Locally advanced gastro-oesophageal cancer: Recent therapeutic advances and research directions

Concordance of microsatellite instability and mismatch repair status in paired biopsies and surgical specimens of resectable gastroesophageal adenocarcinoma: time for a call to action

BACKGROUND

Reliability of mismatch repair proteins and microsatellite instability assessment is essential in order to define treatment strategy and identify candidates to immune checkpoint inhibitors in locally advanced gastroesophageal carcinoma. We evaluated the concordance of deficient mismatch repair (dMMR) and microsatellite instability-high (MSI-H) status between endoscopic biopsies and surgical specimens.

METHODS

Consecutive patients with resectable gastric or gastroesophageal junction adenocarcinoma classified as MSI-H/dMMR by polymerase chain reaction (PCR) or immunohistochemistry (IHC) and operated at three referral Institutions were included. The primary endpoint was the rate of concordance between biopsy and surgical samples. If needed, central revision by IHC/PCR was performed by specialized pathologists from coordinating Institutions.

RESULTS

Thirteen (19.7%) out of 66 patients showed discordant MSI-H/dMMR results in the original pathology reports. In most cases (11, 16.7%) this was due to the diagnosis of proficient mismatch repair status on biopsies. Among the ten cases available for central review, four were due to sample issues, four were reclassified as dMMR, one case showed dMMR status but was classified as microsatellite stable by PCR, one was linked to misdiagnosis of endoscopic biopsy by the local pathologist. Heterogeneity of mismatch repair proteins staining was observed in two cases.

CONCLUSIONS

Available methods can lead to conflicting results in MSI-H/dMMR evaluation between endoscopic biopsies and surgical samples of gastroesophageal adenocarcinoma. Strategies aiming to improve the reliability of assessment should be primarily focused on the optimization of tissue collection and management during endoscopy and adequate training of dedicated gastrointestinal pathologists within the multidisciplinary team.

A novel 450-nm laser-mediated sinoporphyrin sodium-based photodynamic therapy induces autophagic cell death in gastric cancer through regulation of the ROS/PI3K/Akt/mTOR signaling pathway

BACKGROUND

Photodynamic therapy (PDT) has become an ideal and promising therapeutic method for fighting cancer, but its common application in clinical practice is prevented by the limitations of expensive devices in light sources and phototoxicity in photosensitizers. The aim of this study was to explore the antitumor efficiency of the novel 450-nm blue laser (BL) combined with sinoporphyrin sodium (DVDMS)-mediated PDT against human gastric cancer (GC) in vitro and in vivo, focusing on autophagy pathway.

METHODS

Cell viability was detected by Cell Counting Kit-8 and colony formation assays in HGC27, MGC803, AGS, and GES-1 cells. Cell apoptosis was measured by flow cytometry and western blotting. The production of reactive oxygen species (ROS) was measured by fluorescence microscopy and flow cytometry. Autophagy was determined by transmission electron microscopy and western blotting. The antitumor effect of BL-PDT in vivo was detected by a subcutaneous tumor model in nude mice.

RESULTS

The novel 450-nm laser-mediated DVDMS-based PDT caused remarkable growth inhibition and apoptosis induction in GC cells in vitro by the production of excessive ROS. Autophagy flux was induced by BL-PDT in GC cells, as determined by LC3 conversion assay, LC3 turnover assay, and mRFP-GFP-LC3 puncta assay. Furthermore, autophagy induction was demonstrated to positively contribute to BL-PDT-induced apoptotic effects on GC cells. Mechanically, ROS/PI3K/Akt/mTOR pathway was identified to involve in the regulation of BL-PDT-induced autophagy as determined by transcriptomic analysis and functional studies. Consistently, xenograft studies confirmed the significant antitumor effect of BL-PDT and its favorable safety in vivo.

CONCLUSIONS

The novel 450-nm laser-mediated DVDMS-based PDT may be a safe and effective approach against GC. Our results thus provide compelling evidence for the therapeutic application of BL-PDT in human GC.

Impact of perioperative chemotherapy in the treatment of patients with gastric cancer

Background

Perioperative chemotherapy (PeriCh) is the current standard of care for stage II/III gastric cancer tumors in Europe. However, when it concerns patients who endure complications during PeriCh it is unclear if it increases the risk of postoperative complications and other poorer surgical outcomes. We aim to demonstrate if there is an association between having complications during PeriCh and postoperative complications and histopathological response.

Methods

We conducted a retrospective, transversal, and observational study, including all patients with diagnosed gastric cancer who underwent PeriCh followed by surgical resection during the period of eight years.

Results

We included 80 patients with a median age of 64.0years (min 24, max 78). Eighty-eight-point eight percent ended the chemotherapy regime proposed, with a median duration of 42 days, and were also submitted to gastric resection: 58.8% total gastrectomy and 41.2% distal gastrectomy. Twelve-point five percent of the patients had no complications during the PeriCh period and 16.3% had >2 complications. Twenty-five percent of patients had a histological response of <10% of tumor burden, but in 41.3% only regression of <50% could be obtained. No significant association was found between complications during PeriCh and adverse surgical outcomes (P = .497). Patients with complications during PeriCh had slightly higher median time difference from end of PeriCh until surgery, but with no statistical significance (P = .575).

Conclusions

In our sample, the existence of association between complications during PeriCh and postoperative complications or histological response was not demonstrated.

Poria Acid, Triterpenoids Extracted from Poria cocos, Inhibits the Invasion and Metastasis of Gastric Cancer Cells

Background: Poria cocos (P. cocos) is an important medicinal fungus in traditional Chinese medicine. Poria acid (PA), a triterpenoid compound, is an effective component of traditional Chinese medicine P. cocos. This experiment investigated the anti-gastric cancer biological activity of PA in vitro. Methods: The effect of PA on the viability of gastric cancer cells was detected by the thiazolyl blue (MTT) assay. Cell adhesion assays were used to detect changes in the adhesion of cells treated after PA (0, 20, 40, and 80 µmol/L). The ability of cell invasion and migration were detected by Transwell assays and wound healing assays. A high-content imaging system was used to dynamically record the motility of the gastric cancer cells after PA (0, 20, 40, and 80 µmol/L) treatment. Western blotting was used to detect the expression of epithelial–mesenchymal transformation (EMT), invasion and migration related proteins. Results: The MTT assay showed that the proliferation of gastric cancer cells was significantly inhibited after PA treatment. Cell adhesion experiments showed that the adhesion of gastric cancer cells was significantly decreased after PA treatment. Compared with the control group, the wound healing area of the gastric cancer cells treated with different concentrations of PA decreased. The Transwell assay showed that the number of gastric cancer cells passing through the cell membrane were significantly reduced after PA treatment. In addition, after PA treatment, the cells’ movement distance and average movement speed were significantly lower than those of the control group. Finally, PA can significantly alter the expression of EMT-related proteins E-cadherin, N-cadherin, and Vimentin and decreased the expressions of metastasis-related proteins matrix metalloproteinase (MMP) 2, MMP-9 and tissue inhibition of matrix metalloproteinase (TIMP)1 in the gastric cancer cells. Conclusions: Triterpenoids from P. cocos have significant biological activity against gastric cancer, and the mechanism may be involved in the process of epithelial–mesenchymal transformation.

EHF is a novel regulator of cellular redox metabolism and predicts patient prognosis in HNSCC

Head and Neck Squamous Cell Carcinoma (HNSCC) is a heterogeneous disease with relatively high morbidity and mortality rates. The lack of effective therapies, high recurrence rates and drug resistance driven in part, by tumor heterogeneity, contribute to the poor prognosis for patients diagnosed with this cancer. This problem is further exacerbated by the fact that key regulatory factors contributing to the disease diversity remains largely elusive. Here, we have identified EHF as an important member of the ETS family of transcription factors that is highly expressed in normal oral tissues, but lost during HNSCC progression. Interestingly, HNSCC tumors and cell lines exhibited a dichotomy of high and low EHF expression, and patients whose tumors retained EHF expression showed significantly better prognosis, suggesting a potential tumor suppressive role for EHF. To address this, we have performed gain and loss of function studies and leveraged bulk and single-cell cancer genomic datasets to identify global EHF targets by RNA-sequencing (RNA-seq) and Chromatin Immunoprecipitation and next generation sequencing (ChIP-seq) experiments of HNSCC cell lines. These mechanistic studies have revealed that EHF, acts as a regulator of a broad spectrum of metabolic processes, specifically targeting regulators of redox homeostasis such as NRF2 and SOX2. Our immunostaining results confirm the mutually exclusive expression patterns of EHF and SOX2 in HNSCC tumors and suggest a possible role for these two factors in establishing discrete metabolic states within the tumor microenvironment. Taken together, EHF may serve as a novel prognostic marker for classifying HNSCC patients for actionable and targeted therapeutic intervention.

Clinicopathologic significance of TROP2 and phospho-TROP2 in gastric cancer

Trophoblast cell-surface antigen 2 (TROP2) is a transmembrane glycoprotein expressed in epithelial cells. Increased TROP2 expression has been reported to be associated with malignant progression in most carcinomas; however, TROP2 has a tumor-suppressive function in certain types of cancer. Since the function of TROP2 is controversial, the present study subsequently aimed to clarify the clinicopathologic significance of TROP2 and pTROP2 expression in human gastric cancer (GC). The cases of 704 patients with GC who underwent gastrectomy were retrospectively analyzed. The expression levels of TROP2 and pTROP2 in each tumor were evaluated by immunohistochemistry. The association between the clinicopathologic features of patients with GC and the levels of TROP2 and pTROP2 in their tumors was analyzed. Increased TROP2 and pTROP2 expression was identified in 330 (46.9%) and 306 (43.5%) of the 704 patients with GC, respectively. Increased TROP2 expression was associated with the histological intestinal type, high tumor invasion depth (T3/T4), lymph node metastasis, lymphatic invasion and venous invasion. By contrast, increased pTROP2 expression was associated with intestinal type, low tumor invasion depth (T1/2), no lymph node metastasis and no lymphatic invasion. Increased TROP2 expression was associated with poorer overall survival (OS) (P<0.01; log rank test), whereas increased pTROP2 expression was significantly associated with improved OS (P<0.01; log rank test). In conclusion, increased expression levels of TROP2, but not pTROP2, may be associated with the metastatic ability of GC, resulting in poor prognosis of patients with GC.

Beyond the Guidelines: The Grey Zones of the Management of Gastric Cancer. Consensus Statements from the Gastric Cancer Italian Network (GAIN)

BACKGROUND

Management of gastric and gastroesophageal junction (GEJ) adenocarcinoma remains challenging, because of the heterogeneity in tumor biology within the upper gastrointestinal tract. Daily clinical practice is full of grey areas regarding the complexity of diagnostic, staging, and therapeutic procedures. The aim of this paper is to provide a guide for clinicians facing challenging situations in routine practice, taking a multidisciplinary consensus approach based on available literature.

METHODS

The GAIN (GAstric cancer Italian Network) group was established with the aims of reviewing literature evidence, discussing key issues in prevention, diagnosis, and management of gastric and GEJ adenocarcinoma, and offering a summary of statements. A Delphi consensus method was used to obtain opinions from the expert panel of specialists.

RESULTS

Forty-nine clinical questions were identified in six areas of interest: role of multidisciplinary team; risk factors; diagnosis; management of early gastric cancer and multimodal approach to localized gastric cancer; treatment of elderly patients with locally advanced resectable disease; and treatment of locally advanced and metastatic cancer.

CONCLUSIONS

The statements presented may guide clinicians in practical management of this disease.

Adverse Biology in Adenocarcinoma of the Esophagus and Esophagogastric Junction Impacts Survival and Response to Neoadjuvant Therapy Independent of Anatomic Subtype

OBJECTIVE

The aim of this study was to propose and test a novel adverse pathology classification in AEG.

BACKGROUND

Recent scientific advances show genomic and molecular concordance across all AEG types, suggesting a rationale for a biologic classification. We tested a 3-dimension adverse pathology classification across the entire junction and per Siewert anatomic subtype.

METHODS

Of 1625 patients with AEG, 650 underwent radical surgery, 55% post-neoadjuvant therapy (NeoT). Adverse features defined a priori were poor differentiation (PD), lymphatic invasion (LI), vascular invasion (VI), and perineural invasion (PN), with 3 groupings: 0 (no adverse feature), 1 to 2, and 3 to 4. Multivariable logistic and Cox proportional hazards regression were applied.

RESULTS

For adverse pathology, 31%, 46%, and 23% had 0, 1 to 2, and 3 to 4, respectively. Fifty percent of cases were AEG I, 25% AEG II, and 25% AEG III. Median survival was not reached, 49 and 17 months for 0, 1 to 2, and 3 to 4 adverse pathology, respectively (P < 0.001), and 76, 51, and 34 months for AEG I, II, and III, respectively (P < 0.001); AEG I was significantly (P< 0.001) associated with lower c (y)pT and c (y)pN stages, and LI, VI, PN, and PD (poor vs other). The pathology model was significant for survival along with (y)pT and (y)pN, and predicted response to chemotherapy and chemoradiation irrespective of anatomic subtype (P < 0.001).

CONCLUSION

A novel classification using standard pathology as proxy for poor biology is associated with survival and response to therapy. This effect is observed across the entire AEG spectrum, highlighting how biology should be aligned with anatomy in the modern paradigm of AEG management and design of clinical trials.

Treatment of Gastric Cancer

Surgery represents the only method for potentially curative intent for gastric cancer (GC) [...].

Neoadjuvant chemotherapy for gastric cancer. Has the time to decelerate the enthusiasm passed us by?

Neoadjuvant therapy for locally advanced gastric cancer is a treatment option well recognized in international guidelines. However, neither completed randomized trials nor ongoing studies (will) offer definitive answers about the efficacy of neoadjuvant therapy. With extensive experience confirming the safety and some efficacy for this approach most current studies are focused on identifying the best preoperative treatment regimen. We try to clarify if is really the time to slow down the enthusiasm about neoadjuvant approach.

Evaluation and validation of the prognostic value of nutrition and immunity parameters in gastric cancer after R0 resection

Precise predictive tools are critical for choosing the individualized treatment protocols and follow-up procedures for patients with gastric cancer (GC). In this study, we aimed to evaluate and validate the prognostic abilities of preoperative nutrition and immunity parameters in GC after curative R0 resection.We established two nomograms based on 437 patients who underwent curative radical gastrectomy for gastric cancer to predict the postoperative overall survival (OS) and recurrence-free survival (RFS), and then compared the predictive accuracy and discriminative ability of the nomograms with the TNM stage systems for GC. An internal validation cohort of 141 patients and an external validation cohort of 116 patients were used to validate the result.The independent predictive factors for OS or RFS, including T stage, N stage, differentiated degree, neutrophil monocyte lymphocyte ratio (NMLR) and albumin globulin ratio (AGR) were used to establish the 2 nomograms. The C-index of the OS nomogram was 0.802, which was higher than that of the AGR, the NMLR and the TNM stage. The C-index of the RFS nomogram was 0.850, which was higher than that of the AGR, the NMLR and the TNM stage. Analogously, the areas under the receiver operating characteristics curves (AUROCs, 0.920 for OS and 0.897 for RFS, respectively) of the two nomograms were higher than that of the NMLR, the AGR and the TNM stage. In the internal validation cohort, the C-indexes of the OS and RFS nomograms were 0.812 and 0.826, respectively. In the external validation cohort, the C-indexes of the OS and RFS nomograms were 0.866 and 0.880, respectively.The proposed nomograms including nutrition and immunity parameters were proved to have excellent predictive ability in survival and recurrence for patients with GC after R0 resection.

Down-regulated hsa_circ_0067934 facilitated the progression of gastric cancer by sponging hsa-mir-4705 to downgrade the expression of BMPR1B

Background

Gastric cancer is the third most lethal cancer worldwide. Finding a novel marker is essential to targeted therapy and the diagnosis of gastric cancer. As newly discovered markers, circRNAs have aroused widespread attention on a global scale. Our research aims to understand the role of circRNAs in gastric cancer and to explore the underlying pathogenesis.

Methods

Raw expression data of circRNAs were obtained from the GEO database. Integrated bioinformatics analysis was used to screen differentially expressed circRNAs (DECs) by RobustRankAggreg package. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed to predict the functions of DECs. Then, the miRNAs and mRNAs at the downstream of DECs were predicted. Expression data of miRNAs and mRNAs were downloaded from The Cancer Genome Atlas (TCGA). The aberrantly expressed miRNAs and mRNAs were selected using the edgeR package.

Results

Four datasets (GSE78092, GSE83521, GSE89143, and GSE93541) were downloaded from the GEO database. Among them, two DECs (hsa_circ_0007991 and hsa_circ_0067934) were screened. The functional analyses of DECs confirmed that they were cancer-related circRNAs. Furthermore, hsa-mir-4705 (miRNA) and BMPR1B (mRNA) at the downstream of hsa_circ_0067934 were found differentially expressed in gastric cancer by expression data from TCGA database.

Conclusions

Our study discovered the critical roles of hsa_circ_0007991 and hsa_circ_0067934 in the development of gastric cancer, and they could be novel markers for targeted therapy and assist the diagnosis of early-stage gastric cancer. Moreover, we discovered that the hsa_circ_0067934/hsa-mir-4705/BMPR1B axis might be involved in the carcinogenesis of gastric cancer.

Evaluating and validating the predictive ability of preoperative systemic inflammatory/immune cells in gastric cancer following R0 resection

The present study aimed to compare the predictive abilities of preoperative systemic inflammatory/immune cell ratios in gastric cancer (GC) following curative R0 resection, and to screen the optimal parameter incorporated into nomograms to predict the postoperative overall survival (OS) and recurrence-free survival (RFS). A total of 679 patients with GC were included in the study, divided into a primary cohort (300 cases), an internal validation cohort (278 cases), and an external validation cohort (101 cases). In the primary cohort, the prognostic abilities of all systemic inflammatory/immune cell accounts or ratios were compared by receiver operating characteristic (ROC) curve analysis. The area under the ROC curve (AUC) of the neutrophil-monocyte-lymphocyte ratio (NMLR) was largest for the prediction of OS (AUC=0.728) and RFS (AUC=0.695). The independent predictive factors for OS or RFS, including NMLR, degree of differentiation (DD), T-stage and N-stage were used to establish the 2 nomograms. The comprehensive predictive power of nomograms was compared with that of the tumor-nodes-metastasis (TNM) staging system and validated by bootstrap resampling. The concordance indexes (C-indexes) of the nomograms for OS [C-index, 0.851; 95% confidence interval (CI), 0.817-0.883] and RFS (C-index, 0.860; 95% CI, 0.831-0.889), were increased compared with those for the DD, the NMLR and the TNM stage. The AUCs of the 2 nomograms (0.933 for OS and 0.944 for RFS) were largest among all predictive scoring systems. In the internal validation cohort, the C-indexes of the nomograms for OS and RFS were 0.840 and 0.916, respectively. In the external validation cohort, the C-indexes of the nomograms for OS and RFS nomograms were 0.827 and 0.891, respectively. The present study demonstrated that the NMLR was an independent prognostic factor for patients with GC. The proposed nomograms were demonstrated to have a good predictive ability with improved sensitivity and accuracy in survival and recurrence in patients with GC undergoing R0 resection.

MAP3K1 rs889312 genotypes influence survival outcomes of Chinese gastric cancer patients who received adjuvant chemotherapy based on platinum and fluorouracil regimes

Background

For patients with gastric cancer (GC), adjuvant chemotherapy is a standard therapy. However, the responses to the treatment are quite different. Mitogen-activated protein kinase (MAPK) pathway is a core pathway that modulates the efficacy of anticancer drugs. The purpose of our study was to investigate the clinical significance of one pivotal functional gene polymorphism in the MAPK pathway – MAP3K1 rs889312 – in patients with stage II GC to stage III GC.

Methods

The genotypes of MAP3K1 rs889312 were analyzed in 591 GC patients enrolled in this study who had received radical gastrectomy. Among them, 204 patients accepted adjuvant chemotherapy based on platinum and fluorouracil (PF) regimens after an operation. Cox regression analysis, log-rank test and Kaplan–Meier method were used to explore the link between MAP3K1 rs889312 variant and overall survival (OS) of GC.

Results

Compared with the AA genotype (mean OS of 68.12 months), MAP3K1 rs889312 AC/CC significantly reduced the mean OS of 56.83 months in patients who received adjuvant chemotherapy only. In addition, AC/CC genotype had a negative impact on OS of patients who received oxaliplatin-based therapy (HR, 8.253; 95% CI: 1.119–60.853, log-rank p=0.013). Stratification analysis showed that MAP3K1 rs889312 AC/CC significantly reduced OS of patients with tumors smaller than or equal to 5 cm in size (HR, 3.706; 95% CI: 1.329–10.335, p=0.012), poorly differentiated tumors (HR, 3.002; 95% CI: 1.076–8.377, p=0.036) and intestinal tumors (HR, 4.780; 95% CI: 1.138–20.073, p=0.033).

Conclusion

Our findings suggested that MAP3K1 rs889312 single-nucleotide polymorphism may be considered as a biomarker for adjuvant chemotherapy reaction and can predict prognosis of GC patients who received PF-based therapy.

Gastric cancer: Translating novels concepts into clinical practice

The overall 5-year survival of gastric cancer (GC) has change only little in the last decades and it remains the fifth leading cause of cancer-related death worldwide. However, in the past few years a more effective combination chemotherapy has raised the bar of curability of about 10% in resectable disease. Morever, a deeper knowledge of GC biology have unveiled biomarkers to help personalize adjunctive treatments in patients candidate to surgery. Despite a plateau in efficacy of fist-line treatment, incremental survival advantages have been recorded in unresectable advanced disease. The growing number of effective drugs in second and later lines along with a more judicious delivery of cytotoxics and early supportive interventions have enabled more patients to proceed beyond first-line. The continuum of care has become a reality in a considerable proportion of patients that offer opportunities to improve outcomes. Finally, the advent of the immune checkpoint inhibitors has brought great expectations in molecularly-defined subset of patients. This Review summarizes the state-of-the art in the management of GC together with novel concepts that have entered clinical development with the potential of change practice in the foreseeable future.

Overexpression of Mst1 reduces gastric cancer cell viability by repressing the AMPK-Sirt3 pathway and activating mitochondrial fission

BACKGROUND AND OBJECTIVE

Mammalian sterile 20-like kinase 1 (Mst1) plays a critical role in regulating cell survival and apoptosis. However, its influence on gastric cancer cell viability is not understood. Our study aims to explore the specific role of Mst1 in gastric cancer.

MATERIALS AND METHODS

Cellular viability was measured via TUNEL staining, MTT assays, and Western blotting. Immunofluorescence was performed to observe mitochondrial fission. Mst1 overexpression assays were conducted to observe the regulatory mechanisms of Mst1 in mitochondrial fission and cell apoptosis.

RESULTS

The results demonstrated that Mst1 was downregulated in AGS cells when compared with GES-1 cells. However, overexpression of Mst1 reduced cell viability and increased apoptosis in AGS cells. Molecular experiments showed that Mst1 overexpression mediated mitochondrial damage, as evidenced by decreased ATP production, increased ROS generation, more cyt-c translocation from the mitochondria into the cytoplasm and nucleus, and activated the caspase-9-related apoptotic pathway. Furthermore, we found that mitochondrial fission was required for Mst1-induced mitochondrial dysfunction; inhibition of mitochondrial fission sustained mitochondrial homeostasis in response to Mst1 overexpression. In addition, our data revealed that Mst1 controlled mitochondrial fission via repressing the AMPK-Sirt3 pathway. Activation of the AMPK-Sirt3 pathway negated the promoting effect of Mst1 overexpression on mitochondrial fission.

CONCLUSION

Altogether, our data identified Mst1 as a novel tumor-suppressive factor in promoting cell death in gastric cancer cells by triggering mitochondrial fission and blocking the AMPK-Sirt3 axis.