Gastric cancer molecular classification based on immunohistochemistry and in situ hybridization: Analysis in western patients after curative-intent surgery

Immunohistochemical-Based Molecular Typing of ACRG Combined With Immune-Associated PD-L1 Expression Can Predict the Prognosis of Gastric Cancer

BACKGROUND

Gastric cancer (GC) is a molecularly heterogeneous disease with diverse clinical outcomes. Traditional classifications lack predictive accuracy, necessitating alternative molecular subtyping approaches for effective prognosis prediction. The Asian Cancer Research Group (ACRG) molecular subtypes, combined with immune-associated PD-L1 expression, offer a promising framework to predict patient outcomes and potentially guide treatment strategies in GC.

METHODS

This study retrospectively analyzed 1007 primary GC patients who underwent surgical resection between January 2017 and June 2019 at the Fourth Hospital of Hebei Medical University. Comprehensive immunohistochemical and fluorescent PCR-capillary electrophoresis analyses were conducted to determine ACRG molecular subtypes (microsatellite instability [MSI], microsatellite stability with epithelial-mesenchymal transition [MSS/EMT], MSS/TP53+, and MSS/TP53-) and PD-L1 expression. We assessed the relationship between these classifications and various clinicopathological parameters, including survival outcomes, using Cox regression and Kaplan-Meier analysis.

RESULTS

The ACRG subtypes showed significant associations with clinicopathological features, including tumor invasion depth, Lauren classification, and HER2 status. The MSI subtype (6.7% of cases) was associated with higher PD-L1 positivity and a favorable prognosis, whereas the EMT subtype had the lowest 5-year survival rate (34.55%) and was predominantly linked to diffuse-type histology. PD-L1 positivity correlated with worse survival outcomes, with independent predictive value alongside ACRG subtypes (HR for PD-L1 = 1.759, p = 0.001; HR for ACRG = 5.144, p < 0.001).

CONCLUSION

The combination of ACRG molecular subtyping and PD-L1 expression serves as an effective predictor of GC prognosis, facilitating tailored clinical decision-making. The ACRG-PD-L1 classification system offers a practical, cost-effective approach for routine clinical application, providing critical insight into GC heterogeneity. Further multicenter studies are needed to validate these findings and explore the impact of ACRG subtypes on therapy responses, particularly in immunotherapy settings.

Transcriptome-Based Survival Analysis Identifies MAP4K4 as a Prognostic Marker in Gastric Cancer with Microsatellite Instability

Background/Objectives: Gastric cancer (GC) is a highly aggressive malignancy with diverse molecular subtypes. While microsatellite instability (MSI) GC generally carries a favorable prognosis, a subset of patients experiences poor outcomes, highlighting the need for refined prognostic markers. Methods: This study utilized transcriptomic and clinical data from two independent cohorts, The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG), to identify novel prognostic genes in MSI-GC. Results: Through rigorous survival analysis, we identified high MAP4K4 expression (MAP4K4high) as an independent and robust predictor of poor overall survival (OS) and disease-free survival (DFS) specifically within the MSI-GC subtype. MAP4K4high was associated with increased hazard ratios for both OS and DFS in both cohorts, even after adjusting for clinicopathological factors. Further analysis revealed that MAP4K4high MSI-GC tumors exhibit a distinct molecular profile characterized by increased extracellular matrix remodeling, epithelial-mesenchymal transition, and a microenvironment enriched in monocytes and cancer-associated fibroblasts (CAFs). Notably, a subgroup of MSI-GC patients with a CIN-like phenotype and high MAP4K4 expression exhibited particularly dismal outcomes. Conclusions: Our findings establish MAP4K4 as a promising prognostic biomarker for risk stratification in MSI-GC and suggest its potential role in driving aggressive tumor behavior through modulation of the tumor microenvironment.

Prognostic effect of immunohistochemically determined molecular subtypes in gastric cancer

INTRODUCTION

Gastric cancer is the fifth most common cancer worldwide and the fourth most common cause of cancer-related death. Two molecular subtyping classifications were recently introduced: The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG) classifications.

METHODS

We classified a cohort of 283 gastric cancer patients undergoing surgery at Helsinki University Hospital between 2000 and 2009. We constructed a tumour tissue microarray immunostained for the following markers: microsatellite instability (MSI) markers MSH2, MSH6, MLH1, and PMS2; p53; E-cadherin; and EBERISH.

RESULTS

In the univariate survival analysis for disease-specific survival, the Epstein-Barr virus (EBV) -positive subtype exhibited the worst prognosis with a hazard ratio (HR) of 2.49 (95% confidence interval [CI] 1.19-5.25, p = 0.016) compared with the most benign subtype, chromosomal instability (CIN). Using TCGA's classification, the genetically stable (GS) and MSI subtypes exhibited a worse survival compared with CIN (HR 1.73 [95% CI 1.15-2.60], p = 0.009 and HR 1.74 [95% CI 1.06-2.84], p = 0.027, respectively). Using the ACRG classification, the p53 aberrant subtype exhibited the best prognosis, whereas wild-type p53, MSI, and the epithelial-mesenchymal transition (EMT) subtypes exhibited poorer prognoses (EMT: HR 1.90 [95% CI 1.30-2.77], p < 0.001) when compared with aberrant p53.

CONCLUSIONS

Immunohistochemical analysis can identify prognostically different molecular subtypes of gastric cancer. The method is inexpensive and fast, yet reveals significant information for clinical decision-making. However, our study did not find that either molecular subtyping performed better than the other classification. Thus, further development of the most optimal grouping of different molecular subtypes is still needed.

Layer Analysis Based on RNA-Seq Reveals Molecular Complexity of Gastric Cancer

Gastric adenocarcinoma (GA) is a significant global health issue with poor prognosis, despite advancements in treatment. Although molecular classifications, such as The Cancer Genome Atlas (TCGA), provide valuable insights, their clinical utility remains limited. We performed a multi-layered functional analysis using TCGA RNA sequencing data to better define molecular subtypes and explore therapeutic implications. We reanalyzed TCGA RNA-seq data from 142 GA patients with localized disease who received adjuvant chemotherapy. Our approach included probabilistic graphical models and recurrent sparse k-means/consensus cluster algorithms for layer-based analysis. Our findings revealed survival differences among TCGA groups, with the GS subtype showing the poorest prognosis. We identified twelve functional nodes and seven biological layers, each with distinct functions. The combined molecular layer (CML) classification identified three prognostic groups that align with TCGA subtypes. CML2 (GS-like) displayed gene expression related to lipid metabolism, correlating with worse survival. Transcriptomic heterogeneity within the CIN subtype revealed clusters tied to proteolysis and lipid metabolism. We identified a subset of CIN tumors with profiles similar to MSI, termed CIN-MSI-like. Claudin-18, a key gene in proteolysis, was overexpressed across TCGA subtypes, suggesting it is a potential therapeutic target. Our study advances GA biology, enabling refined stratification and personalized treatment. Further studies are needed to translate these findings into clinical practice.

Prognostic significance of microsatellite instability in patients with resectable gastric cancer

BACKGROUND

Microsatellite instability (MSI) gastric cancer (GC) generally has a better prognosis than microsatellite-stable (MSS) GC and has been associated with nonsurvival benefit with the addition of chemotherapy (CMT) compared with surgery alone. However, patients with MSI have distinct clinicopathological characteristics. This study aimed to compare the survival outcomes between patients with MSI GC and those with MSS GC. In addition, this study analyzed the survival outcomes of patients with MSI GC who received CMT.

METHODS

This study reviewed all patients with GC who underwent curative gastrectomy. Patients were divided into MSI group and the MSS group. Propensity score matching (PSM) was used to match clinicopathological factors.

RESULTS

Among the 378 patients enrolled, 78 (20.6%) had MSI. Older age (P < .001), subtotal gastrectomy (P = .008), pN0 (P = .020), and earlier pTNM stage (P = .012) were associated with MSI GC. Survival analysis showed better disease-free survival (DFS) and overall survival (OS) of patients in the MSI group (P = .012 and P = .019, respectively). After PSM, 78 patients were matched to each group. All variables assigned to the scores were well matched, and both groups became equivalent. After the matching, the differences in DFS and OS according to MSI/MSS status were estimated to be larger than before (DFS: 63.3% vs 41.4%; P = .002; OS: 65.8% vs 42.5%; P = .002). Regarding patients referred for CMT, there was no difference in DFS and OS between patients with MSI GC who underwent CMT and those who underwent surgery alone (P = .255 and P = .178, respectively).

CONCLUSION

Even after controlling for clinicopathological characteristics, MSI was identified as a prognostic factor for patient survival. MSI GC showed no significant survival benefit with the addition of CMT.

Cluster classification of a Brazilian gastric cancer cohort reveals remarkable populational differences in normal p53 rate

BACKGROUND

Queiroz et al. showed that the application of cluster methodology for classifying gastric cancer is suitable and efficient within a Brazilian cohort, which is known for its population heterogeneity. The study highlighted the potential utilization of this method within public health services due to its low-cost, presenting a viable means to improve the diagnosis and prognosis of gastric cancer.

BACKGROUND

Our Brazilian cohort with gastric cancer has a distinct distribution between mutated and normal p53.

BACKGROUND

New genetic marker-based classifications improve gastric cancer diagnosis accuracy.

BACKGROUND

Machine learning integration enhances predictive value in gastric cancer diagnosis.

BACKGROUND

Molecular biomarkers complement clinical decisions, advancing personalized medicine.

OBJECTIVE

Gastric adenocarcinoma remains an aggressive disease with a poor prognosis, as evidenced by a 5-year survival rate of approximately 31%. The histological classifications already proposed do not accurately reflect the high biological heterogeneity of this neoplasm, particularly in diverse populations, and new classification systems using genetic markers have recently been proposed. Following these newly proposed models, we aimed to assess the cluster distribution in a Brazilian cohort. Furthermore, we evaluated whether the inclusion of other clinical and histological parameters could enhance the predictive value.

METHODS

We used a previously described four-immunohistochemistry/EBER-ISH marker to classify a cohort of 30 Brazilian patients with gastric adenocarcinoma into five different clusters and compared the distribution with other genetically diverse populations. Furthermore, we used artificial intelligence methods to evaluate whether other clinical and pathological parameters could improve the results of the methodology.

RESULTS

Disclosing the genetic variability between populations, we observed a more balanced distribution of the aberrant/normal p53 ratio (0.6) between patients negative for the other markers tested, unlike previous studies with Asian and North American populations. In addition, decision tree analysis reinforced the efficiency of these new classifications, as the stratification accuracy was not altered with or without additional data.

CONCLUSION

Our study underscores the importance of local research in characterizing diverse populations and highlights the complementary role of molecular biomarkers in personalized medicine for gastric adenocarcinoma, enhancing diagnostic accuracy and potentially improving survival rates.

Adjuvant chemotherapy versus preoperative chemotherapy for gastric cancer treated with curative-intent resection: A propensity score-matched analysis

BACKGROUND

Multimodal therapy (MMT), comprising surgery alongside perioperative chemotherapy (PCMT) or adjuvant chemotherapy (ACMT), has demonstrated improve in survival compared with surgery alone for advanced gastric cancer (GC). However, the moment of administering chemotherapy for GC is still a matter of debate. This study aimed to compare PCMT and ACMT in patients with locally advanced GC.

METHOD

We included all gastric adenocarcinoma treated with chemotherapy and curative-intent resection. Using propensity score matching (PSM), patients who received PCMT were matched with patients undergoing ACMT for 10 pretreatment variables.

RESULTS

Among the 552 patients with indication for MMT, 377 (68.3%) received combining chemotherapy (CMT): 116 (30.8%) PCMT and 261 (69.2%) ACMT. After PSM, 109 patients were matched in each group. All variables assigned in the score were well matched and both groups became equivalent. Patients receiving PCMT had less angiolymphatic and perineural invasion, less advanced pT, pN and pTNM stage than ACMT group (p < 0.001 for all). There was no difference in the postoperative complication rate between both groups (p = 0.551). After the matching, disease-free survival (DFS) and overall survival (OS) became similar between PCMT and ACMT groups (DFS: 51.4% vs. 46.9%, p = 0.882, respectively; OS: 54.3% vs. 48.7%, p = 0.638, respectively).

CONCLUSION

After controlling for pretreatments characteristics, there was no significant difference in survival between GC patients who underwent perioperative and adjuvant CMT. PCMT did not result in an increase in survival, but it provides a decrease in the stage of the disease, with no difference in surgical outcomes.

Gastric cancer molecular classification based on immunohistochemistry and in-situ hybridisation and mortality

BACKGROUND AND AIMS

Gastric cancers (GC) are divided into subtypes based on molecular profile: Epstein-Barr virus (EBV)-positive, microsatellite instability (MSI), chromosomal instability (CIN) and genomically stable (GS) tumours. The prognostic impact of this classification is unclear. The aim was to evaluate whether the molecular subtypes determined using in-situ hybridisation (ISH) and immunohistochemistry (IHC) are associated with clinicopathological parameters and prognosis.

METHODS AND RESULTS

The study included 503 GC patients. Based on ISH (EBV) and IHC (MSI and TP53), tumours were divided into EBV-positive, MSI, CIN (EBVneg/MSS/TP53aberrant) and GS (EBVneg/MSS/TP53wild-type) subgroups. Survival analyses with intestinal- and diffuse-type tumours were examined separately. EBV-positive tumours associated with male sex. Both EBV-positive and MSI tumours associated with intestinal type. CIN tumours associated with intestinal-type and positive lymph node status. GS tumours associated with diffuse-type and negative lymph node status. In the total cohort, no significant differences in the 5-year survival were observed. In intestinal tumours, the 5-year survival was better in EBV-positive tumours compared with GS tumours [hazard ratio (HR) = 0.57, 95% confidence interval (CI) = 0.33-0.99]. In diffuse tumours, the 5-year survival was worse in CIN tumours compared with GS tumours (HR = 1.57, 95% CI = 1.14-2.18). In radically resected diffuse tumours, the 5-year survival was worse in MSI tumours compared with GS tumours (HR = 3.26, 95% CI = 1.20-8.82).

CONCLUSIONS

The molecular classification is associated with histological type but not prognosis in GC. As the prognostic effects of molecular subtypes in intestinal- and diffuse-type cancers may differ, combining histological and molecular information is recommended for future studies.

THE MOLECULAR CANCER SUBTYPES VERSUS THE INDUSTRY ARSENAL. WHICH ONE DRIVES GASTRIC CANCER TREATMENT?

Molecular medicine opened new horizons in understanding disease mechanisms and discovering target interventions. The wider availability of DNA and RNA sequencing, immunohistochemical analysis, proteomics, and other molecular tests changed how physicians manage diseases. The gastric cancer molecular classification proposed by The Cancer Genome Atlas Program divides gastric adenocarcinomas into four subtypes. However, the available targets and/or immunotherapies approved for clinical use seem to be dissociated from these molecular subtypes. Until a more reliable interpretation of the stupendous amount of data provided by the molecular classifications is presented, the clinical guidelines will rely on available actionable targets and approved therapies to guide clinicians in conducting cancer management in the era of molecular therapies.

Molecular Classifications in Gastric Cancer: A Call for Interdisciplinary Collaboration

Gastric cancer (GC) is a heterogeneous disease, often diagnosed at advanced stages, with a 5-year survival rate of approximately 20%. Despite notable technological advancements in cancer research over the past decades, their impact on GC management and outcomes has been limited. Numerous molecular alterations have been identified in GC, leading to various molecular classifications, such as those developed by The Cancer Genome Atlas (TCGA) and the Asian Cancer Research Group (ACRG). Other authors have proposed alternative perspectives, including immune, proteomic, or epigenetic-based classifications. However, molecular stratification has not yet transitioned into clinical practice for GC, and little attention has been paid to alternative molecular classifications. In this review, we explore diverse molecular classifications in GC from a practical point of view, emphasizing their relationships with clinicopathological factors, prognosis, and therapeutic approaches. We have focused on classifications beyond those of TCGA and the ACRG, which have been less extensively reviewed previously. Additionally, we discuss the challenges that must be overcome to ensure their impact on patient treatment and prognosis. This review aims to serve as a practical framework to understand the molecular landscape of GC, facilitate the development of consensus molecular categories, and guide the design of innovative molecular studies in the field.

Molecular profile of gastric adenocarcinoma, relevant epidemiological factors - Systematic review and meta-analysis relating sex with Epstein-Barr virus and unstable microsatellites subtypes

INTRODUCTION

Gastric epithelial tumors exhibit morphological heterogeneity, diverse biological behaviors, and different oncopathological pathways. The Cancer Genome Atlas (TCGA) proposed a molecular classification of gastric adenocarcinomas based on genetic and molecular findings, which shows particular characteristics of diagnosis, prognosis, and indirectly, therapeutic alternatives. Within this classification, Epstein-Barr virus-positive (EBV+) and high microsatellite instability (MSI-H) subtypes stand out as subtypes that present a less aggressive biological behavior and a highly mutilated phenotype. This study conducted a systematic review with an emphasis on epidemiological and prognostic factors based on the molecular classification proposed by TCGA.

METHODS

A broad, comprehensive, and reproducible search with methodological rigor was conducted for study selection using the ROBINS-I and GRADEpro protocols and appropriate combinations of keywords.

RESULTS

A total of 25 studies were selected: six with a complete classification similar to TCGA and 19 with a distinction between MSI-H and EBV+. The application of meta-analysis calculations reinforces the prevalence of positive Epstein-Barr adenocarcinomas in males and high microsatellite instability in females, with a high level of certainty of evidence and low risk of bias in the analyzed studies due to the rigorous methods used.

CONCLUSION

The molecular classification proposed by TCGA shows limited dissemination, with MSI-H and EBV+ subtypes being the most researched, probably due to the benefit of the association with immunotherapies. However, the subclassification cannot be restricted to less than a quarter of the cases, and improvements in this aspect are urgent for the construction of knowledge on this important topic of global health.

Prognostic Implication of EBV Infection in Gastric Carcinomas: A Systematic Review and Meta-Analysis

Background and objectives: This study aims to elucidate the prognostic implications of Epstein-Barr virus (EBV) infection in gastric carcinomas (GCs) through a systematic review and meta-analysis. Materials and Methods: In total, 57 eligible studies and 22,943 patients were included in this meta-analysis. We compared the prognoses of EBV-infected and non-infected GC patients. The subgroup analysis was performed based on the study location, molecular classification, and Lauren's classification. This study was checked according to the PRISMA 2020. The meta-analysis was performed using the Comprehensive Meta-Analysis software package. Results: EBV infection was found in 10.4% (95% confidence interval (CI) 0.082-0.131) of GC patients. The EBV-infected GC patients had a better overall survival compared with the EBV-non-infected GC patients (hazard ratio (HR) 0.890, 95% CI 0.816-0.970). In the subgroup analysis based on molecular classification, no significant differences were found between EBV+ and microsatellite instability and microsatellite stable (MSS)/EBV- subgroups (HR 1.099, 95% CI 0.885-1.364 and HR 0.954, 95% CI 0.872-1.044, respectively). In the diffuse type of Lauren's classification, EBV-infected GCs have a better prognosis compared with the EBV-non-infected GCs (HR 0.400, 95% CI 0.300-0.534). The prognostic impact of EBV infection was found in the Asian and American subgroups but not in the European subgroup (HR 0.880, 95% CI 0.782-0.991, HR 0.840, 95% CI 0.750-0.941, and HR 0.915, 95% CI 0.814-1.028). Conclusions: EBV infection is a favorable survival factor for GCs. However, the prognostic implications of EBV infection in the new molecular classification are not clear.

Clinical Significance of Molecular Subtypes in Western Advanced Gastric Cancer: A Real-World Multicenter Experience

In recent years, the molecular subtyping of gastric cancer has led to the identification of novel clinically relevant biomarkers as well as promising therapeutic targets. In parallel, the advent of checkpoint inhibitors has expanded treatment options beyond conventional chemotherapy. Compelling evidence has shown unprecedented efficacy results for anti-PD1-based therapies in the molecular subgroups of dMMR/MSI-h, EBV+ and PD-L1 CPS+ patients, to the point that these are granted approval for gastric cancer adenocarcinoma (AGC) in several countries. Despite this, cytotoxic chemotherapy remains the only treatment choice for the considerable proportion of biomarkers-negative patients. In this context, little is known about the association between subtypes-defining biomarkers (HER2, MMR/MSI, PD-L1, and EBV) and the efficacy of standard chemotherapy in non-Asian AGC. Here, we aimed to investigate the prevalence, the clinic-pathologic features, and the impact on treatment outcome of clinical molecular subtypes in a new-diagnosed Western cohort of AGC.

Immunohistochemical Markers of the Epithelial-to-Mesenchymal Transition (EMT) Are Related to Extensive Lymph Nodal Spread, Peritoneal Dissemination, and Poor Prognosis in the Microsatellite-Stable Diffuse Histotype of Gastric Cancer

Background: Although the prognostic value of the epithelial-to-mesenchymal transition (EMT) in gastric cancer has been reported in several studies, the strong association with the diffuse type may represent a confounding factor. Our aim is to investigate potential correlations among EMT status, tumor advancement, and prognosis in diffuse gastric cancer. Methods: Between 1997 and 2012, 84 patients with microsatellite-stable (MSS) diffuse-type tumors underwent surgery. The EMT phenotype was assessed with the E-cadherin, CD44, and zinc finger E-box binding homeobox 1 (ZEB-1) immunohistochemical markers. Results: Forty-five out of 84 cases (54%) were EMT-positive; more advanced nodal status (p = 0.010), pTNM stage (p = 0.032), and vascular invasion (p = 0.037) were observed in this group. The median numbers of positive nodes (13 vs. 5) and involved nodal stations (4 vs. 2) were higher in the EMT-positive group. The cancer-related survival time was 26 months in EMT-positive cases vs. 51 in negative cases, with five-year survival rates of 17% vs. 51%, respectively (p = 0.001). The EMT status had an impact on the prognosis of patients with <70 years, R0 resections, or treatment with adjuvant chemotherapy. Tumor relapses after surgery and peritoneal spread were significantly higher in the EMT-positive tumors. Conclusions: EMT status, when assessed through immunohistochemistry, identified an aggressive phenotype of MSS diffuse-type tumors with extensive lymph nodal spread, peritoneal dissemination, and worse long-term outcomes.

Chromosomally Unstable Gastric Cancers Overexpressing Claudin-6 Disclose Cross-Talk between HNF1A and HNF4A, and Upregulated Cholesterol Metabolism

(1) Abnormally increased expression of claudin-6 in gastric cancer is considered a prognostic marker of the chromosomal unstable molecular subtype. However, a detailed molecular profile analysis of differentially expressed genes and affected pathways associated with claudin-6 increased (Cldn6^high) expression has not been assessed. (2) The TCGA Stomach Adenocarcinoma Pan-Cancer Atlas Data was evaluated using Cytoscape's Gene Mania, MCODE, and Cytohubba bioinformatic software. (3) 96.88% of Cldn6^high gastric cancer tumors belonging to the chromosomal unstable molecular subtype are associated with a worse prognosis. Cldn6expression coincided with higher mutations in TP53, MIEN1, STARD3, PGAP3, and CCNE1 genes compared to Cldn6^low expression. In Cldn6^high cancers, 1316 genes were highly expressed. Cholesterol metabolism was the most affected pathway as APOA1, APOA2, APOH, APOC2, APOC3, APOB-100, LDL receptor-related protein 1/2, Sterol O-acyltransferase, STARD3, MAGEA-2, -3, -4, -6, -9B, and -12 genes were overexpressed in Cldn6^high gastric cancers; interestingly, APOA2 and MAGEA9b were identified as top hub genes. Functional enrichment of DEGs linked HNF-4α and HNF-1α genes as highly expressed in Cldn6^high gastric cancer. (4) Our results suggest that APOA2 and MAGEA9b could be considered as prognostic markers for Cldn6^high gastric cancers.

Effect of FLOT2 Gene Expression on Invasion and Metastasis of Colorectal Cancer and Its Molecular Mechanism under Nanotechnology and RNA Interference

The study is aimed at investigating the effect of the FLOT2 gene on invasion and metastasis of colorectal cancer (CRC) cells and the corresponding molecular mechanism by preparing polylysine-silicon nanoparticles. Specifically, polylysine was used to modify the silica nanoparticles prepared by the emulsification method to obtain polylysine-silicon nanoparticles. The characterization of polylysine-silicon nanoparticles was completed by nanoparticle size analyzer, laser particle size potentiometer, and transmission microscope. The influence of polylysine-silicon nanoparticles on the survival rate of CRC cell line HT-29 was detected using the method of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). The FLOT2-siRNA expression vector was constructed and transfected with HT-29. The HT-29 transfected with empty plasmid was used as the negative control (NC). Western Blot (WB) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect expression levels of FLOT2 gene and epithelial-mesenchymal transition- (EMT-) related genes. Transwell invasion assay, Transwell migration assay, and CCK8 assay were used to detect the cell invasion, migration, and proliferation. The results showed that the average particle size of polylysine-silicon nanoparticles was 30 nm, the potential was 19.65 mV, the particle size was 65.8 nm, and the dispersion coefficient was 0.103. At the same concentration, the toxicity of silicon nanoparticles to HT-29 was significantly lower than that of liposome reagent, and the transfection efficiency was 60%, higher than that of liposome reagent (40%). The mRNA level and protein expression of the FLOT2 gene in the FLOT2-siRNA group were significantly lower than those in the NC group (P < 0.01). The optical density (OD) value of the NC group and the blank control (CK) group were significantly higher than that of FLOT2-siRNA cells (P < 0.01). The OD value of FLOT2-siRNA cells was lower than that of NC cells at 48 h, 72 h, and 96 h (P < 0.01). The mRNA levels and protein expressions of MMP2 and vimentin in the FLOT2-siRNA group were significantly lower than those in the NC group and CK group (P < 0.01). The mRNA level and protein expression of the E-cadherin gene in the FLOT2-siRNA group were significantly higher than those in the NC group and CK group (P < 0.01). In conclusion, an RNA interference plasmid with high transfection efficiency and low cytotoxicity was established based on nanotechnology. siRNA-mediated FLOT2 protein inhibits the invasion, migration, and proliferation of CRC cells by regulating the expression changes of EMT-related genes, which provides a scientific basis for clinical treatment of CRC.

RhoA, Claudin 18, and c-MET in Gastric Cancer: Clinicopathological Characteristics and Prognostic Significance in Curative Resected Patients

Background: Recently, markers related to molecular classification were suggested as promising therapeutic targets for treatment and prediction of prognosis in gastric cancer (GC), including c-MET, RhoA, and Claudin-18 (CLDN18). This study aimed to investigate their expression in GC and its correlation with clinicopathological characteristics and survival. Methods: We retrospectively evaluated GC patients who underwent curative gastrectomy. c-MET, RhoA, and CLDN18 were analyzed through immunohistochemistry (IHC), and groups for analysis were determined according to the median values obtained for each marker. Results: Among the 349 GC evaluated, 180 (51.6%), 59 (16.9%), and 61 (17.5%) patients were completely negative for c-MET, RhoA, and CLDN18, respectively. Total gastrectomy, D1 lymphadenectomy, poorly differentiated histology, and greater inflammatory infiltrate were more frequent in the c-MET-negative group. Diffuse type, greater inflammatory infiltrate, and advanced pT and pTNM stage were associated with low-RhoA GC. The venous invasion was more frequent in the low-CLDN18 group. Furthermore, c-MET was positively correlated with RhoA and negatively with CLDN18. HER2 expression was associated with c-MET-positive and high-CLDN18 GC; and loss of E-cadherin expression in c-MET-negative and low-RhoA GC. c-MET-negative and Low-RhoA were significantly associated with worse disease-free survival. Conclusions: c-MET, RhoA, and CLD18 expression occurred frequently in GC. RhoA GC had distinct clinicopathological characteristics related to prognosis. c-MET and RhoA were associated with survival but were not independent predictors of prognosis.