Histological diversity and molecular characteristics in gastric cancer: relation of cancer stem cell-related molecules and receptor tyrosine kinase molecules to mixed histological type and more histological patterns

Soluble levels of 4-1BB (CD137) and OX40 (CD134) are associated with cancer progression in gastric adenocarcinoma

BACKGROUND AND OBJECTIVES

Previous studies have demonstrated that soluble forms of T-cell costimulatory molecules 4-1BB (s4-1BB) and OX40 (sOX40) interact with immune cells and may constitute a mechanism of immune evasion by tumors in various cancers. The role of the soluble forms of 4-1BB and OX40 in GC remains unclear. We aimed to examine the association between serum levels of s4-1BB and sOX40 and tumor progression in patients with GC.

METHODS

Between 2017 and 2018, a cross-sectional study was performed with serum samples of 83 GC patients and 20 healthy controls.

RESULTS

Patients with stage IV metastatic gastric cancer had significantly higher levels of soluble OX40 in comparison with stage III patients with lymph nodes metastasis (p = 0.0003) and stages I and II patients (p = 0.005), whereas the opposite was found for soluble 4-1BB levels, with lower levels being found in advanced stage III (p = 0.003) compared with initial stages I/II.

CONCLUSIONS

The sOX40 and s4-1BB-mediated T cell interactions may be involved in antitumor immune responses in GC, possibly favoring tumor escape and progression. Serum levels of sOX40 and s4-1BB are associated with staging in GC and may constitute biomarkers for prognosis, as well as potential targets for immunotherapy.

Clinical significance of CD166 and HER-2 in different types of gastric cancer

INTRODUCTION

Cluster of differentiation 166 (CD166), a cancer stem cell (CSC) marker, and human epidermal growth factor receptor 2 (HER-2) are expressed in a diversity of malignancies and is associated with tumor progression. Although studies regarding the importance of CSC markers and HER-2 in gastric cancer (GC) have rapidly developed, their clinicopathological, prognosis, and diagnosis value still remain unsatisfying in GC. Therefore, the present study aims to investigate the clinical, prognostic, and diagnostic significance of CD166 and HER-2 in different histological types of GC.

MATERIALS AND METHODS

Bioinformatic analysis was applied to determine the clinical importance of CD166 and HER-2 expression based on their tissue localization in primary GC tumors and the normal adjacent samples. The expression patterns, clinical significance, prognosis, and diagnosis value of CD166 and HER-2 proteins in tissue microarrays (TMAs) of 206 GC samples, including Signet Ring Cell (SRC) and intestinal types and also 28 adjacent normal tissues were evaluated using immunohistochemistry (IHC).

RESULTS

The results indicated that the expression of CD166 (membranous and cytoplasmic) and HER-2 were significantly up-regulated in tumor cells compared to adjacent normal tissues (P = 0.010, P < 0.001, and P = 0.011, respectively). A statistically significant association was detected between a high level of membranous expression of CD166 and lymphovascular invasion (P = 0.006); We also observed a statistically significant association between high cytoplasmic expression of CD166 protein and more invasion of the subserosa (P = 0.040) in the SRC type. In contrast, there was no correlation between the expression of HER-2 and clinicopathologic characteristics. Both CD166 and HER-2 showed reasonable accuracy and high specificity as diagnostic markers.

CONCLUSION

Our results confirmed that increased membranous and cytoplasmic expression of CD166 showed clinical significance in the SRC type and is associated with the progression of the disease and more aggressive tumor behaviors. These findings can be used to assist in designating subgroups of patients that require different follow-up strategies, and also, they might be utilized as the prognostic or diagnostic biomarkers in these types of GC for prospective clinical application.

Distribution and Clinicopathological Features of Mott Cells (Plasma Cells Containing Russell Bodies) in Gastric Cancer: Presence of Mott Cells Is Associated with Favorable Prognosis

Gastric cancer (GC) is still one of the leading causes of cancer-related mortality. We previously reported the relationship between histological heterogeneity of tumor cells and molecular features in GC. The tumor microenvironment also has a crucial role in GC progression and therapeutic resistance. In this study, we focused on the tumor microenvironment, especially inflammatory cells in GC. Using GC tissue slides, we investigated the distribution and clinicopathological significance of inflammatory cell counts including eosinophils, neutrophils, lymphocytes, and plasma cells. Additionally, we investigated the relationship between Mott cells (plasma cells containing Russell bodies) and clinicopathological features. In neoplastic gastric mucosa, a high number of plasma cells was associated with low T-grade, early stage, and good prognosis. We then focused on Mott cells and found that their presence in neoplastic gastric mucosa was associated with lower T and N grades, early stage, and Helicobacter pylori infection and was inversely associated with CD44 and EGFR expression. Additionally, the presence of Mott cells was associated with good prognosis in advanced GC and was an independent favorable prognostic predictor. The presence of Mott cells in GC might be one useful prognostic predictor, and Mott cells might have an important role in the carcinogenesis of H. pylori infection.

Risk factors of additional surgery after non-curative endoscopic submucosal dissection for early gastric cancer

BACKGROUND

The criteria for surgical intervention after non-curative endoscopic submucosal dissection (ESD) of early gastric cancer are unclear. We aimed to clarify the risk factors for residual cancer and lymph node metastasis after non-curative ESD and to identify recommendations for additional surgery.

METHODS

We collected data on 133 consecutive patients who underwent additional surgery after non-curative ESD of early gastric cancer at Nanjing Drum Tower Hospital from January 2013 to July 2022. Univariate and multivariate analyses were performed to seek risk factors of residual cancer and lymph node metastasis.

RESULTS

The incidence rates of residual cancer and lymph node metastasis were 13.5% (18/133) and 10.5% (14/133), respectively. There was neither residual tumor nor lymph node metastasis in 104 (78.2%) cases. Multivariate analyses elucidated that horizontal margin was an independent risk factor for local residual cancer, whereas lymphatic infiltration was an independent risk factor for lymph node metastasis. Patients with mixed histological types were more likely to suffer lymph node metastasis and further undergo additional surgery after non-curative ESD than pure histological type.

CONCLUSIONS

Additional gastrectomy with lymph node dissection was strongly recommended in patients with lymphatic infiltration after non-curative ESD of early gastric cancer. Patients with mixed histological type have a high propensity for lymph node metastasis and should be treated as a separate subtype.

FTO Promotes the Stemness of Gastric Cancer Cells

The full name of the FTO gene is fat mass and obesity-associated gene. In recent years, it has also been found that FTO is involved in m6A demethylation and regulates the progression of multiple cancers, including gastric cancer. The cancer stem cell theory argues that cancer stem cells are key factors in cancer metastasis, and inhibiting the expression of stemness genes is a good method to inhibit metastasis of gastric cancer. Currently, the role of the FTO gene in regulating stemness of gastric cancer cells is still unclear. By analyzing public databases, it was discovered that FTO gene expression was increased in gastric cancer, and high expression of FTO was associated with poor prognosis of patients with gastric cancer. After gastric cancer stem cells were isolated, it was found that FTO protein expression was increased in gastric cancer stem cells; stemness of gastric cancer cells was reduced after the FTO gene knockdown; subcutaneous tumors of nude mice were smaller than those of the control group after FTO knockdown; and stemness of gastric cancer cells was enhanced after FTO was overexpressed by plasmid. By reviewing additional literature and experimental validation, we found that SOX2 may be the factor by which FTO promotes the stemness of gastric cancer cells. Therefore, it was concluded that FTO could promote the stemness of gastric cancer cells, and targeting FTO may be a potential therapeutic approach for patients with metastatic gastric cancer. CTR number: TOP-IACUC-2021-0123.

Mixed Histologic Type is a Risk Factor for Lymph Node Metastasis in Submucosal Invasive Early Gastric Cancer

INTRODUCTION

The treatment regimen for early gastric cancer (EGC) with mixed histologic type remains controversial. We aimed to clarify the relationship between mixed histologic type and lymph node metastasis (LNM) in EGC, with emphasis on submucosal invasive EGC.

METHODS

We collected data on 730 consecutive EGC patients at Nanjing Drum Tower hospital between June 2010 and May 2019. Risk factors of LNM and overall survival were analyzed to compare the prognostic differences between different histologic types.

RESULTS

Mixed-type EGC patients had higher LNM rates than differentiated-type patients (29.2 % versus 10.6 %, P < 0.001), while no significant difference was found between mixed-type and undifferentiated-type EGC patients (29.2% versus 24.0%, P = 0.225). Multivariate analyses identified tumor location (cardiac and bottom versus antrum), larger tumor size, submucosal invasion, histologic differentiation (undifferentiated-type, mixed-type versus differentiated-type), and lymphovascular invasion as independent risk factors for LNM in EGC patients. Subgroup analysis further elucidated that mixed histologic type was associated with LNM in submucosa invasive EGC, but not in mucosa-confined EGC. There was no statistical significance in overall survival and disease-specific survival of submucosal invasive EGC patients who underwent radical gastrectomy with lymphadenectomy between different histologic types (P = 0.151).

CONCLUSIONS

Mixed histologic type may be an independent risk factor for LNM in submucosal invasive EGC. Curative resection with lymphadenectomy should be considered the appropriate treatment for submucosal invasive EGC with mixed histologic type.

Relationships of tumor differentiation and immune infiltration in gastric cancers revealed by single-cell RNA-seq analyses

Gastric cancers are highly heterogeneous malignant tumors. To reveal the relationship between differentiation status of cancer cells and tumor immune microenvironments in gastric cancer, single-cell RNA-sequencing was performed on normal mucosa tissue, differentiated gastric cancer (DGC) tissue, poorly differentiated gastric cancer (PDGC) tissue and neuroendocrine carcinoma (NEC) tissue sampled from surgically resected gastric cancer specimens. We identified the signature genes for both DGC and PDGC, and found that signature genes of PDGC strongly enriched in the epithelial-mesenchymal transition (EMT) program. Furthermore, we found that DGC tends to be immune-rich type whereas PDGC tends to be immune-poor type defined according to the density of tumor-infiltrating CD8⁺ T cells. Additionally, interferon alpha and gamma responding genes were specifically expressed in the immune-rich malignant cells compared with immune-poor malignant cells. Through analyzing the mixed adenoneuroendocrine carcinoma, we identified intermediate state malignant cells during the trans-differentiation process from DGC to NEC, which showed double-negative expressions of both DGC marker genes and NEC marker genes. Interferon-related pathways were gradually downregulated along the DGC to NEC trans-differentiation path, which was accompanied by reduced CD8⁺ cytotoxic T-cell infiltration. In summary, molecular features of both malignant cells and immune microenvironment cells of DGC, PDGC and NEC were systematically revealed, which may partially explain the strong tumor heterogeneities of gastric cancer. Especially along the DGC to NEC trans-differentiation path, immune-evasion was gradually enhanced with the decreasing activities of interferon pathway responses in malignant cells.

ALDH1: A potential therapeutic target for cancer stem cells in solid tumors

Solid tumors can be divided into benign solid tumors and solid malignant tumors in the academic community, among which malignant solid tumors are called cancers. Cancer is the second leading cause of death in the world, and the global incidence of cancer is increasing yearly New cancer patients in China are always the first. After the concept of stem cells was introduced in the tumor community, the CSC markers represented by ALDH1 have been widely studied due to their strong CSC cell characteristics and potential to be the driving force of tumor metastasis. In the research results in the past five years, it has been found that ALDH1 is highly expressed in various solid cancers such as breast cancer, lung cancer, colorectal cancer, liver cancer, gastric cancer, cervical cancer, esophageal cancer, ovarian cancer, head,and neck cancer. ALDH1 can activate and transform various pathways (such as the USP28/MYC signaling pathway, ALDH1A1/HIF-1α/VEGF axis, wnt/β-catenin signaling pathway), as well as change the intracellular pH value to promote formation and maintenance, resulting in drug resistance in tumors. By targeting and inhibiting ALDH1 in tumor stem cells, it can enhance the sensitivity of drugs and inhibit the proliferation, differentiation, and metastasis of solid tumor stem cells to some extent. This review discusses the relationship and pathway of ALDH1 with various solid tumors. It proposes that ALDH1 may serve as a diagnosis and therapeutic target for CSC, providing new insights and new strategies for reliable tumor treatment.

The added value of radiomics from dual-energy spectral CT derived iodine-based material decomposition images in predicting histological grade of gastric cancer

BACKGROUND

The histological differentiation grades of gastric cancer (GC) are closely related to treatment choices and prognostic evaluation. Radiomics from dual-energy spectral CT (DESCT) derived iodine-based material decomposition (IMD) images may have the potential to reflect histological grades.

METHODS

A total of 103 patients with pathologically proven GC (low-grade in 40 patients and high-grade in 63 patients) who underwent preoperative DESCT were enrolled in our study. Radiomic features were extracted from conventional polychromatic (CP) images and IMD images, respectively. Three radiomic predictive models (model-CP, model-IMD, and model-CP-IMD) based on solely CP selected features, IMD selected features and CP coupled with IMD selected features were constructed. The clinicopathological data of the enrolled patients were analyzed. Then, we built a combined model (model-Combine) developed with CP-IMD and clinical features. The performance of these models was evaluated and compared.

RESULTS

Model-CP-IMD achieved better AUC results than both model-CP and model-IMD in both cohorts. Model-Combine, which combined CP-IMD radiomic features, pT stage, and pN stage, yielded the highest AUC values of 0.910 and 0.912 in the training and testing cohorts, respectively. Model-CP-IMD and model-Combine outperformed model-CP according to decision curve analysis.

CONCLUSION

DESCT-based radiomics models showed reliable diagnostic performance in predicting GC histologic differentiation grade. The radiomic features extracted from IMD images showed great promise in terms of enhancing diagnostic performance.

Automated Nuclear Segmentation in Head and Neck Squamous Cell Carcinoma Pathology Reveals Relationships between Cytometric Features and ESTIMATE Stromal and Immune Scores

The tumor microenvironment (TME) plays an important role in the progression of head and neck squamous cell carcinoma (HNSCC). Currently, pathologic assessment of TME is nonstandardized and subject to observer bias. Genome-wide transcriptomic approaches to understanding the TME, while less subject to bias, are expensive and not currently a part of the standard of care for HNSCC. To identify pathology-based biomarkers that correlate with genomic and transcriptomic signatures of TME in HNSCC, cytometric feature maps were generated in a publicly available data set from a cohort of patients with HNSCC, including whole-slide tissue images and genomic and transcriptomic phenotyping (N = 49). Cytometric feature maps were generated based on whole-slide nuclear detection, using a deep-learning algorithm trained for StarDist nuclear segmentation. Cytometric features in each patient were compared to transcriptomic measurements, including Estimation of Stromal and Immune Cells in Malignant Tumor Tissues Using Expression Data (ESTIMATE) scores and stemness scores. With correction for multiple comparisons, one feature (nuclear circularity) demonstrated a significant linear correlation with ESTIMATE stromal score. Two features (nuclear maximum and minimum diameter) correlated significantly with ESTIMATE immune score. Three features (nuclear solidity, nuclear minimum diameter, and nuclear circularity) correlated significantly with transcriptomic stemness score. This study provides preliminary evidence that observer-independent, automated tissue-slide analysis can provide insights into the HNSCC TME which correlate with genomic and transcriptomic assessments.

The Percentage of Signet Ring Cells Is Inversely Related to Aggressive Behavior and Poor Prognosis in Mixed-Type Gastric Cancer

Background and Objectives

Only recently the percentage of signet ring cells (SRCs) in gastric cancer (GC) has been proposed as an independent predictor of survival. High amounts of SRCs have been related to lower recurrence and mortality rates, better prognosis, and favorable clinicopathological features in a poorly cohesive histotype. It is not known what the effect of SRC percentage in mixed-type GC is. We investigate the role of SRCs as a prognostic marker in mixed-histotype GC.

Methods

A retrospective analysis was performed through a prospectively maintained database of patients with diagnosed “mixed-type” gastric carcinoma, defined according to 2019 WHO classification. These patients underwent surgery between 1995 and 2016, and their tissue samples were stored in a tissue bank. All slides were analyzed, and patients were divided into three groups according to the percentage of SRCs: “Group 1” (displaying ≤10% of SRCs), “Group 2” (displaying <90% but >10% of SRCs), and “Group 3” (displaying ≥90% of SRCs). We compared clinical and pathological features as well as prognostic factors between the different groups.

Results

Among 164 enrolled patients, 68.9% were male and 31.1% were female (p = 0.612). The mean (±SD) age at diagnosis was 71.4 ± 9.6 years. Ninety-eight (59.7%) patients were classified as “Group 1”, 66 (40.3%) as “Group 2”, and none as “Group 3”. Five-year overall survival was remarkably higher in Group 2 (73.8%) in comparison to Group 1 (35.4%), p < 0.001. Mortality risk was three times higher in patients with ≤10% SRC pattern compared to those with >10% [HR 2.70 (95% CI 1.72–4.24)]. After adjusting according to potential confounding factors, SRC percentage was still an independent predictor of survival.

Conclusions

The proportion of SRCs is inversely related to aggressive behavior and poor prognosis in mixed-type GCs, highlighting the role of SRC amount as an independent predictor of survival.

Undifferentiated-predominant mixed-type early gastric cancer is more aggressive than pure undifferentiated type: a systematic review and meta-analysis

BACKGROUND

Studies have shown that differentiated-predominant mixed-type early gastric cancer (EGC) is more aggressive than pure differentiated-type EGC. However, the biological behaviour of undifferentiated-predominant mixed-type (MU) EGC and pure undifferentiated-type (PU) EGC are controversial. This study was conducted to compare the biological behaviour of MU EGC and PU EGC.

METHODS

A systematic review and meta-analysis of observational studies was conducted using literature published through PubMed and Embase from inception to 9 November 2021. Inclusion criteria were: (1) a direct or indirect comparison of MU and PU; (2) patients with EGC; (3) a specified outcome of lymph node metastasis (LNM), lymphovascular invasion, submucosal invasion and/or ulcer findings; and (4) the primary lesion was obtained. The literature search, data extraction and quality assessment were performed by two independent reviewers. The meta-analysis was conducted with a random-effect model using the Mantel-Haenszel method.

RESULTS

Twelve publications with 5644 patients were included. Patients with MU EGC had significantly higher risk of LNM (OR 2.28; 95% CI 1.72 to 3.03) and submucosal invasion (OR 2.19; 95% CI 1.90 to 2.52) compared with patients with PU EGC. No difference was found between patients with MU and PU EGC with respect to lymphovascular invasion risk (OR 1.81; 95% CI 0.84 to 3.87). After stratifying the data according to depth of tumour invasion, a significantly higher risk for LNM was associated with intramucosal MU EGC (OR 2.56; 95% CI 1.66 to 3.95) and submucosal MU EGC (OR 2.63; 95% CI 2.06 to 3.06). Submucosal MU EGC also had a significantly higher risk of lymphovascular invasion (OR 2.40; 95% CI 1.79 to 3.21) compared with submucosal PU EGC.

DISCUSSION

Patients with MU EGC had an increased risk of submucosal invasion and LNM compared with patients with PU EGC . MU patients with submucosal EGC also had an increased lymphovascular invasion risk compared with PU patients. Therefore, attention should be focused on the clinical management of patients with MU EGC.

Differentiated/undifferentiated mixed type is a prognostic factor for T2/T3 gastric cancer patients

OBJECTIVES

This work aimed to find the association of mixed-type histology and prognosis of T2/T3 GC patients.

METHODS

Eligible T2/T3 gastric cancer patients at our institution were identified. The histological types and risk factors affecting OS were examined. Survival differences were assessed by log-rank tests and Kaplan-Meier curves.

RESULTS

The study identified 972 T2/T3 gastric cancer patients, including 283 differentiated-type patients, 544 undifferentiated-type patients and 145 mixed type. Mixed-type histology was associated with shorter 5-year OS (DT vs UDT vs MT:57.5% vs 44.9% vs 39.6%, P = 0.002). MT histology can be predictive for prognosis of T2/T3 GC patients (HR for OS: 1.386, 95% CI: 1.028-1.868, P = 0.032), and its malignant potential is not inferior to UDT. In the subgroup analysis, MT can potentially be independent risk factor for non-distal GC patients (P = 0.010).

CONCLUSION

This study reported that mixed histology could be regarded as a potential prognostic factor for T2/T3 gastric cancer patients, especially for those with non-distal cancer. MT patients have higher incidence of metastasis and recurrence and had poorer prognosis than those with pure histological type. It is necessary for MT patients to have preoperative pathological examination for accurate histologic classification, so as to make the comprehensive treatment strategies..