Expression Profile of Markers for Targeted Therapy in Gastric Cancer Patients: HER-2, Microsatellite Instability and PD-L1

Three biomarkers (HER2, PD-L1, and microsatellite status) in a large cohort of metastatic gastroesophageal adenocarcinomas: The MD Anderson Cancer Center experience

Human epidermal growth factor receptor-2 (HER2), programmed death-ligand 1 (PD-L1), and microsatellite (MS) status are well-established biomarkers in gastroesophageal adenocarcinomas (GEAs). However, it is unclear how the combination of these biomarkers is associated with clinicopathological factors and prognosis. This retrospective study included baseline metastatic GEA patients who were tested for all three biomarkers (HER2, PD-L1, and MS status) at the MD Anderson Cancer Center between 2012 and 2022. Stratification was performed according to the combination of biomarker profiles: triple negative (TN), single positive (SP), and multiple positive (MP). Comparative analyses of clinicopathological factors and survival using combinations of biomarkers were performed. Among the 698 GEA patients analyzed, 251 (36.0%) were classified as TN, 334 (47.9%) as SP, and 113 (16.1%) as MP. The MP group showed a significant association with tumors located in the esophagus (p < .001), well to moderate differentiation (p < .001), and the absence of signet ring cells (p < .001). In the survival analysis, MP group had a significantly longer overall survival (OS) compared to the other groups (MP vs. TN, p < .001 and MP vs. SP, p < .001). Multivariate Cox regression analysis revealed that MP serves as an independent positive prognostic indicator for OS (hazard ratio = 0.63, p < .01). Our findings indicate that MP biomarkers are associated with a favorable prognosis in metastatic GEA. These results are reflective of clinical practice and offer valuable insights into how therapeutics and future biomarkers could influence therapy/prognosis.

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.

Association between Helicobacter pylori infection, mismatch repair, HER2 and tumor-infiltrating lymphocytes in gastric cancer

BACKGROUND

The influence of Helicobacter-pylori (H. pylori) infection and the characteristics of gastric cancer (GC) on tumor-infiltrating lymphocyte (TIL) levels has not been extensively studied. Analysis of infiltrating-immune-cell subtypes as well as survival is necessary to obtain comprehensive information.

AIM

To determine the rates of deficient mismatch-repair (dMMR), HER2-status and H. pylori infection and their association with TIL levels in GC.

METHODS

Samples from 503 resected GC tumors were included and TIL levels were evaluated following the international-TILs-working-group recommendations with assessment of the intratumoral (IT), stromal (ST) and invasive-border (IB) compartments. The density of CD3, CD8 and CD163 immune cells, and dMMR and HER2-status were determined by immunohistochemistry (IHC). H. pylori infection was evaluated by routine histology and quantitative PCR (qPCR) in a subset of samples.

RESULTS

dMMR was found in 34.4%, HER2+ in 5% and H. pylori-positive in 55.7% of samples. High IT-TIL was associated with grade-3 (P = 0.038), while ST-TIL with grade-1 (P < 0.001), intestinal-histology (P < 0.001) and no-recurrence (P = 0.003). dMMR was associated with high TIL levels in the ST (P = 0.019) and IB (P = 0.01) compartments, and ST-CD3 (P = 0.049) and ST-CD8 (P = 0.05) densities. HER2- was associated with high IT-CD8 (P = 0.009). H. pylori-negative was associated with high IT-TIL levels (P = 0.009) when assessed by routine-histology, and with high TIL levels in the 3 compartments (P = 0.002-0.047) and CD8 density in the IT and ST compartments (P = 0.001) when assessed by qPCR. A longer overall survival was associated with low IT-CD163 (P = 0.003) and CD8/CD3 (P = 0.001 in IT and P = 0.002 in ST) and high IT-CD3 (P = 0.021), ST-CD3 (P = 0.003) and CD3/CD163 (P = 0.002).

CONCLUSION

TIL levels were related to dMMR and H. pylori-negativity. Low CD8/CD3 and high CD163/CD3 were associated with lower recurrence and longer survival.

Association between Helicobacter pylori infection, mismatch repair, HER2 and tumor-infiltrating lymphocytes in gastric cancer

BACKGROUND

The influence of Helicobacter-pylori (H. pylori) infection and the characteristics of gastric cancer (GC) on tumor-infiltrating lymphocyte (TIL) levels has not been extensively studied. Analysis of infiltrating-immune-cell subtypes as well as survival is necessary to obtain comprehensive information.

AIM

To determine the rates of deficient mismatch-repair (dMMR), HER2-status and H. pylori infection and their association with TIL levels in GC.

METHODS

Samples from 503 resected GC tumors were included and TIL levels were evaluated following the international-TILs-working-group recommendations with assessment of the intratumoral (IT), stromal (ST) and invasive-border (IB) compartments. The density of CD3, CD8 and CD163 immune cells, and dMMR and HER2-status were determined by immunohistochemistry (IHC). H. pylori infection was evaluated by routine histology and quantitative PCR (qPCR) in a subset of samples.

RESULTS

dMMR was found in 34.4%, HER2+ in 5% and H. pylori-positive in 55.7% of samples. High IT-TIL was associated with grade-3 (P = 0.038), while ST-TIL with grade-1 (P < 0.001), intestinal-histology (P < 0.001) and no-recurrence (P = 0.003). dMMR was associated with high TIL levels in the ST (P = 0.019) and IB (P = 0.01) compartments, and ST-CD3 (P = 0.049) and ST-CD8 (P = 0.05) densities. HER2- was associated with high IT-CD8 (P = 0.009). H. pylori-negative was associated with high IT-TIL levels (P = 0.009) when assessed by routine-histology, and with high TIL levels in the 3 compartments (P = 0.002-0.047) and CD8 density in the IT and ST compartments (P = 0.001) when assessed by qPCR. A longer overall survival was associated with low IT-CD163 (P = 0.003) and CD8/CD3 (P = 0.001 in IT and P = 0.002 in ST) and high IT-CD3 (P = 0.021), ST-CD3 (P = 0.003) and CD3/CD163 (P = 0.002).

CONCLUSION

TIL levels were related to dMMR and H. pylori-negativity. Low CD8/CD3 and high CD163/CD3 were associated with lower recurrence and longer survival.

Prognostic implications of tumor-infiltrating lymphocytes within the tumor microenvironment in gastric cancer

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) play a regulatory role in the tumor-associated immune response and are important in the prognosis and treatment response of several cancers. However, because of its heterogeneity, the prognostic value of TILs in gastric cancer (GC) is still controversial. Thus, this study aimed to investigate the association between the density of TILs and patients' outcomes in GC.

METHODS

Patients with gastric adenocarcinoma who underwent curative intent gastrectomy were retrospectively investigated. The groups for analysis were determined on the basis of TIL intensity and percentage of CD3+ T-cell infiltration by immunohistochemical. Furthermore, Epstein-Barr virus (EBV), microsatellite instability (MSI), T-cell ratio of CD4 to CD8, and programmed death protein ligand 1 (PD-L1) status were evaluated.

RESULTS

A total of 345 patients were enrolled: 124 patients with GCs (35.9%) were classified as the low-CD3+ TIL group, and 221 patients with GCs (64.1%) were classified as the high-CD3+ TIL group. Poorly differentiated histology (P = .014), EBV-positive status (P < .001), PD-L1-positive status (P = .001), and CD4 < CD8 (P < .001) were associated with high-CD3+ GC. There was no difference regarding MSI status, the degree of tumor invasion (pT), the presence of lymph node metastasis, and pTNM stage between low- and high-CD3+ groups. In survival analysis, the high-CD3+ group had better disease-free survival and overall survival rates than had the low-CD3+ group (P = .055 and P = .041, respectively). In the multivariate analysis, total gastrectomy, lymph node metastasis, advanced pT stage, and low CD3+ levels were independent factors related to worse survival.

CONCLUSION

High CD3+ TILs levels were significantly associated with improved survival and could serve as prognostic biomarkers in GC. In addition, CD3+ T-cell infiltration was related to both EBV-positive and PD-L1-positive GC and may assist in the investigation of targets in immunotherapy.

Role of microsatellite instability and HER2 positivity in locally advanced esophago-gastric cancer patients treated with peri-operative chemotherapy

PURPOSE

Neoadjuvant chemotherapy (NAC) significantly improved the prognosis of patients with locally advanced gastric cancer (LAGC). Several biomarkers, including HER2 and MMR/MSI are crucial for treatment decisions in the advanced stage but, currently, no biomarkers can guide the choice of NAC in clinical practice. Our aim was to evaluate the role of MSI and HER2 status on clinical outcomes.

METHODS

We retrospectively collected LAGC patients treated with NAC and surgery +/- adjuvant chemotherapy from 2006 to 2018. HER2 and MSI were assessed on endoscopic and surgical samples. Pathologic complete response (pCR) rate, overall survival (OS), and event-free survival (EFS) were estimated and evaluated for association with downstaging and MSI.

RESULTS

We included 76 patients, 8% were classified as MSI-H, entirely consistent between endoscopic and surgical samples. Six percent of patients were HER2 positive on endoscopic and 4% on surgical samples. Tumor downstaging was observed in 52.5% of cases, with three pCR (5.1%), none in MSI-H cancers. According to MSI status, event-free survival (EFS) and overall survival (OS) were higher for MSI-H patients to MSS [EFS not reached vs 30.0 months, p = 0.08; OS not reached vs 39.6 months, p = 0.10].

CONCLUSION

Our work confirms the positive prognostic effect of MSI-H in the curative setting of LAGC, not correlated with pathologic tumor downstaging. Prospective ad-hoc trial and tumor molecular profiling are eagerly needed.

Perioperative Tailored Treatments for Gastric Cancer: Times Are Changing

Resectable gastric or gastroesophageal (G/GEJ) cancer is a heterogeneous disease with no defined molecularly based treatment strategy. Unfortunately, nearly half of patients experience disease recurrence despite standard treatments (neoadjuvant and/or adjuvant chemotherapy/chemoradiotherapy and surgery). In this review, we summarize the evidence of potential tailored approaches in perioperative treatment of G/GEJ cancer, with a special focus on patients with human epidermal growth factor receptor-2(HER2)-positive and microsatellite instability-high (MSI-H) tumors. In patients with resectable MSI-H G/GEJ adenocarcinoma, the ongoing INFINITY trial introduces the concept of non-operative management for patients with complete clinical-pathological-molecular response, and this could be a novel and potential practice changing strategy. Other pathways involving vascular endothelial growth factor receptor (VEGFR), fibroblast growth factor receptor (FGFR), claudin18 isoform 2 (CLDN18.2), and DNA damage repair proteins are also described, with limited evidence until now. Although tailored therapy appears to be a promising strategy for resectable G/GEJ cancer, there are several methodological issues to address: inadequate sample size for pivotal trials, underestimation of subgroup effects, and choice of primary endpoint (tumor-centered vs. patient-centered endpoints). A better optimization of G/GEJ cancer treatment allows maximizing patient outcomes. In the perioperative phase, although caution is mandatory, times are changing and tailored strategies could introduce new treatment concepts. Overall, MSI-H G/GEJ cancer patients possess the characteristics to be the subgroup that could receive the most benefit from a tailored approach.

CT-based radiomic nomogram for preoperative prediction of DNA mismatch repair deficiency in gastric cancer

Background

DNA mismatch repair (MMR) deficiency has attracted considerable attention as a predictor of the immunotherapy efficacy of solid tumors, including gastric cancer. We aimed to develop and validate a computed tomography (CT)-based radiomic nomogram for the preoperative prediction of MMR deficiency in gastric cancer (GC).

Methods

In this retrospective analysis, 225 and 91 GC patients from two distinct hospital cohorts were included. Cohort 1 was randomly divided into a training cohort (n = 176) and an internal validation cohort (n = 76), whereas cohort 2 was considered an external validation cohort. Based on repeatable radiomic features, a radiomic signature was constructed using the least absolute shrinkage and selection operator (LASSO) regression analysis. We employed multivariable logistic regression analysis to build a radiomics-based model based on radiomic features and preoperative clinical characteristics. Furthermore, this prediction model was presented as a radiomic nomogram, which was evaluated in the training, internal validation, and external validation cohorts.

Results

The radiomic signature composed of 15 robust features showed a significant association with MMR protein status in the training, internal validation, and external validation cohorts (both P-values &lt;0.001). A radiomic nomogram incorporating a radiomic signature and two clinical characteristics (age and CT-reported N stage) represented good discrimination in the training cohort with an AUC of 0.902 (95% CI: 0.853–0.951), in the internal validation cohort with an AUC of 0.972 (95% CI: 0.945–1.000) and in the external validation cohort with an AUC of 0.891 (95% CI: 0.825–0.958).

Conclusion

The CT-based radiomic nomogram showed good performance for preoperative prediction of MMR protein status in GC. Furthermore, this model was a noninvasive tool to predict MMR protein status and guide neoadjuvant therapy.

Preoperative chemotherapy is a better strategy than upfront surgery in cT4 gastric cancer

BACKGROUND

Chemotherapy (CMT) followed by surgery is recommended by Western countries for advanced gastric cancer (GC). However, cT4 GC usually undergoes upfront surgery, due to symptoms. This study aimed to evaluate if preoperative CMT is a better strategy than upfront surgery in cT4 GC.

METHODS

All cT4 GCs who underwent curative gastrectomy were included. Patients were divided according to their initial treatment: upfront surgery (SURG) or CMT + SURG.

RESULTS

Among the 226 GC initially staged as cT4, 150 underwent SURG and 76 CMT + SURG. Groups were similar concerning age, comorbidities, American Society of Anesthesiologists, gastrectomy performed, and postoperative complications. The CMT + SURG group had less advanced pTNM. Median overall survival (OS) was 32 and 58.5 months for SURG and CMT + SURG, respectively (p = 0.04). Patients who received perioperative or adjuvant CMT had better OS compared to surgery alone (49.4 vs. 15.9 months, p < 0.001). OS was similar for those receiving preoperative and adjuvant CMT. Non-CMT, pN+, and R1 resection were independent risk factors for worse OS.

CONCLUSION

Multimodal treatment associating CMT with surgery, regardless of whether the approach is pre- or postoperative, is essential to improve the survival of cT4 GC. As tolerance to adjuvant treatment is reduced, preoperative CMT is a better strategy than upfront surgery in these patients.

Associations of HER2 Mutation With Immune-Related Features and Immunotherapy Outcomes in Solid Tumors

Background

HER2 is one of the most extensively studied oncogenes in solid tumors. However, the association between tumor microenvironment (TME) and HER2 mutation remains elusive, and there are no specific therapies for HER2-mutated tumors. Immune checkpoint inhibitors (ICIs) have been approved for some tumor subgroups that lack targeted therapies, while their effects are still unclear in HER2-mutated tumors. We examined whether HER2 mutation impacts treatment outcomes of ICIs in solid tumors via its association with anticancer immunity.

Methods

Multi-omics data of solid tumors from The Cancer Genome Atlas (TCGA), the Asian Cancer Research Group and the Affiliated Hospital of Jiangsu University were used to analyze the association between HER2 mutations and tumor features. Data of patients with multiple microsatellite-stable solid tumors, who were treated by ICIs including antibodies against programmed cell death-1 (PD-1), programmed cell death ligand-1 (PD-L1), or cytotoxic T lymphocyte-associated protein 4 (CTLA-4) in eight studies, were collected to investigate the effects of HER2 mutations on immunotherapy outcomes.

Results

The mutation rate of HER2 varied in solid tumors of TCGA, with an overall incidence of 3.13%, ranged from 0.39% to 12.2%. Concurrent HER2 mutations and amplifications were rare (0.26%). HER2 mutation was not associated with HER2 protein expression but was positively associated with microsatellite instability, tumor mutation and neoantigen burdens, infiltrating antitumor immune cells, and signal activities of antitumor immunity. Of 321 ICI-treated patients, 18 carried HER2 mutations (5.6%) and showed improved objective response rates compared with those with HER2 wild-type (44.4% vs. 25.7%, p=0.081), especially in the anti-PD-1/anti-PD-L1 subgroup (62.5% vs. 28.4%, p=0.04). Heterogeneity was observed among tumor types. Patients with HER2 mutations also had superior overall survival than those with HER2 wild-type (HR=0.47, 95%CI: 0.23-0.97, p=0.04), especially in the presence of co-mutations in ABCA1 (HR = 0.23, 95% CI: 0.07-0.73, p=0.013), CELSR1 (HR = 0.24, 95% CI: 0.08-0.77, p=0.016), LRP2 (HR = 0.24, 95% CI: 0.07-0.74, p=0.014), or PKHD1L1 (HR = 0.2, 95% CI: 0.05-0.8, p=0.023).

Conclusions

HER2 mutations may improve the TME to favor immunotherapy. A prospective basket trial is needed to further investigate the impacts of HER2 mutations on immunotherapy outcomes in solid tumors.

GASTRIC CANCER WITH POSITIVE EXPRESSION OF ESTROGEN RECEPTOR ALPHA: A CASE SERIES FROM A SINGLE WESTERN CENTER

AIM

Despite advances in therapies, the prognosis of patients with advanced gastric cancer (GC) remains poor. Several studies have demonstrated the expression of estrogen receptor alpha (ERa); however, its significance in GC remains controversial. The present study aims to report a case series of GC with ERa-positive expression and describe their clinicopathological characteristics and prognosis.

METHODS

We retrospectively evaluated patients with GC who underwent gastrectomy with curative intent between 2009 and 2019. ERa expression was assessed by immunohistochemistry through tissue microarray construction. Patients with ERa-negative gastric adenocarcinoma served as a comparison group.

RESULTS

During the selected period, 6 (1.8%) ERa-positive GC were identified among the 345 GC patients analyzed. All ERa-positive patients were men, aged 34-78 years, and had Lauren diffuse GC and pN+ status. Compared with ERa-negative patients, ERa-positive patients had larger tumor size (p=0.031), total gastrectomy (p=0.012), diffuse/mixed Lauren type (p=0.012), presence of perineural invasion (p=0.030), and lymph node metastasis (p=0.215). The final stage was IIA in one case, IIIA in three cases, and IIIB in two cases. Among the six ERa-positive patients, three had disease recurrence (peritoneal) and died. There was no significant difference in survival between ERa-positive and ERa-negative groups.

CONCLUSIONS

ERa expression is less common in GC, is associated with diffuse histology and presence of lymph node metastasis, and may be a marker related to tumor progression and worse prognosis. Also, a high rate of peritoneal recurrence was observed in ERa-positive patients.

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.

Disruption of Her2-Induced PD-L1 Inhibits Tumor Cell Immune Evasion in Patient-Derived Gastric Cancer Organoids

Simple Summary

HER2 may contribute to immune evasion in gastric cancer that is associated with PD-L1 expression. Autologous organoid/immune cell co-cultures serve as an appropriate in vitro model to study the effects of anti-HER2 targeted therapy in combination with anti-PD1 immune checkpoint inhibition and may be used as an ex vivo tool for precision medicine.

Abstract

(1) Background: The expression of programmed death-ligand 1 (PD-L1), which interacts with programmed cell death protein 1 (PD-1) on cytotoxic T lymphocytes (CTLs), enables tumors to escape immunosurveillance. The PD-1/PD-L1 interaction results in the inhibition of CTL proliferation, and effector function, thus promoting tumor cell evasion from immunosurveillance and cancer persistence. Despite 40% of gastric cancer patients exhibiting PD-L1 expression, only a small subset of patients responds to immunotherapy. Human epidermal growth factor receptor2 (HER2) is one of the critical regulators of several solid tumors, including metastatic gastric cancer. Although half of PD-L1-positive gastric tumors co-express HER2, crosstalk between HER2 and PD-1/PD-L1 in gastric cancer remains undetermined. (2) Methods: Human gastric cancer organoids (huTGOs) were generated from biopsied or resected tissues and co-cultured with CTLs and myeloid-derived suppressor cells (MDSCs). Digital Spatial Profiling (DSP) was performed on FFPE tissue microarrays of numerous gastric cancer patients to examine the protein expression of immune markers. (3) Results: Knockdown of HER2 in PD-L1/HER2-positive huTGOs led to a concomitant decrease in PD-L1 expression. Similarly, in huTGOs/immune cell co-cultures, PD-L1 expression decreased in huTGOs and was correlated with an increase in CTL proliferation which enhanced huTGO death. Treatment with Nivolumab exhibited similar effects. However, a combinatorial treatment with Mubritinib and Nivolumab was unable to inhibit HER2 expression in co-cultures containing MDSCs. (4) Conclusions: Our study suggested that co-expression of HER2 and PD-L1 may contribute to tumor cell immune evasion. In addition, autologous organoid/immune cell co-cultures can be exploited to effectively screen responses to a combination of anti-HER2 and immunotherapy to tailor treatment for gastric cancer patients.

Molecular classification reveals the diverse genetic and prognostic features of gastric cancer: A multi-omics consensus ensemble clustering

BACKGROUND

Globally, gastric cancer (GC) is the fifth most common tumor. It is necessary to identify novel molecular subtypes to guide patient selection for specific target therapeutic benefits.

METHODS

Multi-omics data, including transcriptomics RNA-sequencing (mRNA, LncRNA, miRNA), DNA methylation, and gene mutations in the TCGA-STAD cohort were used for the clustering. Ten classical clustering algorithms were executed to recognize patients with different molecular features using the "MOVICS" package in R. The activated signaling pathways were evaluated using the single-sample gene set enrichment analysis. The differential distribution of gene mutations, copy number alterations, and tumor mutation burden was compared, and potential responses to immunotherapy and chemotherapy were also assessed.

RESULTS

Two molecular subtypes (CS1 and CS2) were recognized by ten clustering algorithms with consensus ensembles. Patients in the CS1 group had a shorter average overall survival time (28.5 vs. 68.9 months, P = 0.016), and progression-free survival (19.0 vs. 63.9 months, P = 0.008) as compared to those in the CS2 group. Extracellular associated biological process activation was higher in the CS1 group, while the CS2 group displayed the enhanced activation of cell cycle-associated pathways. Significantly higher total mutation numbers and neoantigens were observed in the CS2 group, along with specific mutations in TTN, MUC16, and ARID1A. Higher infiltration of immunocytes was also observed in the CS2 group, reflective of the potential immunotherapeutic benefits. Moreover, the CS2 group could also respond to 5-fluorouracil, cisplatin, and paclitaxel. The similar diversity in clinical outcomes between CS1 and CS2 groups was successfully validated in the external cohorts, GSE62254, GSE26253, GSE15459, and GSE84437.

CONCLUSION

The findings provided novel insights into the GC subtypes through integrative analysis of five -omics data by ten clustering algorithms. These could provide potential clinical therapeutic targets based on the specific molecular features.

Development and external validation of a prognostic nomogram for patients with gastric cancer after radical gastrectomy

Background

Gastric cancer (GC) is one of the most malignant diseases and threatens the health of individuals across the globe. Hitherto, the identification of prognosis risk stratification on GC has mainly depended on the TNM staging, but owing to its inaccuracy and incompleteness, the prognostic value it offers remains controversial in the current clinical setting. Thus, an effective prognostic model for GC after radical gastrectomy is still needed.

Methods

Patients with pathologically confirmed GC who underwent radical gastrectomy from 2 different centers were retrospectively enrolled into a training and the validation cohort, respectively. The least absolute shrinkage and selection operator (LASSO) algorithm was applied to select variables among multiple factors, including clinical characteristics, pathological parameters, and surgery- and treatment-related indicators. The multivariate Cox regression method was used to establish the model to predict 1-, 2-, and 3-year survival. Both internal and external validations of the nomogram were then completed in terms of discrimination, calibration, and clinical utility. Finally, prognostic risk stratification of GC was conducted with X-tile software.

Results

A total of 1,424 patients with GC were eligible in this study, including 1,010 in the training cohort and 414 in the validation cohort. Seven indicators were selected by LASSO to develop the nomogram, including the number of positive lymph nodes, tumor size, adjacent organ invasion, vascular invasion, the level of carbohydrate antigen 125 (CA 125), depth of invasion, and human epidermal growth factor receptor 2 (HER2) status. The nomogram demonstrated a robust predictive capacity with favorable accuracy, discrimination, and clinical utility both in the internal and external validations. Moreover, we divided the population into 3 risk groups of survival according to the cutoff points generated by X-tile, and in this way, the nomogram was further improved into a risk-stratified prognosis model.

Conclusions

We have developed a prognostic risk stratification nomogram for GC patients after radical gastrectomy with 7 available indicators that may guide clinical practice and help facilitate tailored decision-making, thus avoiding overtreatment or undertreatment and improving communication between clinicians and patients.

ACBD3 is up-regulated in gastric cancer and promotes cell cycle G1-to-S transition in an AKT-dependent manner

It has been reported that ACBD3 is closely related to the malignant process of cells, but its role in gastric cancer has not been elucidated. This study aims to investigate the expression and function of ACBD3 in human gastric cancer. The Cancer Genome Atlas (TCGA) database were selected to analyze mRNA levels of ACBD3 in gastric cancer tissues and normal gastric epithelial tissues. qPCR and Western blot were conducted to detect the expression of ACBD3 in two normal gastric epithelial cell lines and five gastric cancer cell lines which were cultured in our laboratory. To exclude differences in individual background between different patients, we further detected the expression of ACBD3 in 8 pairs of malignant/non-malignant clinical gastric tissues. Through the establishment of stable cells, in vitro cell experiments and in vivo xenotransplantation models in mice, the role of ACBD3 in the proliferation of gastric cancer cells has been further explored. AKT inhibitors were used to deeply explore the molecular regulation mechanism of ACBD3. The results showed that the elevated ACBD3 in gastric cancer tissue were positively correlated with the clinical grade and prognosis of gastric cancer. In terms of molecular function, we found that ACBD3 can enhance the production and growth of gastric cancer cells. At the same time, the activation of AKT kinase played an important role in ACBD3's promotion of G1-to-S transition. The experiments generally indicate that ACBD3 is expected to become a potential diagnostic molecule or therapeutic target for gastric cancer.

CDC42EP3 is a key promoter involved in the development and progression of gastric cancer

Gastric cancer (GC) is one of the most prevalent cancers and severely endangers human health. Due to the low rate of diagnosis, most patients with gastric cancer are diagnosed as advanced. CDC42 effector protein 3 (CDC42EP3) has been revealed to be involved in several types of human cancers' development and progression. However, the function of CDC42EP3 in GC is not yet clear. CDC42EP3 expression was detected by immunohistochemistry (IHC), qRT-PCR and Western blot assay in tumor tissues and cell lines of GC. CDC42EP3 knockdown cell models were constructed by lentivirus transfection. Cell proliferation was evaluated by the MTT assay. The wound-healing assay and the transwell assay were utilized to assess the cell migration. Also, the cell apoptosis and the cell cycle were evaluated by flow cytometry. Moreover, the mechanism was investigated by Human Apoptosis Antibody Array. The in vivo experiments were conducted to verify the effects of CDC42EP3 knockdown on the tumor growth of GC. The expression level of CDC42EP3 was up-regulated in tumor tissues. High CDC42EP3 expression was positively related to more advanced tumor grade. CDC42EP3 knockdown inhibited cell proliferation and migration, promoted cell apoptosis and suppressed the tumor growth. On the other hand, it was also found that the silencing of CDC42EP3 inhibited HSP27 and IGF-1sR expression as well as promoted Caspase3, p53, TNF-α, TNF-β, TRAILR-1 and TRAILR-2 expression. CDC42EP3 was revealed to work as a tumor promoter in the development and progression of GC, which could be a promising therapeutic target for the therapy of GC.

Her2-Positive and Microsatellite Instability Status in Gastric Cancer-Clinicopathological Implications

Gastric cancer (GC) is one of the leading causes of cancer-related death. The combination of new molecular classifications with clinicopathological data could contribute to the individualization of patients and to the development of new therapeutic strategies. We examined the various associations in two molecular types of GC: HER2-positive (human epidermal growth factor receptor 2) and microsatellite instability (MSI), assessing their influence on treatment and prognosis. A retrospective study of 142 GC patients was performed with molecular characterization through HER2 overexpression and DNA repair protein expression for MSI. The percentage of HER2-positive tumors was 13.4%, predominantly in men. Correlations were found with intestinal type, metastases, advanced stages and chemotherapy. Almost 75% of HER2-positive patients died. MSI occurred in 16.2%, associated with advanced age, female sex, distal location and intestinal type. These patients had few metastases and low stages. The percentage of deaths was higher among MSI patients who received perioperative chemotherapy. The determination of HER2 and MSI status in GC is important for their association with specific clinicopathological features and for their prognostic and predictive value.

Remnant gastric cancer: a neglected group with high potential for immunotherapy

PURPOSE

The importance of targeted therapy and interest in the study of predictive markers in gastric cancer (GC) have increased in recent years with the use of anti-HER2 therapy and immunotherapy with anti-PD1/PD-L1 for microsatellite instability (MSI) and PD-L1 + tumors. However, the behavior of remnant GC (RGC) in this scenario is poorly reported. Thus, this study aims to evaluate the clinicopathological characteristics and prognosis of RGC and its association with the expression of current markers for targeted therapy.

METHODS

All RGC resections performed in a single center from 2009 to 2019 were retrospectively reviewed. As a comparison group, 53 primary proximal GC (PGC) who underwent total D2-gastrectomy were selected. HER2, MSI status and PD-L1 expression were analyzed by immunohistochemistry. Combined Positive Score (CPS) was used to determine PD-L1 positivity.

RESULTS

A total of 40 RGC were included. RGC patients were older (p = 0.001), had lower BMI (p = 0.001) and number of resected lymph nodes (p < 0.001) compared to the PGC. Regarding markers expression, MSI was higher in RGC than PGC (27.5% vs 9.4%, p = 0.022). The frequency of CPS-positive was 32.5% and 26.4% in RGC and PGC, respectively (p = 0.522). HER2 positivity was 17.5% and 22.6% for RGC and PGC, respectively (p = 0.543). In survival analysis, DFS was better for RGC CPS-positive than RGC CPS-negative (p = 0.039) patients. There was no difference in survival considering MSI status.

CONCLUSION

RGC had higher incidence of MSI than PGC, and CPS-positive RGC was associated with better survival. The immunological profile of RGC patients suggests that they would be good candidates for immunotherapy.

Trastuzumab with FLOT Regimen for the Perioperative Treatment of Resectable HER2 + Advanced Gastric Cancer: A Retrospective Study

Background

The aim of this study was to evaluate the efficacy and safety of trastuzumab, combined with the FLOT regimen, in the perioperative treatment of resectable HER-2-positive advanced gastric cancer.

Methods

Overall, 45 patients were divided into two groups; 29 patients in the experimental group were treated with trastuzumab combined with FLOT and 16 patients in the control group were treated with FLOT alone. The primary endpoint was objective response rate (ORR), and the secondary endpoints were disease control rate (DCR), tumor regression grade (TRG), surgical margin, side effects, and overall survival.

Results

In the experimental and control groups, ORR was 72.4% and 43.8% (p=0.226), DCR was 89.7% and 87.5%, R0 resection rate was 96.5% and 93.7%, total/subtotal tumor regression grade was 17.2% and 6.3%, partial tumor regression grade was 27.6% and 18.7% (p=0.468), and 2-year survival rate was 78.1% and 73.9% (p=0.932), respectively. The common side effects were agranulocytosis and vomiting. There was no significant difference between the two groups.

Conclusion

Trastuzumab combined with FLOT has a good curative effect and safety profile in the perioperative treatment of patients with resectable HER-2-positive advanced gastric cancer. In addition, trastuzumab + FLOT had the same result as FLOT alone, as there was no significant benefit with the addition of T in the group studied.