243.1 fmol/mL, p<0.01), and after adjusting for hepatitis B and C, they still had an average EGFR level 406.1 fmol/mL higher than that of the controls (p<0.01). When we compared 22 patients residing in an endemic area of arsenic intoxication to 22 age- and sex-matched patients residing outside the area, we found that patients from the endemic area had higher EGFR levels (882.8 vs. 511.6 fmol/mL, p = 0.04). We concluded that EGFR is over-expressed in patients of liver cancer, particularly in those with exposure to arsenic, and therefore, serum EGFR level is not only a potential biomarker of liver cancer, but also a potential biomarker of cancers associated with arsenic exposure.

Phase I and II clinical trials for gastric cancer

Gastric cancer remains a global public health problem with considerable heterogeneity in pathogenesis and clinical presentation across geographic regions. Improved understanding of the molecular biology of this disease has opened avenues for targeted intervention. An individualized treatment approach is required for optimal management of this cancer. Overcoming resistance to therapy requires combining targeted agents with the traditional options of chemotherapy/radiation therapy, and also targeting more than 1 pathway of carcinogenesis at a time. Encouraging molecular hypothesis and biomarker-driven trials will lead to improved patient outcomes and may eventually enable the therapeutic nihilism associated with gastric cancer to be overcome.

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.

Targeted therapies and predictive markers in epithelial malignancies of the gastrointestinal tract

CONTEXT

In recent years, there has been a tremendous amount of interest in the development of targeted therapies for the treatment of human cancers. Increased understanding of the specific molecular pathways and driver mutations critical to cancer cell growth have allowed the development of these advanced therapeutics. Among these, inhibitors of the epidermal growth factor receptor and HER2/neu pathways now play a major role in the management of gastrointestinal cancers in addition to other solid malignancies. In colorectal and gastric cancers, the use of epidermal growth factor receptor inhibitors and HER2/neu inhibitors has increased the available treatment options for patients with advanced disease.

OBJECTIVE

To focus on the current targeted therapies and predictors of response in malignancies of the gastrointestinal tract.

DATA SOURCES

Medical literature searchable on PubMed (US National Library of Medicine) as well as older studies revealed by the literature review were used as the source of data.

CONCLUSION

Gene testing of critical elements of the pathways targeted by these agents (such as KRAS mutational analysis in colorectal tumors and HER2/neu testing in gastric cancers) allows the ability to predict which patients will respond to these treatments. As the molecular profiling of tumors and our understanding of cancer genomics and epigenetic alterations continues to grow, it is expected that these personalized targeted therapies will form one of the mainstays of gastrointestinal cancer treatment.

Chemotherapy for operable gastric cancer: current perspectives

The majority of gastric cancer patients present with advanced, incurable disease and only a minority have localised disease that is suitable for radical treatment. A benefit has generally been demonstrated from adding chemotherapy to surgery for early disease though there are marked differences in how this is done globally. Whilst a perioperative approach, with chemotherapy given before and after gastric surgery is commonly used in the Europe and Australia most patients with operable gastric cancer in North America are treated with surgery and postoperative chemoradiation. In contrast, in East Asia, adjuvant fluoropyrimidine chemotherapy alone is used following D2 gastric resection surgery. However, despite the multimodality treatments, outcomes remain suboptimal as the majority of those treated for localised disease eventually relapse with incurable loco-regional or distant metastases. At the current time, an unmet need exists to further understand the biology of this aggressive disease and develop more efficacious therapies that can improve outcomes from this aggressive disease.

Molecular targeted agents for gastric and gastroesophageal junction cancer

Despite recent improvements in surgical techniques and chemotherapy, advanced cancers of the stomach and gastroesophageal junction (GEJ) continue to have poor clinical outcomes. However, molecules intimately related to cancer cell proliferation, invasion, and metastasis have been studied as candidates for molecular targeted agents. Target molecules, such as the epidermal growth factor receptor, vascular endothelial growth factor receptor, and P13k/Akt/mTor pathway, as well as the insulin-like growth factor receptor, c-Met pathways, fibroblast growth factor receptor, and other pathways are considered to be promising candidates for molecular targeted therapy for gastric and GEJ cancer. In this review we focus on the recent developments in targeting relevant pathways in these types of cancer.