Poorly cohesive cells gastric carcinoma including signet-ring cell cancer: Updated review of definition, classification and therapeutic management

IFIT1 + neutrophil is a causative factor of immunosuppressive features of poorly cohesive carcinoma (PCC)

The importance of the immune microenvironment in poorly cohesive carcinoma (PCC) has been highlighted due to its limited response rate to conventional therapy and emerging treatment resistance. A combination of clinical cohorts, bioinformatics analyses, and functional/molecular experiments revealed that high infiltration of Interferon Induced Protein with Tetratricopeptide Repeats 1 (IFIT1) + tumor-associated neutrophils (TANs) is a distinguishing feature of PCC patients. Upregulation of IFIT1 + TANs promote migration and invasion of gastric cancer (GC) cell lines (MKN45 and MKN74) and stimulates the growth of cell-derived xenograft models. Besides, by promoting macrophage secreted phosphoprotein 1 (SPP1) expression and facilitating cancer-associated fibroblast and endothelial cell recruitment and activation through TANs, IFIT1 promotes a mesenchymal phenotype, which is associated with a poor prognosis. Importantly, compared to non-PCC (NPCC), PCC tumors is more immunosuppressive. Mechanistically, IFIT1 can be stimulated by IFN-γ and contributes to the expression of Programmed Cell Death 1 Ligand (PDL1) in TANs. We demonstrated in mouse models that IFIT1 + PDL1 + TANs can induce acquired resistance to anti-PD-1 immunotherapy, which may be responsible for the difficulty of PCC patients to benefit from immunotherapy. This work highlights the role of IFIT1 + TANs in mediating the remodeling of the tumor immune microenvironment and immunotherapeutic resistance and introduces IFIT1 + TANs as a promising target for precision therapy of PCC.

A Rare Case of Primary Gastric Signet Ring Cell Carcinoma: a Review of Guidelines for the Management of Gastric Cancer

Gastric carcinoma is the fifth most common and the third leading cause of cancer deaths worldwide. The incidence of diffuse-type gastric cancer, of which signet ring cell carcinoma is a subtype, is rising in the world. Due to non-specific gastritis-like symptoms, difficulty in assessing true tumor characteristics owing to its horizontal spread, and non-distinguishable endoscopic appearance from other gastric pathologies, the diagnosis of this subtype is challenging. We present a case of a 67-year-old woman with progressively worsening abdominal pain who came for an endoscopic ultrasound evaluation of an incidentally noted pancreatic cyst on a previous MRI. During endoscopy, a 1-cm gastric ulcer was noted along the lesser curvature of the gastric body. Biopsy confirmed a diagnosis of gastric signet ring cell carcinoma (SRCC) with CDX-2 and keratin positivity. The patient underwent total gastrectomy with Roux-en-Y reconstruction. Gross specimen revealed a diffuse SRCC invading the muscularis propria, along with lymphovascular and perineural invasion. In the context of our case, we discuss the morphological features of SRCC and the effectiveness of treatment options based on existing literature. Early accurate diagnosis and staging play an important role in determining treatment options as well as the clinical course of gastric SRCC.

Gastrointestinal signet ring cell malignancy: current advancement and future prospects

Globally, gastrointestinal cancer is the most widespread neoplastic disease and the primary contributor to cancer-associated fatalities. Gastrointestinal signet ring cell carcinoma (SRCC) exhibits unique distinguishing features in several aspects when compared to adenocarcinomas (ACs). The scarcity of signet ring cell carcinoma has resulted in a heightened significance of related clinical and molecular investigations. However, a comprehensive and systematic review of the clinical, molecular, therapeutic, and research aspects of this disease is currently absent. This review provides an overview of the latest developments in our understanding of the clinical and molecular features of gastrointestinal signet ring cell carcinoma (SRCC). Additionally, we have compiled a list of potential therapeutic targets or biomarkers, as well as an examination of the current treatment options and the possible mechanisms of formation.

Clinical implications and chemo-sensitivity of adjuvant chemotherapy in patients with poorly cohesive cells-gastric cancer

PURPOSE

Poorly cohesive cells-gastric cancer (PCC-GC) represents distinct features within the GC spectrum. The present study investigated the clinicopathologic characteristics and chemo-sensitivity for a relatively large cohort of PCC-GC patients.

MATERIALS AND METHODS

A total of 268 patients diagnosed with stage II or III PCC-GC were included. GC cell lines were also analyzed for drug sensitivity to 5-fluorouracil (5-FU) and oxaliplatin in vitro.

RESULTS

One hundred fifteen (42.9%) patients were stage II and 153 (57.1%) were stage III. Two hundred twenty-three (83.2%) patients received adjuvant therapy. Among these patients, 139 (62.3%) received CAPOX and 84 (37.7%) received S-1. With a median follow-up of 38.9 (1.6-137.8) months, the estimated 5-year disease-free survival (DFS) and overall survival (OS) rates were 52.3% and 61.0%, respectively. In the univariate analysis, survival was significantly better in the adjuvant chemotherapy group than in the surgery only group. In the subgroup analysis, there was no significant difference in DFS or OS between the types of adjuvant chemotherapy for either disease stage. In vitro cell line analysis, different responses to 5-FU and oxaliplatin were observed in SRC and non-SRC, where the treatment in KATOIII cell lines with oxaliplatin had less effect at a higher concentration compared to non-SRC cell lines.

CONCLUSION

The current study found that adjuvant chemotherapy was not significantly associated with survival benefit for patients with resected stage II and III PCC-GC. Plus, S-1 showed numerically longer DFS and OS compared to CAPOX in PCC-GC patients, although no significant in the multivariate analysis.

The Genomic Signatures of Linitis Plastica Signal the Entrance into a New Era: Novel Approaches for Diagnosis and Treatment

Linitis Plastica (LP) is a rare and aggressive tumor with a distinctive development pattern, leading to the infiltration of the gastric wall, the thickening of the gastric folds and a "leather bottle appearance". LP is an extremely heterogeneous tumor caused by mutations in oncogenic and tumor suppressive genes, as well as molecular pathways, along with mutations in stromal cells and proteins related to tight junctions. Elucidating the molecular background of tumorigenesis and clarifying the correlation between cancerous cells and stromal cells are crucial steps toward discovering novel diagnostic methods, biomarkers and therapeutic targets/agents. Surgery plays a pivotal role in LP management, serving both as a palliative and curative procedure. In this comprehensive review, we aim to present all recent data on the molecular background of LP and the novel approaches to its management.

Novel nomogram to predict the overall survival of postoperative patients with gastric signet

BACKGROUND

The TNM staging system cannot accurately predict the prognosis of postoperative gastric signet ring cell carcinoma (GSRC) given its unique biological behavior, epidemiological features, and various prognostic factors. Therefore, a reliable postoperative prognostic evaluation system for GSRC is required. This study aimed to establish a nomogram to predict the overall survival (OS) rate of postoperative patients with GSRC and validate it in the real world.

METHODS

Clinical data of postoperative patients with GSRC from 2002 to 2014 were collected from the Surveillance, Epidemiology, and End Results database and randomly assigned to training and internal validation sets at a 7:3 ratio. The external validation set used data from 124 postoperative patients with GSRC who were admitted to the Affiliated Tumor Hospital of Harbin Medical University between 2002 and 2014. The independent risk factors affecting OS were screened using univariate and multivariate analyses to construct a nomogram. The performance of the model was evaluated using the C-index, receiver operating characteristic curve (ROC), calibration curve, decision analysis (DCA) curve, and adjuvant chemotherapy decision analysis.

RESULTS

Univariate/multivariate analysis indicated that age, stage, T, M, regional nodes optimized (RNE), and lymph node metastasis rate (LNMR) were independent risk factors affecting prognosis. The C-indices of the training, internal validation, and external validation sets are 0.741, 0.741, and 0.786, respectively. The ROC curves for the first, third, and fifth years in three sets had higher areas under the curves, (training set, 0.782, 0.864, 0.883; internal validation set, 0.781, 0.863, 0.877; external validation set, 0.819, 0.863, 0.835). The calibration curve showed high consistency between the nomogram-predicted 1-, 3-, and 5-year OS and the actual OS in the three queues. The DCA curve indicated that applying the nomogram enhanced the net clinical benefits. The nomogram effectively distinguished patients in each subgroup into high- and low-risk groups. Adjuvant chemotherapy can significantly improve OS in high-risk group (P = 0.034), while the presence or absence of adjuvant chemotherapy in low-risk group has no significant impact on OS (P = 0.192).

CONCLUSIONS

The nomogram can effectively predict the OS of patients with GSRC and may help doctors make personalized prognostic judgments and clinical treatment decisions.

USP51/ZEB1/ACTA2 axis promotes mesenchymal phenotype in gastric cancer and is associated with low cohesion characteristics

poorly cohesive (PC) gastric cancer (GC) (PC-GC) is a distinct histological subtype of GC and is defined as a tumor consisting of isolated or small clusters of tumor cells with poorly differentiated and metastatic characteristics. According to multiple studies, PC-GC is intrinsically heterogeneous, with mesenchymal variants being the most aggressive. However, to date, the molecular mechanisms associated with PC-GC are still not fully understood. This study investigated the role of the USP51/ZEB1/ACTA2 axis in promoting GC metastasis. Single-cell sequencing revealed that E-box binding homeobox 1 (ZEB1) expression was significantly increased in a subpopulation of low-adherent cells and was an independent prognostic factor in GC patients. Furthermore, the bulk transcriptome analysis revealed a significant positive correlation between Ubiquitin Specific Peptidase 51 (USP51), ZEB1, and Actin Alpha 2 (ACTA2), and our data further confirmed that all three were highly co-localized in PC-GC tissues. According to the findings of in vitro and in vivo experiments, USP51 was able to maintain ZEB1 expression to promote ACTA2 transcription, thereby activating the mesenchymal phenotype of GC cells and promoting tumor metastasis. Moreover, USP51 could recruit and activate stromal cells, including M2-like macrophages and fibroblasts, through cancer cells. Clinical data suggested that overexpression of USP51 predicts that patients have difficulty benefiting from immunotherapy and is associated with immune-exclusion tumor characteristics. Collectively, the findings of this study shed light on a key mechanism by which elevated USP51 expression induces Epithelial-mesenchymal transition (EMT) in GC cells, hence facilitating GC cell proliferation, survival, and dissemination. In this view, USP51/ZEB1/ACTA2 may serve as a candidate therapeutic target against GC metastasis.