Clinical efficacy of immune checkpoint inhibitors in the treatment of unresectable advanced or recurrent gastric cancer: an evidence-based review of therapies

Biomarker-oriented chemo-immunotherapy for advanced gastric cancer

The biomarker-oriented chemo-immunotherapy is useful and promising in the development of new anticancer agents, since the responders can be enriched by selecting patients with biomarkers. Compared to colorectal and lung cancers, the development of biomarker-driven molecular-targeted therapeutics for gastric cancers has been straggled. However, several new biomarkers in gastric cancers have been discovered and clinical trials in enrichment design with certain biomarkers have been conducted. Therefore, there are currently several treatment options to treat gastric cancer patients based on individual biomarker-oriented strategies. In the present review, we describe the useful biomarkers in gastric cancer, with focusing on HER2, PD-L1, and Claudin18.2, in relation to their clinical significance and associated targeted agents.

Association of probiotic use with nivolumab effectiveness against various cancers: A multicenter retrospective cohort study

BACKGROUND

Previous studies have revealed an association between probiotic use and effectiveness of immune checkpoint inhibitors in renal and lung cancers. However, little is known regarding other cancers, including gastrointestinal cancer.

METHODS

To address this issue, we conducted a multicenter retrospective cohort study and the duration of nivolumab treatment for various cancers was compared between probiotic users and non-users.

RESULTS AND CONCLUSIONS

In total, 488 patients who received nivolumab therapy were included. In all cancers, no significant differences in treatment duration of nivolumab were observed between probiotic users and non-users (median 62.0 vs. 56.0, hazard ratio = 1.02, p = 0.825), whereas probiotic use, compared with non-use, in patients with gastric cancer was significantly associated with a longer duration of nivolumab treatment (55.0 vs. 31.0 days, hazard ratio = 0.69, p = 0.039). In conclusion, probiotics may improve the response to nivolumab and potentially prolong progression-free survival in patients with gastric cancer.

Expression pattern of PCAT1, PCAT2, and PCAT5 lncRNAs and their value as diagnostic biomarkers in patients with gastric cancer

BACKGROUND

Gastric cancer (GC), is a complex multifactorial neoplasm with a high mortality and prevalence rate all over the world. Hence, it is necessary to identify the multiple pathways that are previously unknown and are involved in its initiation and progression. Recently, it has become clear that long non-coding RNAs (lncRNAs) play a crucial role in the onset and spread of cancer. The current study assessed the lncRNAs PCAT1, PCAT2, and PCAT5 expression in primary gastric tumors and adjacent noncancerous tissues.

METHODS

90 pairs of GC and adjacent noncancerous tissue samples were obtained. Total RNA was extracted, then cDNA was synthesized. Using quantitative reverse transcriptase PCR (qRT-PCR), PCAT1, PCAT2, and PCAT5 expression levels were evaluated. Using the SPSS statistical package, the correlation between clinicopathological characteristics and the expression of PCAT1, PCAT2, and PCAT5 was investigated. The diagnostic value of PCAT1, PCAT2, and PCAT5 in GC was assessed using the receiver operating characteristic (ROC) curve analysis.

RESULTS

Compared to surrounding non-cancerous tissues, PCAT1, PCAT2, and PCAT5 were all significantly overexpressed in tumoral tissues (P = 0.001, P = 0.019, and P = 0.0001, respectively). PCAT5 expression was significantly associated with gender (P = 0.020), according to our research. The ROC curve's findings indicated that PCAT1, PCAT2, and PCAT5 may each function as poor diagnostic biomarkers, with respective AUC values of 64 %, 60 %, and 68 %, specificity values of 68 %, 60 %, and 76 %, and sensitivity values of 55 %, 72 %, and 52 %.

CONCLUSION

Our research suggested that PCAT1, PCAT2, and PCAT5 may be engaged in promoting and developing GC cells as a novel oncogene because of the increased expression of PCAT1, PCAT2 and PCAT5 in tumor tissues of GC patients. Additionally, PCAT1, PCAT2, and PCAT5 can be thought of as poor diagnostic biomarkers for GC case detection.

Mutational Signatures in Gastric Cancer and Their Clinical Implications

Gastric cancer is characterised by high inter- and intratumour heterogeneity. The majority of patients are older than 65 years and the global burden of this disease is increasing due to the aging of the population. The disease is usually diagnosed at advanced stages, which is a consequence of nonspecific symptoms. Few improvements have been made at the level of noninvasive molecular diagnosis of sporadic gastric cancer, and therefore the mortality rate remains high. A new field of mutational signatures has emerged in the past decade with advances in the genome sequencing technology. These distinct mutational patterns in the genome, caused by exogenous and endogenous mutational processes, can be associated with tumour aetiology and disease progression, and could provide novel perception on the treatment possibilities. This review assesses the mutational signatures found in gastric cancer and summarises their potential for use in clinical setting as diagnostic or prognostic biomarkers. Associated treatment options and biomarkers already implemented in clinical use are discussed, together with those that are still being explored or are in clinical studies.

Incidence and Risk of Hematological Adverse Events Associated With Immune Checkpoint Inhibitors: A Systematic Literature Review and Meta-Analysis

Background

Immune checkpoint inhibitors (ICIs) have been a breakthrough in cancer therapy. ICI therapy is generally better tolerated than cytotoxic chemotherapy; however, hematological adverse events (AEs) have not been fully analyzed. Hence, we performed a meta-analysis to evaluate the incidence and risk of ICI-related hematological AEs.

Methods

A systematic literature search was performed using PubMed, EMBASE, Cochrane Library, and the Web of Science Core Collection. Phase III randomized controlled trials (RCTs) involving ICI combination regimens were selected. The experimental group received ICIs with systemic treatment, and the control group received only the same systemic treatment. Odds ratios (ORs) for anemia, neutropenia, and thrombocytopenia were calculated using a random-model meta-analysis.

Results

We identified 29 RCTs with 20,033 patients. The estimated incidence rates for anemia of all grades and grades III-V were 36.5% (95% confidence interval (CI) 30.23 - 42.75) and 4.1% (95% CI 3.85 - 4.42), respectively. The incidence of neutropenia (all grades 29.7%, grades III-V 5.3%) and thrombocytopenia (all grades 18.0%, grades III-V 1.6%) was also calculated.

Conclusion

Treatment with ICIs seemed unlikely to increase the incidence of anemia, neutropenia, and thrombocytopenia in all grades. However, programmed cell death-1 receptor ligand inhibitors significantly increased the risk of grades III-V thrombocytopenia (OR 1.53; 95% CI 1.11 - 2.11). Further research is needed to examine the potential risk factors.

Characteristics of gastric cancer around the world

Gastric cancer is one of the most important malignancies in the world due to the high burden of disease and lethality. In this work, we compared the main characteristics of gastric cancer between different regions of the world. We reviewed public repositories to retrieve epidemiological, molecular, clinicopathological, and risk factor data. Eastern Asia presents the highest incidence of gastric cancer, followed by eastern and central Europe. Intestinal histology was more frequent in Caucasians, while gastric tumors located in the cardias were less frequent in Africa and Latin America. TP53, LRP1B, and ARID1A are consistently the most frequently altered genes in all population groups. Gastric cancer is most frequent in men. African patients tend to be younger and have a higher proportion of women patients. Different patterns can be observed in the presentation of gastric cancer between different regions of the world. More research is needed in Latin America and Africa since these populations are underrepresented.

Hyperprogressive Disease After Combined Anti-PD-L1 and Anti-CTLA-4 Immunotherapy for MSI-H/dMMR Gastric Cancer: A Case Report

Immune checkpoint inhibitors (ICI) have been developed in gastric adenocarcinomas and approved in first-line metastatic setting (in combination with chemotherapy) as well as in pretreated patients. Microsatellite instability-high (MSI-H) tumors are predicted to derive high benefit from ICI but data in gastric locations are limited. Here, we describe the case of a 68-year old patient with stage IV MSI-H gastric adenocarcinoma, referred to our center to receive immunotherapy after failure of standard of care (surgery with perioperative platin-based chemotherapy and paclitaxel plus ramucirumab at disease progression). The patient received one injection of durvalumab and tremelimumab and was hospitalized eighteen days after because of occlusive syndrome. The CT scan showed hyperprogression of the lymph nodes and hepatic lesions, compressing the gastric stump. He died few days later. Molecular analyses did not explain this outcome. To our knowledge, this is one of the first reported cases of hyperprogressive disease after combined ICI for a patient with MSI-H tumor. We review the potential causes and discuss the emerging literature regarding predictive factors of hyperprogression in the particular subset of MSI-H patients. If some data were available in retrospective studies, validation of strong predictive factors is needed to avoid such dramatic evolutions.

Treatment Patterns and Outcomes in Chinese Patients with Gastric Cancer by HER2 Status: A Noninterventional Registry Study (EVIDENCE)

BACKGROUND

Real-world safety and effectiveness data for trastuzumab plus chemotherapy treatment of patients with HER2-positive metastatic gastric cancer (mGC) in China are lacking.

PATIENTS AND METHODS

EVIDENCE was a prospective, multicenter, noninterventional registry study evaluating the safety and effectiveness of trastuzumab in five cohorts of Chinese patients with gastric cancer, stratified by HER2 status and trastuzumab treatment. Effectiveness was analyzed for cohorts I (HER2-positive, trastuzumab treated), II (HER2-positive, trastuzumab untreated), and IV (HER2-negative, trastuzumab untreated); trastuzumab-related adverse events (AEs) were analyzed for cohort I.

RESULTS

Cohorts I, II, and IV included 174, 113, and 422 patients, respectively. Most patients received first-line chemotherapy (87.6%). Median overall survival (OS1) for first-line treatment was 22.3, 17.2, and 17.4 months in cohorts I, II, and IV, respectively. After excluding patients who had surgery, respective median OS1 was 19.9, 15.3, and 12.9 months. Respective first-line progression-free survival (PFS1) was 8.2, 6.9, and 6.2 months; and respective first-line response rates (RR) were 51.7%, 18.4%, and 32.8%. Cohort I was significantly favored over cohort II for propensity score-matched first-line median OS1 (hazard ratio [HR], 0.61), PFS1 (HR, 0.64), and RR (odds ratio, 4.93). Trastuzumab-related AEs, grade 3-5 AEs, serious AEs, and AEs with a fatal outcome occurred in 23.6%, 3.4%, 2.3%, and 0.6% of cohort I patients, respectively.

CONCLUSION

Safety profiles were consistent with those known for trastuzumab and chemotherapy; trastuzumab treatment improved outcomes. Our study provides real-world data supporting first-line trastuzumab plus chemotherapy in Chinese patients with HER2-positive mGC.

IMPLICATIONS FOR PRACTICE

This prospective, noninterventional registry study aimed to provide safety and effectiveness data for the use of trastuzumab in combination with chemotherapy in Chinese patients with HER2-positive metastatic gastric cancer (mGC) from the real-world clinical setting. Trastuzumab plus first-line chemotherapy was shown to be safe and to improve outcomes when compared with patients treated with chemotherapy alone. Trastuzumab was effective within a range of treatment regimens; subgroup analysis showed that trastuzumab paired most effectively with the XELOX regimen. This study provides real-world clinical safety and effectiveness data supporting the use of trastuzumab in the treatment of Chinese patients with HER2-positive mGC.

Current status and future potential of predictive biomarkers for immune checkpoint inhibitors in gastric cancer

Immunotherapy is revolutionising cancer treatment and has already emerged as standard treatment for patients with recurrent or metastatic gastric cancer (GC). Recent research has been focused on identifying robust predictive biomarkers for GC treated with immune checkpoint inhibitors (ICIs). The expression of programmed cell death protein-ligand-1 (PD-L1) is considered a manifestation of immune response evasion, and several studies have already reported the potential of PD-L1 expression as a predictive parameter for various human malignancies. Meanwhile, based on comprehensive molecular characterisation of GC, testing for Epstein-Barr virus and microsatellite instability is a potential predictive biomarker. Culminating evidence suggests that novel biomarkers, such as the tumour mutational burden and gene expression signature, could indicate the success of treatment with ICIs. However, the exact roles of these biomarkers in GC treated with ICIs remain unclear. Therefore, this study reviews recent scientific data on current and emerging biomarkers for ICIs in GC, which have potential to improve treatment outcomes.

KMT2D promotes proliferation of gastric cancer cells: evidence from ctDNA sequencing

BACKGROUND

ctDNA sequencing could be used for early cancer screening, prognosis prediction, and medication guidance. However, data of its application in gastric cancer are still lacking. In this study, using ctDNA sequencing, we aimed to screen the mutant genes closely associated with gastric cancer and to explore the impact of these genes on gastric cancer development.

METHODS

ctDNA for high-throughput sequencing was obtained from gastric cancer patients, and the high-frequency mutant gene KMT2D was identified. Immunohistochemical examination was conducted to assess the expression of KMT2D in gastric cancer tissues. KMT2D knockdown was performed to establish the stably transfected gastric cancer cells. Then, CCK8, plate clone formation assay, and Transwell assay were conducted, and a subcutaneous tumor-bearing model was induced in nude mice to investigate the changes in cell proliferation and invasion capability. Transcriptome sequencing was also performed to investigate the differences in cellular gene expression.

RESULTS

Detection of ctDNA found 113 gastric cancer-related mutations, 11 of which are the top 20 high-frequency mutations of gastric cancer recorded by COSMIC (Catalogue of Somatic Mutations in Cancer, COSMIC). They are TP53, ARID1A, CDH1, PIK3CA, KMT2C, KMT2D, APC, SPEN, CTNNB1, SETBP1, and KMT2A. The gene closely related to the clinical characteristics of the patient is KMT2D. The high-frequency mutant gene KMT2D was identified in gastric cancer tissues. The positive rate of KMT2D expression in cancer tissues was 74.3%, which was higher than that in para-carcinoma tissues (56.8%). The knockdown of KMT2D inhibited the proliferation, invasion, and tumor formation capacity of the gastric cancer cells, causing differences in the gene expression profiles, and the expression of different functional gene clusters was up- or downregulated.

CONCLUSION

The findings of this study revealed that KMT2D could be an oncogene capable of promoting gastric cancer proliferation.

Collision of Epstein-Barr virus-positive and -negative gastric cancer, diagnosed by molecular analysis: a case report

Background

Epstein–Barr virus (EBV)-positive gastric carcinoma (GC) is defined by the proliferation of GC cells with EBV infection. The co-existence of EBV-positive and -negative components in a single GC is rare. We report a case of GC with the co-existence of EBV-positive and EBV-negative components, in which we performed—for the first time—various molecular analyses to elucidate their histogenesis.

Case presentation

An 81-year-old man was diagnosed with GC based on the results of endoscopy and a pathological examination of the biopsy specimen. Systemic chemotherapy was performed, since lymph node and lung metastases were diagnosed based on computed tomography. Total gastrectomy and lymph node dissection were performed after chemotherapy, after confirming that the size of the metastatic lymph nodes had decreased and that the lung metastasis had disappeared. Grossly, a type 3 tumor was located in the middle posterior part of the stomach body. At the cut section, the tumor consisted of a white and solid part on the anal side of the tumor and a flat and elevated part on the oral side. Histologically, the former part consisted of GC with lymphoid stroma and the latter part was composed of poorly differentiated adenocarcinoma without prominent lymphocytic infiltration. The two histopathological components were clearly separated from each other. On EBV-encoded small RNA (EBER)-in situ hybridization (ISH), the part with the lymphoid stroma component was positive, while the other part was negative. Immunohistochemistry revealed that both components showed the overexpression of p53. Sequencing of TP53 using DNA extracted from the two components was conducted, and revealed different patterns. Targeted next generation sequencing revealed MYC amplification in the EBV-positive component of the tumor and HER2 amplification in the EBV-negative part. Immunohistochemistry revealed that the EBV-positive part was C-MYC( +)/HER2(−) and the EBV-negative part was C-MYC(−)/HER2( +). Correspondingly, chromogenic ISH and dual-color ISH showed amplification of C-MYC and no amplification of HER2 in the EBV-positive part, and no amplification of C-MYC and amplification of HER2 in the EBV-negative part.

Conclusion

We presented a case of collision of two different GCs composed of EBER-ISH ( +)/C-MYC ( +) and EBER-ISH (−)/HER2 ( +) cells.

Long Non-coding RNA Expression Patterns in Stomach Adenocarcinoma Serve as an Indicator of Tumor Mutation Burden and Are Associated With Tumor-Infiltrating Lymphocytes and Microsatellite Instability

Long non-coding RNAs (lncRNAs) are crucial in controlling important aspects of tumor immunity. However, whether the expression pattern of lncRNAs in stomach adenocarcinoma (STAD) reflects tumor immunity is not fully understood. We screened differentially expressed lncRNAs (DElncRNAs) between high and low tumor mutation burden (TMB) STAD samples. Using the least absolute shrinkage and selection operator method, 33 DElncRNAs were chosen to establish a lncRNA-based signature classifier for predicting TMB levels. The accuracy of the 33-lncRNA-based signature classifier was 0.970 in the training set and 0.950 in the test set, suggesting the expression patterns of the 33 lncRNAs may be an indicator of TMB in STAD. Survival analysis showed that a lower classifier index reflected better prognosis for STAD patients, and the index showed correlation with expression of immune checkpoint molecules (PD1, PDL1, and CTLA4), tumor-infiltrating lymphocytes, and microsatellite instability. In conclusion, STAD samples with different tumor mutation burdens have different lncRNA expression patterns. The 33-lncRNA-based signature classifier index may be an indicator of TMB and is associated expression of immune checkpoints, tumor-infiltrating lymphocytes, and microsatellite instability.

Efficacy and safety of immune checkpoint inhibitors in gastric cancer: a network meta-analysis of well-designed randomized controlled trials

Background

Immune checkpoint inhibitors (ICIs) that inhibit the programmed death 1 (PD-1)/programmed death-ligand 1 (PD-L1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) interactions have shown promising prospects as treatment options for advanced gastric cancer (AGC). This manuscript analyzed well designed clinical trials to evaluate the efficacy and safety of immunotherapy in AGC.

Methods

PubMed, Embase, the Cochrane Library, and Medline were searched for randomized controlled trials (RCTs) of AGC treatments that were published before April 2020. Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and treatment-related adverse events (TRAEs) were evaluated to determine the efficacy and safety of ICIs. Network meta-analysis was performed using a random-effects model under the Bayesian framework. The ability of each treatment was ranked using the surface under the cumulative ranking (SUCRA) curve.

Results

Our analysis included five studies having seven immunotherapy regimens and 1,730 patients. The network meta-analysis showed that nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks (88.369%) was the regimen most likely to improve PFS. Nivolumab 3 mg/kg every 3 weeks (84.563%) and nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks (84.556%) were similarly best for OS outcome with excellent tolerance. The regimen of avelumab 10 mg/kg every 2 weeks (91.167%) had the lowest TRAEs. All immunotherapies had similar response rates.

Conclusions

We recommend nivolumab 3 mg/kg every 2 weeks or nivolumab 1 mg/kg every 3 weeks plus ipilimumab 3 mg/kg every 3 weeks as the preferred regimen due to their high efficacies.

Long Noncoding RNAs: New Regulators of Resistance to Systemic Therapies for Gastric Cancer

Gastric cancer (GC) is the second leading cause of cancer mortality and the fourth most commonly diagnosed malignant disease, with approximately 951,000 new cases diagnosed and approximately 723,000 cases of mortality each year. The highest mortality rate of GC is in East Asia, and the lowest is in North America. A large number of studies have demonstrated that GC patients are characterized by higher morbidity, metastasis rates, and mortality and lower early diagnosis rates, radical resection rates, and 5-year survival rates. All cases of GC can be divided into two important stages, namely, early- and advanced-stage GC, and the stage mainly determines the treatment strategy for and the therapeutic effect in GC patients. Patients with early-stage GC undergo radical surgery followed by chemotherapy, and the 5-year survival rate can be as high as 90%. However, patients with advanced-stage GC cannot undergo radical surgery because they are at risk for metastasis; therefore, they can choose only radiotherapy or chemotherapy and have a poor prognosis. Based on the lack of specific clinical manifestations and detection methods, most GC patients (>70%) are diagnosed in the advanced stage; therefore, continued efforts toward developing treatments have been focused on advanced-stage GC patients and include molecular targeted therapy, immunotherapy, and small molecular therapy. Nevertheless, in recent years, accumulating evidence has indicated that small molecules, especially long noncoding RNAs (lncRNAs), are involved in the occurrence, development, and progression of GC, and their abundantly dysregulated expression has been identified in GC tissues and cell lines. Therefore, lncRNAs are considered easily detectable molecules and ideal biomarkers or target-specific agents for the future diagnosis or treatment of GC. In this review, we primarily discuss the status of GC, the role of lncRNAs in GC, and the emerging systemic treatments for GC.

Nivolumab versus chemotherapy in Japanese patients with advanced esophageal squamous cell carcinoma: a subgroup analysis of a multicenter, randomized, open-label, phase 3 trial (ATTRACTION-3)

BACKGROUND

The efficacy and safety of nivolumab versus chemotherapy was evaluated in the Japanese subpopulation from the overall intent-to-treat (ITT) population of the ATTRACTION-3 trial conducted in patients with advanced esophageal squamous cell carcinoma (ESCC) as second-line treatment.

METHODS

Data from Japanese patients enrolled in the multicenter, randomized, open-label, phase 3 ATTRACTION-3 trial were analyzed. The primary endpoint was overall survival (OS). Secondary endpoints included duration of response (DOR), objective response rate (ORR), disease control rate (DCR), and safety. Exploratory subgroup analyses evaluated the association between OS and stratification factors/baseline variables.

RESULTS

Overall, 274 (nivolumab, 136; chemotherapy, 138) of the 419 patients in ATTRACTION-3 were enrolled from Japan: response-evaluable population (107; 108) and safety population (135; 138). OS tended to be longer in the nivolumab group versus the chemotherapy group (median: 13.4 months vs. 9.4 months; HR, 0.77; 95% CI 0.59-1.01). Median DOR was longer in the nivolumab group (7.6 months) versus the chemotherapy group (3.6 months). ORRs were similar between the nivolumab [22.4% of patients (24/107)] and chemotherapy groups [22.2% (24/108); odds ratio, 0.98; 95% CI 0.52-1.87]. DCR was lower in the nivolumab group [41.1% (44/107)] versus the chemotherapy group [66.7% (72/108)]. OS in the exploratory analysis consistently favored the nivolumab group versus the chemotherapy group. Overall, nivolumab demonstrated favorable efficacy and safety versus chemotherapy in the Japanese subpopulation, and the trend was similar to that observed in the overall ATTRACTION-3 ITT population.

CONCLUSION

Nivolumab represents a new standard second-line treatment option for Japanese patients with advanced ESCC.

Chronological Changes in Neutrophil/lymphocyte Ratio in Advanced Gastric Cancer Patients Treated with Nivolumab: a Report of Nine Cases

Background:

Nivolumab has been approved for use in advanced gastric cancer (GC) after third-line chemotherapy in Japan. However, it remains difficult to predict favorable nivolumab response before treatment.

Methods:

We evaluated the clinical course with a focus on the chronological changes in neutrophil/lymphocyte ratio (NLR) throughout the chemotherapy and assessed the relationship between nivolumab response and chronological changes in NLR before nivolumab administration.

Results:

We experienced nine cases who received nivolumab monotherapy for unresectable advanced or postoperative recurrent GC. Nivolumab was used as third-line chemotherapy in all patients, and partial response (PR) and stable disease (SD) were observed in two patients each. Nivolumab treatment resulted in progressive disease (PD) in five patients. In patients with PR or SD, changes in the NLR tended to correspond to the response of target metastatic lymph nodes to first- and second-line chemotherapy. In the four cases with PR or SD following nivolumab, ∆NLR_responses that was the difference in the degree of decline during the most effective pretreatment chemotherapy were 1.39, 0.73, 1.62, and 1.22. However, the patients with PD showed lower ∆NLR_responses, at 0.66, 0.66, 0.25, 0.13, and -0.05 in the five cases. Mean ∆NLR_responses in the patients with PR or SD and patients with PD were 1.17 and 0.33, respectively (P = 0.0008).

Conclusions:

We experienced nine GC cases treated with nivolumab and assessed the association between chronological NLR changes throughout chemotherapy and tumor response to nivolumab. Changes in NLR during pretreatment chemotherapy might predict tumor response to nivolumab monotherapy in patients with advanced GC.

Inhibition of NF-κB is required for oleanolic acid to downregulate PD-L1 by promoting DNA demethylation in gastric cancer cells

Gastric cancer is one of the most common causes of cancer-related death worldwide. Immunotherapy via programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) blockade has shown benefits for gastric cancer. Epigenetic DNA methylation critically regulates cancer immune checkpoints. We investigated how the natural compound oleanolic acid (OA) affected PD-L1 expression in gastric cancer cells. Interleukin-1β (IL-1β) at 20 ng/mL was used to stimulate human gastric cancer MKN-45 cells. IL-1β significantly increased PD-L1 expression, which was abolished by OA. Next, OA-treated MKN-45 cells were co-cultured with activated and PD-1-overexpressing Jurkat T cells. OA restored IL-2 levels in the co-culture system and increased T cell killing toward MKN-45 cells. Overexpression of PD-L1 eliminated OA-enhanced T cell killing capacity; however, PD-1 blocking antibody abrogated the cytotoxicity of T cells. Moreover, OA abolished IL-1β-increased DNA demethylase activity in MKN-45 cells. DNA methyltransferase inhibitor 5-azacytidine rescued OA-reduced PD-L1 expression; whereas DNA demethylation inhibitor gemcitabine inhibited PD-L1 expression, and, in combination with OA, provided more potent inhibitory effects. Furthermore, OA selectively reduced the expression of DNA demethylase TET3 in IL-1β-treated MKN-45 cells, and overexpression of TET3 restored OA-reduced PD-L1 expression. Finally, OA disrupted nuclear factor κB (NF-κB) signaling IL-1β-treated MKN-45 cells, and overexpression of NF-κB restored OA downregulation of TET3 and PD-L1. The cytotoxicity of T cells toward MKN-45 cells was also weakened by NF-κB overexpression. Altogether, OA blocked the IL-1β/NF-κB/TET3 axis in gastric cancer cells, leading to DNA hypomethylation and downregulation of PD-L1. Our discoveries suggested OA as an epigenetic modulator for immunotherapy or an adjuvant therapy against gastric cancer.

ctDNA Concentration, MIKI67 Mutations and Hyper-Progressive Disease Related Gene Mutations Are Prognostic Markers for Camrelizumab and Apatinib Combined Multiline Treatment in Advanced NSCLC

Immunotherapy by immune checkpoint inhibitors (ICIs) has showed outstanding efficacy in the treatment of advanced non-small cell lung cancer (NSCLC). The combination of immunotherapy with anti-angiogenic therapy exhibited enhanced efficacy in multiline treatment. However, the potential biomarkers for predicting and monitoring the therapeutic response of the combined therapy remain undefined. In this study, we performed a pilot study by prospectively recruiting 22 advanced NSCLC patients who failed to previous lines of chemotherapy, chemoradiotherapy, TKI therapy, surgery, or any combination of the therapies, and investigated the prognostic factors for patients who received anti-PD-1 (Camrelizumab) and anti-angiogenic (Apatinib) combined therapy. The objective response rate (ORR) assessed by an independent radiology review was 22.7%, and the median progression-free survival (PFS) was 5.25 months. We found that high concentration of circulating-free DNA (cfDNA) (HR = 27.75, P = 0.003), MIKI67 mutation (HR = 114.11, P = 0.009) and gene variations related to hyper-progressive disease (HPD) (HR = 36.85, P = 0.004) were independent risk factors and exhibited significant correlation with PFS. Circulating tumor DNA (ctDNA) mutational status was also a predicting indicator for PFS. In contrast, the blood tumor mutational burden (bTMB) could not stratify the clinical benefit in this combined therapy (HR = 0.81, P = 0.137). Furthermore, we found that the variant allele fraction (VAF) of mutations in ctDNA was sensitive indicators of therapeutic response and therefore can be used to monitor the tumor relief or progression. In conclusion, cfDNA concentration, MIKI67 mutations and HPD-related mutations were independent risk factors and PFS predictors for multiline combined anti-angiogenic/ICI combined therapy. ctDNA may be a novel monitoring biomarker for therapeutic response and predicting biomarker for prognosis in future combined therapy involving PD-1 blockade.

Margetuximab plus pembrolizumab in patients with previously treated, HER2-positive gastro-oesophageal adenocarcinoma (CP-MGAH22-05): a single-arm, phase 1b-2 trial

BACKGROUND

Margetuximab, a novel, investigational, Fc-engineered, anti-HER2 monoclonal antibody, is designed to more effectively potentiate innate immunity than trastuzumab. We aimed to evaluate the safety, tolerability, and antitumour activity of margetuximab plus pembrolizumab (an anti-PD-1 monoclonal antibody) in previously treated patients with HER2-positive gastro-oesophageal adenocarcinoma.

METHODS

CP-MGAH22-05 was a single-arm, open-label, phase 1b-2 dose-escalation and cohort expansion study done at 11 academic centres in the USA and Canada and 15 centres in southeast Asia (Korea, Taiwan, and Singapore) that enrolled men and women aged 18 years or older with histologically proven, unresectable, locally advanced or metastatic, HER2-positive, PD-L1-unselected gastro-oesophageal adenocarcinoma, with an Eastern Cooperative Oncology Group performance status of 0 or 1, who had progressed after at least one previous line of therapy with trastuzumab plus chemotherapy in the locally advanced unresectable or metastatic setting. In the dose-escalation phase, nine patients were treated: three received margetuximab 10 mg/kg intravenously plus pembrolizumab 200 mg intravenously every 3 weeks and six received the recommended phase 2 dose of margetuximab 15 mg/kg plus pembrolizumab 200 mg intravenously every 3 weeks. An additional 86 patients were enrolled in the phase 2 cohort expansion and received the recommended phase 2 dose. The primary endpoints were safety and tolerability, assessed in the safety population (patients who received at least one dose of either margetuximab or pembrolizumab) and the objective response rate as assessed by the investigator according to both Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, in the response-evaluable population (patients with measurable disease at baseline and who received the recommended phase 2 dose of margetuximab and pembrolizumab). This trial is registered with ClinicalTrials.gov, NCT02689284. Recruitment for the trial has completed and follow-up is ongoing.

FINDINGS

Between Feb 11, 2016, and Oct 2, 2018, 95 patients were enrolled. Median follow-up was 19·9 months (IQR 10·7-23·1). The combination therapy showed acceptable safety and tolerability; there were no dose-limiting toxicities in the dose-escalation phase. The most common grade 3-4 treatment-related adverse events were anaemia (four [4%]) and infusion-related reactions (three [3%]). Serious treatment-related adverse events were reported in nine (9%) patients. No treatment-related deaths were reported. Objective responses were observed in 17 (18·48%; 95% CI 11·15-27·93) of 92 evaluable patients.

INTERPRETATION

These findings serve as proof of concept of synergistic antitumour activity with the combination of an Fc-optimised anti-HER2 agent (margetuximab) along with anti-PD-1 checkpoint blockade (pembrolizumab).

FUNDING

MacroGenics.

Current status of immune checkpoint inhibitors for gastric cancer

Recent breakthrough results from immune checkpoint inhibitors (ICI) have paved the way to a new era of cancer immunotherapy. In particular, inhibition of programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) axis with ICI including nivolumab and pembrolizumab has been emerging as a novel treatment strategy for advanced gastric cancers (GC). In a meta-analysis for anti-PD-1/PD-L1 therapy in GC, the objective response rate was 12.0% and the disease control ratio was 34.7%. The ICI treatment in GC provided modest survival benefit and especially, anti-PD-1 treatment could improve the 12-month and 18-month overall survival rate and prolonged the duration of the response. Moreover, it is likely that anti-PD-1/PD-L1 therapy is more effective in subgroups with microsatellite instability-high, Epstein-Barr virus-positive or high mutation burden in advanced GC. The next steps for developing ICI in GC are mainly two challenges as follows. First is the identification of accurate biomarkers that can predict the response to ICI. The second challenge is the clinical development of combinatorial approaches to maximize the efficacy of ICI. In this review, recent advances in ICI for GC are discussed from a viewpoint of translational aspect including biomarkers and tumor microenvironment, and from a viewpoint of clinical aspects including combination therapies.

Systemic Therapies for Melanoma Brain Metastases: A Primer for Radiologists

OBJECTIVE

The purpose of this article is to provide a primer for radiologists outlining the modern systemic therapies used in melanoma brain metastases, including tyrosine kinase inhibitors and immune checkpoint inhibitors. The role of radiologic treatment response evaluation will be discussed from the standpoint of both modern systemic therapies and more traditional treatments.

CONCLUSION

Understanding the role of systemic treatments in melanoma brain metastases is critical for oncologic imaging interpretation in this unique patient population.

A CT-based radiomics signature for evaluating tumor infiltrating Treg cells and outcome prediction of gastric cancer

Background

Tumor infiltrating regulatory T (TITreg) cells are highly infiltrated in gastric cancer (GC) and associated with worse prognosis of GC patients. We aim to develop and validate a radiomics signature for evaluation of TITreg cells and outcome prediction of GC patients.

Methods

A total of 165 GC patients from three independent cohorts were enrolled in this retrospective study. The abundance of TITreg cells were evaluated by using multispectral immunohistochemical analysis and CIBERSORT algorithm. The radiomics features were extracted by using PyRadiomics software and the radiomics signature was generated by using the least absolute shrinkage and selection operator (LASSO) logistic regression model. The receiver operator characteristic (ROC) curves were applied to assess the performance of radiomics signature for estimating TITreg cells. Univariable and multivariable Cox regression analysis were used for identifying risk factor of overall survival (OS). The prognostic value of the radiomics signature and the TITreg cells were evaluated by using the Kaplan-Meier method and log-rank test.

Results

Six robust features were selected for building the radiomics signature. The radiomics signature showed good ability for estimating TITreg in the training, validation and testing cohort, with area under the curve (AUC) of 0.884, 0.869 and 0.847, respectively. Multivariable Cox regression analysis showed that the radiomics signature was an independent risk factor of unfavorable OS of GC patients.

Conclusions

The proposed CT-based radiomics signature is a promising non-invasive biomarker of TITreg cells and outcome prediction of GC patients.

Esophageal, gastric and colorectal cancers: Looking beyond classical serological biomarkers towards glycoproteomics-assisted precision oncology

Esophageal (OC), gastric (GC) and colorectal (CRC) cancers are amongst the digestive track tumors with higher incidence and mortality due to significant molecular heterogeneity. This constitutes a major challenge for patients' management at different levels, including non-invasive detection of the disease, prognostication, therapy selection, patient's follow-up and the introduction of improved and safer therapeutics. Nevertheless, important milestones have been accomplished pursuing the goal of molecular-based precision oncology. Over the past five years, high-throughput technologies have been used to interrogate tumors of distinct clinicopathological natures, generating large-scale biological datasets (e.g. genomics, transcriptomics, and proteomics). As a result, GC and CRC molecular subtypes have been established to assist patient stratification in the clinical settings. However, such molecular panels still require refinement and are yet to provide targetable biomarkers. In parallel, outstanding advances have been made regarding targeted therapeutics and immunotherapy, paving the way for improved patient care; nevertheless, important milestones towards treatment personalization and reduced off-target effects are also to be accomplished. Exploiting the cancer glycoproteome for unique molecular fingerprints generated by dramatic alterations in protein glycosylation may provide the necessary molecular rationale towards this end. Therefore, this review presents functional and clinical evidences supporting a reinvestigation of classical serological glycan biomarkers such as sialyl-Tn (STn) and sialyl-Lewis A (SLe^A) antigens from a tumor glycoproteomics perspective. We anticipate that these glycobiomarkers that have so far been employed in non-invasive cancer prognostication may hold unexplored value for patients' management in precision oncology settings.

Reader-free ELISPOT assay for immuno-monitoring in peptide-based cancer vaccine immunotherapy

Cancer vaccine immunotherapy is a therapy that induces cellular immune responses against a target molecule to elicit clinical anti-tumor effects. These cellular immune responses against the target molecule are monitored to evaluate whether the antigen-specific cellular immune responses are induced and maintained during the vaccination period. Enzyme-linked immunospot (ELISPOT) assay is widely performed to analyze not only the frequency of immune cells, but also their effector functions as determined by their cytokine production/secretion. The present study aimed to develop a reader-free ELISPOT assay using a handy membrane-punching device termed ELI 8. With the assistance of particle analysis by ImageJ software, the results of spot counting were reproducible with high inter-assay and inter-examiner concordance. Immune cells that produce and secrete Th1 cytokines without antigen-peptide stimulation of peripheral blood mononuclear cells (PBMCs) were detected, and their frequencies in patients with cancer were significantly higher compared with those in healthy individuals. These frequencies varied between individuals, as well as between time points during the course of cancer vaccine immunotherapy in each patient. Due to the variability in spontaneous cytokine production/secretion by PBMCs, an antigen-specific immune response (IR) index is proposed, which is a ratio of the number of spot-forming cells (SFCs) subjected to antigen-stimulation to that of SFCs with spontaneous cytokine secretion without antigen-stimulation. This index may be used as a marker for antigen-specific cellular immune responses in patients treated with cancer immunotherapy. The IR index successfully detected the induction of Wilms' tumor 1-specific cellular immune responses in patients with cancer treated with cancer vaccine immunotherapy.

A Case of Antiphospholipid Syndrome Following Gastric Signet Ring Cell Adenocarcinoma

Patient: Female, 53-year-old

Final Diagnosis: —

Symptoms: Antiphospholipid syndrome (APS)

Medication: —

Clinical Procedure: —

Specialty: Oncology

Immune Checkpoint Inhibitors in Pre-Treated Gastric Cancer Patients: Results from a Literature-Based Meta-Analysis

Immunotherapy has recently changed the treatment of several cancers. We performed a literature-based meta-analysis of randomised controlled trials to assess the efficacy of the novel immune checkpoint inhibitors (ICIs) in metastatic gastric cancer. The main outcome was overall survival. Based on age (cut-off agreed at 65 years), tumour location (gastric vs. gastro-oesophageal junction), programmed death-ligand 1 (PD-L1) status, sex and Eastern Cooperative Oncology Group (ECOG) status (1 vs. 0), we scheduled a subgroup analysis for the overall survival. Three studies were included in the analysis for a total of 1456 cases (811 cases were in the experimental group and 645 cases in the control group). The pooled analysis showed improved overall survival in the experimental arm in the absence of statistical significance (hazard ratio (HR) = 0.87, 95% CI: 0.64-1.18; p = 0.37). The subgroup of patients with PD-L1-positive tumours (HR = 0.82 vs. 1.04) and gastro-oesophageal junction cancer (HR = 0.82 vs. 1.04) showed a statistically significant advantage of overall survival. This study supports the efficacy of immune checkpoint inhibitors in the subgroup of patients with metastatic gastric cancer with PD-L1-positive and gastro-oesophageal junction tumour location. Future studies are needed with the aim of identifying reliable predictive biomarkers of ICI efficacy.

MicroRNA expression profiling provides novel insights into immune-related pathways involved in gastric cancer

Gastric cancer is one of the most common cancers, and an increasing number of studies have found that microRNAs (miRNAs) play essential roles in gastric cancer progression; however, the roles of specific miRNAs involved in the immune response to this disease remain unclear. We compared the miRNA expression in tissues from primary gastric cancer patients and healthy controls to find miRNAs dysregulated in gastric cancer and used bioinformatics tools to determine potential roles of these miRNAs in the immune system. We evaluated 25 primary gastric cancer tissues and five healthy gastric tissues. Quantitative real-time polymerase chain reaction was performed for a set of miRNAs, followed by the prediction of their target genes and functional enrichment analysis of these targets. Analysis of a microarray dataset showed that the miRNA miR-196a-5p was significantly upregulated, while miR-374a-5p and miR-375 were downregulated in gastric cancer patients. In addition, miR-374-5p was significantly downregulated in patients with metastasis compared with its expression levels in non-metastatic patients (p = 0.03). Bioinformatics analysis suggested that the pathways regulated by these differentially expressed miRNAs were related to the immune response, cell adhesion, and cell migration. Most importantly, this study provides a new insight into the potential use of multiple miRNAs to find distinct pathways of immune regulation in gastric cancer.

Avelumab in gastric cancer

Gastric cancer (GC) is the fifth most common malignancy and the third cause of cancer-related deaths worldwide. Currently, surgery and chemotherapy remain the main therapeutic options and the prognosis of the disease is still poor in the metastatic setting. Avelumab is a human IgG1 antibody directed against PD-L1 approved for Merkel cell carcinoma and urothelial carcinoma that could be useful also for the treatment of GC. This review describes the chemical structure, the pharmacologic properties and the current knowledge of the efficacy of avelumab in the treatment of GC from the data available on the first and later phase clinical trials. The ongoing studies testing this drug either alone or in combination with other drugs are also described.

MIR100HG: a credible prognostic biomarker and an oncogenic lncRNA in gastric cancer

The MIR100HG expression was observed to be up-regulated or down-regulated in human cancer tissues depending on tumor types. However, there was no report about the role of MIR100HG in gastric cancer. In our study, we first found levels of MIR100HG expression were increased in gastric cancer cell lines and tissue samples compared with normal gastric epithelial cell line and adjacent normal gastric mucosa tissue samples, respectively. Moreover, high MIR100HG expression was positively associated with clinical stage, tumor invasion, lymph node metastasis, and distant metastasis in gastric cancer patients. Survival analysis showed MIR100HG expression was negative correlated with clinical outcome in gastric cancer patients from The Cancer Genome Atlas (TCGA) database or our study, and high MIR100HG expression served as an independent poor prognostic factor for gastric cancer patient's overall survival. The study in vitro suggested down-regulation of MIR100HG expression inhibits cell proliferation, migration, and invasion in gastric cancer. In conclusion, MIR100HG is a credible prognostic biomarker and functions as an oncogenic lncRNA in gastric cancer.