Phase I dose-escalation study of the c-Met tyrosine kinase inhibitor SAR125844 in Asian patients with advanced solid tumors, including patients with MET-amplified gastric cancer

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.

Characterization of MET Alterations in 37 Gastroesophageal Cancer Cell Lines for MET-Targeted Therapy

Capmatinib and savolitinib, selective MET inhibitors, are widely used to treat various MET-positive cancers. In this study, we aimed to determine the effects of these inhibitors on MET-amplified gastric cancer (GC) cells. Methods: After screening 37 GC cell lines, the following cell lines were found to be MET-positive with copy number variation >10: SNU-620, ESO51, MKN-45, SNU-5, and OE33 cell lines. Next, we assessed the cytotoxic response of these cell lines to capmatinib or savolitinib alone using cell counting kit-8 and clonogenic cell survival assays. Western blotting was performed to assess the effects of capmatinib and savolitinib on the MET signaling pathway. Xenograft studies were performed to evaluate the in vivo therapeutic efficacy of savolitinib in MKN-45 cells. Savolitinib and capmatinib exerted anti-proliferative effects on MET-amplified GC cell lines in a dose-dependent manner. Savolitinib inhibited the phosphorylation of MET and downstream signaling pathways, such as the protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) pathways, in MET-amplified GC cells. Additionally, savolitinib significantly decreased the number of colonies formed on the soft agar and exerted dose-dependent anti-tumor effects in an MKN-45 GC cell xenograft model. Furthermore, a combination of trastuzumab and capmatinib exhibited enhanced inhibition of AKT and ERK activation in human epidermal growth factor receptor-2 (HER2)- and MET-positive OE33 cells. Targeting MET with savolitinib and capmatinib efficiently suppressed the growth of MET-amplified GC cells. Moreover, these MET inhibitors exerted synergistic effects with trastuzumab on HER2- and MET-amplified GC cells.

Advances in MET tyrosine kinase inhibitors in gastric cancer

Gastric cancer is among the most frequently occurring cancers and a leading cause of cancer-related deaths globally. Because gastric cancer is highly heterogenous and comprised of different subtypes with distinct molecular and clinical characteristics, the management of gastric cancer calls for better-defined, biomarker-guided, molecular-based treatment strategies. MET is a receptor tyrosine kinase mediating important physiologic processes, such as embryogenesis, tissue regeneration, and wound healing. However, mounting evidence suggests that aberrant MET pathway activation contributes to tumour proliferation and metastasis in multiple cancer types, including gastric cancer, and is associated with poor patient outcomes. As such, MET-targeting therapies are being actively developed and promising progress has been demonstrated, especially with MET tyrosine kinase inhibitors. This review aims to briefly introduce the role of MET alterations in gastric cancer and summarize in detail the current progress of MET tyrosine kinase inhibitors in this disease area with a focus on savolitinib, tepotinib, capmatinib, and crizotinib. Building on current knowledge, this review further discusses existing challenges in MET alterations testing, possible resistance mechanisms to MET inhibitors, and future directions of MET-targeting therapies.

Current molecular biomarkers evaluation in gastric/gastroesophageal junction adenocarcinoma: pathologist does matter

The comprehensive molecular characterization of gastric and gastroesophageal junction adenocarcinomas has led to the improvement of targeted and more effective treatments. As a result, several biomarkers have been introduced into clinical practice and the implementation of innovative diagnostic tools is under study. Such assessments are mainly based on the evaluation of limited biopsy material in clinical practice. In this setting, the pathologist represents a key player in the selection of patients facilitating precision medicine approaches.

Management and Treatment of Non-small Cell Lung Cancer with MET Alteration and Mechanisms of Resistance

OPINION STATEMENT

MET-driven tumors are a heterogenous group of non-small cell lung cancers (NSCLC) with activating mutations. Pathologic activation of MET can be achieved with increased number of gene copies overexpression, or decreased protein degradation through several mechanisms, including mutations, amplifications, or fusions. Besides its role as primary driver, MET activation might also mediate resistance to kinase inhibitors in NSCLC with various other actionable alterations. While checkpoint inhibitors have modest efficacy in MET-driven tumors, several approaches of targeted blockade are available. Among them the most promising are small tyrosine kinase inhibitors, antibody-drug conjugates, and bispecific antibodies. Unfortunately, resistance is virtually inevitable. Resistance to small kinase inhibitors might be mediated by kinase domain mutations or activation of shunting cascades. Various resistance mechanisms might be present in one patient, making it overcoming an unresolved problem.

Opportunities and challenges of targeting c-Met in the treatment of digestive tumors

At present, a large number of studies have demonstrated that c-Met generally exerts a crucial function of promoting tumor cells proliferation and differentiation in digestive system tumors. c-Met also mediates tumor progression and drug resistance by signaling interactions with other oncogenic molecules and then activating downstream pathways. Therefore, c-Met is a promising target for the treatment of digestive system tumors. Many anti-tumor therapies targeting c-Met (tyrosine kinase inhibitors, monoclonal antibodies, and adoptive immunotherapy) have been developed in treating digestive system tumors. Some drugs have been successfully applied to clinic, but most of them are defective due to their efficacy and complications. In order to promote the clinical application of targeting c-Met drugs in digestive system tumors, it is necessary to further explore the mechanism of c-Met action in digestive system tumors and optimize the anti-tumor treatment of targeting c-Met drugs. Through reading a large number of literatures, the author systematically reviewed the biological functions and molecular mechanisms of c-Met associated with tumor and summarized the current status of targeting c-Met in the treatment of digestive system tumors so as to provide new ideas for the treatment of digestive system tumors.

Study on the expression of c-Met in gastric cancer and its correlation with preoperative serum tumor markers and prognosis

Background

Studies have found that c-Met plays a critical role in the progression of solid tumors. This study aimed to investigate the expression of c-Met in gastric cancer (GC) and its correlation with preoperative serum tumor markers and prognosis, in order to provide a more theoretical basis for targeting c-Met in the treatment of GC.

Methods

Ninety-seven patients who underwent curative gastrectomy in our hospital from December 2013 to September 2015 were included in this study. The tissue microarray was constructed by paraffin-embedded tumor tissue of enrolled patients, including 97 GC points and 83 paracancerous points. Then, it was used for c-Met immunohistochemical staining, followed by an immunological H-score. The clinical baseline data and 5-year survival of patients with low and high c-Met expression were compared. Besides, the correlation between the expression of c-Met in tumor tissues and preoperative serum tumor markers was investigated. Finally, multivariate Cox regression analysis was used to explore the survival risk factors of patients.

Results

c-Met has a high expression rate in GC tissues 64.95% (63/97). The expression of c-Met was significantly different in different clinicopathological stages (p < 0.05); the high expression group also had a higher M stage and clinicopathological stage of GC. The correlation test between the c-Met H-score and CA125 was statistically significant (p = 0.004), indicating a positive correlation. Furthermore, high c-Met expression correlated with poor overall survival (OS) for 5 years (p = 0.005). It was also found that the high expression of c-Met in stage I–II patients was correlative with poor OS for 5 years (p = 0.026), while stage III–IV patients had no statistical significance (p > 0.05). Multivariate Cox regression analysis showed that c-Met might be an independent risk factor for survival 5 years after surgery.

Conclusion

This study found that the high expression of c-Met in GC tissues was associated with poor 5-year OS in GC patients and was an independent risk factor for 5-year survival after curative gastrectomy. The expression of c-Met in GC tissues was also positively correlated with preoperative serum CA125.

MET-Targeted Therapies and Clinical Outcomes: A Systematic Literature Review

Introduction

Numerous therapeutic agents specifically targeting the mesenchymal-epithelial transition (MET) oncogene are being developed.

Objective

The aim of the current review was to systematically identify and analyze clinical trials that have evaluated MET inhibitors in various cancer types and to provide an overview of their clinical outcomes.

Methods

An electronic literature search was carried out in the PubMed and Embase databases to identify published clinical trials related to MET inhibitors. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement was followed for the systematic appraisal of the literature. Data related to clinical outcomes, including progression-free survival, overall survival, objective response rate, and overall tumor response, were extracted.

Results

In total, 49 publications were included. Among these, 51.02% were phase II studies, 14.28% were randomized controlled trials, three were phase III studies, two were prospective observational studies, and the remainder were either phase I or Ib studies. The majority (44.89%) of articles reported the clinical outcomes of MET inhibitors, including small molecules, monoclonal antibodies, and other agents, in patients with non-small-cell lung cancer (NSCLC) harboring MET alterations. MET amplification, overexpression, and MET exon 14 skipping mutations were the major MET alteration types reported across the included studies. Clinical responses/outcomes varied considerably.

Conclusion

This systematic literature review provides an overview of the literature available in Embase and PubMed regarding MET-targeted therapies. MET-selective tyrosine kinase inhibitors (TKIs) (capmatinib, tepotinib, and savolitinib) may become a new standard of care in NSCLC, specifically with MET exon 14 skipping mutations. A combination of MET TKIs with epidermal growth factor receptor (EGFR) TKIs (osimertinib + savolitinib, tepotinib + gefitinib) may be a potential solution for MET-driven EGFR TKI resistance. Further, MET alteration (MET amplification/overexpression) may be an actionable target in gastric cancer and papillary renal cell carcinoma.

OUP accepted manuscript

Bone metastases are often difficult to manage as they can be symptomatic and skeletal-related events (SREs) can contribute to significant morbidity and declines in performance status. We sought to identify a novel medical treatment for bone metastasis by testing the safety and efficacy of cabozantinib in patients with bone metastasis arising from non-breast, non-prostate, malignant solid tumors. Patients were administered cabozantinib as an oral drug starting at 60 mg per day and radiologic measurements were performed at baseline and every 8 weeks. Thirty-seven patients were enrolled. No SREs were observed throughout the study. Twenty patients had disease measurable by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Four of 20 had a partial response by RECIST. An additional 12 patients had some decrease in tumor burden with nine of these having a decrease in tumor burden of at least 10% by RECIST. Six of the patients with at least a minor response had sarcoma. Sixteen patients had biomarkers of bone turnover measured before and after treatment. Most of these patients demonstrated decrease in urine and serum N-telopeptide and serum C-telopeptide. However, these changes in biomarkers of bone turnover did not correlate with radiographic changes measured by RECIST. This study demonstrates clinical activity and safety for cabozantinib in heavily pretreated patients with bone metastasis and shows activity for cabozantinib in patients with metastatic sarcoma.

Epithelial to Mesenchymal Transition: A Challenging Playground for Translational Research. Current Models and Focus on TWIST1 Relevance and Gastrointestinal Cancers

Resembling the development of cancer by multistep carcinogenesis, the evolution towards metastasis involves several passages, from local invasion and intravasation, encompassing surviving anoikis into the circulation, landing at distant sites and therein establishing colonization, possibly followed by the outgrowth of macroscopic lesions. Within this cascade, epithelial to mesenchymal transition (EMT) works as a pleiotropic program enabling cancer cells to overcome local, systemic, and distant barriers against diffusion by replacing traits and functions of the epithelial signature with mesenchymal-like ones. Along the transition, a full-blown mesenchymal phenotype may not be accomplished. Rather, the plasticity of the program and its dependency on heterotopic signals implies a pendulum with oscillations towards its reversal, that is mesenchymal to epithelial transition. Cells in intermixed E⇔M states can also display stemness, enabling their replication together with the epithelial reversion next to successful distant colonization. If we aim to include the EMT among the hallmarks of cancer that could modify clinical practice, the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers needs to be filled. We review the knowledge on EMT, derived from models and mechanistic studies as well as from translational studies, with an emphasis on gastrointestinal cancers (GI).

Small molecules in targeted cancer therapy: advances, challenges, and future perspectives

Due to the advantages in efficacy and safety compared with traditional chemotherapy drugs, targeted therapeutic drugs have become mainstream cancer treatments. Since the first tyrosine kinase inhibitor imatinib was approved to enter the market by the US Food and Drug Administration (FDA) in 2001, an increasing number of small-molecule targeted drugs have been developed for the treatment of malignancies. By December 2020, 89 small-molecule targeted antitumor drugs have been approved by the US FDA and the National Medical Products Administration (NMPA) of China. Despite great progress, small-molecule targeted anti-cancer drugs still face many challenges, such as a low response rate and drug resistance. To better promote the development of targeted anti-cancer drugs, we conducted a comprehensive review of small-molecule targeted anti-cancer drugs according to the target classification. We present all the approved drugs as well as important drug candidates in clinical trials for each target, discuss the current challenges, and provide insights and perspectives for the research and development of anti-cancer drugs.

Molecular-targeted therapy toward precision medicine for gastrointestinal cancer: Current progress and challenges

Gastrointestinal (GI) cancer remains the deadliest cancer in the world. The current standard treatment for GI cancer focuses on 5-fluorouracil-based chemotherapeutic regimens and surgery, and molecular-targeted therapy is expected to be a more effective and less toxic therapeutic strategy for GI cancer. There is well-established evidence for the use of epidermal growth factor receptor-targeted and vascular endothelial growth factor-targeted antibodies, which should routinely be incorporated into treatment strategies for GI cancer. Other potential therapeutic targets involve the PI3K/AKT pathway, tumor growth factor-β pathway, mesenchymal-epithelial transition pathway, WNT pathway, poly (ADP-ribose) polymerase, and immune checkpoints. Many clinical trials assessing the agents of targeted therapy are underway and have presented promising and thought-provoking results. With the development of molecular biology techniques, we can identify more targetable molecular alterations in larger patient populations with GI cancer. Targeting these molecules will allow us to reach the goal of precision medicine and improve the outcomes of patients with GI cancer.

Targeted dual inhibition of c-Met/VEGFR2 signalling by foretinib improves antitumour effects of nanoparticle paclitaxel in gastric cancer models

Elevated expression of multiple growth factors and receptors including c‐Met and VEGFR has been reported in gastric adenocarcinoma (GAC) and thus provides a potentially useful therapeutic target. The therapeutic efficacy of foretinib, a c‐Met/VEGFR2 inhibitor, was determined in combination with nanoparticle paclitaxel (NPT) in GAC. Animal studies were conducted in NOD/SCID mice in subcutaneous and peritoneal dissemination xenografts. The mechanism of action was assessed by Immunohistochemical and Immunoblot analyses. In c‐Met overexpressing MKN‐45 cell‐derived xenografts, NPT and foretinib demonstrated inhibition in tumour growth, while NPT plus foretinib showed additive effects. In c‐Met low‐expressing SNU‐1 or patient‐derived xenografts, the foretinib effect was smaller, while NPT had a similar effect compared with MKN‐45, as NPT plus foretinib still exhibited an additive response. Median mice survival was markedly improved by NPT (83%), foretinib (100%) and NPT plus foretinib (230%) in peritoneal dissemination xenografts. Subcutaneous tumour analyses exhibited that foretinib increased cancer cell death and decreased cancer cell proliferation and tumour vasculature. NPT and foretinib suppressed the proliferation of GAC cells in vitro and had additive effects in combination. Further, foretinib caused a dramatic decrease in phosphorylated forms of c‐Met, ERK, AKT and p38. Foretinib led to a decrease in Bcl‐2, and an increase in p27, Bax, Bim, cleaved PARP‐1 and cleaved caspase‐3. Thus, these findings highlight the antitumour impact of simultaneous suppression of c‐Met and VEGFR2 signalling in GAC and its potential to enhance nanoparticle paclitaxel response. This therapeutic approach might lead to a clinically beneficial combination to increase GAC patients’ survival.

The impact of recent next generation sequencing and the need for a new classification in gastric cancer

The phenotypical and molecular heterogeneity of gastric cancer has hampered the introduction in clinical practice of a unifying classification of the disease. However, as next generation sequencing (NGS) technologies enhanced the comprehension of the molecular landscape of gastric cancer, novel molecular classification systems have been proposed, allowing the dissection of molecular tumor heterogeneity and paving the way for the development of new targeted therapies. Moreover, the use of NGS analyses in the molecular profiling of formalin-fixed paraffin-embedded (FFPE) specimens will improve patient selection for the enrolment in novel clinical trials. In conclusion, the application of NGS in precision oncology will revolutionize the diagnosis and clinical management in gastric cancer patients.

Emerging role of phytochemicals in targeting predictive, prognostic, and diagnostic biomarkers of lung cancer

Lung-cancer is the foremost cause of cancer in humans worldwide, of which 80-85% cases are composed of non-small cell lung carcinoma. All treatment decisions depend on the pattern of biomarkers selection to enhance the response to the targeted therapies. Although advanced treatments are available for lung-cancer, the disease treatment remains not adequate. There are several synthetic chemotherapeutic agents available for the treatment of lung cancer. However, due to their toxic effect, survival rate is still 15-18%. Besides, medicinal plants are a huge reservoir of natural products that provide protective effects against lung cancer. Likewise, successful studies of potential phytochemicals in targeting lung-cancer biomarkers have created a novel paradigm for the discovery of potent drugs against lung-cancer. Hence, to defeat severe toxicity and resistance towards the synthetic drugs, detailed studies are required regarding the available phytochemicals and targets responsible for the treatment of lung-cancer. The present review provides a comprehensive information about the lung-cancer biomarkers under the classification of predictive, prognostic, and diagnostic type. Moreover, it discusses and enlists the phytochemicals with mode of action against different biomarkers, effective doses in in vitro, in vivo, and clinical studies, the limitations associated with usage of phytochemicals as a drug to prevent/cure lung-cancer and the latest techniques employed to overcome such issues.

Differential Inhibitory Actions of Multitargeted Tyrosine Kinase Inhibitors on Different Ionic Current Types in Cardiomyocytes

Lapatinib (LAP) and sorafenib (SOR) are multitargeted tyrosine kinase inhibitors (TKIs) with antineoplastic properties. In clinical observations, LAP and SOR may contribute to QTc prolongation, but the detailed mechanism for this has been largely unexplored. In this study, we investigated whether LAP and SOR affect the activities of membrane ion channels. Using a small animal model and primary cardiomyocytes, we studied the impact of LAP and SOR on Na⁺ and K⁺ currents. We found that LAP-induced QTc prolongation in mice was reversed by isoproterenol. LAP or SOR suppressed the amplitude of the slowly activating delayed-rectifier K⁺ current (I_K(S)) in H9c2 cells in a time- and concentration-dependent fashion. The LAP-mediated inhibition of I_K(S) was reversed by adding isoproterenol or meclofenamic acid, but not by adding diazoxide. The steady-state activation curve of I_K(S) during exposure to LAP or SOR was shifted toward a less negative potential, with no change in the gating charge required to activate the current. LAP shortened the recovery from I_K(S) deactivation. As rapid repetitive stimuli, the I_K(S) amplitude decreased; however; the LAP-induced inhibition of I_K(S) remained effective. LAP or SOR alone also suppressed inwardly rectifying K⁺ and voltage-gated Na⁺ current in neonatal rat ventricular myocytes. The inhibition of ionic currents during exposure to TKIs could be an important mechanism underlying changes in QTc intervals.

HGF/MET pathway aberrations as diagnostic, prognostic, and predictive biomarkers in human cancers

Cancer is a major cause of death worldwide. MET tyrosine kinase receptor [MET, c-MET, hepatocyte growth factor (HGF) receptor] pathway activation is associated with the appearance of several hallmarks of cancer. The HGF/MET pathway has emerged as an important actionable target across many solid tumors; therefore, biomarker discovery becomes essential in order to guide clinical intervention and patient stratification with the aim of moving towards personalized medicine. The focus of this review is on how the aberrant activation of the HGF/MET pathway in tumor tissue or the circulation can provide diagnostic and prognostic biomarkers and predictive biomarkers of drug response. Many meta-analyses have shown that aberrant activation of the MET pathway in tumor tissue, including MET gene overexpression, gene amplification, exon 14 skipping and other activating mutations, is almost invariably associated with shorter survival and poor prognosis. Most meta-analyses have been performed in non-small cell lung cancer (NSCLC), breast, head and neck cancers as well as colorectal, gastric, pancreatic and other gastrointestinal cancers. Furthermore, several studies have shown the predictive value of MET biomarkers in the identification of patients who gain the most benefit from HGF/MET targeted therapies administered as single or combination therapies. The highest predictive values have been observed for response to foretinib and savolitinib in renal cancer, as well as tivantinib in NSCLC and colorectal cancer. However, some studies, especially those based on MET expression, have failed to show much value in these stratifications. This may be rooted in lack of standardization of methodologies, in particular in scoring systems applied in immunohistochemistry determinations or absence of oncogenic addiction of cancer cells to the MET pathway, despite detection of overexpression. Measurements of amplification and mutation aberrations are less likely to suffer from these pitfalls. Increased levels of MET soluble ectodomain (sMET) in circulation have also been associated with poor prognosis; however, the evidence is not as strong as it is with tissue-based biomarkers. As a diagnostic biomarker, sMET has shown its value in distinguishing cancer patients from healthy individuals in prostate and bladder cancers and in melanoma. On the other hand, increased circulating HGF has also been presented as a valuable prognostic and diagnostic biomarker in many cancers; however, there is controversy on the predictive value of HGF as a biomarker. Other biomarkers such as circulating tumor DNA (ctDNA) and tumor HGF levels have also been briefly covered. In conclusion, HGF/MET aberrations can provide valuable diagnostic, prognostic and predictive biomarkers and represent vital assets for personalized cancer therapy.

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.

Circulating Tumor DNA Profiling in Small-Cell Lung Cancer Identifies Potentially Targetable Alterations

PURPOSE

Patients with SCLC rarely undergo biopsies at relapse. When pursued, tissue obtained can be inadequate for molecular testing, posing a challenge in identifying potentially targetable alterations in a clinically meaningful time frame. We examined the feasibility of circulating tumor DNA (ctDNA) testing in identifying potentially targetable alterations in SCLC.

EXPERIMENTAL DESIGN

ctDNA test results were prospectively collected from patients with SCLC between 2014 and 2017 and analyzed. ctDNA profiles of SCLC at diagnosis and relapse were also compared.

RESULTS

A total of 609 samples collected from 564 patients between 2014 and 2017 were analyzed. The median turnaround time for test results was 14 days. Among patients with data on treatment status, there were 61 samples from 59 patients and 219 samples from 206 patients collected at diagnosis and relapse, respectively. The number of mutations or amplifications detected per sample did not differ by treatment status. Potentially targetable alterations in DNA repair, MAPK and PI3K pathways, and genes such as MYC and ARID1A were identifiable through ctDNA testing. Furthermore, our results support that it may be possible to reconstruct the clonal relationship between detected variants through ctDNA testing.

CONCLUSIONS

Patients with relapsed SCLC rarely undergo biopsies for molecular testing and often require prompt treatment initiation. ctDNA testing is less invasive and capable of identifying alterations in relapsed disease in a clinically meaningful timeframe. ctDNA testing on an expanded gene panel has the potential to advance our knowledge of the mechanisms underlying treatment resistance in SCLC and aid in the development of novel treatment strategies.

Next-generation sequencing and biomarkers for gastric cancer: what is the future?

Recent years have witnessed an improved understanding of tumour biology and the molecular features of gastric cancer. Remarkable advances in next-generation sequencing technologies have defined the genomic landscape of gastric cancer. In fact, several molecular classifications have been proposed, and distinct molecular subtypes have been identified, which could serve as a roadmap for patient stratification and trials of targeted therapies. At present, clinical trials of new agents, such as receptor tyrosine kinases inhibitors, antibody-drug conjugates and IMAB362 (anti-Claudin 18.2), are ongoing. Furthermore, biomarkers of immune checkpoint inhibitors or combination therapy have been ardently investigated. These developments could facilitate precision medicine for gastric cancer in the near future.

Dawn of precision medicine on gastric cancer

BACKGROUND

In recent years, a better understanding of tumor biology and molecular features of gastric cancer has been reached. It may serve as a roadmap for patient stratification and trials of targeted therapies. The apparent efficacy of PD-1 blockade might be limited to a relatively small subset of advanced gastric cancer patients.

MATERIALS AND METHODS

In this study, preclinical and clinical studies, which investigated molecular features, promising treatment targets, and immune checkpoint inhibitor in gastric cancer, were reviewed via PubMed and the congress webpages of the American Society of Clinical Oncology and European Society of Medical Oncology.

RESULTS

Next-generation sequencing technologies have defined the genomic landscape of gastric cancer. Indeed, several molecular classifications have been proposed, and distinct molecular subtypes have been identified. Based on these molecular profiles, clinical trials of new agents such as receptor tyrosine kinases inhibitors, antibody-drug conjugates, and IMAB362 (anti-Claudin 18.2) are ongoing. In addition, biomarkers to predict response during immune checkpoint inhibitors and combination therapy have been enthusiastically investigated.

CONCLUSION

Remarkable advances in an understanding of molecular profiles of gastric cancer enable the development of novel agents. The better treatment selection of immune checkpoint inhibitors or combination therapy should be established. These developments could facilitate precision medicine on gastric cancer in the near future.

MET Inhibition in Non-Small Cell Lung Cancer

Cancer treatment paradigms have evolved over recent years with an emphasis on personalised medicine. Targeted agents are being used to improve treatment outcomes and quality of life. For the treatment of non-small cell lung cancer, several agents with unique genetic and epigenetic targets are available. To this extent, mesenchymal–epithelial transition (MET), a heterodimer receptor tyrosine kinase involved in embryogenesis and organogenesis, has been investigated as a potential target for biological agents. MET dysregulation can occur via different mechanisms and trigger tumourigenesis and disease spread. Besides driving the oncogenic dependence of cells, MET is also involved in acquired resistance to epidermal growth factor receptor inhibitors. As such, many small molecule kinase inhibitors and antibodies have been developed or are currently in different phases of clinical trials to counteract the MET-induced neoplastic activity. Some of these agents are selective while others are nonselective with multiple other potential targets. This article aims to present an overview of biological functioning of MET, its role in oncogenesis and resistance to treatment, and clinical studies evaluating MET inhibitors for treatment of non-small cell lung cancer.

HGF/c-MET: A Promising Therapeutic Target in the Digestive System Cancers

The HGF/c-MET pathway is active in the development of digestive system cancers, indicating that inhibition of HGF/c-MET signaling may have therapeutic potential. Various HGF/c-MET signaling inhibitors, mainly c-MET inhibitors, have been tested in clinical trials. The observed efficacy and adverse events of some c-MET inhibitors were not very suitable for treating digestive system cancers. The development of new HGF/c-MET inhibitors in preclinical studies may bring promising treatments and synergistic combination (traditional anticancer drugs and c-MET inhibitors) strategies provided anacceptable safety and tolerability. Insights into miRNA biology and miRNA therapeutics have made miRNAs attractive tools to inhibit HGF/c-MET signaling. Recent reports show that several microRNAs participate in inhibiting HGF/c-MET signaling networks through antagonizing c-MET or HGF in digestive system cancers, and the miRNAs-HGF/c-MET axis plays crucial and novel roles for cancer treatment. In the current review, we will discuss recent findings about inhibitors of HGF/c-MET signaling in treating digestive system cancers, and how miRNAs regulate digestive system cancers via mediating HGF/c-MET pathway.

Status of Agents Targeting the HGF/c-Met Axis in Lung Cancer

Hepatocyte growth factor (HGF) is the ligand for the tyrosine kinase receptor c-Met (Mesenchymal Epithelial Transition Factor also known as Hepatocyte Growth Factor Receptor, HGFR), a receptor with expression throughout epithelial and endothelial cell types. Activation of c-Met enhances cell proliferation, invasion, survival, angiogenesis, and motility. The c-Met pathway also stimulates tissue repair in normal cells. A body of past research shows that increased levels of HGF and/or overexpression of c-Met are associated with poor prognosis in several solid tumors, including lung cancer, as well as cancers of the head and neck, gastro-intestinal tract, breast, ovary and cervix. The HGF/c-Met signaling network is complex; both ligand-dependent and ligand-independent signaling occur. This article will provide an update on signaling through the HGF/c-Met axis, the mechanism of action of HGF/c-Met inhibitors, the lung cancer patient populations most likely to benefit, and possible mechanisms of resistance to these inhibitors. Although c-Met as a target in non-small cell lung cancer (NSCLC) showed promise based on preclinical data, clinical responses in NSCLC patients have been disappointing in the absence of MET mutation or MET gene amplification. New therapeutics that selectively target c-Met or HGF, or that target c-Met and a wider spectrum of interacting tyrosine kinases, will be discussed.