Clinical significance of hepatocyte growth factor/c-Met expression in the assessment of gastric cancer progression

Ferroptosis regulating lipid peroxidation metabolism in the occurrence and development of gastric cancer

BACKGROUND

Gastric cancer is one of the most common malignant tumors in the world, and its occurrence and development involve complex biological processes. Iron death, as a new cell death mode, has attracted wide attention in recent years. However, the regulatory mechanism of iron death in gastric cancer and its effect on lipid peroxidation metabolism remain unclear.

AIM

To explore the role of iron death in the development of gastric cancer, reveal its relationship with lipid peroxidation, and provide a new theoretical basis for revealing the molecular mechanism of the occurrence and development of gastric cancer.

METHODS

The process of iron death in gastric cancer cells was simulated by cell culture model, and the occurrence of iron death was detected by fluorescence microscopy and flow cytometry. The changes of gene expression related to iron death and lipid peroxidation metabolism were analyzed by high-throughput sequencing technology. In addition, a mouse model of gastric cancer was established, and the role of iron death in vivo was studied by histology and immunohistochemistry, and the level of lipid peroxidation was detected. These methods comprehensively and deeply reveal the regulatory mechanism of iron death on lipid peroxidation metabolism in the occurrence and development of gastric cancer.

RESULTS

Iron death was significantly activated in gastric cancer cells, and at the same time, associated lipid peroxidation levels increased significantly. Through high-throughput sequencing analysis, it was found that iron death regulated the expression of several genes related to lipid metabolism. In vivo experiments demonstrated that increased iron death in gastric cancer mice was accompanied by a significant increase in lipid peroxidation.

CONCLUSION

This study confirmed the important role of iron death in regulating lipid peroxidation metabolism in the occurrence and development of gastric cancer. The activation of iron death significantly increased lipid peroxidation levels, revealing its regulatory mechanism inside the cell.

Therapeutic Strategies for Ovarian Cancer in Point of HGF/c-MET Targeting

Ovarian cancer is the fifth leading cause of cancer deaths in women and is regarded as one of the most difficult cancers to treat. Currently, studies are being conducted to develop therapeutic agents for effective treatment of ovarian cancer. In this review, we explain the properties of the hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-MET) and how the signaling pathway of HGF/c-MET is activated in different cancers and involved in tumorigenesis and metastasis of ovarian cancer. We present the findings of clinical studies using small chemicals or antibodies targeting HGF/c-MET signaling in various cancer types, particularly in ovarian cancer. We also discuss that HGF/c-MET-targeted therapy, when combined with chemo drugs, could be an effective strategy for ovarian cancer therapeutics.

Impact of Selected Serum Factors on Metastatic Potential of Gastric Cancer Cells

(1) Background: stromal-derived factor-1 (SDF-1/CXCL12), hepatocyte and vascular-endothelial growth factors (HGF and VEGF) have been shown to facilitate cell motility, proliferation and promote local tumor progression and metastatic spread. Recent research shows the important role of these cytokines in gastric cancer (GC) progression. (2) Methods: 21 gastric cancer patients and 19 healthy controls were included in the study. SDF-1, HGF and VEGF levels were evaluated in sera by ELISA. Patients and control sera were used to stimulate CRL-1739 GC cell line, and chemotaxis, adhesion and proliferation potential were assessed. (3) Results: Concentrations of SDF-1, HGF and VEGF were significantly higher in patients than in controls. Chemotaxis and adhesion assays revealed a significant response of GC cells to patients’ serum. Furthermore, significant relationships were seen between chemotactic/adhesion response and tumor stage. Serum from intestinal early GC patients produced significantly stronger chemotactic response when compared to patients with metastatic spread. In turn, serum from patients with distal metastases significantly increased the adhesion of GC cells when compared to sera from the patients with no distal metastases. We also observed that HGF strongly stimulated the proliferation of CRL-1739 cells. (4) Conclusions: We observed that the sera from GC patients, but also SDF-1, HGF and VEGF used alone, have a strong pro-metastatic effect on CRL-1739 cells. We also demonstrated that the concentration of these cytokines is specifically elevated in the sera of patients in an early stage of malignancy. Our results indicate that SDF-1, HGF and VEGF are very important molecules involved in gastric cancer progression.

Expression levels of MCP-1, HGF, and IGF-1 in endometriotic patients compared with non-endometriotic controls

BACKGROUND

To study the concentrations of monocyte chemoattractant protein-1 (MCP-1), hepatocyte growth factor (HGF), and insulin-like growth factor-1 (IGF-1) in peritoneal fluid (PF) and serum, and to evaluate their expressions by PF and peripheral blood mononuclear cells (PFMCs and PBMCs, respectively), and ectopic and eutopic endometrial stromal cells of patients with endometriosis (EESCs and EuESCs, respectively) compared with controls.

METHODS

The concentrations of mentioned cytokines in serum and PF, as well as their expression in PBMCs, PFMCs, EuESCs and EESCs from endometriosis patients and controls were assessed.

RESULTS

The levels of MCP-1, HGF, and IGF-1 in serum and PF in women with endometriosis were significantly higher than the controls (P < 0.05-P < 0.001). Gene expression of MCP-1 and IGF-1 in the PFMCs, PBMCs and EESCs also showed an increased level compared to controls (P < 0.05-P < 0.01). The protein expression of MCP-1 and IGF-1 by PFMCs was statistically higher in endometriotic women (P < 0.05 and P < 0.01, respectively). The gene and protein expression of HGF in PFMCs and its gene expression by EESCs were significantly higher in endometriotic women compared to controls (P < 0.05-P < 0.01).

CONCLUSIONS

The higher concentrations of mentioned cytokines in serum and PF and their higher expression by PFMCs and EESCs in endometriosis patients may contribute to the development of endometriosis.

Safety, Efficacy, and Pharmacokinetics of Metatinib Tromethamine Tablet in Patients with Advanced Refractory Solid Tumors: A Phase I Clinical Trial

LESSONS LEARNED

MET overexpression is uncommon, and positive MET immunohistochemistry (1+/2+) was an independent positive prognostic factor for response rate and progression-free survival. Whether MET overexpression can be considered a potential predictive biomarker and be used as an inclusion criterion is worth investigating in a future study.

BACKGROUND

Metatinib tromethamine tablet (metatinib) is a small molecule receptor kinase inhibitor targeting both c-MET and vascular endothelial growth factor receptor 2. This phase I trial aimed to determine the dose-limiting toxicity (DLT) and maximum tolerated dose (MTD), pharmacokinetics, safety, and efficacy of metatinib in patients with advanced solid tumors.

METHODS

Eligible patients received a single dose of metatinib in a 3 + 3 dose-escalation design with dose levels of 25-800 mg/day, after a single dose on day 1, then 2 days off, and then a multidose schedule of once-daily doses for 25 consecutive days (days 4-28). Primary endpoints were MTD and safety; secondary and exploratory endpoints included pharmacokinetics (PK), efficacy, and biomarkers.

RESULTS

Eighteen patients (including nine patients with hepatocellular carcinoma [HCC]) received at least one dose of study drug (one patient quit the study without continuous multiple-dose administration after receiving a single dose of metatinib). Hand-foot skin reaction, diarrhea, and liver dysfunction were the DLTs, and 200 mg/day was the MTD. The most common treatment-related adverse events (TRAEs) were skin toxicity (50%), diarrhea (33.3%), and liver dysfunction (27.8%). Three patients (only one of six in the 200 mg/day cohort; the other two in the 300 mg/day cohort) experienced severe TRAEs: one patient with severe liver dysfunction and two patients with severe liver dysfunction and skin toxicity, respectively. Pharmacokinetics assessment indicated that metatinib was rapidly absorbed and metabolized to the formation of reactive metabolite, SCR-1510, after single-dose administration. The mean time taken to achieve maximum concentration and terminal elimination half-life of SCR-1510 was approximately 2.0-3.0 hours and ranged from 8 to 14 hours. Two patients had partial responses. The objective response rate and disease control rate (DCR) were 11.1% and 61.1%, respectively. The median progression-free survival (PFS) was 2.75 months.

CONCLUSION

Metatinib administration of 200 mg/day was well tolerated, safe, and effective. The MTD was 200 mg/day, which should be recommended in further investigations.

The prognostic value of HGF-c-MET signaling pathway in Gastric Cancer: a study based on TCGA and GEO databases

Gastric cancer is a heterogeneous tumor that underlying molecular mechanisms are largely unclear. This study aimed to elucidate the expression level of HGF-c-MET in gastric cancer patients and to investigate the prognostic and diagnostic value of HGF-c-MET. In silico analysis of the TCGA and GEO database found that HGF and c-MET mRNA expression are significantly higher in gastric cancer tissues than those in peritumor tissues. Both higher mRNA expression of HGF and c-MET were associated with a poorer prognosis. c-MET expression was modulated by methylation in the promoter regions. HGF was positively correlated with CD8+ T cell, CD4+ T cell, macrophage, neutrophil and dendritic cell. Furthermore, functional enrichment analysis and protein-protein interaction networks further shown that HGF-c-MET and related proteins mainly participated in growth factor receptor binding, protein tyrosine kinase activity and signaling receptor binding. Finally, outcome of GSEA analysis showed 13 shared KEGG pathways enriched in high expressed group of HGF and c-MET.

Clinical significance of various growth factors in patients with different gastric neoplasms

Growth factors represent a family of important biological molecules that can also be critical in the pathogenesis of various gastrointestinal cancers. In this study, we conducted a comprehensive analysis of the systemic levels of selected growth factors - hepatocyte, vascular-endothelial, fibroblast, and insulin-like 1 growth factors (HGF, VEGF, FGF, and IGF-1, respectively), as well as granulocyte-colony stimulating factor (G-CSF) in 75 patients with different gastric neoplasms (carcinomas, gastrointestinal stromal tumors - GISTs, neuroendocrine neoplasms - NENs, and lymphomas) and 40 healthy volunteers. Patients with gastric carcinoma or other types of gastric neoplasms had higher HGF and IGF-1 levels than healthy individuals (P < 0.05 in all cases). In comparison to healthy control subjects, systemic VEGF concentrations were elevated in patients with gastric carcinoma (P < 0.05), but not in individuals with other types of gastric malignancies. No statistically significant differences were observed between the analyzed groups in terms of FGF and G-CSF levels. When patients with gastric carcinoma were subdivided according to the Japanese classification system, significantly elevated levels of HGF, VEGF, and IGF-1 concentrations were observed in patients with advanced gastric carcinoma (extending beyond the submucosal layer of the stomach). Only the systemic levels of HGF were associated with tumor node metastasis - TNM staging, the absolute numbers of bone marrow-derived mesenchymal cells, and very small embryonic/epiblast-like stem cells circulating in patients with gastric carcinoma. ROC curves analyses demonstrated that AUC values of systemic levels of examined growth factors ranged from 0.40-0.65 (P > 0.06 in all cases). In conclusion, patients with gastric malignancies showed a systemic biochemical imbalance in multiple growth factors, which appears to be associated with clinical presentation of these neoplasms in humans. However, none of the growth factors examined here seem to be suitable diagnostic biomarkers for detecting or differentiating different types of gastric malignancies in humans.

Precision medicine in gastric cancer

Gastric cancer (GC) is a complex disease linked to a series of environmental factors and unhealthy lifestyle habits, and especially to genetic alterations. GC represents the second leading cause of cancer-related deaths worldwide. Its onset is subtle, and the majority of patients are diagnosed once the cancer is already advanced. In recent years, there have been innovations in the management of advanced GC including the introduction of new classifications based on its molecular characteristics. Thanks to new technologies such as next-generation sequencing and microarray, the Cancer Genome Atlas and Asian Cancer Research Group classifications have also paved the way for precision medicine in GC, making it possible to integrate diagnostic and therapeutic methods. Among the objectives of the subdivision of GC into subtypes is to select patients in whom molecular targeted drugs can achieve the best results; many lines of research have been initiated to this end. After phase III clinical trials, trastuzumab, anti-Erb-B2 receptor tyrosine kinase 2 (commonly known as ERBB2) and ramucirumab, anti-vascular endothelial growth factor receptor 2 (commonly known as VEGFR2) monoclonal antibodies, were approved and introduced into first- and second-line therapies for patients with advanced/metastatic GC. However, the heterogeneity of this neoplasia makes the practical application of such approaches difficult. Unfortunately, scientific progress has not been matched by progress in clinical practice in terms of significant improvements in prognosis. Survival continues to be low in contrast to the reduction in deaths from many common cancers such as colorectal, lung, breast, and prostate cancers. Although several target molecules have been identified on which targeted drugs can act and novel products have been introduced into experimental therapeutic protocols, the overall approach to treating advanced stage GC has not substantially changed. Currently, surgical resection with adjuvant or neoadjuvant radiotherapy and chemotherapy are the most effective treatments for this disease. Future research should not underestimate the heterogeneity of GC when developing diagnostic and therapeutic strategies aimed toward improving patient survival.

Volumetric parameters on 18F-FDG PET/CT predict the survival of patients with gastric cancer associated with their expression status of c-MET

Background

This study aimed to investigate the prognostic value of volumetric parameters on ¹⁸F- fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in gastric-cancer patients, according to the expression status of c-MET (MET proto-oncogene, receptor tyrosine kinase), which was previously unclear.

Methods

The study included 61 patients with advanced gastric cancer. Data on the baseline ¹⁸F-FDG PET/CT, clinical-pathological information, progression-free survival (PFS), and overall survival (OS) were collected. The maximum standardized uptake value (SUV_max), peak SUV (SUV_peak), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of gastric tumors in situ were measured on PET/CT. The expression status of c-MET was recorded based on immunohistochemical staining. Associations between the parameters on PET/CT and patients’ survival outcomes were analyzed in relation to expression status of c-MET.

Results

Patients with positive c-MET expression had significantly shorter PFS (11.5 vs. 17.6 months, P = 0.039) and OS (17.0 vs. 24.3 months, P = 0.043), and had gastric tumors with a larger MTV (70.8 ± 53.11 vs. 41.1 ± 52.32, P = 0.034) and TLG (428.39 ± 442.95 vs. 205.7 ± 354.40, P = 0.039), compared with those with negative c-MET expression. However, SUV_max (9.6 ± 7.40 vs. 8.0 ± 4.91, P = 0.335) and SUV_peak (7.7 ± 5.99 vs. 6.62 ± 4.08, P = 0.438) were similar between these two patient groups. In patients with c-MET-positive tumors, MTV and TLG were independent factors in predicting patient OS after correction by distant metastasis (hazards ratio = 1.014 and 1.002, respectively; P = 0.024 and 0.027, respectively), while these associations were not significant in patients with c-MET-negative tumors.

Conclusions

Patients with c-MET-positive gastric cancer had higher MTV and TLG values compared to those with c-MET-negative gastric cancer. In patients with c-MET-positive gastric cancer, volumetric parameters on ¹⁸F-FDG PET/CT have prognostic value for patient overall survival.

Human chorionic gonadotropin promotes cell proliferation through the activation of c-Met in gastric cancer cells

Hormones and their receptors affect the development process of gastric cancer. Previous studies have revealed that human chorionic gonadotropin (hCG) is expressed in gastric cancer tissue. However, the mechanism by which hCG exerts its effects on gastric cancer cells had not been reported. In the present study, the expression of hCG and its receptor was detected in gastric cancer tissues and para-carcinoma tissues of 62 patients with gastric carcinoma. Following the treatment of gastric cancer cells SGC-7901 with hCG, a cell counting kit-8 assay, flow cytometry, a colony formation assay and a xenograft tumor model in nude mice were used to detect the effect of hCG on cell proliferation; and the expression of c-Met was determined by western blot analysis. The expression of hCG and its receptor were significantly higher in gastric cancer tissues compared with that of the matched para-carcinoma tissue (P<0.01). Proliferation of SGC-7901 cells treated with hCG was significant higher and the number of cells at the G₂/M phase of the cell cycle increased compared with the control cells. Hepatocyte growth factor transmembrane protein receptor expression was increased in hCG-treated cells compared with the control cells, which relies on the protein kinase A signaling pathway. The present study revealed the potential function of hCG in the development of gastric cancer, suggesting that hCG may be a molecular marker and potential drug target in gastric cancer.

Biomarkers of gastric cancer: Current topics and future perspective

Gastric cancer (GC) is one of the most prevalent malignant types in the world and an aggressive disease with a poor 5-year survival. This cancer is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Although the incidence is declining, the outcome of patients with GC remains dismal. Thus, the detection at an early stage utilizing useful screening approaches, selection of an appropriate treatment plan, and effective monitoring is pivotal to reduce GC mortalities. Identification of biomarkers in a basis of clinical information and comprehensive genome analysis could improve diagnosis, prognosis, prediction of recurrence and treatment response. This review summarized the current status and approaches in GC biomarker, which could be potentially used for early diagnosis, accurate prediction of therapeutic approaches and discussed the future perspective based on the molecular classification and profiling.

MET overexpression, gene amplification and relevant clinicopathological features in gastric adenocarcinoma

This study was conducted to investigate the expression of MET in Chinese gastric adenocarcinoma cohort, the correlation between MET overexpression and clinical pathological features, HER2 expression and MET gene amplification. A total of 816 gastric adenocarcinoma patients were included and MET and HER2 immunohistochemical (IHC) staining were performed. IHC and dual-color silver in situ hybridization analysis were performed in the tissue microarrays, constructed from the 240 patients who were randomly selected. MET overexpression (IHC 3+) was observed in 6.0% (49/816) of the cohort. MET overexpression rate was higher in patients with poor prognostic factors, such as clinical stages III/IV (p =0.012) and pathologic stages T3/T4 (p =0.027). The HER2 overexpression (IHC 3+) rate was 8.8% (72/816) and MET overexpression rate was higher in HER2 positive patients (9.7%, 7/72). A high concordance rate (94.6%) between MET overexpression and gene amplification was demonstrated. Therefore, MET overexpression could serve as a prognostic biomarker and a potential therapeutic target for gastric cancer.

PKG II reverses HGF-triggered cellular activities by phosphorylating serine 985 of c-Met in gastric cancer cells

Previous studies showed that type II cGMP-dependent protein kinase G (PKG II) could inhibit the activation of epidermal growth factor receptor (EGFR). Both c-Met and EGFR belong to family of receptor tyrosine kinases (RTKs) and have high molecular analogy. However, the effect of PKG II on c-Met activation is unclear. This study was designed to investigate the inhibitory effect of PKG II on the activation of c-Met and consequent biological activities. The results from CCK8 assay, Transwell assay and TUNEL assay showed that HGF enhanced cell proliferation and migration, and decreased cell apoptosis. Activated PKG II reversed the above changes caused by HGF. Immunoprecipitation and Western blotting results showed that PKG II could bind with c-Met and phosphorylate its Ser985, and thereby inhibited HGF-induced activation of c-Met and MAPK/ERK and PI3K/Akt/mTOR mediated signal transduction. When Ser985 of c-Met was mutated to Alanine for preventing phosphorylation of this site, the blocking effect of PKG II on c-Met activation was annulled. When Ser985 of c-Met was mutated to Aspartic acid for mimicking phosphorylation of this site, HGF-induced activation of c-Met was prevented. In conclusion, the results indicated that PKG II could block c-Met activation via phosphorylating Ser985 of this RTK.

Evolving Management Strategies for Metastatic Esophageal and Gastroesophageal Junction Adenocarcinoma

Metastatic or unresectable esophageal and gastroesophageal junction adenocarcinoma represent a devastating disease with 5-year survival rate of <5%. Although cytotoxic chemotherapy with platinum-doublet-based regimens is initially effective, patients inevitably progress. Patients often decline rapidly after this initial progression, making later lines of therapy a challenge to successfully administer There have been multiple efforts to incorporate biologic agents, targeting pathways known to be dysregulated in esophageal adenocarcinoma and gastroesophageal junction adenocarcinoma, into existing chemotherapy backbones. Other than therapeutics targeting human epidermal growth factor receptor-2 (HER2) and vascular endothelial growth factor receptor (VEGFR), other strategies have failed. Given the mixed success of biologic agents, along with the promise of immunotherapy to generate durable and sometimes complete responses, immune-agent based trials are a major area of interest for patients with this disease. Checkpoint inhibitors blocking programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have demonstrated modest single-agent efficacy in patients with progressive esophageal adenocarcinoma and gastroesophageal junction adenocarcinoma. However, other approaches such as novel checkpoint combinations, vaccine-based approaches and autologous T cells hold more promise to change the trajectory of disease.

Roles of Fibroblast Activation Protein and Hepatocyte Growth Factor Expressions in Angiogenesis and Metastasis of Gastric Cancer

This study aims to explore the roles of fibroblast activation protein (FAP) and hepatocyte growth factor (HGF) expressions in the angiogenesis and metastasis of gastric cancer (GC). From May 2012 to December 2015, 110 GC patients who received surgical treatment in the First Hospital of Qinhuangdao were selected. The HGF and FAP expressions in 110 cases of GC, 130 cases of normal gastric mucosa and 115 cases of gastric ulcer were detected by streptavidin-perosidase (SP) method. Venous blood HGF level of GC patients was tested by enzyme-linked immunosorbent assay (ELISA). The micro-vessel number of the patients in the three groups were calculated and analyzed. In GC group, positive expression rates of FAP and HGF protein were 61.8% and 67.3% respectively, which were both higher than those in normal gastric mucosa and gastric ulcer groups. The micro-vessel numbers in patients of the normal gastric mucosa and gastric ulcer groups are far less than that in GC group. FAP, HGF and micro-vessel density (MVD) were significantly correlated with infiltration depth, tumor-node-metastasis (TNM) staging, lymph node metastasis (LNM) and distant metastasis. The results of ELISA showed that serum HGF level was related to tumor size, infiltration degree, TNM staging, LNM and distant metastasis. FAP and HGF expressions in GC were positively correlated with MVD, and the expressions of FAP and HGF in GC were in positive correlation. Our study provided evidence that high FAP and HGF expressions may be positively correlated with the angiogenesis and metastasis of GC.

Clinical impact of high serum hepatocyte growth factor in advanced non-small cell lung cancer

Activation of c-MET through hepatocyte growth factor (HGF) increases tumorigenesis, induces resistance, and is associated with poor prognosis in various solid tumors. However, the clinical value of serum HGF (sHGF) in patients with advanced non-small cell lung cancer (NSCLC), especially those receiving cytotoxic chemotherapy, remains unknown. Here, we show that sHGF may be useful to predict tumor response and progression-free survival (PFS) in patients with advanced NSCLC. A total of 81 patients with NSCLC were investigated. sHGF levels were evaluated using ELISA at 4 time-points: at pre-treatment, at response-evaluation (1-2 months after treatment initiation), at the best tumor response, and at disease progression. As a control biomarker, CEA was also evaluated in lung adenocarcinoma. Positive-sHGF at response-evaluation predicted poor PFS compared with Negative-sHGF in both first-line (median, 153.5 vs. 288.0; P < 0.05) and second-line treatment (87.0 vs. 219.5; P = 0.01). In 55 patients that received cytotoxic chemotherapy, multiple Cox proportional hazards models showed significant independent associations between poor PFS and Positive-sHGF at response-evaluation (hazard ratio, 4.24; 95% CI, 2.05 to 9.46; P < 0.01). Lung adenocarcinoma subgroup analysis showed that in patients receiving second cytotoxic chemotherapy, there were no significant differences in PFS between patients with low-CEA compared with those with high-CEA, but Positive-sHGF at pre-treatment or at response-evaluation predicted poor PFS (35.0 vs. 132.0; P < 0.01, 50.0 vs. 215.0; P < 0.01, respectively). These findings give a rationale for future research investigating the merit of sHGF as a potential clinical biomarker to evaluate HGF/c-MET activity, which would be useful to indicate administration of c-MET inhibitors.

Expression of c-Met and hepatocyte growth factor in various gastric pathologies and its association with Helicobacter pylori infection

Activation of the hepatocyte growth factor (HGF)/c-Met signaling pathway was identified to be associated with malignant tumors. The present study aimed at determining the expression of HGF and c-Met in gastric carcinogenesis and its association with Helicobacter pylori infection. Gastric biopsies were obtained from 160 H. pylori-negative and -positive patients, including those with chronic gastritis, intestinal metaplasia, dysplasia and gastric cancer (GC). Proteins were extracted from GES-1, gastric epithelial, and AGS, gastric adenocarcinoma, cells following co-culture with H. pylori in vitro. The expression of HGF and c-Met in gastric tissues or cells was determined using immunohistochemistry and western blot analysis. The expression of c-Met increased in GC tissues (72.5%) compared with that in pre-cancerous lesions (17.5, 17.5 and 30%). Additional analysis identified that the expression of HGF and c-Met was significantly increased in the presence of H. pylori infection in dysplasia and gastric cancer samples. Furthermore, H. pylori may activate the HGF/c-Met signaling pathway in vitro, which may contribute to gastric carcinogenesis.

Hepatocyte growth factor/MET in cancer progression and biomarker discovery

Signaling driven by hepatocyte growth factor (HGF) and MET receptor facilitates conspicuous biological responses such as epithelial cell migration, 3‐D morphogenesis, and survival. The dynamic migration and promotion of cell survival induced by MET activation are bases for invasion–metastasis and resistance, respectively, against targeted drugs in cancers. Recent studies indicated that MET in tumor‐derived exosomes facilitates metastatic niche formation and metastasis in malignant melanoma. In lung cancer, gene amplification‐induced MET activation and ligand‐dependent MET activation in an autocrine/paracrine manner are causes for resistance to epidermal growth factor receptor tyrosine kinase inhibitors and anaplastic lymphoma kinase inhibitors. Hepatocyte growth factor secreted in the tumor microenvironment contributes to the innate and acquired resistance to RAF inhibitors. Changes in serum/plasma HGF, soluble MET (sMET), and phospho‐MET have been confirmed to be associated with disease progression, metastasis, therapy response, and survival. Higher serum/plasma HGF levels are associated with therapy resistance and/or metastasis, while lower HGF levels are associated with progression‐free survival and overall survival after treatment with targeted drugs in lung cancer, gastric cancer, colon cancer, and malignant melanoma. Urinary sMET levels in patients with bladder cancer are higher than those in patients without bladder cancer and associated with disease progression. Some of the multi‐kinase inhibitors that target MET have received regulatory approval, whereas none of the selective HGF‐MET inhibitors have shown efficacy in phase III clinical trials. Validation of the HGF‐MET pathway as a critical driver in cancer development/progression and utilization of appropriate biomarkers are key to development and approval of HGF‐MET inhibitors for clinical use.

Identifying the Appropriate FISH Criteria for Defining MET Copy Number-Driven Lung Adenocarcinoma through Oncogene Overlap Analysis

INTRODUCTION

Mesenchymal-epithelial transition factor gene (MET) gene copy number gain may be a predictive biomarker for mesenchymal-epithelial transition factor (MET) inhibition in lung cancer, but the most appropriate method and criteria for defining MET positivity are uncertain.

METHODS

MET copy number was assessed by fluorescence in situ hybridization in lung adenocarcinoma. Positivity criteria included mean MET per cell values greater than 5 (low [≥5 to <6], intermediate [≥6 to <7], and high [≥7]) and mean MET-to-chromosome 7 centromere ratios (MET/CEP7) of at least 1.8 (low [≥1.8 to ≤2.2], intermediate [>2.2 to <5], and high [≥5]). Associated clinical and molecular characteristics were captured.

RESULTS

Of 686 cases, 99 (14%) had a mean MET per cell value of 5 or greater, 52 of 1164 (4.5%) had a MET/CEP7 ratio of 1.8 or higher. Other oncogenic drivers (in EGFR, KRAS, anaplastic lymphoma receptor tyrosine kinase gene [ALK], erb-b2 receptor tyrosine kinase 2 gene [ERBB2], BRAF, NRAS, ROS1, or ret proto-oncogene [RET]) were detectable in 56% of the group with a mean MET per cell value of 5 or higher and 47% of the group with a MET/CEP7 ratio of 1.8 or higher, suggesting that many MET-positive cases are not truly MET addicted. The rates of concomitant drivers in the groups of patients in the low, indeterminate, and high categories of mean MET per cell were 32 of 52 (62%), 12 of 19 (63%), and 11 of 27 (41%) (p = 0.2), and the rates of concomitant drivers in the low, intermediate, and high categories of MET/CEP7 ratios were 15 of 29 (52%), 9 of 18 (50%), and 0 of 4 (0%), respectively (p = 0.04). A MET/CEP7 ratio of 1.8 or higher in the absence of other oncogenes was associated with a higher rate of adrenal metastases (p = 0.03) but not with never-smoking status.

CONCLUSIONS

A fluorescence in situ hybridization MET/CEP7 ratio of 5 or higher defined a "MET-positive" group with no oncogenic overlap. As this method and criteria are also associated with the highest response rate to MET inhibition, it represents the clearest definition of a MET copy number gain-addicted state. However, a MET-associated phenotype may also exist across cases with a MET/CEP7 of 1.8 or higher when no other oncogene overlap occurs.

A plasma cytokine and angiogenic factor (CAF) analysis for selection of bevacizumab therapy in patients with metastatic colorectal cancer

This study intends to identify biomarkers that could refine the selection of patients with metastatic colorectal cancer (mCRC) for bevacizumab treatment. Pretreatment 36 plasma cytokines and angiogenic factors (CAFs) were first measured by protein microarray analysis in patients who received first-line bevacizumab-containing therapies (discovery cohort, n = 64), and further evaluated by enzyme-linked immunosorbent assay in patients treated on regimens with or without bevacizumab (validation cohort, n = 186). Factor levels were correlated with clinical outcomes, predictive values were assessed using a treatment by marker interaction term in the Cox model. Patients with lower pretreatment levels of hepatocyte growth factor (HGF) or VEGF-A¹²¹ gain much more benefit from bevacizumab treatment as measured by progression-free survival (PFS) and overall survival (OS), while angiopoietin-like 4 (ANGPTL4) levels negatively correlated with PFS and response rate following bevacizumab (all adjusted interaction P < 0.05). A baseline CAF signature combining these three markers has greater predictive ability than individual markers. Signature-negative patients showed impaired survival following bevacizumab treatment (PFS, 7.3 vs 7.0 months; hazard ratio [HR] 1.03; OS, 29.9 vs 21.1 months, HR 1.33) compared with signature-positive patients (PFS, 6.5 vs 11.9 months, HR 0.52; OS, 28.0 vs 55.3 months, HR 0.67). These promising results warrant further prospective studies.

Upfront molecular testing in patients with advanced gastro-esophageal cancer: Is it time yet?

INTRODUCTION

Targeting HER2 has improved outcomes in metastatic GE (mGE) cancer. In this study, we aim to explore the feasibility of molecular profiling in patients with refractory mGE cancer in routine clinical practice.

METHODS

Archival formalin-fixed, paraffin-embedded (FFPE) samples for patients with mGE were analyzed with commercially available targeted next generation sequencing (NGS) and/or FISH for MET amplification. We also reviewed the patients' medical records for concurrent HER 2 testing.

RESULTS

Tumor samples from 99 patients with mGE cancer were analyzed as follows: NGS (N = 56), FISH for MET amplification (N = 65), IHC and/or FISH for HER2 (N = 87). Of patients who underwent NGS, 50/56 (89%) had at least one actionable molecular alteration. The most notable actionable alterations included cell cycle abnormalities (58%), HER2 amplification (30%), PI3KCA mutation (14%), MCL1 amplification (11%), PTEN loss (9%), CDH1 mutation (2%) and MET amplification (5%). Ninety-two percent (12/13) of patients with HER2 amplification by NGS were positive for HER2 by IHC and/or FISH. In contrast, only 12/18 (66%) patients positive for HER2 by IHC and/or FISH demonstrated HER2 amplification by NGS.

CONCLUSION

Comprehensive molecular testing is feasible in clinical practice and provides a platform for screening patients for molecularly guided clinical trials and available targeted therapies.

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.